/* * linux/fs/ext4/inode.c * * Copyright (C) 1992, 1993, 1994, 1995 * Remy Card (card@masi.ibp.fr) * Laboratoire MASI - Institut Blaise Pascal * Universite Pierre et Marie Curie (Paris VI) * * from * * linux/fs/minix/inode.c * * Copyright (C) 1991, 1992 Linus Torvalds * * Goal-directed block allocation by Stephen Tweedie * (sct@redhat.com), 1993, 1998 * Big-endian to little-endian byte-swapping/bitmaps by * David S. Miller (davem@caip.rutgers.edu), 1995 * 64-bit file support on 64-bit platforms by Jakub Jelinek * (jj@sunsite.ms.mff.cuni.cz) * * Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "ext4_jbd2.h" #include "xattr.h" #include "acl.h" #include "ext4_extents.h" static inline int ext4_begin_ordered_truncate(struct inode *inode, loff_t new_size) { return jbd2_journal_begin_ordered_truncate(&EXT4_I(inode)->jinode, new_size); } static void ext4_invalidatepage(struct page *page, unsigned long offset); /* * Test whether an inode is a fast symlink. */ static int ext4_inode_is_fast_symlink(struct inode *inode) { int ea_blocks = EXT4_I(inode)->i_file_acl ? (inode->i_sb->s_blocksize >> 9) : 0; return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0); } /* * The ext4 forget function must perform a revoke if we are freeing data * which has been journaled. Metadata (eg. indirect blocks) must be * revoked in all cases. * * "bh" may be NULL: a metadata block may have been freed from memory * but there may still be a record of it in the journal, and that record * still needs to be revoked. */ int ext4_forget(handle_t *handle, int is_metadata, struct inode *inode, struct buffer_head *bh, ext4_fsblk_t blocknr) { int err; might_sleep(); BUFFER_TRACE(bh, "enter"); jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, " "data mode %lx\n", bh, is_metadata, inode->i_mode, test_opt(inode->i_sb, DATA_FLAGS)); /* Never use the revoke function if we are doing full data * journaling: there is no need to, and a V1 superblock won't * support it. Otherwise, only skip the revoke on un-journaled * data blocks. */ if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA || (!is_metadata && !ext4_should_journal_data(inode))) { if (bh) { BUFFER_TRACE(bh, "call jbd2_journal_forget"); return ext4_journal_forget(handle, bh); } return 0; } /* * data!=journal && (is_metadata || should_journal_data(inode)) */ BUFFER_TRACE(bh, "call ext4_journal_revoke"); err = ext4_journal_revoke(handle, blocknr, bh); if (err) ext4_abort(inode->i_sb, __func__, "error %d when attempting revoke", err); BUFFER_TRACE(bh, "exit"); return err; } /* * Work out how many blocks we need to proceed with the next chunk of a * truncate transaction. */ static unsigned long blocks_for_truncate(struct inode *inode) { ext4_lblk_t needed; needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9); /* Give ourselves just enough room to cope with inodes in which * i_blocks is corrupt: we've seen disk corruptions in the past * which resulted in random data in an inode which looked enough * like a regular file for ext4 to try to delete it. Things * will go a bit crazy if that happens, but at least we should * try not to panic the whole kernel. */ if (needed < 2) needed = 2; /* But we need to bound the transaction so we don't overflow the * journal. */ if (needed > EXT4_MAX_TRANS_DATA) needed = EXT4_MAX_TRANS_DATA; return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed; } /* * Truncate transactions can be complex and absolutely huge. So we need to * be able to restart the transaction at a conventient checkpoint to make * sure we don't overflow the journal. * * start_transaction gets us a new handle for a truncate transaction, * and extend_transaction tries to extend the existing one a bit. If * extend fails, we need to propagate the failure up and restart the * transaction in the top-level truncate loop. --sct */ static handle_t *start_transaction(struct inode *inode) { handle_t *result; result = ext4_journal_start(inode, blocks_for_truncate(inode)); if (!IS_ERR(result)) return result; ext4_std_error(inode->i_sb, PTR_ERR(result)); return result; } /* * Try to extend this transaction for the purposes of truncation. * * Returns 0 if we managed to create more room. If we can't create more * room, and the transaction must be restarted we return 1. */ static int try_to_extend_transaction(handle_t *handle, struct inode *inode) { if (handle->h_buffer_credits > EXT4_RESERVE_TRANS_BLOCKS) return 0; if (!ext4_journal_extend(handle, blocks_for_truncate(inode))) return 0; return 1; } /* * Restart the transaction associated with *handle. This does a commit, * so before we call here everything must be consistently dirtied against * this transaction. */ static int ext4_journal_test_restart(handle_t *handle, struct inode *inode) { jbd_debug(2, "restarting handle %p\n", handle); return ext4_journal_restart(handle, blocks_for_truncate(inode)); } /* * Called at the last iput() if i_nlink is zero. */ void ext4_delete_inode (struct inode * inode) { handle_t *handle; if (ext4_should_order_data(inode)) ext4_begin_ordered_truncate(inode, 0); truncate_inode_pages(&inode->i_data, 0); if (is_bad_inode(inode)) goto no_delete; handle = start_transaction(inode); if (IS_ERR(handle)) { /* * If we're going to skip the normal cleanup, we still need to * make sure that the in-core orphan linked list is properly * cleaned up. */ ext4_orphan_del(NULL, inode); goto no_delete; } if (IS_SYNC(inode)) handle->h_sync = 1; inode->i_size = 0; if (inode->i_blocks) ext4_truncate(inode); /* * Kill off the orphan record which ext4_truncate created. * AKPM: I think this can be inside the above `if'. * Note that ext4_orphan_del() has to be able to cope with the * deletion of a non-existent orphan - this is because we don't * know if ext4_truncate() actually created an orphan record. * (Well, we could do this if we need to, but heck - it works) */ ext4_orphan_del(handle, inode); EXT4_I(inode)->i_dtime = get_seconds(); /* * One subtle ordering requirement: if anything has gone wrong * (transaction abort, IO errors, whatever), then we can still * do these next steps (the fs will already have been marked as * having errors), but we can't free the inode if the mark_dirty * fails. */ if (ext4_mark_inode_dirty(handle, inode)) /* If that failed, just do the required in-core inode clear. */ clear_inode(inode); else ext4_free_inode(handle, inode); ext4_journal_stop(handle); return; no_delete: clear_inode(inode); /* We must guarantee clearing of inode... */ } typedef struct { __le32 *p; __le32 key; struct buffer_head *bh; } Indirect; static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v) { p->key = *(p->p = v); p->bh = bh; } /** * ext4_block_to_path - parse the block number into array of offsets * @inode: inode in question (we are only interested in its superblock) * @i_block: block number to be parsed * @offsets: array to store the offsets in * @boundary: set this non-zero if the referred-to block is likely to be * followed (on disk) by an indirect block. * * To store the locations of file's data ext4 uses a data structure common * for UNIX filesystems - tree of pointers anchored in the inode, with * data blocks at leaves and indirect blocks in intermediate nodes. * This function translates the block number into path in that tree - * return value is the path length and @offsets[n] is the offset of * pointer to (n+1)th node in the nth one. If @block is out of range * (negative or too large) warning is printed and zero returned. * * Note: function doesn't find node addresses, so no IO is needed. All * we need to know is the capacity of indirect blocks (taken from the * inode->i_sb). */ /* * Portability note: the last comparison (check that we fit into triple * indirect block) is spelled differently, because otherwise on an * architecture with 32-bit longs and 8Kb pages we might get into trouble * if our filesystem had 8Kb blocks. We might use long long, but that would * kill us on x86. Oh, well, at least the sign propagation does not matter - * i_block would have to be negative in the very beginning, so we would not * get there at all. */ static int ext4_block_to_path(struct inode *inode, ext4_lblk_t i_block, ext4_lblk_t offsets[4], int *boundary) { int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb); int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb); const long direct_blocks = EXT4_NDIR_BLOCKS, indirect_blocks = ptrs, double_blocks = (1 << (ptrs_bits * 2)); int n = 0; int final = 0; if (i_block < 0) { ext4_warning (inode->i_sb, "ext4_block_to_path", "block < 0"); } else if (i_block < direct_blocks) { offsets[n++] = i_block; final = direct_blocks; } else if ( (i_block -= direct_blocks) < indirect_blocks) { offsets[n++] = EXT4_IND_BLOCK; offsets[n++] = i_block; final = ptrs; } else if ((i_block -= indirect_blocks) < double_blocks) { offsets[n++] = EXT4_DIND_BLOCK; offsets[n++] = i_block >> ptrs_bits; offsets[n++] = i_block & (ptrs - 1); final = ptrs; } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) { offsets[n++] = EXT4_TIND_BLOCK; offsets[n++] = i_block >> (ptrs_bits * 2); offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1); offsets[n++] = i_block & (ptrs - 1); final = ptrs; } else { ext4_warning(inode->i_sb, "ext4_block_to_path", "block %lu > max", i_block + direct_blocks + indirect_blocks + double_blocks); } if (boundary) *boundary = final - 1 - (i_block & (ptrs - 1)); return n; } /** * ext4_get_branch - read the chain of indirect blocks leading to data * @inode: inode in question * @depth: depth of the chain (1 - direct pointer, etc.) * @offsets: offsets of pointers in inode/indirect blocks * @chain: place to store the result * @err: here we store the error value * * Function fills the array of triples and returns %NULL * if everything went OK or the pointer to the last filled triple * (incomplete one) otherwise. Upon the return chain[i].key contains * the number of (i+1)-th block in the chain (as it is stored in memory, * i.e. little-endian 32-bit), chain[i].p contains the address of that * number (it points into struct inode for i==0 and into the bh->b_data * for i>0) and chain[i].bh points to the buffer_head of i-th indirect * block for i>0 and NULL for i==0. In other words, it holds the block * numbers of the chain, addresses they were taken from (and where we can * verify that chain did not change) and buffer_heads hosting these * numbers. * * Function stops when it stumbles upon zero pointer (absent block) * (pointer to last triple returned, *@err == 0) * or when it gets an IO error reading an indirect block * (ditto, *@err == -EIO) * or when it reads all @depth-1 indirect blocks successfully and finds * the whole chain, all way to the data (returns %NULL, *err == 0). * * Need to be called with * down_read(&EXT4_I(inode)->i_data_sem) */ static Indirect *ext4_get_branch(struct inode *inode, int depth, ext4_lblk_t *offsets, Indirect chain[4], int *err) { struct super_block *sb = inode->i_sb; Indirect *p = chain; struct buffer_head *bh; *err = 0; /* i_data is not going away, no lock needed */ add_chain (chain, NULL, EXT4_I(inode)->i_data + *offsets); if (!p->key) goto no_block; while (--depth) { bh = sb_bread(sb, le32_to_cpu(p->key)); if (!bh) goto failure; add_chain(++p, bh, (__le32*)bh->b_data + *++offsets); /* Reader: end */ if (!p->key) goto no_block; } return NULL; failure: *err = -EIO; no_block: return p; } /** * ext4_find_near - find a place for allocation with sufficient locality * @inode: owner * @ind: descriptor of indirect block. * * This function returns the preferred place for block allocation. * It is used when heuristic for sequential allocation fails. * Rules are: * + if there is a block to the left of our position - allocate near it. * + if pointer will live in indirect block - allocate near that block. * + if pointer will live in inode - allocate in the same * cylinder group. * * In the latter case we colour the starting block by the callers PID to * prevent it from clashing with concurrent allocations for a different inode * in the same block group. The PID is used here so that functionally related * files will be close-by on-disk. * * Caller must make sure that @ind is valid and will stay that way. */ static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind) { struct ext4_inode_info *ei = EXT4_I(inode); __le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data; __le32 *p; ext4_fsblk_t bg_start; ext4_fsblk_t last_block; ext4_grpblk_t colour; /* Try to find previous block */ for (p = ind->p - 1; p >= start; p--) { if (*p) return le32_to_cpu(*p); } /* No such thing, so let's try location of indirect block */ if (ind->bh) return ind->bh->b_blocknr; /* * It is going to be referred to from the inode itself? OK, just put it * into the same cylinder group then. */ bg_start = ext4_group_first_block_no(inode->i_sb, ei->i_block_group); last_block = ext4_blocks_count(EXT4_SB(inode->i_sb)->s_es) - 1; if (bg_start + EXT4_BLOCKS_PER_GROUP(inode->i_sb) <= last_block) colour = (current->pid % 16) * (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16); else colour = (current->pid % 16) * ((last_block - bg_start) / 16); return bg_start + colour; } /** * ext4_find_goal - find a preferred place for allocation. * @inode: owner * @block: block we want * @partial: pointer to the last triple within a chain * * Normally this function find the preferred place for block allocation, * returns it. */ static ext4_fsblk_t ext4_find_goal(struct inode *inode, ext4_lblk_t block, Indirect *partial) { struct ext4_block_alloc_info *block_i; block_i = EXT4_I(inode)->i_block_alloc_info; /* * try the heuristic for sequential allocation, * failing that at least try to get decent locality. */ if (block_i && (block == block_i->last_alloc_logical_block + 1) && (block_i->last_alloc_physical_block != 0)) { return block_i->last_alloc_physical_block + 1; } return ext4_find_near(inode, partial); } /** * ext4_blks_to_allocate: Look up the block map and count the number * of direct blocks need to be allocated for the given branch. * * @branch: chain of indirect blocks * @k: number of blocks need for indirect blocks * @blks: number of data blocks to be mapped. * @blocks_to_boundary: the offset in the indirect block * * return the total number of blocks to be allocate, including the * direct and indirect blocks. */ static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned long blks, int blocks_to_boundary) { unsigned long count = 0; /* * Simple case, [t,d]Indirect block(s) has not allocated yet * then it's clear blocks on that path have not allocated */ if (k > 0) { /* right now we don't handle cross boundary allocation */ if (blks < blocks_to_boundary + 1) count += blks; else count += blocks_to_boundary + 1; return count; } count++; while (count < blks && count <= blocks_to_boundary && le32_to_cpu(*(branch[0].p + count)) == 0) { count++; } return count; } /** * ext4_alloc_blocks: multiple allocate blocks needed for a branch * @indirect_blks: the number of blocks need to allocate for indirect * blocks * * @new_blocks: on return it will store the new block numbers for * the indirect blocks(if needed) and the first direct block, * @blks: on return it will store the total number of allocated * direct blocks */ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode, ext4_lblk_t iblock, ext4_fsblk_t goal, int indirect_blks, int blks, ext4_fsblk_t new_blocks[4], int *err) { int target, i; unsigned long count = 0, blk_allocated = 0; int index = 0; ext4_fsblk_t current_block = 0; int ret = 0; /* * Here we try to allocate the requested multiple blocks at once, * on a best-effort basis. * To build a branch, we should allocate blocks for * the indirect blocks(if not allocated yet), and at least * the first direct block of this branch. That's the * minimum number of blocks need to allocate(required) */ /* first we try to allocate the indirect blocks */ target = indirect_blks; while (target > 0) { count = target; /* allocating blocks for indirect blocks and direct blocks */ current_block = ext4_new_meta_blocks(handle, inode, goal, &count, err); if (*err) goto failed_out; target -= count; /* allocate blocks for indirect blocks */ while (index < indirect_blks && count) { new_blocks[index++] = current_block++; count--; } if (count > 0) { /* * save the new block number * for the first direct block */ new_blocks[index] = current_block; printk(KERN_INFO "%s returned more blocks than " "requested\n", __func__); WARN_ON(1); break; } } target = blks - count ; blk_allocated = count; if (!target) goto allocated; /* Now allocate data blocks */ count = target; /* allocating blocks for data blocks */ current_block = ext4_new_blocks(handle, inode, iblock, goal, &count, err); if (*err && (target == blks)) { /* * if the allocation failed and we didn't allocate * any blocks before */ goto failed_out; } if (!*err) { if (target == blks) { /* * save the new block number * for the first direct block */ new_blocks[index] = current_block; } blk_allocated += count; } allocated: /* total number of blocks allocated for direct blocks */ ret = blk_allocated; *err = 0; return ret; failed_out: for (i = 0; i key). Upon the exit we have the same * picture as after the successful ext4_get_block(), except that in one * place chain is disconnected - *branch->p is still zero (we did not * set the last link), but branch->key contains the number that should * be placed into *branch->p to fill that gap. * * If allocation fails we free all blocks we've allocated (and forget * their buffer_heads) and return the error value the from failed * ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain * as described above and return 0. */ static int ext4_alloc_branch(handle_t *handle, struct inode *inode, ext4_lblk_t iblock, int indirect_blks, int *blks, ext4_fsblk_t goal, ext4_lblk_t *offsets, Indirect *branch) { int blocksize = inode->i_sb->s_blocksize; int i, n = 0; int err = 0; struct buffer_head *bh; int num; ext4_fsblk_t new_blocks[4]; ext4_fsblk_t current_block; num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks, *blks, new_blocks, &err); if (err) return err; branch[0].key = cpu_to_le32(new_blocks[0]); /* * metadata blocks and data blocks are allocated. */ for (n = 1; n <= indirect_blks; n++) { /* * Get buffer_head for parent block, zero it out * and set the pointer to new one, then send * parent to disk. */ bh = sb_getblk(inode->i_sb, new_blocks[n-1]); branch[n].bh = bh; lock_buffer(bh); BUFFER_TRACE(bh, "call get_create_access"); err = ext4_journal_get_create_access(handle, bh); if (err) { unlock_buffer(bh); brelse(bh); goto failed; } memset(bh->b_data, 0, blocksize); branch[n].p = (__le32 *) bh->b_data + offsets[n]; branch[n].key = cpu_to_le32(new_blocks[n]); *branch[n].p = branch[n].key; if ( n == indirect_blks) { current_block = new_blocks[n]; /* * End of chain, update the last new metablock of * the chain to point to the new allocated * data blocks numbers */ for (i=1; i < num; i++) *(branch[n].p + i) = cpu_to_le32(++current_block); } BUFFER_TRACE(bh, "marking uptodate"); set_buffer_uptodate(bh); unlock_buffer(bh); BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata"); err = ext4_journal_dirty_metadata(handle, bh); if (err) goto failed; } *blks = num; return err; failed: /* Allocation failed, free what we already allocated */ for (i = 1; i <= n ; i++) { BUFFER_TRACE(branch[i].bh, "call jbd2_journal_forget"); ext4_journal_forget(handle, branch[i].bh); } for (i = 0; i i_blocks, etc.). In case of success we end up with the full * chain to new block and return 0. */ static int ext4_splice_branch(handle_t *handle, struct inode *inode, ext4_lblk_t block, Indirect *where, int num, int blks) { int i; int err = 0; struct ext4_block_alloc_info *block_i; ext4_fsblk_t current_block; block_i = EXT4_I(inode)->i_block_alloc_info; /* * If we're splicing into a [td]indirect block (as opposed to the * inode) then we need to get write access to the [td]indirect block * before the splice. */ if (where->bh) { BUFFER_TRACE(where->bh, "get_write_access"); err = ext4_journal_get_write_access(handle, where->bh); if (err) goto err_out; } /* That's it */ *where->p = where->key; /* * Update the host buffer_head or inode to point to more just allocated * direct blocks blocks */ if (num == 0 && blks > 1) { current_block = le32_to_cpu(where->key) + 1; for (i = 1; i < blks; i++) *(where->p + i ) = cpu_to_le32(current_block++); } /* * update the most recently allocated logical & physical block * in i_block_alloc_info, to assist find the proper goal block for next * allocation */ if (block_i) { block_i->last_alloc_logical_block = block + blks - 1; block_i->last_alloc_physical_block = le32_to_cpu(where[num].key) + blks - 1; } /* We are done with atomic stuff, now do the rest of housekeeping */ inode->i_ctime = ext4_current_time(inode); ext4_mark_inode_dirty(handle, inode); /* had we spliced it onto indirect block? */ if (where->bh) { /* * If we spliced it onto an indirect block, we haven't * altered the inode. Note however that if it is being spliced * onto an indirect block at the very end of the file (the * file is growing) then we *will* alter the inode to reflect * the new i_size. But that is not done here - it is done in * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode. */ jbd_debug(5, "splicing indirect only\n"); BUFFER_TRACE(where->bh, "call ext4_journal_dirty_metadata"); err = ext4_journal_dirty_metadata(handle, where->bh); if (err) goto err_out; } else { /* * OK, we spliced it into the inode itself on a direct block. * Inode was dirtied above. */ jbd_debug(5, "splicing direct\n"); } return err; err_out: for (i = 1; i <= num; i++) { BUFFER_TRACE(where[i].bh, "call jbd2_journal_forget"); ext4_journal_forget(handle, where[i].bh); ext4_free_blocks(handle, inode, le32_to_cpu(where[i-1].key), 1, 0); } ext4_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks, 0); return err; } /* * Allocation strategy is simple: if we have to allocate something, we will * have to go the whole way to leaf. So let's do it before attaching anything * to tree, set linkage between the newborn blocks, write them if sync is * required, recheck the path, free and repeat if check fails, otherwise * set the last missing link (that will protect us from any truncate-generated * removals - all blocks on the path are immune now) and possibly force the * write on the parent block. * That has a nice additional property: no special recovery from the failed * allocations is needed - we simply release blocks and do not touch anything * reachable from inode. * * `handle' can be NULL if create == 0. * * return > 0, # of blocks mapped or allocated. * return = 0, if plain lookup failed. * return < 0, error case. * * * Need to be called with * down_read(&EXT4_I(inode)->i_data_sem) if not allocating file system block * (ie, create is zero). Otherwise down_write(&EXT4_I(inode)->i_data_sem) */ int ext4_get_blocks_handle(handle_t *handle, struct inode *inode, ext4_lblk_t iblock, unsigned long maxblocks, struct buffer_head *bh_result, int create, int extend_disksize) { int err = -EIO; ext4_lblk_t offsets[4]; Indirect chain[4]; Indirect *partial; ext4_fsblk_t goal; int indirect_blks; int blocks_to_boundary = 0; int depth; struct ext4_inode_info *ei = EXT4_I(inode); int count = 0; ext4_fsblk_t first_block = 0; loff_t disksize; J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)); J_ASSERT(handle != NULL || create == 0); depth = ext4_block_to_path(inode, iblock, offsets, &blocks_to_boundary); if (depth == 0) goto out; partial = ext4_get_branch(inode, depth, offsets, chain, &err); /* Simplest case - block found, no allocation needed */ if (!partial) { first_block = le32_to_cpu(chain[depth - 1].key); clear_buffer_new(bh_result); count++; /*map more blocks*/ while (count < maxblocks && count <= blocks_to_boundary) { ext4_fsblk_t blk; blk = le32_to_cpu(*(chain[depth-1].p + count)); if (blk == first_block + count) count++; else break; } goto got_it; } /* Next simple case - plain lookup or failed read of indirect block */ if (!create || err == -EIO) goto cleanup; /* * Okay, we need to do block allocation. Lazily initialize the block * allocation info here if necessary */ if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info)) ext4_init_block_alloc_info(inode); goal = ext4_find_goal(inode, iblock, partial); /* the number of blocks need to allocate for [d,t]indirect blocks */ indirect_blks = (chain + depth) - partial - 1; /* * Next look up the indirect map to count the totoal number of * direct blocks to allocate for this branch. */ count = ext4_blks_to_allocate(partial, indirect_blks, maxblocks, blocks_to_boundary); /* * Block out ext4_truncate while we alter the tree */ err = ext4_alloc_branch(handle, inode, iblock, indirect_blks, &count, goal, offsets + (partial - chain), partial); /* * The ext4_splice_branch call will free and forget any buffers * on the new chain if there is a failure, but that risks using * up transaction credits, especially for bitmaps where the * credits cannot be returned. Can we handle this somehow? We * may need to return -EAGAIN upwards in the worst case. --sct */ if (!err) err = ext4_splice_branch(handle, inode, iblock, partial, indirect_blks, count); /* * i_disksize growing is protected by i_data_sem. Don't forget to * protect it if you're about to implement concurrent * ext4_get_block() -bzzz */ if (!err && extend_disksize) { disksize = ((loff_t) iblock + count) << inode->i_blkbits; if (disksize > i_size_read(inode)) disksize = i_size_read(inode); if (disksize > ei->i_disksize) ei->i_disksize = disksize; } if (err) goto cleanup; set_buffer_new(bh_result); got_it: map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key)); if (count > blocks_to_boundary) set_buffer_boundary(bh_result); err = count; /* Clean up and exit */ partial = chain + depth - 1; /* the whole chain */ cleanup: while (partial > chain) { BUFFER_TRACE(partial->bh, "call brelse"); brelse(partial->bh); partial--; } BUFFER_TRACE(bh_result, "returned"); out: return err; } /* Maximum number of blocks we map for direct IO at once. */ #define DIO_MAX_BLOCKS 4096 /* * Number of credits we need for writing DIO_MAX_BLOCKS: * We need sb + group descriptor + bitmap + inode -> 4 * For B blocks with A block pointers per block we need: * 1 (triple ind.) + (B/A/A + 2) (doubly ind.) + (B/A + 2) (indirect). * If we plug in 4096 for B and 256 for A (for 1KB block size), we get 25. */ #define DIO_CREDITS 25 /* * * * ext4_ext4 get_block() wrapper function * It will do a look up first, and returns if the blocks already mapped. * Otherwise it takes the write lock of the i_data_sem and allocate blocks * and store the allocated blocks in the result buffer head and mark it * mapped. * * If file type is extents based, it will call ext4_ext_get_blocks(), * Otherwise, call with ext4_get_blocks_handle() to handle indirect mapping * based files * * On success, it returns the number of blocks being mapped or allocate. * if create==0 and the blocks are pre-allocated and uninitialized block, * the result buffer head is unmapped. If the create ==1, it will make sure * the buffer head is mapped. * * It returns 0 if plain look up failed (blocks have not been allocated), in * that casem, buffer head is unmapped * * It returns the error in case of allocation failure. */ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block, unsigned long max_blocks, struct buffer_head *bh, int create, int extend_disksize, int flag) { int retval; clear_buffer_mapped(bh); /* * Try to see if we can get the block without requesting * for new file system block. */ down_read((&EXT4_I(inode)->i_data_sem)); if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) { retval = ext4_ext_get_blocks(handle, inode, block, max_blocks, bh, 0, 0); } else { retval = ext4_get_blocks_handle(handle, inode, block, max_blocks, bh, 0, 0); } up_read((&EXT4_I(inode)->i_data_sem)); /* If it is only a block(s) look up */ if (!create) return retval; /* * Returns if the blocks have already allocated * * Note that if blocks have been preallocated * ext4_ext_get_block() returns th create = 0 * with buffer head unmapped. */ if (retval > 0 && buffer_mapped(bh)) return retval; /* * New blocks allocate and/or writing to uninitialized extent * will possibly result in updating i_data, so we take * the write lock of i_data_sem, and call get_blocks() * with create == 1 flag. */ down_write((&EXT4_I(inode)->i_data_sem)); /* * if the caller is from delayed allocation writeout path * we have already reserved fs blocks for allocation * let the underlying get_block() function know to * avoid double accounting */ if (flag) EXT4_I(inode)->i_delalloc_reserved_flag = 1; /* * We need to check for EXT4 here because migrate * could have changed the inode type in between */ if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) { retval = ext4_ext_get_blocks(handle, inode, block, max_blocks, bh, create, extend_disksize); } else { retval = ext4_get_blocks_handle(handle, inode, block, max_blocks, bh, create, extend_disksize); if (retval > 0 && buffer_new(bh)) { /* * We allocated new blocks which will result in * i_data's format changing. Force the migrate * to fail by clearing migrate flags */ EXT4_I(inode)->i_flags = EXT4_I(inode)->i_flags & ~EXT4_EXT_MIGRATE; } } if (flag) { EXT4_I(inode)->i_delalloc_reserved_flag = 0; /* * Update reserved blocks/metadata blocks * after successful block allocation * which were deferred till now */ if ((retval > 0) && buffer_delay(bh)) ext4_da_release_space(inode, retval, 0); } up_write((&EXT4_I(inode)->i_data_sem)); return retval; } static int ext4_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create) { handle_t *handle = ext4_journal_current_handle(); int ret = 0, started = 0; unsigned max_blocks = bh_result->b_size >> inode->i_blkbits; if (create && !handle) { /* Direct IO write... */ if (max_blocks > DIO_MAX_BLOCKS) max_blocks = DIO_MAX_BLOCKS; handle = ext4_journal_start(inode, DIO_CREDITS + 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb)); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out; } started = 1; } ret = ext4_get_blocks_wrap(handle, inode, iblock, max_blocks, bh_result, create, 0, 0); if (ret > 0) { bh_result->b_size = (ret << inode->i_blkbits); ret = 0; } if (started) ext4_journal_stop(handle); out: return ret; } /* * `handle' can be NULL if create is zero */ struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode, ext4_lblk_t block, int create, int *errp) { struct buffer_head dummy; int fatal = 0, err; J_ASSERT(handle != NULL || create == 0); dummy.b_state = 0; dummy.b_blocknr = -1000; buffer_trace_init(&dummy.b_history); err = ext4_get_blocks_wrap(handle, inode, block, 1, &dummy, create, 1, 0); /* * ext4_get_blocks_handle() returns number of blocks * mapped. 0 in case of a HOLE. */ if (err > 0) { if (err > 1) WARN_ON(1); err = 0; } *errp = err; if (!err && buffer_mapped(&dummy)) { struct buffer_head *bh; bh = sb_getblk(inode->i_sb, dummy.b_blocknr); if (!bh) { *errp = -EIO; goto err; } if (buffer_new(&dummy)) { J_ASSERT(create != 0); J_ASSERT(handle != NULL); /* * Now that we do not always journal data, we should * keep in mind whether this should always journal the * new buffer as metadata. For now, regular file * writes use ext4_get_block instead, so it's not a * problem. */ lock_buffer(bh); BUFFER_TRACE(bh, "call get_create_access"); fatal = ext4_journal_get_create_access(handle, bh); if (!fatal && !buffer_uptodate(bh)) { memset(bh->b_data,0,inode->i_sb->s_blocksize); set_buffer_uptodate(bh); } unlock_buffer(bh); BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata"); err = ext4_journal_dirty_metadata(handle, bh); if (!fatal) fatal = err; } else { BUFFER_TRACE(bh, "not a new buffer"); } if (fatal) { *errp = fatal; brelse(bh); bh = NULL; } return bh; } err: return NULL; } struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode, ext4_lblk_t block, int create, int *err) { struct buffer_head * bh; bh = ext4_getblk(handle, inode, block, create, err); if (!bh) return bh; if (buffer_uptodate(bh)) return bh; ll_rw_block(READ_META, 1, &bh); wait_on_buffer(bh); if (buffer_uptodate(bh)) return bh; put_bh(bh); *err = -EIO; return NULL; } static int walk_page_buffers( handle_t *handle, struct buffer_head *head, unsigned from, unsigned to, int *partial, int (*fn)( handle_t *handle, struct buffer_head *bh)) { struct buffer_head *bh; unsigned block_start, block_end; unsigned blocksize = head->b_size; int err, ret = 0; struct buffer_head *next; for ( bh = head, block_start = 0; ret == 0 && (bh != head || !block_start); block_start = block_end, bh = next) { next = bh->b_this_page; block_end = block_start + blocksize; if (block_end <= from || block_start >= to) { if (partial && !buffer_uptodate(bh)) *partial = 1; continue; } err = (*fn)(handle, bh); if (!ret) ret = err; } return ret; } /* * To preserve ordering, it is essential that the hole instantiation and * the data write be encapsulated in a single transaction. We cannot * close off a transaction and start a new one between the ext4_get_block() * and the commit_write(). So doing the jbd2_journal_start at the start of * prepare_write() is the right place. * * Also, this function can nest inside ext4_writepage() -> * block_write_full_page(). In that case, we *know* that ext4_writepage() * has generated enough buffer credits to do the whole page. So we won't * block on the journal in that case, which is good, because the caller may * be PF_MEMALLOC. * * By accident, ext4 can be reentered when a transaction is open via * quota file writes. If we were to commit the transaction while thus * reentered, there can be a deadlock - we would be holding a quota * lock, and the commit would never complete if another thread had a * transaction open and was blocking on the quota lock - a ranking * violation. * * So what we do is to rely on the fact that jbd2_journal_stop/journal_start * will _not_ run commit under these circumstances because handle->h_ref * is elevated. We'll still have enough credits for the tiny quotafile * write. */ static int do_journal_get_write_access(handle_t *handle, struct buffer_head *bh) { if (!buffer_mapped(bh) || buffer_freed(bh)) return 0; return ext4_journal_get_write_access(handle, bh); } static int ext4_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { struct inode *inode = mapping->host; int ret, needed_blocks = ext4_writepage_trans_blocks(inode); handle_t *handle; int retries = 0; struct page *page; pgoff_t index; unsigned from, to; index = pos >> PAGE_CACHE_SHIFT; from = pos & (PAGE_CACHE_SIZE - 1); to = from + len; retry: handle = ext4_journal_start(inode, needed_blocks); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out; } page = __grab_cache_page(mapping, index); if (!page) { ext4_journal_stop(handle); ret = -ENOMEM; goto out; } *pagep = page; ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata, ext4_get_block); if (!ret && ext4_should_journal_data(inode)) { ret = walk_page_buffers(handle, page_buffers(page), from, to, NULL, do_journal_get_write_access); } if (ret) { unlock_page(page); ext4_journal_stop(handle); page_cache_release(page); } if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) goto retry; out: return ret; } /* For write_end() in data=journal mode */ static int write_end_fn(handle_t *handle, struct buffer_head *bh) { if (!buffer_mapped(bh) || buffer_freed(bh)) return 0; set_buffer_uptodate(bh); return ext4_journal_dirty_metadata(handle, bh); } /* * We need to pick up the new inode size which generic_commit_write gave us * `file' can be NULL - eg, when called from page_symlink(). * * ext4 never places buffers on inode->i_mapping->private_list. metadata * buffers are managed internally. */ static int ext4_ordered_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { handle_t *handle = ext4_journal_current_handle(); struct inode *inode = mapping->host; unsigned from, to; int ret = 0, ret2; from = pos & (PAGE_CACHE_SIZE - 1); to = from + len; ret = ext4_jbd2_file_inode(handle, inode); if (ret == 0) { /* * generic_write_end() will run mark_inode_dirty() if i_size * changes. So let's piggyback the i_disksize mark_inode_dirty * into that. */ loff_t new_i_size; new_i_size = pos + copied; if (new_i_size > EXT4_I(inode)->i_disksize) EXT4_I(inode)->i_disksize = new_i_size; ret2 = generic_write_end(file, mapping, pos, len, copied, page, fsdata); copied = ret2; if (ret2 < 0) ret = ret2; } ret2 = ext4_journal_stop(handle); if (!ret) ret = ret2; return ret ? ret : copied; } static int ext4_writeback_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { handle_t *handle = ext4_journal_current_handle(); struct inode *inode = mapping->host; int ret = 0, ret2; loff_t new_i_size; new_i_size = pos + copied; if (new_i_size > EXT4_I(inode)->i_disksize) EXT4_I(inode)->i_disksize = new_i_size; ret2 = generic_write_end(file, mapping, pos, len, copied, page, fsdata); copied = ret2; if (ret2 < 0) ret = ret2; ret2 = ext4_journal_stop(handle); if (!ret) ret = ret2; return ret ? ret : copied; } static int ext4_journalled_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { handle_t *handle = ext4_journal_current_handle(); struct inode *inode = mapping->host; int ret = 0, ret2; int partial = 0; unsigned from, to; from = pos & (PAGE_CACHE_SIZE - 1); to = from + len; if (copied < len) { if (!PageUptodate(page)) copied = 0; page_zero_new_buffers(page, from+copied, to); } ret = walk_page_buffers(handle, page_buffers(page), from, to, &partial, write_end_fn); if (!partial) SetPageUptodate(page); if (pos+copied > inode->i_size) i_size_write(inode, pos+copied); EXT4_I(inode)->i_state |= EXT4_STATE_JDATA; if (inode->i_size > EXT4_I(inode)->i_disksize) { EXT4_I(inode)->i_disksize = inode->i_size; ret2 = ext4_mark_inode_dirty(handle, inode); if (!ret) ret = ret2; } unlock_page(page); ret2 = ext4_journal_stop(handle); if (!ret) ret = ret2; page_cache_release(page); return ret ? ret : copied; } /* * Calculate the number of metadata blocks need to reserve * to allocate @blocks for non extent file based file */ static int ext4_indirect_calc_metadata_amount(struct inode *inode, int blocks) { int icap = EXT4_ADDR_PER_BLOCK(inode->i_sb); int ind_blks, dind_blks, tind_blks; /* number of new indirect blocks needed */ ind_blks = (blocks + icap - 1) / icap; dind_blks = (ind_blks + icap - 1) / icap; tind_blks = 1; return ind_blks + dind_blks + tind_blks; } /* * Calculate the number of metadata blocks need to reserve * to allocate given number of blocks */ static int ext4_calc_metadata_amount(struct inode *inode, int blocks) { if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) return ext4_ext_calc_metadata_amount(inode, blocks); return ext4_indirect_calc_metadata_amount(inode, blocks); } static int ext4_da_reserve_space(struct inode *inode, int nrblocks) { struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); unsigned long md_needed, mdblocks, total = 0; /* * recalculate the amount of metadata blocks to reserve * in order to allocate nrblocks * worse case is one extent per block */ spin_lock(&EXT4_I(inode)->i_block_reservation_lock); total = EXT4_I(inode)->i_reserved_data_blocks + nrblocks; mdblocks = ext4_calc_metadata_amount(inode, total); BUG_ON(mdblocks < EXT4_I(inode)->i_reserved_meta_blocks); md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks; total = md_needed + nrblocks; if (ext4_has_free_blocks(sbi, total) < total) { spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); return -ENOSPC; } /* reduce fs free blocks counter */ percpu_counter_sub(&sbi->s_freeblocks_counter, total); EXT4_I(inode)->i_reserved_data_blocks += nrblocks; EXT4_I(inode)->i_reserved_meta_blocks = mdblocks; spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); return 0; /* success */ } void ext4_da_release_space(struct inode *inode, int used, int to_free) { struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); int total, mdb, mdb_free, release; spin_lock(&EXT4_I(inode)->i_block_reservation_lock); /* recalculate the number of metablocks still need to be reserved */ total = EXT4_I(inode)->i_reserved_data_blocks - used - to_free; mdb = ext4_calc_metadata_amount(inode, total); /* figure out how many metablocks to release */ BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks); mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb; /* Account for allocated meta_blocks */ mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks; release = to_free + mdb_free; /* update fs free blocks counter for truncate case */ percpu_counter_add(&sbi->s_freeblocks_counter, release); /* update per-inode reservations */ BUG_ON(used + to_free > EXT4_I(inode)->i_reserved_data_blocks); EXT4_I(inode)->i_reserved_data_blocks -= (used + to_free); BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks); EXT4_I(inode)->i_reserved_meta_blocks = mdb; EXT4_I(inode)->i_allocated_meta_blocks = 0; spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); } static void ext4_da_page_release_reservation(struct page *page, unsigned long offset) { int to_release = 0; struct buffer_head *head, *bh; unsigned int curr_off = 0; head = page_buffers(page); bh = head; do { unsigned int next_off = curr_off + bh->b_size; if ((offset <= curr_off) && (buffer_delay(bh))) { to_release++; clear_buffer_delay(bh); } curr_off = next_off; } while ((bh = bh->b_this_page) != head); ext4_da_release_space(page->mapping->host, 0, to_release); } /* * Delayed allocation stuff */ struct mpage_da_data { struct inode *inode; struct buffer_head lbh; /* extent of blocks */ unsigned long first_page, next_page; /* extent of pages */ get_block_t *get_block; struct writeback_control *wbc; }; /* * mpage_da_submit_io - walks through extent of pages and try to write * them with __mpage_writepage() * * @mpd->inode: inode * @mpd->first_page: first page of the extent * @mpd->next_page: page after the last page of the extent * @mpd->get_block: the filesystem's block mapper function * * By the time mpage_da_submit_io() is called we expect all blocks * to be allocated. this may be wrong if allocation failed. * * As pages are already locked by write_cache_pages(), we can't use it */ static int mpage_da_submit_io(struct mpage_da_data *mpd) { struct address_space *mapping = mpd->inode->i_mapping; struct mpage_data mpd_pp = { .bio = NULL, .last_block_in_bio = 0, .get_block = mpd->get_block, .use_writepage = 1, }; int ret = 0, err, nr_pages, i; unsigned long index, end; struct pagevec pvec; BUG_ON(mpd->next_page <= mpd->first_page); pagevec_init(&pvec, 0); index = mpd->first_page; end = mpd->next_page - 1; while (index <= end) { /* XXX: optimize tail */ nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE); if (nr_pages == 0) break; for (i = 0; i < nr_pages; i++) { struct page *page = pvec.pages[i]; index = page->index; if (index > end) break; index++; err = __mpage_writepage(page, mpd->wbc, &mpd_pp); /* * In error case, we have to continue because * remaining pages are still locked * XXX: unlock and re-dirty them? */ if (ret == 0) ret = err; } pagevec_release(&pvec); } if (mpd_pp.bio) mpage_bio_submit(WRITE, mpd_pp.bio); return ret; } /* * mpage_put_bnr_to_bhs - walk blocks and assign them actual numbers * * @mpd->inode - inode to walk through * @exbh->b_blocknr - first block on a disk * @exbh->b_size - amount of space in bytes * @logical - first logical block to start assignment with * * the function goes through all passed space and put actual disk * block numbers into buffer heads, dropping BH_Delay */ static void mpage_put_bnr_to_bhs(struct mpage_da_data *mpd, sector_t logical, struct buffer_head *exbh) { struct inode *inode = mpd->inode; struct address_space *mapping = inode->i_mapping; int blocks = exbh->b_size >> inode->i_blkbits; sector_t pblock = exbh->b_blocknr, cur_logical; struct buffer_head *head, *bh; unsigned long index, end; struct pagevec pvec; int nr_pages, i; index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits); end = (logical + blocks - 1) >> (PAGE_CACHE_SHIFT - inode->i_blkbits); cur_logical = index << (PAGE_CACHE_SHIFT - inode->i_blkbits); pagevec_init(&pvec, 0); while (index <= end) { /* XXX: optimize tail */ nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE); if (nr_pages == 0) break; for (i = 0; i < nr_pages; i++) { struct page *page = pvec.pages[i]; index = page->index; if (index > end) break; index++; BUG_ON(!PageLocked(page)); BUG_ON(PageWriteback(page)); BUG_ON(!page_has_buffers(page)); bh = page_buffers(page); head = bh; /* skip blocks out of the range */ do { if (cur_logical >= logical) break; cur_logical++; } while ((bh = bh->b_this_page) != head); do { if (cur_logical >= logical + blocks) break; if (buffer_delay(bh)) { bh->b_blocknr = pblock; clear_buffer_delay(bh); } else if (buffer_mapped(bh)) BUG_ON(bh->b_blocknr != pblock); cur_logical++; pblock++; } while ((bh = bh->b_this_page) != head); } pagevec_release(&pvec); } } /* * __unmap_underlying_blocks - just a helper function to unmap * set of blocks described by @bh */ static inline void __unmap_underlying_blocks(struct inode *inode, struct buffer_head *bh) { struct block_device *bdev = inode->i_sb->s_bdev; int blocks, i; blocks = bh->b_size >> inode->i_blkbits; for (i = 0; i < blocks; i++) unmap_underlying_metadata(bdev, bh->b_blocknr + i); } /* * mpage_da_map_blocks - go through given space * * @mpd->lbh - bh describing space * @mpd->get_block - the filesystem's block mapper function * * The function skips space we know is already mapped to disk blocks. * * The function ignores errors ->get_block() returns, thus real * error handling is postponed to __mpage_writepage() */ static void mpage_da_map_blocks(struct mpage_da_data *mpd) { struct buffer_head *lbh = &mpd->lbh; int err = 0, remain = lbh->b_size; sector_t next = lbh->b_blocknr; struct buffer_head new; /* * We consider only non-mapped and non-allocated blocks */ if (buffer_mapped(lbh) && !buffer_delay(lbh)) return; while (remain) { new.b_state = lbh->b_state; new.b_blocknr = 0; new.b_size = remain; err = mpd->get_block(mpd->inode, next, &new, 1); if (err) { /* * Rather than implement own error handling * here, we just leave remaining blocks * unallocated and try again with ->writepage() */ break; } BUG_ON(new.b_size == 0); if (buffer_new(&new)) __unmap_underlying_blocks(mpd->inode, &new); /* * If blocks are delayed marked, we need to * put actual blocknr and drop delayed bit */ if (buffer_delay(lbh)) mpage_put_bnr_to_bhs(mpd, next, &new); /* go for the remaining blocks */ next += new.b_size >> mpd->inode->i_blkbits; remain -= new.b_size; } } #define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | (1 << BH_Delay)) /* * mpage_add_bh_to_extent - try to add one more block to extent of blocks * * @mpd->lbh - extent of blocks * @logical - logical number of the block in the file * @bh - bh of the block (used to access block's state) * * the function is used to collect contig. blocks in same state */ static void mpage_add_bh_to_extent(struct mpage_da_data *mpd, sector_t logical, struct buffer_head *bh) { struct buffer_head *lbh = &mpd->lbh; sector_t next; next = lbh->b_blocknr + (lbh->b_size >> mpd->inode->i_blkbits); /* * First block in the extent */ if (lbh->b_size == 0) { lbh->b_blocknr = logical; lbh->b_size = bh->b_size; lbh->b_state = bh->b_state & BH_FLAGS; return; } /* * Can we merge the block to our big extent? */ if (logical == next && (bh->b_state & BH_FLAGS) == lbh->b_state) { lbh->b_size += bh->b_size; return; } /* * We couldn't merge the block to our extent, so we * need to flush current extent and start new one */ mpage_da_map_blocks(mpd); /* * Now start a new extent */ lbh->b_size = bh->b_size; lbh->b_state = bh->b_state & BH_FLAGS; lbh->b_blocknr = logical; } /* * __mpage_da_writepage - finds extent of pages and blocks * * @page: page to consider * @wbc: not used, we just follow rules * @data: context * * The function finds extents of pages and scan them for all blocks. */ static int __mpage_da_writepage(struct page *page, struct writeback_control *wbc, void *data) { struct mpage_da_data *mpd = data; struct inode *inode = mpd->inode; struct buffer_head *bh, *head, fake; sector_t logical; /* * Can we merge this page to current extent? */ if (mpd->next_page != page->index) { /* * Nope, we can't. So, we map non-allocated blocks * and start IO on them using __mpage_writepage() */ if (mpd->next_page != mpd->first_page) { mpage_da_map_blocks(mpd); mpage_da_submit_io(mpd); } /* * Start next extent of pages ... */ mpd->first_page = page->index; /* * ... and blocks */ mpd->lbh.b_size = 0; mpd->lbh.b_state = 0; mpd->lbh.b_blocknr = 0; } mpd->next_page = page->index + 1; logical = (sector_t) page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); if (!page_has_buffers(page)) { /* * There is no attached buffer heads yet (mmap?) * we treat the page asfull of dirty blocks */ bh = &fake; bh->b_size = PAGE_CACHE_SIZE; bh->b_state = 0; set_buffer_dirty(bh); set_buffer_uptodate(bh); mpage_add_bh_to_extent(mpd, logical, bh); } else { /* * Page with regular buffer heads, just add all dirty ones */ head = page_buffers(page); bh = head; do { BUG_ON(buffer_locked(bh)); if (buffer_dirty(bh)) mpage_add_bh_to_extent(mpd, logical, bh); logical++; } while ((bh = bh->b_this_page) != head); } return 0; } /* * mpage_da_writepages - walk the list of dirty pages of the given * address space, allocates non-allocated blocks, maps newly-allocated * blocks to existing bhs and issue IO them * * @mapping: address space structure to write * @wbc: subtract the number of written pages from *@wbc->nr_to_write * @get_block: the filesystem's block mapper function. * * This is a library function, which implements the writepages() * address_space_operation. * * In order to avoid duplication of logic that deals with partial pages, * multiple bio per page, etc, we find non-allocated blocks, allocate * them with minimal calls to ->get_block() and re-use __mpage_writepage() * * It's important that we call __mpage_writepage() only once for each * involved page, otherwise we'd have to implement more complicated logic * to deal with pages w/o PG_lock or w/ PG_writeback and so on. * * See comments to mpage_writepages() */ static int mpage_da_writepages(struct address_space *mapping, struct writeback_control *wbc, get_block_t get_block) { struct mpage_da_data mpd; int ret; if (!get_block) return generic_writepages(mapping, wbc); mpd.wbc = wbc; mpd.inode = mapping->host; mpd.lbh.b_size = 0; mpd.lbh.b_state = 0; mpd.lbh.b_blocknr = 0; mpd.first_page = 0; mpd.next_page = 0; mpd.get_block = get_block; ret = write_cache_pages(mapping, wbc, __mpage_da_writepage, &mpd); /* * Handle last extent of pages */ if (mpd.next_page != mpd.first_page) { mpage_da_map_blocks(&mpd); mpage_da_submit_io(&mpd); } return ret; } /* * this is a special callback for ->write_begin() only * it's intention is to return mapped block or reserve space */ static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create) { int ret = 0; BUG_ON(create == 0); BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize); /* * first, we need to know whether the block is allocated already * preallocated blocks are unmapped but should treated * the same as allocated blocks. */ ret = ext4_get_blocks_wrap(NULL, inode, iblock, 1, bh_result, 0, 0, 0); if ((ret == 0) && !buffer_delay(bh_result)) { /* the block isn't (pre)allocated yet, let's reserve space */ /* * XXX: __block_prepare_write() unmaps passed block, * is it OK? */ ret = ext4_da_reserve_space(inode, 1); if (ret) /* not enough space to reserve */ return ret; map_bh(bh_result, inode->i_sb, 0); set_buffer_new(bh_result); set_buffer_delay(bh_result); } else if (ret > 0) { bh_result->b_size = (ret << inode->i_blkbits); ret = 0; } return ret; } #define EXT4_DELALLOC_RSVED 1 static int ext4_da_get_block_write(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create) { int ret; unsigned max_blocks = bh_result->b_size >> inode->i_blkbits; loff_t disksize = EXT4_I(inode)->i_disksize; handle_t *handle = NULL; handle = ext4_journal_current_handle(); if (!handle) { ret = ext4_get_blocks_wrap(handle, inode, iblock, max_blocks, bh_result, 0, 0, 0); BUG_ON(!ret); } else { ret = ext4_get_blocks_wrap(handle, inode, iblock, max_blocks, bh_result, create, 0, EXT4_DELALLOC_RSVED); } if (ret > 0) { bh_result->b_size = (ret << inode->i_blkbits); /* * Update on-disk size along with block allocation * we don't use 'extend_disksize' as size may change * within already allocated block -bzzz */ disksize = ((loff_t) iblock + ret) << inode->i_blkbits; if (disksize > i_size_read(inode)) disksize = i_size_read(inode); if (disksize > EXT4_I(inode)->i_disksize) { /* * XXX: replace with spinlock if seen contended -bzzz */ down_write(&EXT4_I(inode)->i_data_sem); if (disksize > EXT4_I(inode)->i_disksize) EXT4_I(inode)->i_disksize = disksize; up_write(&EXT4_I(inode)->i_data_sem); if (EXT4_I(inode)->i_disksize == disksize) { ret = ext4_mark_inode_dirty(handle, inode); return ret; } } ret = 0; } return ret; } static int ext4_bh_unmapped_or_delay(handle_t *handle, struct buffer_head *bh) { /* * unmapped buffer is possible for holes. * delay buffer is possible with delayed allocation */ return ((!buffer_mapped(bh) || buffer_delay(bh)) && buffer_dirty(bh)); } static int ext4_normal_get_block_write(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create) { int ret = 0; unsigned max_blocks = bh_result->b_size >> inode->i_blkbits; /* * we don't want to do block allocation in writepage * so call get_block_wrap with create = 0 */ ret = ext4_get_blocks_wrap(NULL, inode, iblock, max_blocks, bh_result, 0, 0, 0); if (ret > 0) { bh_result->b_size = (ret << inode->i_blkbits); ret = 0; } return ret; } /* * get called vi ext4_da_writepages after taking page lock (have journal handle) * get called via journal_submit_inode_data_buffers (no journal handle) * get called via shrink_page_list via pdflush (no journal handle) * or grab_page_cache when doing write_begin (have journal handle) */ static int ext4_da_writepage(struct page *page, struct writeback_control *wbc) { int ret = 0; loff_t size; unsigned long len; struct buffer_head *page_bufs; struct inode *inode = page->mapping->host; size = i_size_read(inode); if (page->index == size >> PAGE_CACHE_SHIFT) len = size & ~PAGE_CACHE_MASK; else len = PAGE_CACHE_SIZE; if (page_has_buffers(page)) { page_bufs = page_buffers(page); if (walk_page_buffers(NULL, page_bufs, 0, len, NULL, ext4_bh_unmapped_or_delay)) { /* * We don't want to do block allocation * So redirty the page and return * We may reach here when we do a journal commit * via journal_submit_inode_data_buffers. * If we don't have mapping block we just ignore * them. We can also reach here via shrink_page_list */ redirty_page_for_writepage(wbc, page); unlock_page(page); return 0; } } else { /* * The test for page_has_buffers() is subtle: * We know the page is dirty but it lost buffers. That means * that at some moment in time after write_begin()/write_end() * has been called all buffers have been clean and thus they * must have been written at least once. So they are all * mapped and we can happily proceed with mapping them * and writing the page. * * Try to initialize the buffer_heads and check whether * all are mapped and non delay. We don't want to * do block allocation here. */ ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE, ext4_normal_get_block_write); if (!ret) { page_bufs = page_buffers(page); /* check whether all are mapped and non delay */ if (walk_page_buffers(NULL, page_bufs, 0, len, NULL, ext4_bh_unmapped_or_delay)) { redirty_page_for_writepage(wbc, page); unlock_page(page); return 0; } } else { /* * We can't do block allocation here * so just redity the page and unlock * and return */ redirty_page_for_writepage(wbc, page); unlock_page(page); return 0; } } if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode)) ret = nobh_writepage(page, ext4_normal_get_block_write, wbc); else ret = block_write_full_page(page, ext4_normal_get_block_write, wbc); return ret; } /* * For now just follow the DIO way to estimate the max credits * needed to write out EXT4_MAX_WRITEBACK_PAGES. * todo: need to calculate the max credits need for * extent based files, currently the DIO credits is based on * indirect-blocks mapping way. * * Probably should have a generic way to calculate credits * for DIO, writepages, and truncate */ #define EXT4_MAX_WRITEBACK_PAGES DIO_MAX_BLOCKS #define EXT4_MAX_WRITEBACK_CREDITS DIO_CREDITS static int ext4_da_writepages(struct address_space *mapping, struct writeback_control *wbc) { struct inode *inode = mapping->host; handle_t *handle = NULL; int needed_blocks; int ret = 0; long to_write; loff_t range_start = 0; /* * No pages to write? This is mainly a kludge to avoid starting * a transaction for special inodes like journal inode on last iput() * because that could violate lock ordering on umount */ if (!mapping->nrpages) return 0; /* * Estimate the worse case needed credits to write out * EXT4_MAX_BUF_BLOCKS pages */ needed_blocks = EXT4_MAX_WRITEBACK_CREDITS; to_write = wbc->nr_to_write; if (!wbc->range_cyclic) { /* * If range_cyclic is not set force range_cont * and save the old writeback_index */ wbc->range_cont = 1; range_start = wbc->range_start; } while (!ret && to_write) { /* start a new transaction*/ handle = ext4_journal_start(inode, needed_blocks); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out_writepages; } if (ext4_should_order_data(inode)) { /* * With ordered mode we need to add * the inode to the journal handle * when we do block allocation. */ ret = ext4_jbd2_file_inode(handle, inode); if (ret) { ext4_journal_stop(handle); goto out_writepages; } } /* * set the max dirty pages could be write at a time * to fit into the reserved transaction credits */ if (wbc->nr_to_write > EXT4_MAX_WRITEBACK_PAGES) wbc->nr_to_write = EXT4_MAX_WRITEBACK_PAGES; to_write -= wbc->nr_to_write; ret = mpage_da_writepages(mapping, wbc, ext4_da_get_block_write); ext4_journal_stop(handle); if (wbc->nr_to_write) { /* * There is no more writeout needed * or we requested for a noblocking writeout * and we found the device congested */ to_write += wbc->nr_to_write; break; } wbc->nr_to_write = to_write; } out_writepages: wbc->nr_to_write = to_write; if (range_start) wbc->range_start = range_start; return ret; } static int ext4_da_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { int ret, retries = 0; struct page *page; pgoff_t index; unsigned from, to; struct inode *inode = mapping->host; handle_t *handle; index = pos >> PAGE_CACHE_SHIFT; from = pos & (PAGE_CACHE_SIZE - 1); to = from + len; retry: /* * With delayed allocation, we don't log the i_disksize update * if there is delayed block allocation. But we still need * to journalling the i_disksize update if writes to the end * of file which has an already mapped buffer. */ handle = ext4_journal_start(inode, 1); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out; } page = __grab_cache_page(mapping, index); if (!page) { ext4_journal_stop(handle); ret = -ENOMEM; goto out; } *pagep = page; ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata, ext4_da_get_block_prep); if (ret < 0) { unlock_page(page); ext4_journal_stop(handle); page_cache_release(page); } if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries)) goto retry; out: return ret; } /* * Check if we should update i_disksize * when write to the end of file but not require block allocation */ static int ext4_da_should_update_i_disksize(struct page *page, unsigned long offset) { struct buffer_head *bh; struct inode *inode = page->mapping->host; unsigned int idx; int i; bh = page_buffers(page); idx = offset >> inode->i_blkbits; for (i=0; i < idx; i++) bh = bh->b_this_page; if (!buffer_mapped(bh) || (buffer_delay(bh))) return 0; return 1; } static int ext4_da_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { struct inode *inode = mapping->host; int ret = 0, ret2; handle_t *handle = ext4_journal_current_handle(); loff_t new_i_size; unsigned long start, end; start = pos & (PAGE_CACHE_SIZE - 1); end = start + copied -1; /* * generic_write_end() will run mark_inode_dirty() if i_size * changes. So let's piggyback the i_disksize mark_inode_dirty * into that. */ new_i_size = pos + copied; if (new_i_size > EXT4_I(inode)->i_disksize) { if (ext4_da_should_update_i_disksize(page, end)) { down_write(&EXT4_I(inode)->i_data_sem); if (new_i_size > EXT4_I(inode)->i_disksize) { /* * Updating i_disksize when extending file * without needing block allocation */ if (ext4_should_order_data(inode)) ret = ext4_jbd2_file_inode(handle, inode); EXT4_I(inode)->i_disksize = new_i_size; } up_write(&EXT4_I(inode)->i_data_sem); } } ret2 = generic_write_end(file, mapping, pos, len, copied, page, fsdata); copied = ret2; if (ret2 < 0) ret = ret2; ret2 = ext4_journal_stop(handle); if (!ret) ret = ret2; return ret ? ret : copied; } static void ext4_da_invalidatepage(struct page *page, unsigned long offset) { /* * Drop reserved blocks */ BUG_ON(!PageLocked(page)); if (!page_has_buffers(page)) goto out; ext4_da_page_release_reservation(page, offset); out: ext4_invalidatepage(page, offset); return; } /* * bmap() is special. It gets used by applications such as lilo and by * the swapper to find the on-disk block of a specific piece of data. * * Naturally, this is dangerous if the block concerned is still in the * journal. If somebody makes a swapfile on an ext4 data-journaling * filesystem and enables swap, then they may get a nasty shock when the * data getting swapped to that swapfile suddenly gets overwritten by * the original zero's written out previously to the journal and * awaiting writeback in the kernel's buffer cache. * * So, if we see any bmap calls here on a modified, data-journaled file, * take extra steps to flush any blocks which might be in the cache. */ static sector_t ext4_bmap(struct address_space *mapping, sector_t block) { struct inode *inode = mapping->host; journal_t *journal; int err; if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) && test_opt(inode->i_sb, DELALLOC)) { /* * With delalloc we want to sync the file * so that we can make sure we allocate * blocks for file */ filemap_write_and_wait(mapping); } if (EXT4_I(inode)->i_state & EXT4_STATE_JDATA) { /* * This is a REALLY heavyweight approach, but the use of * bmap on dirty files is expected to be extremely rare: * only if we run lilo or swapon on a freshly made file * do we expect this to happen. * * (bmap requires CAP_SYS_RAWIO so this does not * represent an unprivileged user DOS attack --- we'd be * in trouble if mortal users could trigger this path at * will.) * * NB. EXT4_STATE_JDATA is not set on files other than * regular files. If somebody wants to bmap a directory * or symlink and gets confused because the buffer * hasn't yet been flushed to disk, they deserve * everything they get. */ EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA; journal = EXT4_JOURNAL(inode); jbd2_journal_lock_updates(journal); err = jbd2_journal_flush(journal); jbd2_journal_unlock_updates(journal); if (err) return 0; } return generic_block_bmap(mapping,block,ext4_get_block); } static int bget_one(handle_t *handle, struct buffer_head *bh) { get_bh(bh); return 0; } static int bput_one(handle_t *handle, struct buffer_head *bh) { put_bh(bh); return 0; } /* * Note that we don't need to start a transaction unless we're journaling data * because we should have holes filled from ext4_page_mkwrite(). We even don't * need to file the inode to the transaction's list in ordered mode because if * we are writing back data added by write(), the inode is already there and if * we are writing back data modified via mmap(), noone guarantees in which * transaction the data will hit the disk. In case we are journaling data, we * cannot start transaction directly because transaction start ranks above page * lock so we have to do some magic. * * In all journaling modes block_write_full_page() will start the I/O. * * Problem: * * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() -> * ext4_writepage() * * Similar for: * * ext4_file_write() -> generic_file_write() -> __alloc_pages() -> ... * * Same applies to ext4_get_block(). We will deadlock on various things like * lock_journal and i_data_sem * * Setting PF_MEMALLOC here doesn't work - too many internal memory * allocations fail. * * 16May01: If we're reentered then journal_current_handle() will be * non-zero. We simply *return*. * * 1 July 2001: @@@ FIXME: * In journalled data mode, a data buffer may be metadata against the * current transaction. But the same file is part of a shared mapping * and someone does a writepage() on it. * * We will move the buffer onto the async_data list, but *after* it has * been dirtied. So there's a small window where we have dirty data on * BJ_Metadata. * * Note that this only applies to the last partial page in the file. The * bit which block_write_full_page() uses prepare/commit for. (That's * broken code anyway: it's wrong for msync()). * * It's a rare case: affects the final partial page, for journalled data * where the file is subject to bith write() and writepage() in the same * transction. To fix it we'll need a custom block_write_full_page(). * We'll probably need that anyway for journalling writepage() output. * * We don't honour synchronous mounts for writepage(). That would be * disastrous. Any write() or metadata operation will sync the fs for * us. * */ static int __ext4_normal_writepage(struct page *page, struct writeback_control *wbc) { struct inode *inode = page->mapping->host; if (test_opt(inode->i_sb, NOBH)) return nobh_writepage(page, ext4_normal_get_block_write, wbc); else return block_write_full_page(page, ext4_normal_get_block_write, wbc); } static int ext4_normal_writepage(struct page *page, struct writeback_control *wbc) { struct inode *inode = page->mapping->host; loff_t size = i_size_read(inode); loff_t len; J_ASSERT(PageLocked(page)); if (page->index == size >> PAGE_CACHE_SHIFT) len = size & ~PAGE_CACHE_MASK; else len = PAGE_CACHE_SIZE; if (page_has_buffers(page)) { /* if page has buffers it should all be mapped * and allocated. If there are not buffers attached * to the page we know the page is dirty but it lost * buffers. That means that at some moment in time * after write_begin() / write_end() has been called * all buffers have been clean and thus they must have been * written at least once. So they are all mapped and we can * happily proceed with mapping them and writing the page. */ BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL, ext4_bh_unmapped_or_delay)); } if (!ext4_journal_current_handle()) return __ext4_normal_writepage(page, wbc); redirty_page_for_writepage(wbc, page); unlock_page(page); return 0; } static int __ext4_journalled_writepage(struct page *page, struct writeback_control *wbc) { struct address_space *mapping = page->mapping; struct inode *inode = mapping->host; struct buffer_head *page_bufs; handle_t *handle = NULL; int ret = 0; int err; ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE, ext4_normal_get_block_write); if (ret != 0) goto out_unlock; page_bufs = page_buffers(page); walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL, bget_one); /* As soon as we unlock the page, it can go away, but we have * references to buffers so we are safe */ unlock_page(page); handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode)); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out; } ret = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL, do_journal_get_write_access); err = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL, write_end_fn); if (ret == 0) ret = err; err = ext4_journal_stop(handle); if (!ret) ret = err; walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL, bput_one); EXT4_I(inode)->i_state |= EXT4_STATE_JDATA; goto out; out_unlock: unlock_page(page); out: return ret; } static int ext4_journalled_writepage(struct page *page, struct writeback_control *wbc) { struct inode *inode = page->mapping->host; loff_t size = i_size_read(inode); loff_t len; J_ASSERT(PageLocked(page)); if (page->index == size >> PAGE_CACHE_SHIFT) len = size & ~PAGE_CACHE_MASK; else len = PAGE_CACHE_SIZE; if (page_has_buffers(page)) { /* if page has buffers it should all be mapped * and allocated. If there are not buffers attached * to the page we know the page is dirty but it lost * buffers. That means that at some moment in time * after write_begin() / write_end() has been called * all buffers have been clean and thus they must have been * written at least once. So they are all mapped and we can * happily proceed with mapping them and writing the page. */ BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL, ext4_bh_unmapped_or_delay)); } if (ext4_journal_current_handle()) goto no_write; if (PageChecked(page)) { /* * It's mmapped pagecache. Add buffers and journal it. There * doesn't seem much point in redirtying the page here. */ ClearPageChecked(page); return __ext4_journalled_writepage(page, wbc); } else { /* * It may be a page full of checkpoint-mode buffers. We don't * really know unless we go poke around in the buffer_heads. * But block_write_full_page will do the right thing. */ return block_write_full_page(page, ext4_normal_get_block_write, wbc); } no_write: redirty_page_for_writepage(wbc, page); unlock_page(page); return 0; } static int ext4_readpage(struct file *file, struct page *page) { return mpage_readpage(page, ext4_get_block); } static int ext4_readpages(struct file *file, struct address_space *mapping, struct list_head *pages, unsigned nr_pages) { return mpage_readpages(mapping, pages, nr_pages, ext4_get_block); } static void ext4_invalidatepage(struct page *page, unsigned long offset) { journal_t *journal = EXT4_JOURNAL(page->mapping->host); /* * If it's a full truncate we just forget about the pending dirtying */ if (offset == 0) ClearPageChecked(page); jbd2_journal_invalidatepage(journal, page, offset); } static int ext4_releasepage(struct page *page, gfp_t wait) { journal_t *journal = EXT4_JOURNAL(page->mapping->host); WARN_ON(PageChecked(page)); if (!page_has_buffers(page)) return 0; return jbd2_journal_try_to_free_buffers(journal, page, wait); } /* * If the O_DIRECT write will extend the file then add this inode to the * orphan list. So recovery will truncate it back to the original size * if the machine crashes during the write. * * If the O_DIRECT write is intantiating holes inside i_size and the machine * crashes then stale disk data _may_ be exposed inside the file. But current * VFS code falls back into buffered path in that case so we are safe. */ static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t offset, unsigned long nr_segs) { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; struct ext4_inode_info *ei = EXT4_I(inode); handle_t *handle; ssize_t ret; int orphan = 0; size_t count = iov_length(iov, nr_segs); if (rw == WRITE) { loff_t final_size = offset + count; if (final_size > inode->i_size) { /* Credits for sb + inode write */ handle = ext4_journal_start(inode, 2); if (IS_ERR(handle)) { ret = PTR_ERR(handle); goto out; } ret = ext4_orphan_add(handle, inode); if (ret) { ext4_journal_stop(handle); goto out; } orphan = 1; ei->i_disksize = inode->i_size; ext4_journal_stop(handle); } } ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov, offset, nr_segs, ext4_get_block, NULL); if (orphan) { int err; /* Credits for sb + inode write */ handle = ext4_journal_start(inode, 2); if (IS_ERR(handle)) { /* This is really bad luck. We've written the data * but cannot extend i_size. Bail out and pretend * the write failed... */ ret = PTR_ERR(handle); goto out; } if (inode->i_nlink) ext4_orphan_del(handle, inode); if (ret > 0) { loff_t end = offset + ret; if (end > inode->i_size) { ei->i_disksize = end; i_size_write(inode, end); /* * We're going to return a positive `ret' * here due to non-zero-length I/O, so there's * no way of reporting error returns from * ext4_mark_inode_dirty() to userspace. So * ignore it. */ ext4_mark_inode_dirty(handle, inode); } } err = ext4_journal_stop(handle); if (ret == 0) ret = err; } out: return ret; } /* * Pages can be marked dirty completely asynchronously from ext4's journalling * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do * much here because ->set_page_dirty is called under VFS locks. The page is * not necessarily locked. * * We cannot just dirty the page and leave attached buffers clean, because the * buffers' dirty state is "definitive". We cannot just set the buffers dirty * or jbddirty because all the journalling code will explode. * * So what we do is to mark the page "pending dirty" and next time writepage * is called, propagate that into the buffers appropriately. */ static int ext4_journalled_set_page_dirty(struct page *page) { SetPageChecked(page); return __set_page_dirty_nobuffers(page); } static const struct address_space_operations ext4_ordered_aops = { .readpage = ext4_readpage, .readpages = ext4_readpages, .writepage = ext4_normal_writepage, .sync_page = block_sync_page, .write_begin = ext4_write_begin, .write_end = ext4_ordered_write_end, .bmap = ext4_bmap, .invalidatepage = ext4_invalidatepage, .releasepage = ext4_releasepage, .direct_IO = ext4_direct_IO, .migratepage = buffer_migrate_page, .is_partially_uptodate = block_is_partially_uptodate, }; static const struct address_space_operations ext4_writeback_aops = { .readpage = ext4_readpage, .readpages = ext4_readpages, .writepage = ext4_normal_writepage, .sync_page = block_sync_page, .write_begin = ext4_write_begin, .write_end = ext4_writeback_write_end, .bmap = ext4_bmap, .invalidatepage = ext4_invalidatepage, .releasepage = ext4_releasepage, .direct_IO = ext4_direct_IO, .migratepage = buffer_migrate_page, .is_partially_uptodate = block_is_partially_uptodate, }; static const struct address_space_operations ext4_journalled_aops = { .readpage = ext4_readpage, .readpages = ext4_readpages, .writepage = ext4_journalled_writepage, .sync_page = block_sync_page, .write_begin = ext4_write_begin, .write_end = ext4_journalled_write_end, .set_page_dirty = ext4_journalled_set_page_dirty, .bmap = ext4_bmap, .invalidatepage = ext4_invalidatepage, .releasepage = ext4_releasepage, .is_partially_uptodate = block_is_partially_uptodate, }; static const struct address_space_operations ext4_da_aops = { .readpage = ext4_readpage, .readpages = ext4_readpages, .writepage = ext4_da_writepage, .writepages = ext4_da_writepages, .sync_page = block_sync_page, .write_begin = ext4_da_write_begin, .write_end = ext4_da_write_end, .bmap = ext4_bmap, .invalidatepage = ext4_da_invalidatepage, .releasepage = ext4_releasepage, .direct_IO = ext4_direct_IO, .migratepage = buffer_migrate_page, .is_partially_uptodate = block_is_partially_uptodate, }; void ext4_set_aops(struct inode *inode) { if (ext4_should_order_data(inode) && test_opt(inode->i_sb, DELALLOC)) inode->i_mapping->a_ops = &ext4_da_aops; else if (ext4_should_order_data(inode)) inode->i_mapping->a_ops = &ext4_ordered_aops; else if (ext4_should_writeback_data(inode) && test_opt(inode->i_sb, DELALLOC)) inode->i_mapping->a_ops = &ext4_da_aops; else if (ext4_should_writeback_data(inode)) inode->i_mapping->a_ops = &ext4_writeback_aops; else inode->i_mapping->a_ops = &ext4_journalled_aops; } /* * ext4_block_truncate_page() zeroes out a mapping from file offset `from' * up to the end of the block which corresponds to `from'. * This required during truncate. We need to physically zero the tail end * of that block so it doesn't yield old data if the file is later grown. */ int ext4_block_truncate_page(handle_t *handle, struct address_space *mapping, loff_t from) { ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT; unsigned offset = from & (PAGE_CACHE_SIZE-1); unsigned blocksize, length, pos; ext4_lblk_t iblock; struct inode *inode = mapping->host; struct buffer_head *bh; struct page *page; int err = 0; page = grab_cache_page(mapping, from >> PAGE_CACHE_SHIFT); if (!page) return -EINVAL; blocksize = inode->i_sb->s_blocksize; length = blocksize - (offset & (blocksize - 1)); iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits); /* * For "nobh" option, we can only work if we don't need to * read-in the page - otherwise we create buffers to do the IO. */ if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode) && PageUptodate(page)) { zero_user(page, offset, length); set_page_dirty(page); goto unlock; } if (!page_has_buffers(page)) create_empty_buffers(page, blocksize, 0); /* Find the buffer that contains "offset" */ bh = page_buffers(page); pos = blocksize; while (offset >= pos) { bh = bh->b_this_page; iblock++; pos += blocksize; } err = 0; if (buffer_freed(bh)) { BUFFER_TRACE(bh, "freed: skip"); goto unlock; } if (!buffer_mapped(bh)) { BUFFER_TRACE(bh, "unmapped"); ext4_get_block(inode, iblock, bh, 0); /* unmapped? It's a hole - nothing to do */ if (!buffer_mapped(bh)) { BUFFER_TRACE(bh, "still unmapped"); goto unlock; } } /* Ok, it's mapped. Make sure it's up-to-date */ if (PageUptodate(page)) set_buffer_uptodate(bh); if (!buffer_uptodate(bh)) { err = -EIO; ll_rw_block(READ, 1, &bh); wait_on_buffer(bh); /* Uhhuh. Read error. Complain and punt. */ if (!buffer_uptodate(bh)) goto unlock; } if (ext4_should_journal_data(inode)) { BUFFER_TRACE(bh, "get write access"); err = ext4_journal_get_write_access(handle, bh); if (err) goto unlock; } zero_user(page, offset, length); BUFFER_TRACE(bh, "zeroed end of block"); err = 0; if (ext4_should_journal_data(inode)) { err = ext4_journal_dirty_metadata(handle, bh); } else { if (ext4_should_order_data(inode)) err = ext4_jbd2_file_inode(handle, inode); mark_buffer_dirty(bh); } unlock: unlock_page(page); page_cache_release(page); return err; } /* * Probably it should be a library function... search for first non-zero word * or memcmp with zero_page, whatever is better for particular architecture. * Linus? */ static inline int all_zeroes(__le32 *p, __le32 *q) { while (p < q) if (*p++) return 0; return 1; } /** * ext4_find_shared - find the indirect blocks for partial truncation. * @inode: inode in question * @depth: depth of the affected branch * @offsets: offsets of pointers in that branch (see ext4_block_to_path) * @chain: place to store the pointers to partial indirect blocks * @top: place to the (detached) top of branch * * This is a helper function used by ext4_truncate(). * * When we do truncate() we may have to clean the ends of several * indirect blocks but leave the blocks themselves alive. Block is * partially truncated if some data below the new i_size is refered * from it (and it is on the path to the first completely truncated * data block, indeed). We have to free the top of that path along * with everything to the right of the path. Since no allocation * past the truncation point is possible until ext4_truncate() * finishes, we may safely do the latter, but top of branch may * require special attention - pageout below the truncation point * might try to populate it. * * We atomically detach the top of branch from the tree, store the * block number of its root in *@top, pointers to buffer_heads of * partially truncated blocks - in @chain[].bh and pointers to * their last elements that should not be removed - in * @chain[].p. Return value is the pointer to last filled element * of @chain. * * The work left to caller to do the actual freeing of subtrees: * a) free the subtree starting from *@top * b) free the subtrees whose roots are stored in * (@chain[i].p+1 .. end of @chain[i].bh->b_data) * c) free the subtrees growing from the inode past the @chain[0]. * (no partially truncated stuff there). */ static Indirect *ext4_find_shared(struct inode *inode, int depth, ext4_lblk_t offsets[4], Indirect chain[4], __le32 *top) { Indirect *partial, *p; int k, err; *top = 0; /* Make k index the deepest non-null offest + 1 */ for (k = depth; k > 1 && !offsets[k-1]; k--) ; partial = ext4_get_branch(inode, k, offsets, chain, &err); /* Writer: pointers */ if (!partial) partial = chain + k-1; /* * If the branch acquired continuation since we've looked at it - * fine, it should all survive and (new) top doesn't belong to us. */ if (!partial->key && *partial->p) /* Writer: end */ goto no_top; for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--) ; /* * OK, we've found the last block that must survive. The rest of our * branch should be detached before unlocking. However, if that rest * of branch is all ours and does not grow immediately from the inode * it's easier to cheat and just decrement partial->p. */ if (p == chain + k - 1 && p > chain) { p->p--; } else { *top = *p->p; /* Nope, don't do this in ext4. Must leave the tree intact */ #if 0 *p->p = 0; #endif } /* Writer: end */ while(partial > p) { brelse(partial->bh); partial--; } no_top: return partial; } /* * Zero a number of block pointers in either an inode or an indirect block. * If we restart the transaction we must again get write access to the * indirect block for further modification. * * We release `count' blocks on disk, but (last - first) may be greater * than `count' because there can be holes in there. */ static void ext4_clear_blocks(handle_t *handle, struct inode *inode, struct buffer_head *bh, ext4_fsblk_t block_to_free, unsigned long count, __le32 *first, __le32 *last) { __le32 *p; if (try_to_extend_transaction(handle, inode)) { if (bh) { BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata"); ext4_journal_dirty_metadata(handle, bh); } ext4_mark_inode_dirty(handle, inode); ext4_journal_test_restart(handle, inode); if (bh) { BUFFER_TRACE(bh, "retaking write access"); ext4_journal_get_write_access(handle, bh); } } /* * Any buffers which are on the journal will be in memory. We find * them on the hash table so jbd2_journal_revoke() will run jbd2_journal_forget() * on them. We've already detached each block from the file, so * bforget() in jbd2_journal_forget() should be safe. * * AKPM: turn on bforget in jbd2_journal_forget()!!! */ for (p = first; p < last; p++) { u32 nr = le32_to_cpu(*p); if (nr) { struct buffer_head *tbh; *p = 0; tbh = sb_find_get_block(inode->i_sb, nr); ext4_forget(handle, 0, inode, tbh, nr); } } ext4_free_blocks(handle, inode, block_to_free, count, 0); } /** * ext4_free_data - free a list of data blocks * @handle: handle for this transaction * @inode: inode we are dealing with * @this_bh: indirect buffer_head which contains *@first and *@last * @first: array of block numbers * @last: points immediately past the end of array * * We are freeing all blocks refered from that array (numbers are stored as * little-endian 32-bit) and updating @inode->i_blocks appropriately. * * We accumulate contiguous runs of blocks to free. Conveniently, if these * blocks are contiguous then releasing them at one time will only affect one * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't * actually use a lot of journal space. * * @this_bh will be %NULL if @first and @last point into the inode's direct * block pointers. */ static void ext4_free_data(handle_t *handle, struct inode *inode, struct buffer_head *this_bh, __le32 *first, __le32 *last) { ext4_fsblk_t block_to_free = 0; /* Starting block # of a run */ unsigned long count = 0; /* Number of blocks in the run */ __le32 *block_to_free_p = NULL; /* Pointer into inode/ind corresponding to block_to_free */ ext4_fsblk_t nr; /* Current block # */ __le32 *p; /* Pointer into inode/ind for current block */ int err; if (this_bh) { /* For indirect block */ BUFFER_TRACE(this_bh, "get_write_access"); err = ext4_journal_get_write_access(handle, this_bh); /* Important: if we can't update the indirect pointers * to the blocks, we can't free them. */ if (err) return; } for (p = first; p < last; p++) { nr = le32_to_cpu(*p); if (nr) { /* accumulate blocks to free if they're contiguous */ if (count == 0) { block_to_free = nr; block_to_free_p = p; count = 1; } else if (nr == block_to_free + count) { count++; } else { ext4_clear_blocks(handle, inode, this_bh, block_to_free, count, block_to_free_p, p); block_to_free = nr; block_to_free_p = p; count = 1; } } } if (count > 0) ext4_clear_blocks(handle, inode, this_bh, block_to_free, count, block_to_free_p, p); if (this_bh) { BUFFER_TRACE(this_bh, "call ext4_journal_dirty_metadata"); /* * The buffer head should have an attached journal head at this * point. However, if the data is corrupted and an indirect * block pointed to itself, it would have been detached when * the block was cleared. Check for this instead of OOPSing. */ if (bh2jh(this_bh)) ext4_journal_dirty_metadata(handle, this_bh); else ext4_error(inode->i_sb, __func__, "circular indirect block detected, " "inode=%lu, block=%llu", inode->i_ino, (unsigned long long) this_bh->b_blocknr); } } /** * ext4_free_branches - free an array of branches * @handle: JBD handle for this transaction * @inode: inode we are dealing with * @parent_bh: the buffer_head which contains *@first and *@last * @first: array of block numbers * @last: pointer immediately past the end of array * @depth: depth of the branches to free * * We are freeing all blocks refered from these branches (numbers are * stored as little-endian 32-bit) and updating @inode->i_blocks * appropriately. */ static void ext4_free_branches(handle_t *handle, struct inode *inode, struct buffer_head *parent_bh, __le32 *first, __le32 *last, int depth) { ext4_fsblk_t nr; __le32 *p; if (is_handle_aborted(handle)) return; if (depth--) { struct buffer_head *bh; int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb); p = last; while (--p >= first) { nr = le32_to_cpu(*p); if (!nr) continue; /* A hole */ /* Go read the buffer for the next level down */ bh = sb_bread(inode->i_sb, nr); /* * A read failure? Report error and clear slot * (should be rare). */ if (!bh) { ext4_error(inode->i_sb, "ext4_free_branches", "Read failure, inode=%lu, block=%llu", inode->i_ino, nr); continue; } /* This zaps the entire block. Bottom up. */ BUFFER_TRACE(bh, "free child branches"); ext4_free_branches(handle, inode, bh, (__le32*)bh->b_data, (__le32*)bh->b_data + addr_per_block, depth); /* * We've probably journalled the indirect block several * times during the truncate. But it's no longer * needed and we now drop it from the transaction via * jbd2_journal_revoke(). * * That's easy if it's exclusively part of this * transaction. But if it's part of the committing * transaction then jbd2_journal_forget() will simply * brelse() it. That means that if the underlying * block is reallocated in ext4_get_block(), * unmap_underlying_metadata() will find this block * and will try to get rid of it. damn, damn. * * If this block has already been committed to the * journal, a revoke record will be written. And * revoke records must be emitted *before* clearing * this block's bit in the bitmaps. */ ext4_forget(handle, 1, inode, bh, bh->b_blocknr); /* * Everything below this this pointer has been * released. Now let this top-of-subtree go. * * We want the freeing of this indirect block to be * atomic in the journal with the updating of the * bitmap block which owns it. So make some room in * the journal. * * We zero the parent pointer *after* freeing its * pointee in the bitmaps, so if extend_transaction() * for some reason fails to put the bitmap changes and * the release into the same transaction, recovery * will merely complain about releasing a free block, * rather than leaking blocks. */ if (is_handle_aborted(handle)) return; if (try_to_extend_transaction(handle, inode)) { ext4_mark_inode_dirty(handle, inode); ext4_journal_test_restart(handle, inode); } ext4_free_blocks(handle, inode, nr, 1, 1); if (parent_bh) { /* * The block which we have just freed is * pointed to by an indirect block: journal it */ BUFFER_TRACE(parent_bh, "get_write_access"); if (!ext4_journal_get_write_access(handle, parent_bh)){ *p = 0; BUFFER_TRACE(parent_bh, "call ext4_journal_dirty_metadata"); ext4_journal_dirty_metadata(handle, parent_bh); } } } } else { /* We have reached the bottom of the tree. */ BUFFER_TRACE(parent_bh, "free data blocks"); ext4_free_data(handle, inode, parent_bh, first, last); } } int ext4_can_truncate(struct inode *inode) { if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) return 0; if (S_ISREG(inode->i_mode)) return 1; if (S_ISDIR(inode->i_mode)) return 1; if (S_ISLNK(inode->i_mode)) return !ext4_inode_is_fast_symlink(inode); return 0; } /* * ext4_truncate() * * We block out ext4_get_block() block instantiations across the entire * transaction, and VFS/VM ensures that ext4_truncate() cannot run * simultaneously on behalf of the same inode. * * As we work through the truncate and commmit bits of it to the journal there * is one core, guiding principle: the file's tree must always be consistent on * disk. We must be able to restart the truncate after a crash. * * The file's tree may be transiently inconsistent in memory (although it * probably isn't), but whenever we close off and commit a journal transaction, * the contents of (the filesystem + the journal) must be consistent and * restartable. It's pretty simple, really: bottom up, right to left (although * left-to-right works OK too). * * Note that at recovery time, journal replay occurs *before* the restart of * truncate against the orphan inode list. * * The committed inode has the new, desired i_size (which is the same as * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see * that this inode's truncate did not complete and it will again call * ext4_truncate() to have another go. So there will be instantiated blocks * to the right of the truncation point in a crashed ext4 filesystem. But * that's fine - as long as they are linked from the inode, the post-crash * ext4_truncate() run will find them and release them. */ void ext4_truncate(struct inode *inode) { handle_t *handle; struct ext4_inode_info *ei = EXT4_I(inode); __le32 *i_data = ei->i_data; int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb); struct address_space *mapping = inode->i_mapping; ext4_lblk_t offsets[4]; Indirect chain[4]; Indirect *partial; __le32 nr = 0; int n; ext4_lblk_t last_block; unsigned blocksize = inode->i_sb->s_blocksize; if (!ext4_can_truncate(inode)) return; if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) { ext4_ext_truncate(inode); return; } handle = start_transaction(inode); if (IS_ERR(handle)) return; /* AKPM: return what? */ last_block = (inode->i_size + blocksize-1) >> EXT4_BLOCK_SIZE_BITS(inode->i_sb); if (inode->i_size & (blocksize - 1)) if (ext4_block_truncate_page(handle, mapping, inode->i_size)) goto out_stop; n = ext4_block_to_path(inode, last_block, offsets, NULL); if (n == 0) goto out_stop; /* error */ /* * OK. This truncate is going to happen. We add the inode to the * orphan list, so that if this truncate spans multiple transactions, * and we crash, we will resume the truncate when the filesystem * recovers. It also marks the inode dirty, to catch the new size. * * Implication: the file must always be in a sane, consistent * truncatable state while each transaction commits. */ if (ext4_orphan_add(handle, inode)) goto out_stop; /* * From here we block out all ext4_get_block() callers who want to * modify the block allocation tree. */ down_write(&ei->i_data_sem); /* * The orphan list entry will now protect us from any crash which * occurs before the truncate completes, so it is now safe to propagate * the new, shorter inode size (held for now in i_size) into the * on-disk inode. We do this via i_disksize, which is the value which * ext4 *really* writes onto the disk inode. */ ei->i_disksize = inode->i_size; if (n == 1) { /* direct blocks */ ext4_free_data(handle, inode, NULL, i_data+offsets[0], i_data + EXT4_NDIR_BLOCKS); goto do_indirects; } partial = ext4_find_shared(inode, n, offsets, chain, &nr); /* Kill the top of shared branch (not detached) */ if (nr) { if (partial == chain) { /* Shared branch grows from the inode */ ext4_free_branches(handle, inode, NULL, &nr, &nr+1, (chain+n-1) - partial); *partial->p = 0; /* * We mark the inode dirty prior to restart, * and prior to stop. No need for it here. */ } else { /* Shared branch grows from an indirect block */ BUFFER_TRACE(partial->bh, "get_write_access"); ext4_free_branches(handle, inode, partial->bh, partial->p, partial->p+1, (chain+n-1) - partial); } } /* Clear the ends of indirect blocks on the shared branch */ while (partial > chain) { ext4_free_branches(handle, inode, partial->bh, partial->p + 1, (__le32*)partial->bh->b_data+addr_per_block, (chain+n-1) - partial); BUFFER_TRACE(partial->bh, "call brelse"); brelse (partial->bh); partial--; } do_indirects: /* Kill the remaining (whole) subtrees */ switch (offsets[0]) { default: nr = i_data[EXT4_IND_BLOCK]; if (nr) { ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1); i_data[EXT4_IND_BLOCK] = 0; } case EXT4_IND_BLOCK: nr = i_data[EXT4_DIND_BLOCK]; if (nr) { ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2); i_data[EXT4_DIND_BLOCK] = 0; } case EXT4_DIND_BLOCK: nr = i_data[EXT4_TIND_BLOCK]; if (nr) { ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3); i_data[EXT4_TIND_BLOCK] = 0; } case EXT4_TIND_BLOCK: ; } ext4_discard_reservation(inode); up_write(&ei->i_data_sem); inode->i_mtime = inode->i_ctime = ext4_current_time(inode); ext4_mark_inode_dirty(handle, inode); /* * In a multi-transaction truncate, we only make the final transaction * synchronous */ if (IS_SYNC(inode)) handle->h_sync = 1; out_stop: /* * If this was a simple ftruncate(), and the file will remain alive * then we need to clear up the orphan record which we created above. * However, if this was a real unlink then we were called by * ext4_delete_inode(), and we allow that function to clean up the * orphan info for us. */ if (inode->i_nlink) ext4_orphan_del(handle, inode); ext4_journal_stop(handle); } static ext4_fsblk_t ext4_get_inode_block(struct super_block *sb, unsigned long ino, struct ext4_iloc *iloc) { ext4_group_t block_group; unsigned long offset; ext4_fsblk_t block; struct ext4_group_desc *gdp; if (!ext4_valid_inum(sb, ino)) { /* * This error is already checked for in namei.c unless we are * looking at an NFS filehandle, in which case no error * report is needed */ return 0; } block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb); gdp = ext4_get_group_desc(sb, block_group, NULL); if (!gdp) return 0; /* * Figure out the offset within the block group inode table */ offset = ((ino - 1) % EXT4_INODES_PER_GROUP(sb)) * EXT4_INODE_SIZE(sb); block = ext4_inode_table(sb, gdp) + (offset >> EXT4_BLOCK_SIZE_BITS(sb)); iloc->block_group = block_group; iloc->offset = offset & (EXT4_BLOCK_SIZE(sb) - 1); return block; } /* * ext4_get_inode_loc returns with an extra refcount against the inode's * underlying buffer_head on success. If 'in_mem' is true, we have all * data in memory that is needed to recreate the on-disk version of this * inode. */ static int __ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc, int in_mem) { ext4_fsblk_t block; struct buffer_head *bh; block = ext4_get_inode_block(inode->i_sb, inode->i_ino, iloc); if (!block) return -EIO; bh = sb_getblk(inode->i_sb, block); if (!bh) { ext4_error (inode->i_sb, "ext4_get_inode_loc", "unable to read inode block - " "inode=%lu, block=%llu", inode->i_ino, block); return -EIO; } if (!buffer_uptodate(bh)) { lock_buffer(bh); /* * If the buffer has the write error flag, we have failed * to write out another inode in the same block. In this * case, we don't have to read the block because we may * read the old inode data successfully. */ if (buffer_write_io_error(bh) && !buffer_uptodate(bh)) set_buffer_uptodate(bh); if (buffer_uptodate(bh)) { /* someone brought it uptodate while we waited */ unlock_buffer(bh); goto has_buffer; } /* * If we have all information of the inode in memory and this * is the only valid inode in the block, we need not read the * block. */ if (in_mem) { struct buffer_head *bitmap_bh; struct ext4_group_desc *desc; int inodes_per_buffer; int inode_offset, i; ext4_group_t block_group; int start; block_group = (inode->i_ino - 1) / EXT4_INODES_PER_GROUP(inode->i_sb); inodes_per_buffer = bh->b_size / EXT4_INODE_SIZE(inode->i_sb); inode_offset = ((inode->i_ino - 1) % EXT4_INODES_PER_GROUP(inode->i_sb)); start = inode_offset & ~(inodes_per_buffer - 1); /* Is the inode bitmap in cache? */ desc = ext4_get_group_desc(inode->i_sb, block_group, NULL); if (!desc) goto make_io; bitmap_bh = sb_getblk(inode->i_sb, ext4_inode_bitmap(inode->i_sb, desc)); if (!bitmap_bh) goto make_io; /* * If the inode bitmap isn't in cache then the * optimisation may end up performing two reads instead * of one, so skip it. */ if (!buffer_uptodate(bitmap_bh)) { brelse(bitmap_bh); goto make_io; } for (i = start; i < start + inodes_per_buffer; i++) { if (i == inode_offset) continue; if (ext4_test_bit(i, bitmap_bh->b_data)) break; } brelse(bitmap_bh); if (i == start + inodes_per_buffer) { /* all other inodes are free, so skip I/O */ memset(bh->b_data, 0, bh->b_size); set_buffer_uptodate(bh); unlock_buffer(bh); goto has_buffer; } } make_io: /* * There are other valid inodes in the buffer, this inode * has in-inode xattrs, or we don't have this inode in memory. * Read the block from disk. */ get_bh(bh); bh->b_end_io = end_buffer_read_sync; submit_bh(READ_META, bh); wait_on_buffer(bh); if (!buffer_uptodate(bh)) { ext4_error(inode->i_sb, "ext4_get_inode_loc", "unable to read inode block - " "inode=%lu, block=%llu", inode->i_ino, block); brelse(bh); return -EIO; } } has_buffer: iloc->bh = bh; return 0; } int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc) { /* We have all inode data except xattrs in memory here. */ return __ext4_get_inode_loc(inode, iloc, !(EXT4_I(inode)->i_state & EXT4_STATE_XATTR)); } void ext4_set_inode_flags(struct inode *inode) { unsigned int flags = EXT4_I(inode)->i_flags; inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC); if (flags & EXT4_SYNC_FL) inode->i_flags |= S_SYNC; if (flags & EXT4_APPEND_FL) inode->i_flags |= S_APPEND; if (flags & EXT4_IMMUTABLE_FL) inode->i_flags |= S_IMMUTABLE; if (flags & EXT4_NOATIME_FL) inode->i_flags |= S_NOATIME; if (flags & EXT4_DIRSYNC_FL) inode->i_flags |= S_DIRSYNC; } /* Propagate flags from i_flags to EXT4_I(inode)->i_flags */ void ext4_get_inode_flags(struct ext4_inode_info *ei) { unsigned int flags = ei->vfs_inode.i_flags; ei->i_flags &= ~(EXT4_SYNC_FL|EXT4_APPEND_FL| EXT4_IMMUTABLE_FL|EXT4_NOATIME_FL|EXT4_DIRSYNC_FL); if (flags & S_SYNC) ei->i_flags |= EXT4_SYNC_FL; if (flags & S_APPEND) ei->i_flags |= EXT4_APPEND_FL; if (flags & S_IMMUTABLE) ei->i_flags |= EXT4_IMMUTABLE_FL; if (flags & S_NOATIME) ei->i_flags |= EXT4_NOATIME_FL; if (flags & S_DIRSYNC) ei->i_flags |= EXT4_DIRSYNC_FL; } static blkcnt_t ext4_inode_blocks(struct ext4_inode *raw_inode, struct ext4_inode_info *ei) { blkcnt_t i_blocks ; struct inode *inode = &(ei->vfs_inode); struct super_block *sb = inode->i_sb; if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) { /* we are using combined 48 bit field */ i_blocks = ((u64)le16_to_cpu(raw_inode->i_blocks_high)) << 32 | le32_to_cpu(raw_inode->i_blocks_lo); if (ei->i_flags & EXT4_HUGE_FILE_FL) { /* i_blocks represent file system block size */ return i_blocks << (inode->i_blkbits - 9); } else { return i_blocks; } } else { return le32_to_cpu(raw_inode->i_blocks_lo); } } struct inode *ext4_iget(struct super_block *sb, unsigned long ino) { struct ext4_iloc iloc; struct ext4_inode *raw_inode; struct ext4_inode_info *ei; struct buffer_head *bh; struct inode *inode; long ret; int block; inode = iget_locked(sb, ino); if (!inode) return ERR_PTR(-ENOMEM); if (!(inode->i_state & I_NEW)) return inode; ei = EXT4_I(inode); #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL ei->i_acl = EXT4_ACL_NOT_CACHED; ei->i_default_acl = EXT4_ACL_NOT_CACHED; #endif ei->i_block_alloc_info = NULL; ret = __ext4_get_inode_loc(inode, &iloc, 0); if (ret < 0) goto bad_inode; bh = iloc.bh; raw_inode = ext4_raw_inode(&iloc); inode->i_mode = le16_to_cpu(raw_inode->i_mode); inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low); inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low); if(!(test_opt (inode->i_sb, NO_UID32))) { inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16; inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16; } inode->i_nlink = le16_to_cpu(raw_inode->i_links_count); ei->i_state = 0; ei->i_dir_start_lookup = 0; ei->i_dtime = le32_to_cpu(raw_inode->i_dtime); /* We now have enough fields to check if the inode was active or not. * This is needed because nfsd might try to access dead inodes * the test is that same one that e2fsck uses * NeilBrown 1999oct15 */ if (inode->i_nlink == 0) { if (inode->i_mode == 0 || !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) { /* this inode is deleted */ brelse (bh); ret = -ESTALE; goto bad_inode; } /* The only unlinked inodes we let through here have * valid i_mode and are being read by the orphan * recovery code: that's fine, we're about to complete * the process of deleting those. */ } ei->i_flags = le32_to_cpu(raw_inode->i_flags); inode->i_blocks = ext4_inode_blocks(raw_inode, ei); ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl_lo); if (EXT4_SB(inode->i_sb)->s_es->s_creator_os != cpu_to_le32(EXT4_OS_HURD)) { ei->i_file_acl |= ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32; } inode->i_size = ext4_isize(raw_inode); ei->i_disksize = inode->i_size; inode->i_generation = le32_to_cpu(raw_inode->i_generation); ei->i_block_group = iloc.block_group; /* * NOTE! The in-memory inode i_data array is in little-endian order * even on big-endian machines: we do NOT byteswap the block numbers! */ for (block = 0; block < EXT4_N_BLOCKS; block++) ei->i_data[block] = raw_inode->i_block[block]; INIT_LIST_HEAD(&ei->i_orphan); if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) { ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize); if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize > EXT4_INODE_SIZE(inode->i_sb)) { brelse (bh); ret = -EIO; goto bad_inode; } if (ei->i_extra_isize == 0) { /* The extra space is currently unused. Use it. */ ei->i_extra_isize = sizeof(struct ext4_inode) - EXT4_GOOD_OLD_INODE_SIZE; } else { __le32 *magic = (void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize; if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC)) ei->i_state |= EXT4_STATE_XATTR; } } else ei->i_extra_isize = 0; EXT4_INODE_GET_XTIME(i_ctime, inode, raw_inode); EXT4_INODE_GET_XTIME(i_mtime, inode, raw_inode); EXT4_INODE_GET_XTIME(i_atime, inode, raw_inode); EXT4_EINODE_GET_XTIME(i_crtime, ei, raw_inode); inode->i_version = le32_to_cpu(raw_inode->i_disk_version); if (EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) { if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi)) inode->i_version |= (__u64)(le32_to_cpu(raw_inode->i_version_hi)) << 32; } if (S_ISREG(inode->i_mode)) { inode->i_op = &ext4_file_inode_operations; inode->i_fop = &ext4_file_operations; ext4_set_aops(inode); } else if (S_ISDIR(inode->i_mode)) { inode->i_op = &ext4_dir_inode_operations; inode->i_fop = &ext4_dir_operations; } else if (S_ISLNK(inode->i_mode)) { if (ext4_inode_is_fast_symlink(inode)) inode->i_op = &ext4_fast_symlink_inode_operations; else { inode->i_op = &ext4_symlink_inode_operations; ext4_set_aops(inode); } } else { inode->i_op = &ext4_special_inode_operations; if (raw_inode->i_block[0]) init_special_inode(inode, inode->i_mode, old_decode_dev(le32_to_cpu(raw_inode->i_block[0]))); else init_special_inode(inode, inode->i_mode, new_decode_dev(le32_to_cpu(raw_inode->i_block[1]))); } brelse (iloc.bh); ext4_set_inode_flags(inode); unlock_new_inode(inode); return inode; bad_inode: iget_failed(inode); return ERR_PTR(ret); } static int ext4_inode_blocks_set(handle_t *handle, struct ext4_inode *raw_inode, struct ext4_inode_info *ei) { struct inode *inode = &(ei->vfs_inode); u64 i_blocks = inode->i_blocks; struct super_block *sb = inode->i_sb; int err = 0; if (i_blocks <= ~0U) { /* * i_blocks can be represnted in a 32 bit variable * as multiple of 512 bytes */ raw_inode->i_blocks_lo = cpu_to_le32(i_blocks); raw_inode->i_blocks_high = 0; ei->i_flags &= ~EXT4_HUGE_FILE_FL; } else if (i_blocks <= 0xffffffffffffULL) { /* * i_blocks can be represented in a 48 bit variable * as multiple of 512 bytes */ err = ext4_update_rocompat_feature(handle, sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE); if (err) goto err_out; /* i_block is stored in the split 48 bit fields */ raw_inode->i_blocks_lo = cpu_to_le32(i_blocks); raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32); ei->i_flags &= ~EXT4_HUGE_FILE_FL; } else { /* * i_blocks should be represented in a 48 bit variable * as multiple of file system block size */ err = ext4_update_rocompat_feature(handle, sb, EXT4_FEATURE_RO_COMPAT_HUGE_FILE); if (err) goto err_out; ei->i_flags |= EXT4_HUGE_FILE_FL; /* i_block is stored in file system block size */ i_blocks = i_blocks >> (inode->i_blkbits - 9); raw_inode->i_blocks_lo = cpu_to_le32(i_blocks); raw_inode->i_blocks_high = cpu_to_le16(i_blocks >> 32); } err_out: return err; } /* * Post the struct inode info into an on-disk inode location in the * buffer-cache. This gobbles the caller's reference to the * buffer_head in the inode location struct. * * The caller must have write access to iloc->bh. */ static int ext4_do_update_inode(handle_t *handle, struct inode *inode, struct ext4_iloc *iloc) { struct ext4_inode *raw_inode = ext4_raw_inode(iloc); struct ext4_inode_info *ei = EXT4_I(inode); struct buffer_head *bh = iloc->bh; int err = 0, rc, block; /* For fields not not tracking in the in-memory inode, * initialise them to zero for new inodes. */ if (ei->i_state & EXT4_STATE_NEW) memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); ext4_get_inode_flags(ei); raw_inode->i_mode = cpu_to_le16(inode->i_mode); if(!(test_opt(inode->i_sb, NO_UID32))) { raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid)); raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid)); /* * Fix up interoperability with old kernels. Otherwise, old inodes get * re-used with the upper 16 bits of the uid/gid intact */ if(!ei->i_dtime) { raw_inode->i_uid_high = cpu_to_le16(high_16_bits(inode->i_uid)); raw_inode->i_gid_high = cpu_to_le16(high_16_bits(inode->i_gid)); } else { raw_inode->i_uid_high = 0; raw_inode->i_gid_high = 0; } } else { raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(inode->i_uid)); raw_inode->i_gid_low = cpu_to_le16(fs_high2lowgid(inode->i_gid)); raw_inode->i_uid_high = 0; raw_inode->i_gid_high = 0; } raw_inode->i_links_count = cpu_to_le16(inode->i_nlink); EXT4_INODE_SET_XTIME(i_ctime, inode, raw_inode); EXT4_INODE_SET_XTIME(i_mtime, inode, raw_inode); EXT4_INODE_SET_XTIME(i_atime, inode, raw_inode); EXT4_EINODE_SET_XTIME(i_crtime, ei, raw_inode); if (ext4_inode_blocks_set(handle, raw_inode, ei)) goto out_brelse; raw_inode->i_dtime = cpu_to_le32(ei->i_dtime); /* clear the migrate flag in the raw_inode */ raw_inode->i_flags = cpu_to_le32(ei->i_flags & ~EXT4_EXT_MIGRATE); if (EXT4_SB(inode->i_sb)->s_es->s_creator_os != cpu_to_le32(EXT4_OS_HURD)) raw_inode->i_file_acl_high = cpu_to_le16(ei->i_file_acl >> 32); raw_inode->i_file_acl_lo = cpu_to_le32(ei->i_file_acl); ext4_isize_set(raw_inode, ei->i_disksize); if (ei->i_disksize > 0x7fffffffULL) { struct super_block *sb = inode->i_sb; if (!EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_LARGE_FILE) || EXT4_SB(sb)->s_es->s_rev_level == cpu_to_le32(EXT4_GOOD_OLD_REV)) { /* If this is the first large file * created, add a flag to the superblock. */ err = ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh); if (err) goto out_brelse; ext4_update_dynamic_rev(sb); EXT4_SET_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_LARGE_FILE); sb->s_dirt = 1; handle->h_sync = 1; err = ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh); } } raw_inode->i_generation = cpu_to_le32(inode->i_generation); if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) { if (old_valid_dev(inode->i_rdev)) { raw_inode->i_block[0] = cpu_to_le32(old_encode_dev(inode->i_rdev)); raw_inode->i_block[1] = 0; } else { raw_inode->i_block[0] = 0; raw_inode->i_block[1] = cpu_to_le32(new_encode_dev(inode->i_rdev)); raw_inode->i_block[2] = 0; } } else for (block = 0; block < EXT4_N_BLOCKS; block++) raw_inode->i_block[block] = ei->i_data[block]; raw_inode->i_disk_version = cpu_to_le32(inode->i_version); if (ei->i_extra_isize) { if (EXT4_FITS_IN_INODE(raw_inode, ei, i_version_hi)) raw_inode->i_version_hi = cpu_to_le32(inode->i_version >> 32); raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize); } BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata"); rc = ext4_journal_dirty_metadata(handle, bh); if (!err) err = rc; ei->i_state &= ~EXT4_STATE_NEW; out_brelse: brelse (bh); ext4_std_error(inode->i_sb, err); return err; } /* * ext4_write_inode() * * We are called from a few places: * * - Within generic_file_write() for O_SYNC files. * Here, there will be no transaction running. We wait for any running * trasnaction to commit. * * - Within sys_sync(), kupdate and such. * We wait on commit, if tol to. * * - Within prune_icache() (PF_MEMALLOC == true) * Here we simply return. We can't afford to block kswapd on the * journal commit. * * In all cases it is actually safe for us to return without doing anything, * because the inode has been copied into a raw inode buffer in * ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for * knfsd. * * Note that we are absolutely dependent upon all inode dirtiers doing the * right thing: they *must* call mark_inode_dirty() after dirtying info in * which we are interested. * * It would be a bug for them to not do this. The code: * * mark_inode_dirty(inode) * stuff(); * inode->i_size = expr; * * is in error because a kswapd-driven write_inode() could occur while * `stuff()' is running, and the new i_size will be lost. Plus the inode * will no longer be on the superblock's dirty inode list. */ int ext4_write_inode(struct inode *inode, int wait) { if (current->flags & PF_MEMALLOC) return 0; if (ext4_journal_current_handle()) { jbd_debug(1, "called recursively, non-PF_MEMALLOC!\n"); dump_stack(); return -EIO; } if (!wait) return 0; return ext4_force_commit(inode->i_sb); } /* * ext4_setattr() * * Called from notify_change. * * We want to trap VFS attempts to truncate the file as soon as * possible. In particular, we want to make sure that when the VFS * shrinks i_size, we put the inode on the orphan list and modify * i_disksize immediately, so that during the subsequent flushing of * dirty pages and freeing of disk blocks, we can guarantee that any * commit will leave the blocks being flushed in an unused state on * disk. (On recovery, the inode will get truncated and the blocks will * be freed, so we have a strong guarantee that no future commit will * leave these blocks visible to the user.) * * Another thing we have to assure is that if we are in ordered mode * and inode is still attached to the committing transaction, we must * we start writeout of all the dirty pages which are being truncated. * This way we are sure that all the data written in the previous * transaction are already on disk (truncate waits for pages under * writeback). * * Called with inode->i_mutex down. */ int ext4_setattr(struct dentry *dentry, struct iattr *attr) { struct inode *inode = dentry->d_inode; int error, rc = 0; const unsigned int ia_valid = attr->ia_valid; error = inode_change_ok(inode, attr); if (error) return error; if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) || (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) { handle_t *handle; /* (user+group)*(old+new) structure, inode write (sb, * inode block, ? - but truncate inode update has it) */ handle = ext4_journal_start(inode, 2*(EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)+ EXT4_QUOTA_DEL_BLOCKS(inode->i_sb))+3); if (IS_ERR(handle)) { error = PTR_ERR(handle); goto err_out; } error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0; if (error) { ext4_journal_stop(handle); return error; } /* Update corresponding info in inode so that everything is in * one transaction */ if (attr->ia_valid & ATTR_UID) inode->i_uid = attr->ia_uid; if (attr->ia_valid & ATTR_GID) inode->i_gid = attr->ia_gid; error = ext4_mark_inode_dirty(handle, inode); ext4_journal_stop(handle); } if (attr->ia_valid & ATTR_SIZE) { if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) { struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); if (attr->ia_size > sbi->s_bitmap_maxbytes) { error = -EFBIG; goto err_out; } } } if (S_ISREG(inode->i_mode) && attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) { handle_t *handle; handle = ext4_journal_start(inode, 3); if (IS_ERR(handle)) { error = PTR_ERR(handle); goto err_out; } error = ext4_orphan_add(handle, inode); EXT4_I(inode)->i_disksize = attr->ia_size; rc = ext4_mark_inode_dirty(handle, inode); if (!error) error = rc; ext4_journal_stop(handle); if (ext4_should_order_data(inode)) { error = ext4_begin_ordered_truncate(inode, attr->ia_size); if (error) { /* Do as much error cleanup as possible */ handle = ext4_journal_start(inode, 3); if (IS_ERR(handle)) { ext4_orphan_del(NULL, inode); goto err_out; } ext4_orphan_del(handle, inode); ext4_journal_stop(handle); goto err_out; } } } rc = inode_setattr(inode, attr); /* If inode_setattr's call to ext4_truncate failed to get a * transaction handle at all, we need to clean up the in-core * orphan list manually. */ if (inode->i_nlink) ext4_orphan_del(NULL, inode); if (!rc && (ia_valid & ATTR_MODE)) rc = ext4_acl_chmod(inode); err_out: ext4_std_error(inode->i_sb, error); if (!error) error = rc; return error; } int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat) { struct inode *inode; unsigned long delalloc_blocks; inode = dentry->d_inode; generic_fillattr(inode, stat); /* * We can't update i_blocks if the block allocation is delayed * otherwise in the case of system crash before the real block * allocation is done, we will have i_blocks inconsistent with * on-disk file blocks. * We always keep i_blocks updated together with real * allocation. But to not confuse with user, stat * will return the blocks that include the delayed allocation * blocks for this file. */ spin_lock(&EXT4_I(inode)->i_block_reservation_lock); delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks; spin_unlock(&EXT4_I(inode)->i_block_reservation_lock); stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9; return 0; } /* * How many blocks doth make a writepage()? * * With N blocks per page, it may be: * N data blocks * 2 indirect block * 2 dindirect * 1 tindirect * N+5 bitmap blocks (from the above) * N+5 group descriptor summary blocks * 1 inode block * 1 superblock. * 2 * EXT4_SINGLEDATA_TRANS_BLOCKS for the quote files * * 3 * (N + 5) + 2 + 2 * EXT4_SINGLEDATA_TRANS_BLOCKS * * With ordered or writeback data it's the same, less the N data blocks. * * If the inode's direct blocks can hold an integral number of pages then a * page cannot straddle two indirect blocks, and we can only touch one indirect * and dindirect block, and the "5" above becomes "3". * * This still overestimates under most circumstances. If we were to pass the * start and end offsets in here as well we could do block_to_path() on each * block and work out the exact number of indirects which are touched. Pah. */ int ext4_writepage_trans_blocks(struct inode *inode) { int bpp = ext4_journal_blocks_per_page(inode); int indirects = (EXT4_NDIR_BLOCKS % bpp) ? 5 : 3; int ret; if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) return ext4_ext_writepage_trans_blocks(inode, bpp); if (ext4_should_journal_data(inode)) ret = 3 * (bpp + indirects) + 2; else ret = 2 * (bpp + indirects) + 2; #ifdef CONFIG_QUOTA /* We know that structure was already allocated during DQUOT_INIT so * we will be updating only the data blocks + inodes */ ret += 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb); #endif return ret; } /* * The caller must have previously called ext4_reserve_inode_write(). * Give this, we know that the caller already has write access to iloc->bh. */ int ext4_mark_iloc_dirty(handle_t *handle, struct inode *inode, struct ext4_iloc *iloc) { int err = 0; if (test_opt(inode->i_sb, I_VERSION)) inode_inc_iversion(inode); /* the do_update_inode consumes one bh->b_count */ get_bh(iloc->bh); /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */ err = ext4_do_update_inode(handle, inode, iloc); put_bh(iloc->bh); return err; } /* * On success, We end up with an outstanding reference count against * iloc->bh. This _must_ be cleaned up later. */ int ext4_reserve_inode_write(handle_t *handle, struct inode *inode, struct ext4_iloc *iloc) { int err = 0; if (handle) { err = ext4_get_inode_loc(inode, iloc); if (!err) { BUFFER_TRACE(iloc->bh, "get_write_access"); err = ext4_journal_get_write_access(handle, iloc->bh); if (err) { brelse(iloc->bh); iloc->bh = NULL; } } } ext4_std_error(inode->i_sb, err); return err; } /* * Expand an inode by new_extra_isize bytes. * Returns 0 on success or negative error number on failure. */ static int ext4_expand_extra_isize(struct inode *inode, unsigned int new_extra_isize, struct ext4_iloc iloc, handle_t *handle) { struct ext4_inode *raw_inode; struct ext4_xattr_ibody_header *header; struct ext4_xattr_entry *entry; if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) return 0; raw_inode = ext4_raw_inode(&iloc); header = IHDR(inode, raw_inode); entry = IFIRST(header); /* No extended attributes present */ if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR) || header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC)) { memset((void *)raw_inode + EXT4_GOOD_OLD_INODE_SIZE, 0, new_extra_isize); EXT4_I(inode)->i_extra_isize = new_extra_isize; return 0; } /* try to expand with EAs present */ return ext4_expand_extra_isize_ea(inode, new_extra_isize, raw_inode, handle); } /* * What we do here is to mark the in-core inode as clean with respect to inode * dirtiness (it may still be data-dirty). * This means that the in-core inode may be reaped by prune_icache * without having to perform any I/O. This is a very good thing, * because *any* task may call prune_icache - even ones which * have a transaction open against a different journal. * * Is this cheating? Not really. Sure, we haven't written the * inode out, but prune_icache isn't a user-visible syncing function. * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync) * we start and wait on commits. * * Is this efficient/effective? Well, we're being nice to the system * by cleaning up our inodes proactively so they can be reaped * without I/O. But we are potentially leaving up to five seconds' * worth of inodes floating about which prune_icache wants us to * write out. One way to fix that would be to get prune_icache() * to do a write_super() to free up some memory. It has the desired * effect. */ int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode) { struct ext4_iloc iloc; struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); static unsigned int mnt_count; int err, ret; might_sleep(); err = ext4_reserve_inode_write(handle, inode, &iloc); if (EXT4_I(inode)->i_extra_isize < sbi->s_want_extra_isize && !(EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND)) { /* * We need extra buffer credits since we may write into EA block * with this same handle. If journal_extend fails, then it will * only result in a minor loss of functionality for that inode. * If this is felt to be critical, then e2fsck should be run to * force a large enough s_min_extra_isize. */ if ((jbd2_journal_extend(handle, EXT4_DATA_TRANS_BLOCKS(inode->i_sb))) == 0) { ret = ext4_expand_extra_isize(inode, sbi->s_want_extra_isize, iloc, handle); if (ret) { EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND; if (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count)) { ext4_warning(inode->i_sb, __func__, "Unable to expand inode %lu. Delete" " some EAs or run e2fsck.", inode->i_ino); mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count); } } } } if (!err) err = ext4_mark_iloc_dirty(handle, inode, &iloc); return err; } /* * ext4_dirty_inode() is called from __mark_inode_dirty() * * We're really interested in the case where a file is being extended. * i_size has been changed by generic_commit_write() and we thus need * to include the updated inode in the current transaction. * * Also, DQUOT_ALLOC_SPACE() will always dirty the inode when blocks * are allocated to the file. * * If the inode is marked synchronous, we don't honour that here - doing * so would cause a commit on atime updates, which we don't bother doing. * We handle synchronous inodes at the highest possible level. */ void ext4_dirty_inode(struct inode *inode) { handle_t *current_handle = ext4_journal_current_handle(); handle_t *handle; handle = ext4_journal_start(inode, 2); if (IS_ERR(handle)) goto out; if (current_handle && current_handle->h_transaction != handle->h_transaction) { /* This task has a transaction open against a different fs */ printk(KERN_EMERG "%s: transactions do not match!\n", __func__); } else { jbd_debug(5, "marking dirty. outer handle=%p\n", current_handle); ext4_mark_inode_dirty(handle, inode); } ext4_journal_stop(handle); out: return; } #if 0 /* * Bind an inode's backing buffer_head into this transaction, to prevent * it from being flushed to disk early. Unlike * ext4_reserve_inode_write, this leaves behind no bh reference and * returns no iloc structure, so the caller needs to repeat the iloc * lookup to mark the inode dirty later. */ static int ext4_pin_inode(handle_t *handle, struct inode *inode) { struct ext4_iloc iloc; int err = 0; if (handle) { err = ext4_get_inode_loc(inode, &iloc); if (!err) { BUFFER_TRACE(iloc.bh, "get_write_access"); err = jbd2_journal_get_write_access(handle, iloc.bh); if (!err) err = ext4_journal_dirty_metadata(handle, iloc.bh); brelse(iloc.bh); } } ext4_std_error(inode->i_sb, err); return err; } #endif int ext4_change_inode_journal_flag(struct inode *inode, int val) { journal_t *journal; handle_t *handle; int err; /* * We have to be very careful here: changing a data block's * journaling status dynamically is dangerous. If we write a * data block to the journal, change the status and then delete * that block, we risk forgetting to revoke the old log record * from the journal and so a subsequent replay can corrupt data. * So, first we make sure that the journal is empty and that * nobody is changing anything. */ journal = EXT4_JOURNAL(inode); if (is_journal_aborted(journal)) return -EROFS; jbd2_journal_lock_updates(journal); jbd2_journal_flush(journal); /* * OK, there are no updates running now, and all cached data is * synced to disk. We are now in a completely consistent state * which doesn't have anything in the journal, and we know that * no filesystem updates are running, so it is safe to modify * the inode's in-core data-journaling state flag now. */ if (val) EXT4_I(inode)->i_flags |= EXT4_JOURNAL_DATA_FL; else EXT4_I(inode)->i_flags &= ~EXT4_JOURNAL_DATA_FL; ext4_set_aops(inode); jbd2_journal_unlock_updates(journal); /* Finally we can mark the inode as dirty. */ handle = ext4_journal_start(inode, 1); if (IS_ERR(handle)) return PTR_ERR(handle); err = ext4_mark_inode_dirty(handle, inode); handle->h_sync = 1; ext4_journal_stop(handle); ext4_std_error(inode->i_sb, err); return err; } static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh) { return !buffer_mapped(bh); } int ext4_page_mkwrite(struct vm_area_struct *vma, struct page *page) { loff_t size; unsigned long len; int ret = -EINVAL; struct file *file = vma->vm_file; struct inode *inode = file->f_path.dentry->d_inode; struct address_space *mapping = inode->i_mapping; /* * Get i_alloc_sem to stop truncates messing with the inode. We cannot * get i_mutex because we are already holding mmap_sem. */ down_read(&inode->i_alloc_sem); size = i_size_read(inode); if (page->mapping != mapping || size <= page_offset(page) || !PageUptodate(page)) { /* page got truncated from under us? */ goto out_unlock; } ret = 0; if (PageMappedToDisk(page)) goto out_unlock; if (page->index == size >> PAGE_CACHE_SHIFT) len = size & ~PAGE_CACHE_MASK; else len = PAGE_CACHE_SIZE; if (page_has_buffers(page)) { /* return if we have all the buffers mapped */ if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL, ext4_bh_unmapped)) goto out_unlock; } /* * OK, we need to fill the hole... Do write_begin write_end * to do block allocation/reservation.We are not holding * inode.i__mutex here. That allow * parallel write_begin, * write_end call. lock_page prevent this from happening * on the same page though */ ret = mapping->a_ops->write_begin(file, mapping, page_offset(page), len, AOP_FLAG_UNINTERRUPTIBLE, &page, NULL); if (ret < 0) goto out_unlock; ret = mapping->a_ops->write_end(file, mapping, page_offset(page), len, len, page, NULL); if (ret < 0) goto out_unlock; ret = 0; out_unlock: up_read(&inode->i_alloc_sem); return ret; }