/* * mdt.c - meta data file for NILFS * * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA * * Written by Ryusuke Konishi <ryusuke@osrg.net> */ #include <linux/buffer_head.h> #include <linux/mpage.h> #include <linux/mm.h> #include <linux/writeback.h> #include <linux/backing-dev.h> #include <linux/swap.h> #include <linux/slab.h> #include "nilfs.h" #include "btnode.h" #include "segment.h" #include "page.h" #include "mdt.h" #define NILFS_MDT_MAX_RA_BLOCKS (16 - 1) static int nilfs_mdt_insert_new_block(struct inode *inode, unsigned long block, struct buffer_head *bh, void (*init_block)(struct inode *, struct buffer_head *, void *)) { struct nilfs_inode_info *ii = NILFS_I(inode); void *kaddr; int ret; /* Caller exclude read accesses using page lock */ /* set_buffer_new(bh); */ bh->b_blocknr = 0; ret = nilfs_bmap_insert(ii->i_bmap, block, (unsigned long)bh); if (unlikely(ret)) return ret; set_buffer_mapped(bh); kaddr = kmap_atomic(bh->b_page); memset(kaddr + bh_offset(bh), 0, 1 << inode->i_blkbits); if (init_block) init_block(inode, bh, kaddr); flush_dcache_page(bh->b_page); kunmap_atomic(kaddr); set_buffer_uptodate(bh); mark_buffer_dirty(bh); nilfs_mdt_mark_dirty(inode); return 0; } static int nilfs_mdt_create_block(struct inode *inode, unsigned long block, struct buffer_head **out_bh, void (*init_block)(struct inode *, struct buffer_head *, void *)) { struct super_block *sb = inode->i_sb; struct nilfs_transaction_info ti; struct buffer_head *bh; int err; nilfs_transaction_begin(sb, &ti, 0); err = -ENOMEM; bh = nilfs_grab_buffer(inode, inode->i_mapping, block, 0); if (unlikely(!bh)) goto failed_unlock; err = -EEXIST; if (buffer_uptodate(bh)) goto failed_bh; wait_on_buffer(bh); if (buffer_uptodate(bh)) goto failed_bh; bh->b_bdev = sb->s_bdev; err = nilfs_mdt_insert_new_block(inode, block, bh, init_block); if (likely(!err)) { get_bh(bh); *out_bh = bh; } failed_bh: unlock_page(bh->b_page); page_cache_release(bh->b_page); brelse(bh); failed_unlock: if (likely(!err)) err = nilfs_transaction_commit(sb); else nilfs_transaction_abort(sb); return err; } static int nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff, int mode, struct buffer_head **out_bh) { struct buffer_head *bh; __u64 blknum = 0; int ret = -ENOMEM; bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0); if (unlikely(!bh)) goto failed; ret = -EEXIST; /* internal code */ if (buffer_uptodate(bh)) goto out; if (mode == READA) { if (!trylock_buffer(bh)) { ret = -EBUSY; goto failed_bh; } } else /* mode == READ */ lock_buffer(bh); if (buffer_uptodate(bh)) { unlock_buffer(bh); goto out; } ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum); if (unlikely(ret)) { unlock_buffer(bh); goto failed_bh; } map_bh(bh, inode->i_sb, (sector_t)blknum); bh->b_end_io = end_buffer_read_sync; get_bh(bh); submit_bh(mode, bh); ret = 0; out: get_bh(bh); *out_bh = bh; failed_bh: unlock_page(bh->b_page); page_cache_release(bh->b_page); brelse(bh); failed: return ret; } static int nilfs_mdt_read_block(struct inode *inode, unsigned long block, int readahead, struct buffer_head **out_bh) { struct buffer_head *first_bh, *bh; unsigned long blkoff; int i, nr_ra_blocks = NILFS_MDT_MAX_RA_BLOCKS; int err; err = nilfs_mdt_submit_block(inode, block, READ, &first_bh); if (err == -EEXIST) /* internal code */ goto out; if (unlikely(err)) goto failed; if (readahead) { blkoff = block + 1; for (i = 0; i < nr_ra_blocks; i++, blkoff++) { err = nilfs_mdt_submit_block(inode, blkoff, READA, &bh); if (likely(!err || err == -EEXIST)) brelse(bh); else if (err != -EBUSY) break; /* abort readahead if bmap lookup failed */ if (!buffer_locked(first_bh)) goto out_no_wait; } } wait_on_buffer(first_bh); out_no_wait: err = -EIO; if (!buffer_uptodate(first_bh)) goto failed_bh; out: *out_bh = first_bh; return 0; failed_bh: brelse(first_bh); failed: return err; } /** * nilfs_mdt_get_block - read or create a buffer on meta data file. * @inode: inode of the meta data file * @blkoff: block offset * @create: create flag * @init_block: initializer used for newly allocated block * @out_bh: output of a pointer to the buffer_head * * nilfs_mdt_get_block() looks up the specified buffer and tries to create * a new buffer if @create is not zero. On success, the returned buffer is * assured to be either existing or formatted using a buffer lock on success. * @out_bh is substituted only when zero is returned. * * Return Value: On success, it returns 0. On error, the following negative * error code is returned. * * %-ENOMEM - Insufficient memory available. * * %-EIO - I/O error * * %-ENOENT - the specified block does not exist (hole block) * * %-EROFS - Read only filesystem (for create mode) */ int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create, void (*init_block)(struct inode *, struct buffer_head *, void *), struct buffer_head **out_bh) { int ret; /* Should be rewritten with merging nilfs_mdt_read_block() */ retry: ret = nilfs_mdt_read_block(inode, blkoff, !create, out_bh); if (!create || ret != -ENOENT) return ret; ret = nilfs_mdt_create_block(inode, blkoff, out_bh, init_block); if (unlikely(ret == -EEXIST)) { /* create = 0; */ /* limit read-create loop retries */ goto retry; } return ret; } /** * nilfs_mdt_find_block - find and get a buffer on meta data file. * @inode: inode of the meta data file * @start: start block offset (inclusive) * @end: end block offset (inclusive) * @blkoff: block offset * @out_bh: place to store a pointer to buffer_head struct * * nilfs_mdt_find_block() looks up an existing block in range of * [@start, @end] and stores pointer to a buffer head of the block to * @out_bh, and block offset to @blkoff, respectively. @out_bh and * @blkoff are substituted only when zero is returned. * * Return Value: On success, it returns 0. On error, the following negative * error code is returned. * * %-ENOMEM - Insufficient memory available. * * %-EIO - I/O error * * %-ENOENT - no block was found in the range */ int nilfs_mdt_find_block(struct inode *inode, unsigned long start, unsigned long end, unsigned long *blkoff, struct buffer_head **out_bh) { __u64 next; int ret; if (unlikely(start > end)) return -ENOENT; ret = nilfs_mdt_read_block(inode, start, true, out_bh); if (!ret) { *blkoff = start; goto out; } if (unlikely(ret != -ENOENT || start == ULONG_MAX)) goto out; ret = nilfs_bmap_seek_key(NILFS_I(inode)->i_bmap, start + 1, &next); if (!ret) { if (next <= end) { ret = nilfs_mdt_read_block(inode, next, true, out_bh); if (!ret) *blkoff = next; } else { ret = -ENOENT; } } out: return ret; } /** * nilfs_mdt_delete_block - make a hole on the meta data file. * @inode: inode of the meta data file * @block: block offset * * Return Value: On success, zero is returned. * On error, one of the following negative error code is returned. * * %-ENOMEM - Insufficient memory available. * * %-EIO - I/O error */ int nilfs_mdt_delete_block(struct inode *inode, unsigned long block) { struct nilfs_inode_info *ii = NILFS_I(inode); int err; err = nilfs_bmap_delete(ii->i_bmap, block); if (!err || err == -ENOENT) { nilfs_mdt_mark_dirty(inode); nilfs_mdt_forget_block(inode, block); } return err; } /** * nilfs_mdt_forget_block - discard dirty state and try to remove the page * @inode: inode of the meta data file * @block: block offset * * nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and * tries to release the page including the buffer from a page cache. * * Return Value: On success, 0 is returned. On error, one of the following * negative error code is returned. * * %-EBUSY - page has an active buffer. * * %-ENOENT - page cache has no page addressed by the offset. */ int nilfs_mdt_forget_block(struct inode *inode, unsigned long block) { pgoff_t index = (pgoff_t)block >> (PAGE_CACHE_SHIFT - inode->i_blkbits); struct page *page; unsigned long first_block; int ret = 0; int still_dirty; page = find_lock_page(inode->i_mapping, index); if (!page) return -ENOENT; wait_on_page_writeback(page); first_block = (unsigned long)index << (PAGE_CACHE_SHIFT - inode->i_blkbits); if (page_has_buffers(page)) { struct buffer_head *bh; bh = nilfs_page_get_nth_block(page, block - first_block); nilfs_forget_buffer(bh); } still_dirty = PageDirty(page); unlock_page(page); page_cache_release(page); if (still_dirty || invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0) ret = -EBUSY; return ret; } /** * nilfs_mdt_mark_block_dirty - mark a block on the meta data file dirty. * @inode: inode of the meta data file * @block: block offset * * Return Value: On success, it returns 0. On error, the following negative * error code is returned. * * %-ENOMEM - Insufficient memory available. * * %-EIO - I/O error * * %-ENOENT - the specified block does not exist (hole block) */ int nilfs_mdt_mark_block_dirty(struct inode *inode, unsigned long block) { struct buffer_head *bh; int err; err = nilfs_mdt_read_block(inode, block, 0, &bh); if (unlikely(err)) return err; mark_buffer_dirty(bh); nilfs_mdt_mark_dirty(inode); brelse(bh); return 0; } int nilfs_mdt_fetch_dirty(struct inode *inode) { struct nilfs_inode_info *ii = NILFS_I(inode); if (nilfs_bmap_test_and_clear_dirty(ii->i_bmap)) { set_bit(NILFS_I_DIRTY, &ii->i_state); return 1; } return test_bit(NILFS_I_DIRTY, &ii->i_state); } static int nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc) { struct inode *inode = page->mapping->host; struct super_block *sb; int err = 0; if (inode && (inode->i_sb->s_flags & MS_RDONLY)) { /* * It means that filesystem was remounted in read-only * mode because of error or metadata corruption. But we * have dirty pages that try to be flushed in background. * So, here we simply discard this dirty page. */ nilfs_clear_dirty_page(page, false); unlock_page(page); return -EROFS; } redirty_page_for_writepage(wbc, page); unlock_page(page); if (!inode) return 0; sb = inode->i_sb; if (wbc->sync_mode == WB_SYNC_ALL) err = nilfs_construct_segment(sb); else if (wbc->for_reclaim) nilfs_flush_segment(sb, inode->i_ino); return err; } static const struct address_space_operations def_mdt_aops = { .writepage = nilfs_mdt_write_page, }; static const struct inode_operations def_mdt_iops; static const struct file_operations def_mdt_fops; int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz) { struct nilfs_mdt_info *mi; mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS); if (!mi) return -ENOMEM; init_rwsem(&mi->mi_sem); inode->i_private = mi; inode->i_mode = S_IFREG; mapping_set_gfp_mask(inode->i_mapping, gfp_mask); inode->i_op = &def_mdt_iops; inode->i_fop = &def_mdt_fops; inode->i_mapping->a_ops = &def_mdt_aops; return 0; } void nilfs_mdt_set_entry_size(struct inode *inode, unsigned entry_size, unsigned header_size) { struct nilfs_mdt_info *mi = NILFS_MDT(inode); mi->mi_entry_size = entry_size; mi->mi_entries_per_block = (1 << inode->i_blkbits) / entry_size; mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size); } /** * nilfs_mdt_setup_shadow_map - setup shadow map and bind it to metadata file * @inode: inode of the metadata file * @shadow: shadow mapping */ int nilfs_mdt_setup_shadow_map(struct inode *inode, struct nilfs_shadow_map *shadow) { struct nilfs_mdt_info *mi = NILFS_MDT(inode); INIT_LIST_HEAD(&shadow->frozen_buffers); address_space_init_once(&shadow->frozen_data); nilfs_mapping_init(&shadow->frozen_data, inode); address_space_init_once(&shadow->frozen_btnodes); nilfs_mapping_init(&shadow->frozen_btnodes, inode); mi->mi_shadow = shadow; return 0; } /** * nilfs_mdt_save_to_shadow_map - copy bmap and dirty pages to shadow map * @inode: inode of the metadata file */ int nilfs_mdt_save_to_shadow_map(struct inode *inode) { struct nilfs_mdt_info *mi = NILFS_MDT(inode); struct nilfs_inode_info *ii = NILFS_I(inode); struct nilfs_shadow_map *shadow = mi->mi_shadow; int ret; ret = nilfs_copy_dirty_pages(&shadow->frozen_data, inode->i_mapping); if (ret) goto out; ret = nilfs_copy_dirty_pages(&shadow->frozen_btnodes, &ii->i_btnode_cache); if (ret) goto out; nilfs_bmap_save(ii->i_bmap, &shadow->bmap_store); out: return ret; } int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh) { struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow; struct buffer_head *bh_frozen; struct page *page; int blkbits = inode->i_blkbits; page = grab_cache_page(&shadow->frozen_data, bh->b_page->index); if (!page) return -ENOMEM; if (!page_has_buffers(page)) create_empty_buffers(page, 1 << blkbits, 0); bh_frozen = nilfs_page_get_nth_block(page, bh_offset(bh) >> blkbits); if (!buffer_uptodate(bh_frozen)) nilfs_copy_buffer(bh_frozen, bh); if (list_empty(&bh_frozen->b_assoc_buffers)) { list_add_tail(&bh_frozen->b_assoc_buffers, &shadow->frozen_buffers); set_buffer_nilfs_redirected(bh); } else { brelse(bh_frozen); /* already frozen */ } unlock_page(page); page_cache_release(page); return 0; } struct buffer_head * nilfs_mdt_get_frozen_buffer(struct inode *inode, struct buffer_head *bh) { struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow; struct buffer_head *bh_frozen = NULL; struct page *page; int n; page = find_lock_page(&shadow->frozen_data, bh->b_page->index); if (page) { if (page_has_buffers(page)) { n = bh_offset(bh) >> inode->i_blkbits; bh_frozen = nilfs_page_get_nth_block(page, n); } unlock_page(page); page_cache_release(page); } return bh_frozen; } static void nilfs_release_frozen_buffers(struct nilfs_shadow_map *shadow) { struct list_head *head = &shadow->frozen_buffers; struct buffer_head *bh; while (!list_empty(head)) { bh = list_first_entry(head, struct buffer_head, b_assoc_buffers); list_del_init(&bh->b_assoc_buffers); brelse(bh); /* drop ref-count to make it releasable */ } } /** * nilfs_mdt_restore_from_shadow_map - restore dirty pages and bmap state * @inode: inode of the metadata file */ void nilfs_mdt_restore_from_shadow_map(struct inode *inode) { struct nilfs_mdt_info *mi = NILFS_MDT(inode); struct nilfs_inode_info *ii = NILFS_I(inode); struct nilfs_shadow_map *shadow = mi->mi_shadow; down_write(&mi->mi_sem); if (mi->mi_palloc_cache) nilfs_palloc_clear_cache(inode); nilfs_clear_dirty_pages(inode->i_mapping, true); nilfs_copy_back_pages(inode->i_mapping, &shadow->frozen_data); nilfs_clear_dirty_pages(&ii->i_btnode_cache, true); nilfs_copy_back_pages(&ii->i_btnode_cache, &shadow->frozen_btnodes); nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store); up_write(&mi->mi_sem); } /** * nilfs_mdt_clear_shadow_map - truncate pages in shadow map caches * @inode: inode of the metadata file */ void nilfs_mdt_clear_shadow_map(struct inode *inode) { struct nilfs_mdt_info *mi = NILFS_MDT(inode); struct nilfs_shadow_map *shadow = mi->mi_shadow; down_write(&mi->mi_sem); nilfs_release_frozen_buffers(shadow); truncate_inode_pages(&shadow->frozen_data, 0); truncate_inode_pages(&shadow->frozen_btnodes, 0); up_write(&mi->mi_sem); }