/* FUSE: Filesystem in Userspace Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> This program can be distributed under the terms of the GNU GPL. See the file COPYING. */ #include "fuse_i.h" #include <linux/pagemap.h> #include <linux/slab.h> #include <linux/kernel.h> #include <linux/sched.h> #include <linux/sched/signal.h> #include <linux/module.h> #include <linux/swap.h> #include <linux/falloc.h> #include <linux/uio.h> #include <linux/fs.h> static int fuse_send_open(struct fuse_mount *fm, u64 nodeid, unsigned int open_flags, int opcode, struct fuse_open_out *outargp) { struct fuse_open_in inarg; FUSE_ARGS(args); memset(&inarg, 0, sizeof(inarg)); inarg.flags = open_flags & ~(O_CREAT | O_EXCL | O_NOCTTY); if (!fm->fc->atomic_o_trunc) inarg.flags &= ~O_TRUNC; if (fm->fc->handle_killpriv_v2 && (inarg.flags & O_TRUNC) && !capable(CAP_FSETID)) { inarg.open_flags |= FUSE_OPEN_KILL_SUIDGID; } args.opcode = opcode; args.nodeid = nodeid; args.in_numargs = 1; args.in_args[0].size = sizeof(inarg); args.in_args[0].value = &inarg; args.out_numargs = 1; args.out_args[0].size = sizeof(*outargp); args.out_args[0].value = outargp; return fuse_simple_request(fm, &args); } struct fuse_release_args { struct fuse_args args; struct fuse_release_in inarg; struct inode *inode; }; struct fuse_file *fuse_file_alloc(struct fuse_mount *fm) { struct fuse_file *ff; ff = kzalloc(sizeof(struct fuse_file), GFP_KERNEL_ACCOUNT); if (unlikely(!ff)) return NULL; ff->fm = fm; ff->release_args = kzalloc(sizeof(*ff->release_args), GFP_KERNEL_ACCOUNT); if (!ff->release_args) { kfree(ff); return NULL; } INIT_LIST_HEAD(&ff->write_entry); mutex_init(&ff->readdir.lock); refcount_set(&ff->count, 1); RB_CLEAR_NODE(&ff->polled_node); init_waitqueue_head(&ff->poll_wait); ff->kh = atomic64_inc_return(&fm->fc->khctr); return ff; } void fuse_file_free(struct fuse_file *ff) { kfree(ff->release_args); mutex_destroy(&ff->readdir.lock); kfree(ff); } static struct fuse_file *fuse_file_get(struct fuse_file *ff) { refcount_inc(&ff->count); return ff; } static void fuse_release_end(struct fuse_mount *fm, struct fuse_args *args, int error) { struct fuse_release_args *ra = container_of(args, typeof(*ra), args); iput(ra->inode); kfree(ra); } static void fuse_file_put(struct fuse_file *ff, bool sync, bool isdir) { if (refcount_dec_and_test(&ff->count)) { struct fuse_args *args = &ff->release_args->args; if (isdir ? ff->fm->fc->no_opendir : ff->fm->fc->no_open) { /* Do nothing when client does not implement 'open' */ fuse_release_end(ff->fm, args, 0); } else if (sync) { fuse_simple_request(ff->fm, args); fuse_release_end(ff->fm, args, 0); } else { args->end = fuse_release_end; if (fuse_simple_background(ff->fm, args, GFP_KERNEL | __GFP_NOFAIL)) fuse_release_end(ff->fm, args, -ENOTCONN); } kfree(ff); } } struct fuse_file *fuse_file_open(struct fuse_mount *fm, u64 nodeid, unsigned int open_flags, bool isdir) { struct fuse_conn *fc = fm->fc; struct fuse_file *ff; int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN; ff = fuse_file_alloc(fm); if (!ff) return ERR_PTR(-ENOMEM); ff->fh = 0; /* Default for no-open */ ff->open_flags = FOPEN_KEEP_CACHE | (isdir ? FOPEN_CACHE_DIR : 0); if (isdir ? !fc->no_opendir : !fc->no_open) { struct fuse_open_out outarg; int err; err = fuse_send_open(fm, nodeid, open_flags, opcode, &outarg); if (!err) { ff->fh = outarg.fh; ff->open_flags = outarg.open_flags; } else if (err != -ENOSYS) { fuse_file_free(ff); return ERR_PTR(err); } else { if (isdir) fc->no_opendir = 1; else fc->no_open = 1; } } if (isdir) ff->open_flags &= ~FOPEN_DIRECT_IO; ff->nodeid = nodeid; return ff; } int fuse_do_open(struct fuse_mount *fm, u64 nodeid, struct file *file, bool isdir) { struct fuse_file *ff = fuse_file_open(fm, nodeid, file->f_flags, isdir); if (!IS_ERR(ff)) file->private_data = ff; return PTR_ERR_OR_ZERO(ff); } EXPORT_SYMBOL_GPL(fuse_do_open); static void fuse_link_write_file(struct file *file) { struct inode *inode = file_inode(file); struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_file *ff = file->private_data; /* * file may be written through mmap, so chain it onto the * inodes's write_file list */ spin_lock(&fi->lock); if (list_empty(&ff->write_entry)) list_add(&ff->write_entry, &fi->write_files); spin_unlock(&fi->lock); } void fuse_finish_open(struct inode *inode, struct file *file) { struct fuse_file *ff = file->private_data; struct fuse_conn *fc = get_fuse_conn(inode); if (ff->open_flags & FOPEN_STREAM) stream_open(inode, file); else if (ff->open_flags & FOPEN_NONSEEKABLE) nonseekable_open(inode, file); if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) { struct fuse_inode *fi = get_fuse_inode(inode); spin_lock(&fi->lock); fi->attr_version = atomic64_inc_return(&fc->attr_version); i_size_write(inode, 0); spin_unlock(&fi->lock); truncate_pagecache(inode, 0); file_update_time(file); fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE); } else if (!(ff->open_flags & FOPEN_KEEP_CACHE)) { invalidate_inode_pages2(inode->i_mapping); } if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache) fuse_link_write_file(file); } int fuse_open_common(struct inode *inode, struct file *file, bool isdir) { struct fuse_mount *fm = get_fuse_mount(inode); struct fuse_conn *fc = fm->fc; int err; bool is_wb_truncate = (file->f_flags & O_TRUNC) && fc->atomic_o_trunc && fc->writeback_cache; bool dax_truncate = (file->f_flags & O_TRUNC) && fc->atomic_o_trunc && FUSE_IS_DAX(inode); if (fuse_is_bad(inode)) return -EIO; err = generic_file_open(inode, file); if (err) return err; if (is_wb_truncate || dax_truncate) { inode_lock(inode); fuse_set_nowrite(inode); } if (dax_truncate) { filemap_invalidate_lock(inode->i_mapping); err = fuse_dax_break_layouts(inode, 0, 0); if (err) goto out; } err = fuse_do_open(fm, get_node_id(inode), file, isdir); if (!err) fuse_finish_open(inode, file); out: if (dax_truncate) filemap_invalidate_unlock(inode->i_mapping); if (is_wb_truncate | dax_truncate) { fuse_release_nowrite(inode); inode_unlock(inode); } return err; } static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff, unsigned int flags, int opcode) { struct fuse_conn *fc = ff->fm->fc; struct fuse_release_args *ra = ff->release_args; /* Inode is NULL on error path of fuse_create_open() */ if (likely(fi)) { spin_lock(&fi->lock); list_del(&ff->write_entry); spin_unlock(&fi->lock); } spin_lock(&fc->lock); if (!RB_EMPTY_NODE(&ff->polled_node)) rb_erase(&ff->polled_node, &fc->polled_files); spin_unlock(&fc->lock); wake_up_interruptible_all(&ff->poll_wait); ra->inarg.fh = ff->fh; ra->inarg.flags = flags; ra->args.in_numargs = 1; ra->args.in_args[0].size = sizeof(struct fuse_release_in); ra->args.in_args[0].value = &ra->inarg; ra->args.opcode = opcode; ra->args.nodeid = ff->nodeid; ra->args.force = true; ra->args.nocreds = true; } void fuse_file_release(struct inode *inode, struct fuse_file *ff, unsigned int open_flags, fl_owner_t id, bool isdir) { struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_release_args *ra = ff->release_args; int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE; fuse_prepare_release(fi, ff, open_flags, opcode); if (ff->flock) { ra->inarg.release_flags |= FUSE_RELEASE_FLOCK_UNLOCK; ra->inarg.lock_owner = fuse_lock_owner_id(ff->fm->fc, id); } /* Hold inode until release is finished */ ra->inode = igrab(inode); /* * Normally this will send the RELEASE request, however if * some asynchronous READ or WRITE requests are outstanding, * the sending will be delayed. * * Make the release synchronous if this is a fuseblk mount, * synchronous RELEASE is allowed (and desirable) in this case * because the server can be trusted not to screw up. */ fuse_file_put(ff, ff->fm->fc->destroy, isdir); } void fuse_release_common(struct file *file, bool isdir) { fuse_file_release(file_inode(file), file->private_data, file->f_flags, (fl_owner_t) file, isdir); } static int fuse_open(struct inode *inode, struct file *file) { return fuse_open_common(inode, file, false); } static int fuse_release(struct inode *inode, struct file *file) { fuse_release_common(file, false); /* return value is ignored by VFS */ return 0; } void fuse_sync_release(struct fuse_inode *fi, struct fuse_file *ff, unsigned int flags) { WARN_ON(refcount_read(&ff->count) > 1); fuse_prepare_release(fi, ff, flags, FUSE_RELEASE); /* * iput(NULL) is a no-op and since the refcount is 1 and everything's * synchronous, we are fine with not doing igrab() here" */ fuse_file_put(ff, true, false); } EXPORT_SYMBOL_GPL(fuse_sync_release); /* * Scramble the ID space with XTEA, so that the value of the files_struct * pointer is not exposed to userspace. */ u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id) { u32 *k = fc->scramble_key; u64 v = (unsigned long) id; u32 v0 = v; u32 v1 = v >> 32; u32 sum = 0; int i; for (i = 0; i < 32; i++) { v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]); sum += 0x9E3779B9; v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]); } return (u64) v0 + ((u64) v1 << 32); } struct fuse_writepage_args { struct fuse_io_args ia; struct rb_node writepages_entry; struct list_head queue_entry; struct fuse_writepage_args *next; struct inode *inode; struct fuse_sync_bucket *bucket; }; static struct fuse_writepage_args *fuse_find_writeback(struct fuse_inode *fi, pgoff_t idx_from, pgoff_t idx_to) { struct rb_node *n; n = fi->writepages.rb_node; while (n) { struct fuse_writepage_args *wpa; pgoff_t curr_index; wpa = rb_entry(n, struct fuse_writepage_args, writepages_entry); WARN_ON(get_fuse_inode(wpa->inode) != fi); curr_index = wpa->ia.write.in.offset >> PAGE_SHIFT; if (idx_from >= curr_index + wpa->ia.ap.num_pages) n = n->rb_right; else if (idx_to < curr_index) n = n->rb_left; else return wpa; } return NULL; } /* * Check if any page in a range is under writeback * * This is currently done by walking the list of writepage requests * for the inode, which can be pretty inefficient. */ static bool fuse_range_is_writeback(struct inode *inode, pgoff_t idx_from, pgoff_t idx_to) { struct fuse_inode *fi = get_fuse_inode(inode); bool found; spin_lock(&fi->lock); found = fuse_find_writeback(fi, idx_from, idx_to); spin_unlock(&fi->lock); return found; } static inline bool fuse_page_is_writeback(struct inode *inode, pgoff_t index) { return fuse_range_is_writeback(inode, index, index); } /* * Wait for page writeback to be completed. * * Since fuse doesn't rely on the VM writeback tracking, this has to * use some other means. */ static void fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index) { struct fuse_inode *fi = get_fuse_inode(inode); wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index)); } /* * Wait for all pending writepages on the inode to finish. * * This is currently done by blocking further writes with FUSE_NOWRITE * and waiting for all sent writes to complete. * * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage * could conflict with truncation. */ static void fuse_sync_writes(struct inode *inode) { fuse_set_nowrite(inode); fuse_release_nowrite(inode); } static int fuse_flush(struct file *file, fl_owner_t id) { struct inode *inode = file_inode(file); struct fuse_mount *fm = get_fuse_mount(inode); struct fuse_file *ff = file->private_data; struct fuse_flush_in inarg; FUSE_ARGS(args); int err; if (fuse_is_bad(inode)) return -EIO; if (ff->open_flags & FOPEN_NOFLUSH && !fm->fc->writeback_cache) return 0; err = write_inode_now(inode, 1); if (err) return err; inode_lock(inode); fuse_sync_writes(inode); inode_unlock(inode); err = filemap_check_errors(file->f_mapping); if (err) return err; err = 0; if (fm->fc->no_flush) goto inval_attr_out; memset(&inarg, 0, sizeof(inarg)); inarg.fh = ff->fh; inarg.lock_owner = fuse_lock_owner_id(fm->fc, id); args.opcode = FUSE_FLUSH; args.nodeid = get_node_id(inode); args.in_numargs = 1; args.in_args[0].size = sizeof(inarg); args.in_args[0].value = &inarg; args.force = true; err = fuse_simple_request(fm, &args); if (err == -ENOSYS) { fm->fc->no_flush = 1; err = 0; } inval_attr_out: /* * In memory i_blocks is not maintained by fuse, if writeback cache is * enabled, i_blocks from cached attr may not be accurate. */ if (!err && fm->fc->writeback_cache) fuse_invalidate_attr_mask(inode, STATX_BLOCKS); return err; } int fuse_fsync_common(struct file *file, loff_t start, loff_t end, int datasync, int opcode) { struct inode *inode = file->f_mapping->host; struct fuse_mount *fm = get_fuse_mount(inode); struct fuse_file *ff = file->private_data; FUSE_ARGS(args); struct fuse_fsync_in inarg; memset(&inarg, 0, sizeof(inarg)); inarg.fh = ff->fh; inarg.fsync_flags = datasync ? FUSE_FSYNC_FDATASYNC : 0; args.opcode = opcode; args.nodeid = get_node_id(inode); args.in_numargs = 1; args.in_args[0].size = sizeof(inarg); args.in_args[0].value = &inarg; return fuse_simple_request(fm, &args); } static int fuse_fsync(struct file *file, loff_t start, loff_t end, int datasync) { struct inode *inode = file->f_mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); int err; if (fuse_is_bad(inode)) return -EIO; inode_lock(inode); /* * Start writeback against all dirty pages of the inode, then * wait for all outstanding writes, before sending the FSYNC * request. */ err = file_write_and_wait_range(file, start, end); if (err) goto out; fuse_sync_writes(inode); /* * Due to implementation of fuse writeback * file_write_and_wait_range() does not catch errors. * We have to do this directly after fuse_sync_writes() */ err = file_check_and_advance_wb_err(file); if (err) goto out; err = sync_inode_metadata(inode, 1); if (err) goto out; if (fc->no_fsync) goto out; err = fuse_fsync_common(file, start, end, datasync, FUSE_FSYNC); if (err == -ENOSYS) { fc->no_fsync = 1; err = 0; } out: inode_unlock(inode); return err; } void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos, size_t count, int opcode) { struct fuse_file *ff = file->private_data; struct fuse_args *args = &ia->ap.args; ia->read.in.fh = ff->fh; ia->read.in.offset = pos; ia->read.in.size = count; ia->read.in.flags = file->f_flags; args->opcode = opcode; args->nodeid = ff->nodeid; args->in_numargs = 1; args->in_args[0].size = sizeof(ia->read.in); args->in_args[0].value = &ia->read.in; args->out_argvar = true; args->out_numargs = 1; args->out_args[0].size = count; } static void fuse_release_user_pages(struct fuse_args_pages *ap, bool should_dirty) { unsigned int i; for (i = 0; i < ap->num_pages; i++) { if (should_dirty) set_page_dirty_lock(ap->pages[i]); put_page(ap->pages[i]); } } static void fuse_io_release(struct kref *kref) { kfree(container_of(kref, struct fuse_io_priv, refcnt)); } static ssize_t fuse_get_res_by_io(struct fuse_io_priv *io) { if (io->err) return io->err; if (io->bytes >= 0 && io->write) return -EIO; return io->bytes < 0 ? io->size : io->bytes; } /** * In case of short read, the caller sets 'pos' to the position of * actual end of fuse request in IO request. Otherwise, if bytes_requested * == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1. * * An example: * User requested DIO read of 64K. It was split into two 32K fuse requests, * both submitted asynchronously. The first of them was ACKed by userspace as * fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The * second request was ACKed as short, e.g. only 1K was read, resulting in * pos == 33K. * * Thus, when all fuse requests are completed, the minimal non-negative 'pos' * will be equal to the length of the longest contiguous fragment of * transferred data starting from the beginning of IO request. */ static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos) { int left; spin_lock(&io->lock); if (err) io->err = io->err ? : err; else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes)) io->bytes = pos; left = --io->reqs; if (!left && io->blocking) complete(io->done); spin_unlock(&io->lock); if (!left && !io->blocking) { ssize_t res = fuse_get_res_by_io(io); if (res >= 0) { struct inode *inode = file_inode(io->iocb->ki_filp); struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); spin_lock(&fi->lock); fi->attr_version = atomic64_inc_return(&fc->attr_version); spin_unlock(&fi->lock); } io->iocb->ki_complete(io->iocb, res); } kref_put(&io->refcnt, fuse_io_release); } static struct fuse_io_args *fuse_io_alloc(struct fuse_io_priv *io, unsigned int npages) { struct fuse_io_args *ia; ia = kzalloc(sizeof(*ia), GFP_KERNEL); if (ia) { ia->io = io; ia->ap.pages = fuse_pages_alloc(npages, GFP_KERNEL, &ia->ap.descs); if (!ia->ap.pages) { kfree(ia); ia = NULL; } } return ia; } static void fuse_io_free(struct fuse_io_args *ia) { kfree(ia->ap.pages); kfree(ia); } static void fuse_aio_complete_req(struct fuse_mount *fm, struct fuse_args *args, int err) { struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args); struct fuse_io_priv *io = ia->io; ssize_t pos = -1; fuse_release_user_pages(&ia->ap, io->should_dirty); if (err) { /* Nothing */ } else if (io->write) { if (ia->write.out.size > ia->write.in.size) { err = -EIO; } else if (ia->write.in.size != ia->write.out.size) { pos = ia->write.in.offset - io->offset + ia->write.out.size; } } else { u32 outsize = args->out_args[0].size; if (ia->read.in.size != outsize) pos = ia->read.in.offset - io->offset + outsize; } fuse_aio_complete(io, err, pos); fuse_io_free(ia); } static ssize_t fuse_async_req_send(struct fuse_mount *fm, struct fuse_io_args *ia, size_t num_bytes) { ssize_t err; struct fuse_io_priv *io = ia->io; spin_lock(&io->lock); kref_get(&io->refcnt); io->size += num_bytes; io->reqs++; spin_unlock(&io->lock); ia->ap.args.end = fuse_aio_complete_req; ia->ap.args.may_block = io->should_dirty; err = fuse_simple_background(fm, &ia->ap.args, GFP_KERNEL); if (err) fuse_aio_complete_req(fm, &ia->ap.args, err); return num_bytes; } static ssize_t fuse_send_read(struct fuse_io_args *ia, loff_t pos, size_t count, fl_owner_t owner) { struct file *file = ia->io->iocb->ki_filp; struct fuse_file *ff = file->private_data; struct fuse_mount *fm = ff->fm; fuse_read_args_fill(ia, file, pos, count, FUSE_READ); if (owner != NULL) { ia->read.in.read_flags |= FUSE_READ_LOCKOWNER; ia->read.in.lock_owner = fuse_lock_owner_id(fm->fc, owner); } if (ia->io->async) return fuse_async_req_send(fm, ia, count); return fuse_simple_request(fm, &ia->ap.args); } static void fuse_read_update_size(struct inode *inode, loff_t size, u64 attr_ver) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); spin_lock(&fi->lock); if (attr_ver >= fi->attr_version && size < inode->i_size && !test_bit(FUSE_I_SIZE_UNSTABLE, &fi->state)) { fi->attr_version = atomic64_inc_return(&fc->attr_version); i_size_write(inode, size); } spin_unlock(&fi->lock); } static void fuse_short_read(struct inode *inode, u64 attr_ver, size_t num_read, struct fuse_args_pages *ap) { struct fuse_conn *fc = get_fuse_conn(inode); /* * If writeback_cache is enabled, a short read means there's a hole in * the file. Some data after the hole is in page cache, but has not * reached the client fs yet. So the hole is not present there. */ if (!fc->writeback_cache) { loff_t pos = page_offset(ap->pages[0]) + num_read; fuse_read_update_size(inode, pos, attr_ver); } } static int fuse_do_readpage(struct file *file, struct page *page) { struct inode *inode = page->mapping->host; struct fuse_mount *fm = get_fuse_mount(inode); loff_t pos = page_offset(page); struct fuse_page_desc desc = { .length = PAGE_SIZE }; struct fuse_io_args ia = { .ap.args.page_zeroing = true, .ap.args.out_pages = true, .ap.num_pages = 1, .ap.pages = &page, .ap.descs = &desc, }; ssize_t res; u64 attr_ver; /* * Page writeback can extend beyond the lifetime of the * page-cache page, so make sure we read a properly synced * page. */ fuse_wait_on_page_writeback(inode, page->index); attr_ver = fuse_get_attr_version(fm->fc); /* Don't overflow end offset */ if (pos + (desc.length - 1) == LLONG_MAX) desc.length--; fuse_read_args_fill(&ia, file, pos, desc.length, FUSE_READ); res = fuse_simple_request(fm, &ia.ap.args); if (res < 0) return res; /* * Short read means EOF. If file size is larger, truncate it */ if (res < desc.length) fuse_short_read(inode, attr_ver, res, &ia.ap); SetPageUptodate(page); return 0; } static int fuse_readpage(struct file *file, struct page *page) { struct inode *inode = page->mapping->host; int err; err = -EIO; if (fuse_is_bad(inode)) goto out; err = fuse_do_readpage(file, page); fuse_invalidate_atime(inode); out: unlock_page(page); return err; } static void fuse_readpages_end(struct fuse_mount *fm, struct fuse_args *args, int err) { int i; struct fuse_io_args *ia = container_of(args, typeof(*ia), ap.args); struct fuse_args_pages *ap = &ia->ap; size_t count = ia->read.in.size; size_t num_read = args->out_args[0].size; struct address_space *mapping = NULL; for (i = 0; mapping == NULL && i < ap->num_pages; i++) mapping = ap->pages[i]->mapping; if (mapping) { struct inode *inode = mapping->host; /* * Short read means EOF. If file size is larger, truncate it */ if (!err && num_read < count) fuse_short_read(inode, ia->read.attr_ver, num_read, ap); fuse_invalidate_atime(inode); } for (i = 0; i < ap->num_pages; i++) { struct page *page = ap->pages[i]; if (!err) SetPageUptodate(page); else SetPageError(page); unlock_page(page); put_page(page); } if (ia->ff) fuse_file_put(ia->ff, false, false); fuse_io_free(ia); } static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file) { struct fuse_file *ff = file->private_data; struct fuse_mount *fm = ff->fm; struct fuse_args_pages *ap = &ia->ap; loff_t pos = page_offset(ap->pages[0]); size_t count = ap->num_pages << PAGE_SHIFT; ssize_t res; int err; ap->args.out_pages = true; ap->args.page_zeroing = true; ap->args.page_replace = true; /* Don't overflow end offset */ if (pos + (count - 1) == LLONG_MAX) { count--; ap->descs[ap->num_pages - 1].length--; } WARN_ON((loff_t) (pos + count) < 0); fuse_read_args_fill(ia, file, pos, count, FUSE_READ); ia->read.attr_ver = fuse_get_attr_version(fm->fc); if (fm->fc->async_read) { ia->ff = fuse_file_get(ff); ap->args.end = fuse_readpages_end; err = fuse_simple_background(fm, &ap->args, GFP_KERNEL); if (!err) return; } else { res = fuse_simple_request(fm, &ap->args); err = res < 0 ? res : 0; } fuse_readpages_end(fm, &ap->args, err); } static void fuse_readahead(struct readahead_control *rac) { struct inode *inode = rac->mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); unsigned int i, max_pages, nr_pages = 0; if (fuse_is_bad(inode)) return; max_pages = min_t(unsigned int, fc->max_pages, fc->max_read / PAGE_SIZE); for (;;) { struct fuse_io_args *ia; struct fuse_args_pages *ap; if (fc->num_background >= fc->congestion_threshold && rac->ra->async_size >= readahead_count(rac)) /* * Congested and only async pages left, so skip the * rest. */ break; nr_pages = readahead_count(rac) - nr_pages; if (nr_pages > max_pages) nr_pages = max_pages; if (nr_pages == 0) break; ia = fuse_io_alloc(NULL, nr_pages); if (!ia) return; ap = &ia->ap; nr_pages = __readahead_batch(rac, ap->pages, nr_pages); for (i = 0; i < nr_pages; i++) { fuse_wait_on_page_writeback(inode, readahead_index(rac) + i); ap->descs[i].length = PAGE_SIZE; } ap->num_pages = nr_pages; fuse_send_readpages(ia, rac->file); } } static ssize_t fuse_cache_read_iter(struct kiocb *iocb, struct iov_iter *to) { struct inode *inode = iocb->ki_filp->f_mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); /* * In auto invalidate mode, always update attributes on read. * Otherwise, only update if we attempt to read past EOF (to ensure * i_size is up to date). */ if (fc->auto_inval_data || (iocb->ki_pos + iov_iter_count(to) > i_size_read(inode))) { int err; err = fuse_update_attributes(inode, iocb->ki_filp, STATX_SIZE); if (err) return err; } return generic_file_read_iter(iocb, to); } static void fuse_write_args_fill(struct fuse_io_args *ia, struct fuse_file *ff, loff_t pos, size_t count) { struct fuse_args *args = &ia->ap.args; ia->write.in.fh = ff->fh; ia->write.in.offset = pos; ia->write.in.size = count; args->opcode = FUSE_WRITE; args->nodeid = ff->nodeid; args->in_numargs = 2; if (ff->fm->fc->minor < 9) args->in_args[0].size = FUSE_COMPAT_WRITE_IN_SIZE; else args->in_args[0].size = sizeof(ia->write.in); args->in_args[0].value = &ia->write.in; args->in_args[1].size = count; args->out_numargs = 1; args->out_args[0].size = sizeof(ia->write.out); args->out_args[0].value = &ia->write.out; } static unsigned int fuse_write_flags(struct kiocb *iocb) { unsigned int flags = iocb->ki_filp->f_flags; if (iocb->ki_flags & IOCB_DSYNC) flags |= O_DSYNC; if (iocb->ki_flags & IOCB_SYNC) flags |= O_SYNC; return flags; } static ssize_t fuse_send_write(struct fuse_io_args *ia, loff_t pos, size_t count, fl_owner_t owner) { struct kiocb *iocb = ia->io->iocb; struct file *file = iocb->ki_filp; struct fuse_file *ff = file->private_data; struct fuse_mount *fm = ff->fm; struct fuse_write_in *inarg = &ia->write.in; ssize_t err; fuse_write_args_fill(ia, ff, pos, count); inarg->flags = fuse_write_flags(iocb); if (owner != NULL) { inarg->write_flags |= FUSE_WRITE_LOCKOWNER; inarg->lock_owner = fuse_lock_owner_id(fm->fc, owner); } if (ia->io->async) return fuse_async_req_send(fm, ia, count); err = fuse_simple_request(fm, &ia->ap.args); if (!err && ia->write.out.size > count) err = -EIO; return err ?: ia->write.out.size; } bool fuse_write_update_attr(struct inode *inode, loff_t pos, ssize_t written) { struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); bool ret = false; spin_lock(&fi->lock); fi->attr_version = atomic64_inc_return(&fc->attr_version); if (written > 0 && pos > inode->i_size) { i_size_write(inode, pos); ret = true; } spin_unlock(&fi->lock); fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE); return ret; } static ssize_t fuse_send_write_pages(struct fuse_io_args *ia, struct kiocb *iocb, struct inode *inode, loff_t pos, size_t count) { struct fuse_args_pages *ap = &ia->ap; struct file *file = iocb->ki_filp; struct fuse_file *ff = file->private_data; struct fuse_mount *fm = ff->fm; unsigned int offset, i; bool short_write; int err; for (i = 0; i < ap->num_pages; i++) fuse_wait_on_page_writeback(inode, ap->pages[i]->index); fuse_write_args_fill(ia, ff, pos, count); ia->write.in.flags = fuse_write_flags(iocb); if (fm->fc->handle_killpriv_v2 && !capable(CAP_FSETID)) ia->write.in.write_flags |= FUSE_WRITE_KILL_SUIDGID; err = fuse_simple_request(fm, &ap->args); if (!err && ia->write.out.size > count) err = -EIO; short_write = ia->write.out.size < count; offset = ap->descs[0].offset; count = ia->write.out.size; for (i = 0; i < ap->num_pages; i++) { struct page *page = ap->pages[i]; if (err) { ClearPageUptodate(page); } else { if (count >= PAGE_SIZE - offset) count -= PAGE_SIZE - offset; else { if (short_write) ClearPageUptodate(page); count = 0; } offset = 0; } if (ia->write.page_locked && (i == ap->num_pages - 1)) unlock_page(page); put_page(page); } return err; } static ssize_t fuse_fill_write_pages(struct fuse_io_args *ia, struct address_space *mapping, struct iov_iter *ii, loff_t pos, unsigned int max_pages) { struct fuse_args_pages *ap = &ia->ap; struct fuse_conn *fc = get_fuse_conn(mapping->host); unsigned offset = pos & (PAGE_SIZE - 1); size_t count = 0; int err; ap->args.in_pages = true; ap->descs[0].offset = offset; do { size_t tmp; struct page *page; pgoff_t index = pos >> PAGE_SHIFT; size_t bytes = min_t(size_t, PAGE_SIZE - offset, iov_iter_count(ii)); bytes = min_t(size_t, bytes, fc->max_write - count); again: err = -EFAULT; if (fault_in_iov_iter_readable(ii, bytes)) break; err = -ENOMEM; page = grab_cache_page_write_begin(mapping, index, 0); if (!page) break; if (mapping_writably_mapped(mapping)) flush_dcache_page(page); tmp = copy_page_from_iter_atomic(page, offset, bytes, ii); flush_dcache_page(page); if (!tmp) { unlock_page(page); put_page(page); goto again; } err = 0; ap->pages[ap->num_pages] = page; ap->descs[ap->num_pages].length = tmp; ap->num_pages++; count += tmp; pos += tmp; offset += tmp; if (offset == PAGE_SIZE) offset = 0; /* If we copied full page, mark it uptodate */ if (tmp == PAGE_SIZE) SetPageUptodate(page); if (PageUptodate(page)) { unlock_page(page); } else { ia->write.page_locked = true; break; } if (!fc->big_writes) break; } while (iov_iter_count(ii) && count < fc->max_write && ap->num_pages < max_pages && offset == 0); return count > 0 ? count : err; } static inline unsigned int fuse_wr_pages(loff_t pos, size_t len, unsigned int max_pages) { return min_t(unsigned int, ((pos + len - 1) >> PAGE_SHIFT) - (pos >> PAGE_SHIFT) + 1, max_pages); } static ssize_t fuse_perform_write(struct kiocb *iocb, struct address_space *mapping, struct iov_iter *ii, loff_t pos) { struct inode *inode = mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); int err = 0; ssize_t res = 0; if (inode->i_size < pos + iov_iter_count(ii)) set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); do { ssize_t count; struct fuse_io_args ia = {}; struct fuse_args_pages *ap = &ia.ap; unsigned int nr_pages = fuse_wr_pages(pos, iov_iter_count(ii), fc->max_pages); ap->pages = fuse_pages_alloc(nr_pages, GFP_KERNEL, &ap->descs); if (!ap->pages) { err = -ENOMEM; break; } count = fuse_fill_write_pages(&ia, mapping, ii, pos, nr_pages); if (count <= 0) { err = count; } else { err = fuse_send_write_pages(&ia, iocb, inode, pos, count); if (!err) { size_t num_written = ia.write.out.size; res += num_written; pos += num_written; /* break out of the loop on short write */ if (num_written != count) err = -EIO; } } kfree(ap->pages); } while (!err && iov_iter_count(ii)); fuse_write_update_attr(inode, pos, res); clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); return res > 0 ? res : err; } static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct file *file = iocb->ki_filp; struct address_space *mapping = file->f_mapping; ssize_t written = 0; ssize_t written_buffered = 0; struct inode *inode = mapping->host; ssize_t err; struct fuse_conn *fc = get_fuse_conn(inode); loff_t endbyte = 0; if (fc->writeback_cache) { /* Update size (EOF optimization) and mode (SUID clearing) */ err = fuse_update_attributes(mapping->host, file, STATX_SIZE | STATX_MODE); if (err) return err; if (fc->handle_killpriv_v2 && should_remove_suid(file_dentry(file))) { goto writethrough; } return generic_file_write_iter(iocb, from); } writethrough: inode_lock(inode); /* We can write back this queue in page reclaim */ current->backing_dev_info = inode_to_bdi(inode); err = generic_write_checks(iocb, from); if (err <= 0) goto out; err = file_remove_privs(file); if (err) goto out; err = file_update_time(file); if (err) goto out; if (iocb->ki_flags & IOCB_DIRECT) { loff_t pos = iocb->ki_pos; written = generic_file_direct_write(iocb, from); if (written < 0 || !iov_iter_count(from)) goto out; pos += written; written_buffered = fuse_perform_write(iocb, mapping, from, pos); if (written_buffered < 0) { err = written_buffered; goto out; } endbyte = pos + written_buffered - 1; err = filemap_write_and_wait_range(file->f_mapping, pos, endbyte); if (err) goto out; invalidate_mapping_pages(file->f_mapping, pos >> PAGE_SHIFT, endbyte >> PAGE_SHIFT); written += written_buffered; iocb->ki_pos = pos + written_buffered; } else { written = fuse_perform_write(iocb, mapping, from, iocb->ki_pos); if (written >= 0) iocb->ki_pos += written; } out: current->backing_dev_info = NULL; inode_unlock(inode); if (written > 0) written = generic_write_sync(iocb, written); return written ? written : err; } static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii) { return (unsigned long)ii->iov->iov_base + ii->iov_offset; } static inline size_t fuse_get_frag_size(const struct iov_iter *ii, size_t max_size) { return min(iov_iter_single_seg_count(ii), max_size); } static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii, size_t *nbytesp, int write, unsigned int max_pages) { size_t nbytes = 0; /* # bytes already packed in req */ ssize_t ret = 0; /* Special case for kernel I/O: can copy directly into the buffer */ if (iov_iter_is_kvec(ii)) { unsigned long user_addr = fuse_get_user_addr(ii); size_t frag_size = fuse_get_frag_size(ii, *nbytesp); if (write) ap->args.in_args[1].value = (void *) user_addr; else ap->args.out_args[0].value = (void *) user_addr; iov_iter_advance(ii, frag_size); *nbytesp = frag_size; return 0; } while (nbytes < *nbytesp && ap->num_pages < max_pages) { unsigned npages; size_t start; ret = iov_iter_get_pages(ii, &ap->pages[ap->num_pages], *nbytesp - nbytes, max_pages - ap->num_pages, &start); if (ret < 0) break; iov_iter_advance(ii, ret); nbytes += ret; ret += start; npages = DIV_ROUND_UP(ret, PAGE_SIZE); ap->descs[ap->num_pages].offset = start; fuse_page_descs_length_init(ap->descs, ap->num_pages, npages); ap->num_pages += npages; ap->descs[ap->num_pages - 1].length -= (PAGE_SIZE - ret) & (PAGE_SIZE - 1); } ap->args.user_pages = true; if (write) ap->args.in_pages = true; else ap->args.out_pages = true; *nbytesp = nbytes; return ret < 0 ? ret : 0; } ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter, loff_t *ppos, int flags) { int write = flags & FUSE_DIO_WRITE; int cuse = flags & FUSE_DIO_CUSE; struct file *file = io->iocb->ki_filp; struct inode *inode = file->f_mapping->host; struct fuse_file *ff = file->private_data; struct fuse_conn *fc = ff->fm->fc; size_t nmax = write ? fc->max_write : fc->max_read; loff_t pos = *ppos; size_t count = iov_iter_count(iter); pgoff_t idx_from = pos >> PAGE_SHIFT; pgoff_t idx_to = (pos + count - 1) >> PAGE_SHIFT; ssize_t res = 0; int err = 0; struct fuse_io_args *ia; unsigned int max_pages; max_pages = iov_iter_npages(iter, fc->max_pages); ia = fuse_io_alloc(io, max_pages); if (!ia) return -ENOMEM; if (!cuse && fuse_range_is_writeback(inode, idx_from, idx_to)) { if (!write) inode_lock(inode); fuse_sync_writes(inode); if (!write) inode_unlock(inode); } io->should_dirty = !write && iter_is_iovec(iter); while (count) { ssize_t nres; fl_owner_t owner = current->files; size_t nbytes = min(count, nmax); err = fuse_get_user_pages(&ia->ap, iter, &nbytes, write, max_pages); if (err && !nbytes) break; if (write) { if (!capable(CAP_FSETID)) ia->write.in.write_flags |= FUSE_WRITE_KILL_SUIDGID; nres = fuse_send_write(ia, pos, nbytes, owner); } else { nres = fuse_send_read(ia, pos, nbytes, owner); } if (!io->async || nres < 0) { fuse_release_user_pages(&ia->ap, io->should_dirty); fuse_io_free(ia); } ia = NULL; if (nres < 0) { iov_iter_revert(iter, nbytes); err = nres; break; } WARN_ON(nres > nbytes); count -= nres; res += nres; pos += nres; if (nres != nbytes) { iov_iter_revert(iter, nbytes - nres); break; } if (count) { max_pages = iov_iter_npages(iter, fc->max_pages); ia = fuse_io_alloc(io, max_pages); if (!ia) break; } } if (ia) fuse_io_free(ia); if (res > 0) *ppos = pos; return res > 0 ? res : err; } EXPORT_SYMBOL_GPL(fuse_direct_io); static ssize_t __fuse_direct_read(struct fuse_io_priv *io, struct iov_iter *iter, loff_t *ppos) { ssize_t res; struct inode *inode = file_inode(io->iocb->ki_filp); res = fuse_direct_io(io, iter, ppos, 0); fuse_invalidate_atime(inode); return res; } static ssize_t fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter); static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to) { ssize_t res; if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) { res = fuse_direct_IO(iocb, to); } else { struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb); res = __fuse_direct_read(&io, to, &iocb->ki_pos); } return res; } static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct inode *inode = file_inode(iocb->ki_filp); struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb); ssize_t res; /* Don't allow parallel writes to the same file */ inode_lock(inode); res = generic_write_checks(iocb, from); if (res > 0) { if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) { res = fuse_direct_IO(iocb, from); } else { res = fuse_direct_io(&io, from, &iocb->ki_pos, FUSE_DIO_WRITE); fuse_write_update_attr(inode, iocb->ki_pos, res); } } inode_unlock(inode); return res; } static ssize_t fuse_file_read_iter(struct kiocb *iocb, struct iov_iter *to) { struct file *file = iocb->ki_filp; struct fuse_file *ff = file->private_data; struct inode *inode = file_inode(file); if (fuse_is_bad(inode)) return -EIO; if (FUSE_IS_DAX(inode)) return fuse_dax_read_iter(iocb, to); if (!(ff->open_flags & FOPEN_DIRECT_IO)) return fuse_cache_read_iter(iocb, to); else return fuse_direct_read_iter(iocb, to); } static ssize_t fuse_file_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct file *file = iocb->ki_filp; struct fuse_file *ff = file->private_data; struct inode *inode = file_inode(file); if (fuse_is_bad(inode)) return -EIO; if (FUSE_IS_DAX(inode)) return fuse_dax_write_iter(iocb, from); if (!(ff->open_flags & FOPEN_DIRECT_IO)) return fuse_cache_write_iter(iocb, from); else return fuse_direct_write_iter(iocb, from); } static void fuse_writepage_free(struct fuse_writepage_args *wpa) { struct fuse_args_pages *ap = &wpa->ia.ap; int i; if (wpa->bucket) fuse_sync_bucket_dec(wpa->bucket); for (i = 0; i < ap->num_pages; i++) __free_page(ap->pages[i]); if (wpa->ia.ff) fuse_file_put(wpa->ia.ff, false, false); kfree(ap->pages); kfree(wpa); } static void fuse_writepage_finish(struct fuse_mount *fm, struct fuse_writepage_args *wpa) { struct fuse_args_pages *ap = &wpa->ia.ap; struct inode *inode = wpa->inode; struct fuse_inode *fi = get_fuse_inode(inode); struct backing_dev_info *bdi = inode_to_bdi(inode); int i; for (i = 0; i < ap->num_pages; i++) { dec_wb_stat(&bdi->wb, WB_WRITEBACK); dec_node_page_state(ap->pages[i], NR_WRITEBACK_TEMP); wb_writeout_inc(&bdi->wb); } wake_up(&fi->page_waitq); } /* Called under fi->lock, may release and reacquire it */ static void fuse_send_writepage(struct fuse_mount *fm, struct fuse_writepage_args *wpa, loff_t size) __releases(fi->lock) __acquires(fi->lock) { struct fuse_writepage_args *aux, *next; struct fuse_inode *fi = get_fuse_inode(wpa->inode); struct fuse_write_in *inarg = &wpa->ia.write.in; struct fuse_args *args = &wpa->ia.ap.args; __u64 data_size = wpa->ia.ap.num_pages * PAGE_SIZE; int err; fi->writectr++; if (inarg->offset + data_size <= size) { inarg->size = data_size; } else if (inarg->offset < size) { inarg->size = size - inarg->offset; } else { /* Got truncated off completely */ goto out_free; } args->in_args[1].size = inarg->size; args->force = true; args->nocreds = true; err = fuse_simple_background(fm, args, GFP_ATOMIC); if (err == -ENOMEM) { spin_unlock(&fi->lock); err = fuse_simple_background(fm, args, GFP_NOFS | __GFP_NOFAIL); spin_lock(&fi->lock); } /* Fails on broken connection only */ if (unlikely(err)) goto out_free; return; out_free: fi->writectr--; rb_erase(&wpa->writepages_entry, &fi->writepages); fuse_writepage_finish(fm, wpa); spin_unlock(&fi->lock); /* After fuse_writepage_finish() aux request list is private */ for (aux = wpa->next; aux; aux = next) { next = aux->next; aux->next = NULL; fuse_writepage_free(aux); } fuse_writepage_free(wpa); spin_lock(&fi->lock); } /* * If fi->writectr is positive (no truncate or fsync going on) send * all queued writepage requests. * * Called with fi->lock */ void fuse_flush_writepages(struct inode *inode) __releases(fi->lock) __acquires(fi->lock) { struct fuse_mount *fm = get_fuse_mount(inode); struct fuse_inode *fi = get_fuse_inode(inode); loff_t crop = i_size_read(inode); struct fuse_writepage_args *wpa; while (fi->writectr >= 0 && !list_empty(&fi->queued_writes)) { wpa = list_entry(fi->queued_writes.next, struct fuse_writepage_args, queue_entry); list_del_init(&wpa->queue_entry); fuse_send_writepage(fm, wpa, crop); } } static struct fuse_writepage_args *fuse_insert_writeback(struct rb_root *root, struct fuse_writepage_args *wpa) { pgoff_t idx_from = wpa->ia.write.in.offset >> PAGE_SHIFT; pgoff_t idx_to = idx_from + wpa->ia.ap.num_pages - 1; struct rb_node **p = &root->rb_node; struct rb_node *parent = NULL; WARN_ON(!wpa->ia.ap.num_pages); while (*p) { struct fuse_writepage_args *curr; pgoff_t curr_index; parent = *p; curr = rb_entry(parent, struct fuse_writepage_args, writepages_entry); WARN_ON(curr->inode != wpa->inode); curr_index = curr->ia.write.in.offset >> PAGE_SHIFT; if (idx_from >= curr_index + curr->ia.ap.num_pages) p = &(*p)->rb_right; else if (idx_to < curr_index) p = &(*p)->rb_left; else return curr; } rb_link_node(&wpa->writepages_entry, parent, p); rb_insert_color(&wpa->writepages_entry, root); return NULL; } static void tree_insert(struct rb_root *root, struct fuse_writepage_args *wpa) { WARN_ON(fuse_insert_writeback(root, wpa)); } static void fuse_writepage_end(struct fuse_mount *fm, struct fuse_args *args, int error) { struct fuse_writepage_args *wpa = container_of(args, typeof(*wpa), ia.ap.args); struct inode *inode = wpa->inode; struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_conn *fc = get_fuse_conn(inode); mapping_set_error(inode->i_mapping, error); /* * A writeback finished and this might have updated mtime/ctime on * server making local mtime/ctime stale. Hence invalidate attrs. * Do this only if writeback_cache is not enabled. If writeback_cache * is enabled, we trust local ctime/mtime. */ if (!fc->writeback_cache) fuse_invalidate_attr_mask(inode, FUSE_STATX_MODIFY); spin_lock(&fi->lock); rb_erase(&wpa->writepages_entry, &fi->writepages); while (wpa->next) { struct fuse_mount *fm = get_fuse_mount(inode); struct fuse_write_in *inarg = &wpa->ia.write.in; struct fuse_writepage_args *next = wpa->next; wpa->next = next->next; next->next = NULL; next->ia.ff = fuse_file_get(wpa->ia.ff); tree_insert(&fi->writepages, next); /* * Skip fuse_flush_writepages() to make it easy to crop requests * based on primary request size. * * 1st case (trivial): there are no concurrent activities using * fuse_set/release_nowrite. Then we're on safe side because * fuse_flush_writepages() would call fuse_send_writepage() * anyway. * * 2nd case: someone called fuse_set_nowrite and it is waiting * now for completion of all in-flight requests. This happens * rarely and no more than once per page, so this should be * okay. * * 3rd case: someone (e.g. fuse_do_setattr()) is in the middle * of fuse_set_nowrite..fuse_release_nowrite section. The fact * that fuse_set_nowrite returned implies that all in-flight * requests were completed along with all of their secondary * requests. Further primary requests are blocked by negative * writectr. Hence there cannot be any in-flight requests and * no invocations of fuse_writepage_end() while we're in * fuse_set_nowrite..fuse_release_nowrite section. */ fuse_send_writepage(fm, next, inarg->offset + inarg->size); } fi->writectr--; fuse_writepage_finish(fm, wpa); spin_unlock(&fi->lock); fuse_writepage_free(wpa); } static struct fuse_file *__fuse_write_file_get(struct fuse_inode *fi) { struct fuse_file *ff; spin_lock(&fi->lock); ff = list_first_entry_or_null(&fi->write_files, struct fuse_file, write_entry); if (ff) fuse_file_get(ff); spin_unlock(&fi->lock); return ff; } static struct fuse_file *fuse_write_file_get(struct fuse_inode *fi) { struct fuse_file *ff = __fuse_write_file_get(fi); WARN_ON(!ff); return ff; } int fuse_write_inode(struct inode *inode, struct writeback_control *wbc) { struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_file *ff; int err; /* * Inode is always written before the last reference is dropped and * hence this should not be reached from reclaim. * * Writing back the inode from reclaim can deadlock if the request * processing itself needs an allocation. Allocations triggering * reclaim while serving a request can't be prevented, because it can * involve any number of unrelated userspace processes. */ WARN_ON(wbc->for_reclaim); ff = __fuse_write_file_get(fi); err = fuse_flush_times(inode, ff); if (ff) fuse_file_put(ff, false, false); return err; } static struct fuse_writepage_args *fuse_writepage_args_alloc(void) { struct fuse_writepage_args *wpa; struct fuse_args_pages *ap; wpa = kzalloc(sizeof(*wpa), GFP_NOFS); if (wpa) { ap = &wpa->ia.ap; ap->num_pages = 0; ap->pages = fuse_pages_alloc(1, GFP_NOFS, &ap->descs); if (!ap->pages) { kfree(wpa); wpa = NULL; } } return wpa; } static void fuse_writepage_add_to_bucket(struct fuse_conn *fc, struct fuse_writepage_args *wpa) { if (!fc->sync_fs) return; rcu_read_lock(); /* Prevent resurrection of dead bucket in unlikely race with syncfs */ do { wpa->bucket = rcu_dereference(fc->curr_bucket); } while (unlikely(!atomic_inc_not_zero(&wpa->bucket->count))); rcu_read_unlock(); } static int fuse_writepage_locked(struct page *page) { struct address_space *mapping = page->mapping; struct inode *inode = mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_writepage_args *wpa; struct fuse_args_pages *ap; struct page *tmp_page; int error = -ENOMEM; set_page_writeback(page); wpa = fuse_writepage_args_alloc(); if (!wpa) goto err; ap = &wpa->ia.ap; tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); if (!tmp_page) goto err_free; error = -EIO; wpa->ia.ff = fuse_write_file_get(fi); if (!wpa->ia.ff) goto err_nofile; fuse_writepage_add_to_bucket(fc, wpa); fuse_write_args_fill(&wpa->ia, wpa->ia.ff, page_offset(page), 0); copy_highpage(tmp_page, page); wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE; wpa->next = NULL; ap->args.in_pages = true; ap->num_pages = 1; ap->pages[0] = tmp_page; ap->descs[0].offset = 0; ap->descs[0].length = PAGE_SIZE; ap->args.end = fuse_writepage_end; wpa->inode = inode; inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK); inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP); spin_lock(&fi->lock); tree_insert(&fi->writepages, wpa); list_add_tail(&wpa->queue_entry, &fi->queued_writes); fuse_flush_writepages(inode); spin_unlock(&fi->lock); end_page_writeback(page); return 0; err_nofile: __free_page(tmp_page); err_free: kfree(wpa); err: mapping_set_error(page->mapping, error); end_page_writeback(page); return error; } static int fuse_writepage(struct page *page, struct writeback_control *wbc) { struct fuse_conn *fc = get_fuse_conn(page->mapping->host); int err; if (fuse_page_is_writeback(page->mapping->host, page->index)) { /* * ->writepages() should be called for sync() and friends. We * should only get here on direct reclaim and then we are * allowed to skip a page which is already in flight */ WARN_ON(wbc->sync_mode == WB_SYNC_ALL); redirty_page_for_writepage(wbc, page); unlock_page(page); return 0; } if (wbc->sync_mode == WB_SYNC_NONE && fc->num_background >= fc->congestion_threshold) return AOP_WRITEPAGE_ACTIVATE; err = fuse_writepage_locked(page); unlock_page(page); return err; } struct fuse_fill_wb_data { struct fuse_writepage_args *wpa; struct fuse_file *ff; struct inode *inode; struct page **orig_pages; unsigned int max_pages; }; static bool fuse_pages_realloc(struct fuse_fill_wb_data *data) { struct fuse_args_pages *ap = &data->wpa->ia.ap; struct fuse_conn *fc = get_fuse_conn(data->inode); struct page **pages; struct fuse_page_desc *descs; unsigned int npages = min_t(unsigned int, max_t(unsigned int, data->max_pages * 2, FUSE_DEFAULT_MAX_PAGES_PER_REQ), fc->max_pages); WARN_ON(npages <= data->max_pages); pages = fuse_pages_alloc(npages, GFP_NOFS, &descs); if (!pages) return false; memcpy(pages, ap->pages, sizeof(struct page *) * ap->num_pages); memcpy(descs, ap->descs, sizeof(struct fuse_page_desc) * ap->num_pages); kfree(ap->pages); ap->pages = pages; ap->descs = descs; data->max_pages = npages; return true; } static void fuse_writepages_send(struct fuse_fill_wb_data *data) { struct fuse_writepage_args *wpa = data->wpa; struct inode *inode = data->inode; struct fuse_inode *fi = get_fuse_inode(inode); int num_pages = wpa->ia.ap.num_pages; int i; wpa->ia.ff = fuse_file_get(data->ff); spin_lock(&fi->lock); list_add_tail(&wpa->queue_entry, &fi->queued_writes); fuse_flush_writepages(inode); spin_unlock(&fi->lock); for (i = 0; i < num_pages; i++) end_page_writeback(data->orig_pages[i]); } /* * Check under fi->lock if the page is under writeback, and insert it onto the * rb_tree if not. Otherwise iterate auxiliary write requests, to see if there's * one already added for a page at this offset. If there's none, then insert * this new request onto the auxiliary list, otherwise reuse the existing one by * swapping the new temp page with the old one. */ static bool fuse_writepage_add(struct fuse_writepage_args *new_wpa, struct page *page) { struct fuse_inode *fi = get_fuse_inode(new_wpa->inode); struct fuse_writepage_args *tmp; struct fuse_writepage_args *old_wpa; struct fuse_args_pages *new_ap = &new_wpa->ia.ap; WARN_ON(new_ap->num_pages != 0); new_ap->num_pages = 1; spin_lock(&fi->lock); old_wpa = fuse_insert_writeback(&fi->writepages, new_wpa); if (!old_wpa) { spin_unlock(&fi->lock); return true; } for (tmp = old_wpa->next; tmp; tmp = tmp->next) { pgoff_t curr_index; WARN_ON(tmp->inode != new_wpa->inode); curr_index = tmp->ia.write.in.offset >> PAGE_SHIFT; if (curr_index == page->index) { WARN_ON(tmp->ia.ap.num_pages != 1); swap(tmp->ia.ap.pages[0], new_ap->pages[0]); break; } } if (!tmp) { new_wpa->next = old_wpa->next; old_wpa->next = new_wpa; } spin_unlock(&fi->lock); if (tmp) { struct backing_dev_info *bdi = inode_to_bdi(new_wpa->inode); dec_wb_stat(&bdi->wb, WB_WRITEBACK); dec_node_page_state(new_ap->pages[0], NR_WRITEBACK_TEMP); wb_writeout_inc(&bdi->wb); fuse_writepage_free(new_wpa); } return false; } static bool fuse_writepage_need_send(struct fuse_conn *fc, struct page *page, struct fuse_args_pages *ap, struct fuse_fill_wb_data *data) { WARN_ON(!ap->num_pages); /* * Being under writeback is unlikely but possible. For example direct * read to an mmaped fuse file will set the page dirty twice; once when * the pages are faulted with get_user_pages(), and then after the read * completed. */ if (fuse_page_is_writeback(data->inode, page->index)) return true; /* Reached max pages */ if (ap->num_pages == fc->max_pages) return true; /* Reached max write bytes */ if ((ap->num_pages + 1) * PAGE_SIZE > fc->max_write) return true; /* Discontinuity */ if (data->orig_pages[ap->num_pages - 1]->index + 1 != page->index) return true; /* Need to grow the pages array? If so, did the expansion fail? */ if (ap->num_pages == data->max_pages && !fuse_pages_realloc(data)) return true; return false; } static int fuse_writepages_fill(struct page *page, struct writeback_control *wbc, void *_data) { struct fuse_fill_wb_data *data = _data; struct fuse_writepage_args *wpa = data->wpa; struct fuse_args_pages *ap = &wpa->ia.ap; struct inode *inode = data->inode; struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_conn *fc = get_fuse_conn(inode); struct page *tmp_page; int err; if (!data->ff) { err = -EIO; data->ff = fuse_write_file_get(fi); if (!data->ff) goto out_unlock; } if (wpa && fuse_writepage_need_send(fc, page, ap, data)) { fuse_writepages_send(data); data->wpa = NULL; } err = -ENOMEM; tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); if (!tmp_page) goto out_unlock; /* * The page must not be redirtied until the writeout is completed * (i.e. userspace has sent a reply to the write request). Otherwise * there could be more than one temporary page instance for each real * page. * * This is ensured by holding the page lock in page_mkwrite() while * checking fuse_page_is_writeback(). We already hold the page lock * since clear_page_dirty_for_io() and keep it held until we add the * request to the fi->writepages list and increment ap->num_pages. * After this fuse_page_is_writeback() will indicate that the page is * under writeback, so we can release the page lock. */ if (data->wpa == NULL) { err = -ENOMEM; wpa = fuse_writepage_args_alloc(); if (!wpa) { __free_page(tmp_page); goto out_unlock; } fuse_writepage_add_to_bucket(fc, wpa); data->max_pages = 1; ap = &wpa->ia.ap; fuse_write_args_fill(&wpa->ia, data->ff, page_offset(page), 0); wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE; wpa->next = NULL; ap->args.in_pages = true; ap->args.end = fuse_writepage_end; ap->num_pages = 0; wpa->inode = inode; } set_page_writeback(page); copy_highpage(tmp_page, page); ap->pages[ap->num_pages] = tmp_page; ap->descs[ap->num_pages].offset = 0; ap->descs[ap->num_pages].length = PAGE_SIZE; data->orig_pages[ap->num_pages] = page; inc_wb_stat(&inode_to_bdi(inode)->wb, WB_WRITEBACK); inc_node_page_state(tmp_page, NR_WRITEBACK_TEMP); err = 0; if (data->wpa) { /* * Protected by fi->lock against concurrent access by * fuse_page_is_writeback(). */ spin_lock(&fi->lock); ap->num_pages++; spin_unlock(&fi->lock); } else if (fuse_writepage_add(wpa, page)) { data->wpa = wpa; } else { end_page_writeback(page); } out_unlock: unlock_page(page); return err; } static int fuse_writepages(struct address_space *mapping, struct writeback_control *wbc) { struct inode *inode = mapping->host; struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_fill_wb_data data; int err; err = -EIO; if (fuse_is_bad(inode)) goto out; if (wbc->sync_mode == WB_SYNC_NONE && fc->num_background >= fc->congestion_threshold) return 0; data.inode = inode; data.wpa = NULL; data.ff = NULL; err = -ENOMEM; data.orig_pages = kcalloc(fc->max_pages, sizeof(struct page *), GFP_NOFS); if (!data.orig_pages) goto out; err = write_cache_pages(mapping, wbc, fuse_writepages_fill, &data); if (data.wpa) { WARN_ON(!data.wpa->ia.ap.num_pages); fuse_writepages_send(&data); } if (data.ff) fuse_file_put(data.ff, false, false); kfree(data.orig_pages); out: return err; } /* * It's worthy to make sure that space is reserved on disk for the write, * but how to implement it without killing performance need more thinking. */ static int fuse_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) { pgoff_t index = pos >> PAGE_SHIFT; struct fuse_conn *fc = get_fuse_conn(file_inode(file)); struct page *page; loff_t fsize; int err = -ENOMEM; WARN_ON(!fc->writeback_cache); page = grab_cache_page_write_begin(mapping, index, flags); if (!page) goto error; fuse_wait_on_page_writeback(mapping->host, page->index); if (PageUptodate(page) || len == PAGE_SIZE) goto success; /* * Check if the start this page comes after the end of file, in which * case the readpage can be optimized away. */ fsize = i_size_read(mapping->host); if (fsize <= (pos & PAGE_MASK)) { size_t off = pos & ~PAGE_MASK; if (off) zero_user_segment(page, 0, off); goto success; } err = fuse_do_readpage(file, page); if (err) goto cleanup; success: *pagep = page; return 0; cleanup: unlock_page(page); put_page(page); error: return err; } static int fuse_write_end(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned copied, struct page *page, void *fsdata) { struct inode *inode = page->mapping->host; /* Haven't copied anything? Skip zeroing, size extending, dirtying. */ if (!copied) goto unlock; pos += copied; if (!PageUptodate(page)) { /* Zero any unwritten bytes at the end of the page */ size_t endoff = pos & ~PAGE_MASK; if (endoff) zero_user_segment(page, endoff, PAGE_SIZE); SetPageUptodate(page); } if (pos > inode->i_size) i_size_write(inode, pos); set_page_dirty(page); unlock: unlock_page(page); put_page(page); return copied; } static int fuse_launder_folio(struct folio *folio) { int err = 0; if (folio_clear_dirty_for_io(folio)) { struct inode *inode = folio->mapping->host; /* Serialize with pending writeback for the same page */ fuse_wait_on_page_writeback(inode, folio->index); err = fuse_writepage_locked(&folio->page); if (!err) fuse_wait_on_page_writeback(inode, folio->index); } return err; } /* * Write back dirty data/metadata now (there may not be any suitable * open files later for data) */ static void fuse_vma_close(struct vm_area_struct *vma) { int err; err = write_inode_now(vma->vm_file->f_mapping->host, 1); mapping_set_error(vma->vm_file->f_mapping, err); } /* * Wait for writeback against this page to complete before allowing it * to be marked dirty again, and hence written back again, possibly * before the previous writepage completed. * * Block here, instead of in ->writepage(), so that the userspace fs * can only block processes actually operating on the filesystem. * * Otherwise unprivileged userspace fs would be able to block * unrelated: * * - page migration * - sync(2) * - try_to_free_pages() with order > PAGE_ALLOC_COSTLY_ORDER */ static vm_fault_t fuse_page_mkwrite(struct vm_fault *vmf) { struct page *page = vmf->page; struct inode *inode = file_inode(vmf->vma->vm_file); file_update_time(vmf->vma->vm_file); lock_page(page); if (page->mapping != inode->i_mapping) { unlock_page(page); return VM_FAULT_NOPAGE; } fuse_wait_on_page_writeback(inode, page->index); return VM_FAULT_LOCKED; } static const struct vm_operations_struct fuse_file_vm_ops = { .close = fuse_vma_close, .fault = filemap_fault, .map_pages = filemap_map_pages, .page_mkwrite = fuse_page_mkwrite, }; static int fuse_file_mmap(struct file *file, struct vm_area_struct *vma) { struct fuse_file *ff = file->private_data; /* DAX mmap is superior to direct_io mmap */ if (FUSE_IS_DAX(file_inode(file))) return fuse_dax_mmap(file, vma); if (ff->open_flags & FOPEN_DIRECT_IO) { /* Can't provide the coherency needed for MAP_SHARED */ if (vma->vm_flags & VM_MAYSHARE) return -ENODEV; invalidate_inode_pages2(file->f_mapping); return generic_file_mmap(file, vma); } if ((vma->vm_flags & VM_SHARED) && (vma->vm_flags & VM_MAYWRITE)) fuse_link_write_file(file); file_accessed(file); vma->vm_ops = &fuse_file_vm_ops; return 0; } static int convert_fuse_file_lock(struct fuse_conn *fc, const struct fuse_file_lock *ffl, struct file_lock *fl) { switch (ffl->type) { case F_UNLCK: break; case F_RDLCK: case F_WRLCK: if (ffl->start > OFFSET_MAX || ffl->end > OFFSET_MAX || ffl->end < ffl->start) return -EIO; fl->fl_start = ffl->start; fl->fl_end = ffl->end; /* * Convert pid into init's pid namespace. The locks API will * translate it into the caller's pid namespace. */ rcu_read_lock(); fl->fl_pid = pid_nr_ns(find_pid_ns(ffl->pid, fc->pid_ns), &init_pid_ns); rcu_read_unlock(); break; default: return -EIO; } fl->fl_type = ffl->type; return 0; } static void fuse_lk_fill(struct fuse_args *args, struct file *file, const struct file_lock *fl, int opcode, pid_t pid, int flock, struct fuse_lk_in *inarg) { struct inode *inode = file_inode(file); struct fuse_conn *fc = get_fuse_conn(inode); struct fuse_file *ff = file->private_data; memset(inarg, 0, sizeof(*inarg)); inarg->fh = ff->fh; inarg->owner = fuse_lock_owner_id(fc, fl->fl_owner); inarg->lk.start = fl->fl_start; inarg->lk.end = fl->fl_end; inarg->lk.type = fl->fl_type; inarg->lk.pid = pid; if (flock) inarg->lk_flags |= FUSE_LK_FLOCK; args->opcode = opcode; args->nodeid = get_node_id(inode); args->in_numargs = 1; args->in_args[0].size = sizeof(*inarg); args->in_args[0].value = inarg; } static int fuse_getlk(struct file *file, struct file_lock *fl) { struct inode *inode = file_inode(file); struct fuse_mount *fm = get_fuse_mount(inode); FUSE_ARGS(args); struct fuse_lk_in inarg; struct fuse_lk_out outarg; int err; fuse_lk_fill(&args, file, fl, FUSE_GETLK, 0, 0, &inarg); args.out_numargs = 1; args.out_args[0].size = sizeof(outarg); args.out_args[0].value = &outarg; err = fuse_simple_request(fm, &args); if (!err) err = convert_fuse_file_lock(fm->fc, &outarg.lk, fl); return err; } static int fuse_setlk(struct file *file, struct file_lock *fl, int flock) { struct inode *inode = file_inode(file); struct fuse_mount *fm = get_fuse_mount(inode); FUSE_ARGS(args); struct fuse_lk_in inarg; int opcode = (fl->fl_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK; struct pid *pid = fl->fl_type != F_UNLCK ? task_tgid(current) : NULL; pid_t pid_nr = pid_nr_ns(pid, fm->fc->pid_ns); int err; if (fl->fl_lmops && fl->fl_lmops->lm_grant) { /* NLM needs asynchronous locks, which we don't support yet */ return -ENOLCK; } /* Unlock on close is handled by the flush method */ if ((fl->fl_flags & FL_CLOSE_POSIX) == FL_CLOSE_POSIX) return 0; fuse_lk_fill(&args, file, fl, opcode, pid_nr, flock, &inarg); err = fuse_simple_request(fm, &args); /* locking is restartable */ if (err == -EINTR) err = -ERESTARTSYS; return err; } static int fuse_file_lock(struct file *file, int cmd, struct file_lock *fl) { struct inode *inode = file_inode(file); struct fuse_conn *fc = get_fuse_conn(inode); int err; if (cmd == F_CANCELLK) { err = 0; } else if (cmd == F_GETLK) { if (fc->no_lock) { posix_test_lock(file, fl); err = 0; } else err = fuse_getlk(file, fl); } else { if (fc->no_lock) err = posix_lock_file(file, fl, NULL); else err = fuse_setlk(file, fl, 0); } return err; } static int fuse_file_flock(struct file *file, int cmd, struct file_lock *fl) { struct inode *inode = file_inode(file); struct fuse_conn *fc = get_fuse_conn(inode); int err; if (fc->no_flock) { err = locks_lock_file_wait(file, fl); } else { struct fuse_file *ff = file->private_data; /* emulate flock with POSIX locks */ ff->flock = true; err = fuse_setlk(file, fl, 1); } return err; } static sector_t fuse_bmap(struct address_space *mapping, sector_t block) { struct inode *inode = mapping->host; struct fuse_mount *fm = get_fuse_mount(inode); FUSE_ARGS(args); struct fuse_bmap_in inarg; struct fuse_bmap_out outarg; int err; if (!inode->i_sb->s_bdev || fm->fc->no_bmap) return 0; memset(&inarg, 0, sizeof(inarg)); inarg.block = block; inarg.blocksize = inode->i_sb->s_blocksize; args.opcode = FUSE_BMAP; args.nodeid = get_node_id(inode); args.in_numargs = 1; args.in_args[0].size = sizeof(inarg); args.in_args[0].value = &inarg; args.out_numargs = 1; args.out_args[0].size = sizeof(outarg); args.out_args[0].value = &outarg; err = fuse_simple_request(fm, &args); if (err == -ENOSYS) fm->fc->no_bmap = 1; return err ? 0 : outarg.block; } static loff_t fuse_lseek(struct file *file, loff_t offset, int whence) { struct inode *inode = file->f_mapping->host; struct fuse_mount *fm = get_fuse_mount(inode); struct fuse_file *ff = file->private_data; FUSE_ARGS(args); struct fuse_lseek_in inarg = { .fh = ff->fh, .offset = offset, .whence = whence }; struct fuse_lseek_out outarg; int err; if (fm->fc->no_lseek) goto fallback; args.opcode = FUSE_LSEEK; args.nodeid = ff->nodeid; args.in_numargs = 1; args.in_args[0].size = sizeof(inarg); args.in_args[0].value = &inarg; args.out_numargs = 1; args.out_args[0].size = sizeof(outarg); args.out_args[0].value = &outarg; err = fuse_simple_request(fm, &args); if (err) { if (err == -ENOSYS) { fm->fc->no_lseek = 1; goto fallback; } return err; } return vfs_setpos(file, outarg.offset, inode->i_sb->s_maxbytes); fallback: err = fuse_update_attributes(inode, file, STATX_SIZE); if (!err) return generic_file_llseek(file, offset, whence); else return err; } static loff_t fuse_file_llseek(struct file *file, loff_t offset, int whence) { loff_t retval; struct inode *inode = file_inode(file); switch (whence) { case SEEK_SET: case SEEK_CUR: /* No i_mutex protection necessary for SEEK_CUR and SEEK_SET */ retval = generic_file_llseek(file, offset, whence); break; case SEEK_END: inode_lock(inode); retval = fuse_update_attributes(inode, file, STATX_SIZE); if (!retval) retval = generic_file_llseek(file, offset, whence); inode_unlock(inode); break; case SEEK_HOLE: case SEEK_DATA: inode_lock(inode); retval = fuse_lseek(file, offset, whence); inode_unlock(inode); break; default: retval = -EINVAL; } return retval; } /* * All files which have been polled are linked to RB tree * fuse_conn->polled_files which is indexed by kh. Walk the tree and * find the matching one. */ static struct rb_node **fuse_find_polled_node(struct fuse_conn *fc, u64 kh, struct rb_node **parent_out) { struct rb_node **link = &fc->polled_files.rb_node; struct rb_node *last = NULL; while (*link) { struct fuse_file *ff; last = *link; ff = rb_entry(last, struct fuse_file, polled_node); if (kh < ff->kh) link = &last->rb_left; else if (kh > ff->kh) link = &last->rb_right; else return link; } if (parent_out) *parent_out = last; return link; } /* * The file is about to be polled. Make sure it's on the polled_files * RB tree. Note that files once added to the polled_files tree are * not removed before the file is released. This is because a file * polled once is likely to be polled again. */ static void fuse_register_polled_file(struct fuse_conn *fc, struct fuse_file *ff) { spin_lock(&fc->lock); if (RB_EMPTY_NODE(&ff->polled_node)) { struct rb_node **link, *parent; link = fuse_find_polled_node(fc, ff->kh, &parent); BUG_ON(*link); rb_link_node(&ff->polled_node, parent, link); rb_insert_color(&ff->polled_node, &fc->polled_files); } spin_unlock(&fc->lock); } __poll_t fuse_file_poll(struct file *file, poll_table *wait) { struct fuse_file *ff = file->private_data; struct fuse_mount *fm = ff->fm; struct fuse_poll_in inarg = { .fh = ff->fh, .kh = ff->kh }; struct fuse_poll_out outarg; FUSE_ARGS(args); int err; if (fm->fc->no_poll) return DEFAULT_POLLMASK; poll_wait(file, &ff->poll_wait, wait); inarg.events = mangle_poll(poll_requested_events(wait)); /* * Ask for notification iff there's someone waiting for it. * The client may ignore the flag and always notify. */ if (waitqueue_active(&ff->poll_wait)) { inarg.flags |= FUSE_POLL_SCHEDULE_NOTIFY; fuse_register_polled_file(fm->fc, ff); } args.opcode = FUSE_POLL; args.nodeid = ff->nodeid; args.in_numargs = 1; args.in_args[0].size = sizeof(inarg); args.in_args[0].value = &inarg; args.out_numargs = 1; args.out_args[0].size = sizeof(outarg); args.out_args[0].value = &outarg; err = fuse_simple_request(fm, &args); if (!err) return demangle_poll(outarg.revents); if (err == -ENOSYS) { fm->fc->no_poll = 1; return DEFAULT_POLLMASK; } return EPOLLERR; } EXPORT_SYMBOL_GPL(fuse_file_poll); /* * This is called from fuse_handle_notify() on FUSE_NOTIFY_POLL and * wakes up the poll waiters. */ int fuse_notify_poll_wakeup(struct fuse_conn *fc, struct fuse_notify_poll_wakeup_out *outarg) { u64 kh = outarg->kh; struct rb_node **link; spin_lock(&fc->lock); link = fuse_find_polled_node(fc, kh, NULL); if (*link) { struct fuse_file *ff; ff = rb_entry(*link, struct fuse_file, polled_node); wake_up_interruptible_sync(&ff->poll_wait); } spin_unlock(&fc->lock); return 0; } static void fuse_do_truncate(struct file *file) { struct inode *inode = file->f_mapping->host; struct iattr attr; attr.ia_valid = ATTR_SIZE; attr.ia_size = i_size_read(inode); attr.ia_file = file; attr.ia_valid |= ATTR_FILE; fuse_do_setattr(file_dentry(file), &attr, file); } static inline loff_t fuse_round_up(struct fuse_conn *fc, loff_t off) { return round_up(off, fc->max_pages << PAGE_SHIFT); } static ssize_t fuse_direct_IO(struct kiocb *iocb, struct iov_iter *iter) { DECLARE_COMPLETION_ONSTACK(wait); ssize_t ret = 0; struct file *file = iocb->ki_filp; struct fuse_file *ff = file->private_data; loff_t pos = 0; struct inode *inode; loff_t i_size; size_t count = iov_iter_count(iter), shortened = 0; loff_t offset = iocb->ki_pos; struct fuse_io_priv *io; pos = offset; inode = file->f_mapping->host; i_size = i_size_read(inode); if ((iov_iter_rw(iter) == READ) && (offset >= i_size)) return 0; io = kmalloc(sizeof(struct fuse_io_priv), GFP_KERNEL); if (!io) return -ENOMEM; spin_lock_init(&io->lock); kref_init(&io->refcnt); io->reqs = 1; io->bytes = -1; io->size = 0; io->offset = offset; io->write = (iov_iter_rw(iter) == WRITE); io->err = 0; /* * By default, we want to optimize all I/Os with async request * submission to the client filesystem if supported. */ io->async = ff->fm->fc->async_dio; io->iocb = iocb; io->blocking = is_sync_kiocb(iocb); /* optimization for short read */ if (io->async && !io->write && offset + count > i_size) { iov_iter_truncate(iter, fuse_round_up(ff->fm->fc, i_size - offset)); shortened = count - iov_iter_count(iter); count -= shortened; } /* * We cannot asynchronously extend the size of a file. * In such case the aio will behave exactly like sync io. */ if ((offset + count > i_size) && io->write) io->blocking = true; if (io->async && io->blocking) { /* * Additional reference to keep io around after * calling fuse_aio_complete() */ kref_get(&io->refcnt); io->done = &wait; } if (iov_iter_rw(iter) == WRITE) { ret = fuse_direct_io(io, iter, &pos, FUSE_DIO_WRITE); fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE); } else { ret = __fuse_direct_read(io, iter, &pos); } iov_iter_reexpand(iter, iov_iter_count(iter) + shortened); if (io->async) { bool blocking = io->blocking; fuse_aio_complete(io, ret < 0 ? ret : 0, -1); /* we have a non-extending, async request, so return */ if (!blocking) return -EIOCBQUEUED; wait_for_completion(&wait); ret = fuse_get_res_by_io(io); } kref_put(&io->refcnt, fuse_io_release); if (iov_iter_rw(iter) == WRITE) { fuse_write_update_attr(inode, pos, ret); if (ret < 0 && offset + count > i_size) fuse_do_truncate(file); } return ret; } static int fuse_writeback_range(struct inode *inode, loff_t start, loff_t end) { int err = filemap_write_and_wait_range(inode->i_mapping, start, LLONG_MAX); if (!err) fuse_sync_writes(inode); return err; } static long fuse_file_fallocate(struct file *file, int mode, loff_t offset, loff_t length) { struct fuse_file *ff = file->private_data; struct inode *inode = file_inode(file); struct fuse_inode *fi = get_fuse_inode(inode); struct fuse_mount *fm = ff->fm; FUSE_ARGS(args); struct fuse_fallocate_in inarg = { .fh = ff->fh, .offset = offset, .length = length, .mode = mode }; int err; bool lock_inode = !(mode & FALLOC_FL_KEEP_SIZE) || (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)); bool block_faults = FUSE_IS_DAX(inode) && lock_inode; if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) return -EOPNOTSUPP; if (fm->fc->no_fallocate) return -EOPNOTSUPP; if (lock_inode) { inode_lock(inode); if (block_faults) { filemap_invalidate_lock(inode->i_mapping); err = fuse_dax_break_layouts(inode, 0, 0); if (err) goto out; } if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) { loff_t endbyte = offset + length - 1; err = fuse_writeback_range(inode, offset, endbyte); if (err) goto out; } } if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + length > i_size_read(inode)) { err = inode_newsize_ok(inode, offset + length); if (err) goto out; } if (!(mode & FALLOC_FL_KEEP_SIZE)) set_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); args.opcode = FUSE_FALLOCATE; args.nodeid = ff->nodeid; args.in_numargs = 1; args.in_args[0].size = sizeof(inarg); args.in_args[0].value = &inarg; err = fuse_simple_request(fm, &args); if (err == -ENOSYS) { fm->fc->no_fallocate = 1; err = -EOPNOTSUPP; } if (err) goto out; /* we could have extended the file */ if (!(mode & FALLOC_FL_KEEP_SIZE)) { if (fuse_write_update_attr(inode, offset + length, length)) file_update_time(file); } if (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) truncate_pagecache_range(inode, offset, offset + length - 1); fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE); out: if (!(mode & FALLOC_FL_KEEP_SIZE)) clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); if (block_faults) filemap_invalidate_unlock(inode->i_mapping); if (lock_inode) inode_unlock(inode); fuse_flush_time_update(inode); return err; } static ssize_t __fuse_copy_file_range(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, size_t len, unsigned int flags) { struct fuse_file *ff_in = file_in->private_data; struct fuse_file *ff_out = file_out->private_data; struct inode *inode_in = file_inode(file_in); struct inode *inode_out = file_inode(file_out); struct fuse_inode *fi_out = get_fuse_inode(inode_out); struct fuse_mount *fm = ff_in->fm; struct fuse_conn *fc = fm->fc; FUSE_ARGS(args); struct fuse_copy_file_range_in inarg = { .fh_in = ff_in->fh, .off_in = pos_in, .nodeid_out = ff_out->nodeid, .fh_out = ff_out->fh, .off_out = pos_out, .len = len, .flags = flags }; struct fuse_write_out outarg; ssize_t err; /* mark unstable when write-back is not used, and file_out gets * extended */ bool is_unstable = (!fc->writeback_cache) && ((pos_out + len) > inode_out->i_size); if (fc->no_copy_file_range) return -EOPNOTSUPP; if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb) return -EXDEV; inode_lock(inode_in); err = fuse_writeback_range(inode_in, pos_in, pos_in + len - 1); inode_unlock(inode_in); if (err) return err; inode_lock(inode_out); err = file_modified(file_out); if (err) goto out; /* * Write out dirty pages in the destination file before sending the COPY * request to userspace. After the request is completed, truncate off * pages (including partial ones) from the cache that have been copied, * since these contain stale data at that point. * * This should be mostly correct, but if the COPY writes to partial * pages (at the start or end) and the parts not covered by the COPY are * written through a memory map after calling fuse_writeback_range(), * then these partial page modifications will be lost on truncation. * * It is unlikely that someone would rely on such mixed style * modifications. Yet this does give less guarantees than if the * copying was performed with write(2). * * To fix this a mapping->invalidate_lock could be used to prevent new * faults while the copy is ongoing. */ err = fuse_writeback_range(inode_out, pos_out, pos_out + len - 1); if (err) goto out; if (is_unstable) set_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state); args.opcode = FUSE_COPY_FILE_RANGE; args.nodeid = ff_in->nodeid; args.in_numargs = 1; args.in_args[0].size = sizeof(inarg); args.in_args[0].value = &inarg; args.out_numargs = 1; args.out_args[0].size = sizeof(outarg); args.out_args[0].value = &outarg; err = fuse_simple_request(fm, &args); if (err == -ENOSYS) { fc->no_copy_file_range = 1; err = -EOPNOTSUPP; } if (err) goto out; truncate_inode_pages_range(inode_out->i_mapping, ALIGN_DOWN(pos_out, PAGE_SIZE), ALIGN(pos_out + outarg.size, PAGE_SIZE) - 1); file_update_time(file_out); fuse_write_update_attr(inode_out, pos_out + outarg.size, outarg.size); err = outarg.size; out: if (is_unstable) clear_bit(FUSE_I_SIZE_UNSTABLE, &fi_out->state); inode_unlock(inode_out); file_accessed(file_in); fuse_flush_time_update(inode_out); return err; } static ssize_t fuse_copy_file_range(struct file *src_file, loff_t src_off, struct file *dst_file, loff_t dst_off, size_t len, unsigned int flags) { ssize_t ret; ret = __fuse_copy_file_range(src_file, src_off, dst_file, dst_off, len, flags); if (ret == -EOPNOTSUPP || ret == -EXDEV) ret = generic_copy_file_range(src_file, src_off, dst_file, dst_off, len, flags); return ret; } static const struct file_operations fuse_file_operations = { .llseek = fuse_file_llseek, .read_iter = fuse_file_read_iter, .write_iter = fuse_file_write_iter, .mmap = fuse_file_mmap, .open = fuse_open, .flush = fuse_flush, .release = fuse_release, .fsync = fuse_fsync, .lock = fuse_file_lock, .get_unmapped_area = thp_get_unmapped_area, .flock = fuse_file_flock, .splice_read = generic_file_splice_read, .splice_write = iter_file_splice_write, .unlocked_ioctl = fuse_file_ioctl, .compat_ioctl = fuse_file_compat_ioctl, .poll = fuse_file_poll, .fallocate = fuse_file_fallocate, .copy_file_range = fuse_copy_file_range, }; static const struct address_space_operations fuse_file_aops = { .readpage = fuse_readpage, .readahead = fuse_readahead, .writepage = fuse_writepage, .writepages = fuse_writepages, .launder_folio = fuse_launder_folio, .dirty_folio = filemap_dirty_folio, .bmap = fuse_bmap, .direct_IO = fuse_direct_IO, .write_begin = fuse_write_begin, .write_end = fuse_write_end, }; void fuse_init_file_inode(struct inode *inode, unsigned int flags) { struct fuse_inode *fi = get_fuse_inode(inode); inode->i_fop = &fuse_file_operations; inode->i_data.a_ops = &fuse_file_aops; INIT_LIST_HEAD(&fi->write_files); INIT_LIST_HEAD(&fi->queued_writes); fi->writectr = 0; init_waitqueue_head(&fi->page_waitq); fi->writepages = RB_ROOT; if (IS_ENABLED(CONFIG_FUSE_DAX)) fuse_dax_inode_init(inode, flags); }