diff options
Diffstat (limited to 'fs/fuse/file.c')
| -rw-r--r-- | fs/fuse/file.c | 3216 |
1 files changed, 3216 insertions, 0 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c new file mode 100644 index 000000000..c996c0ef8 --- /dev/null +++ b/fs/fuse/file.c @@ -0,0 +1,3216 @@ +/* + 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); + file_update_time(file); + fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE); + } + 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); + + if (dax_truncate) { + filemap_invalidate_lock(inode->i_mapping); + err = fuse_dax_break_layouts(inode, 0, 0); + if (err) + goto out_inode_unlock; + } + + if (is_wb_truncate || dax_truncate) + fuse_set_nowrite(inode); + + err = fuse_do_open(fm, get_node_id(inode), file, isdir); + if (!err) + fuse_finish_open(inode, file); + + if (is_wb_truncate || dax_truncate) + fuse_release_nowrite(inode); + if (!err) { + struct fuse_file *ff = file->private_data; + + if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) + truncate_pagecache(inode, 0); + else if (!(ff->open_flags & FOPEN_KEEP_CACHE)) + invalidate_inode_pages2(inode->i_mapping); + } + if (dax_truncate) + filemap_invalidate_unlock(inode->i_mapping); +out_inode_unlock: + if (is_wb_truncate || dax_truncate) + 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) +{ + struct fuse_conn *fc = get_fuse_conn(inode); + + /* + * Dirty pages might remain despite write_inode_now() call from + * fuse_flush() due to writes racing with the close. + */ + if (fc->writeback_cache) + write_inode_now(inode, 1); + + 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_read_folio(struct file *file, struct folio *folio) +{ + struct page *page = &folio->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_is_dsync(iocb)) + 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); + 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 && + setattr_should_drop_suidgid(&init_user_ns, file_inode(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_pages2(ii, &ap->pages[ap->num_pages], + *nbytesp - nbytes, + max_pages - ap->num_pages, + &start); + if (ret < 0) + break; + + 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 && user_backed_iter(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, 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); + 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 block_faults = FUSE_IS_DAX(inode) && + (!(mode & FALLOC_FL_KEEP_SIZE) || + (mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))); + + if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | + FALLOC_FL_ZERO_RANGE)) + return -EOPNOTSUPP; + + if (fm->fc->no_fallocate) + return -EOPNOTSUPP; + + 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; + } + + err = file_modified(file); + 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); + + 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 = { + .read_folio = fuse_read_folio, + .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); +} |