diff options
Diffstat (limited to 'fs/fuse/file.c')
| -rw-r--r-- | fs/fuse/file.c | 3120 |
1 files changed, 3120 insertions, 0 deletions
diff --git a/fs/fuse/file.c b/fs/fuse/file.c new file mode 100644 index 000000000..f2c081f09 --- /dev/null +++ b/fs/fuse/file.c @@ -0,0 +1,3120 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + FUSE: Filesystem in Userspace + Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu> +*/ + +#include "fuse_i.h" +#include "dev.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> +#include <linux/filelock.h> +#include <linux/splice.h> +#include <linux/task_io_accounting_ops.h> +#include <linux/iomap.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_file *fuse_file_alloc(struct fuse_mount *fm, bool release) +{ + struct fuse_file *ff; + + ff = kzalloc_obj(struct fuse_file, GFP_KERNEL_ACCOUNT); + if (unlikely(!ff)) + return NULL; + + ff->fm = fm; + if (release) { + ff->args = kzalloc_obj(*ff->args, GFP_KERNEL_ACCOUNT); + if (!ff->args) { + kfree(ff); + return NULL; + } + } + + INIT_LIST_HEAD(&ff->write_entry); + 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->args); + 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_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) +{ + if (refcount_dec_and_test(&ff->count)) { + struct fuse_release_args *ra = &ff->args->release_args; + struct fuse_args *args = (ra ? &ra->args : NULL); + + if (ra && ra->inode) + fuse_file_io_release(ff, ra->inode); + + if (!args) { + /* Do nothing when server does not implement 'opendir' */ + } else if (args->opcode == FUSE_RELEASE && ff->fm->fc->no_open) { + fuse_release_end(args, 0); + } else if (sync) { + fuse_simple_request(ff->fm, args); + fuse_release_end(args, 0); + } else { + /* + * DAX inodes may need to issue a number of synchronous + * request for clearing the mappings. + */ + if (ra && ra->inode && FUSE_IS_DAX(ra->inode)) + args->may_block = true; + args->end = fuse_release_end; + if (fuse_simple_background(ff->fm, args, + GFP_KERNEL | __GFP_NOFAIL)) + fuse_release_end(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; + bool open = isdir ? !fc->no_opendir : !fc->no_open; + bool release = !isdir || open; + + /* + * ff->args->release_args still needs to be allocated (so we can hold an + * inode reference while there are pending inflight file operations when + * ->release() is called, see fuse_prepare_release()) even if + * fc->no_open is set else it becomes possible for reclaim to deadlock + * if while servicing the readahead request the server triggers reclaim + * and reclaim evicts the inode of the file being read ahead. + */ + ff = fuse_file_alloc(fm, release); + 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 (open) { + /* Store outarg for fuse_finish_open() */ + struct fuse_open_out *outargp = &ff->args->open_outarg; + int err; + + err = fuse_send_open(fm, nodeid, open_flags, opcode, outargp); + if (!err) { + ff->fh = outargp->fh; + ff->open_flags = outargp->open_flags; + } else if (err != -ENOSYS) { + fuse_file_free(ff); + return ERR_PTR(err); + } else { + if (isdir) { + /* No release needed */ + kfree(ff->args); + ff->args = NULL; + 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); +} + +int fuse_finish_open(struct inode *inode, struct file *file) +{ + struct fuse_file *ff = file->private_data; + struct fuse_conn *fc = get_fuse_conn(inode); + int err; + + err = fuse_file_io_open(file, inode); + if (err) + return err; + + if (ff->open_flags & FOPEN_STREAM) + stream_open(inode, file); + else if (ff->open_flags & FOPEN_NONSEEKABLE) + nonseekable_open(inode, file); + + if ((file->f_mode & FMODE_WRITE) && fc->writeback_cache) + fuse_link_write_file(file); + + return 0; +} + +static void fuse_truncate_update_attr(struct inode *inode, struct file *file) +{ + 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); + i_size_write(inode, 0); + spin_unlock(&fi->lock); + file_update_time(file); + fuse_invalidate_attr_mask(inode, FUSE_STATX_MODSIZE); +} + +static int fuse_open(struct inode *inode, struct file *file) +{ + struct fuse_mount *fm = get_fuse_mount(inode); + struct fuse_inode *fi = get_fuse_inode(inode); + struct fuse_conn *fc = fm->fc; + struct fuse_file *ff; + int err; + bool is_truncate = (file->f_flags & O_TRUNC) && fc->atomic_o_trunc; + bool is_wb_truncate = is_truncate && fc->writeback_cache; + bool dax_truncate = is_truncate && 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, -1); + 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, false); + if (!err) { + ff = file->private_data; + err = fuse_finish_open(inode, file); + if (err) + fuse_sync_release(fi, ff, file->f_flags); + else if (is_truncate) + fuse_truncate_update_attr(inode, file); + } + + if (is_wb_truncate || dax_truncate) + fuse_release_nowrite(inode); + if (!err) { + if (is_truncate) + 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, bool sync) +{ + struct fuse_conn *fc = ff->fm->fc; + struct fuse_release_args *ra = &ff->args->release_args; + + if (fuse_file_passthrough(ff)) + fuse_passthrough_release(ff, fuse_inode_backing(fi)); + + /* 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); + + if (!ra) + return; + + /* ff->args was used for open outarg */ + memset(ff->args, 0, sizeof(*ff->args)); + 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; + + /* + * Hold inode until release is finished. + * From fuse_sync_release() the refcount is 1 and everything's + * synchronous, so we are fine with not doing igrab() here. + */ + ra->inode = sync ? NULL : igrab(&fi->inode); +} + +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->args->release_args; + int opcode = isdir ? FUSE_RELEASEDIR : FUSE_RELEASE; + + fuse_prepare_release(fi, ff, open_flags, opcode, false); + + if (ra && ff->flock) { + ra->inarg.release_flags |= FUSE_RELEASE_FLOCK_UNLOCK; + ra->inarg.lock_owner = fuse_lock_owner_id(ff->fm->fc, id); + } + + /* + * 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. + * + * Always use the asynchronous file put because the current thread + * might be the fuse server. This can happen if a process starts some + * aio and closes the fd before the aio completes. Since aio takes its + * own ref to the file, the IO completion has to drop the ref, which is + * how the fuse server can end up closing its clients' files. + * + * Exception is virtio-fs, which is not affected by the above (server is + * on host, cannot close open files in guest). Virtio-fs needs sync + * release, because the num_waiting mechanism to wait for all requests + * before commencing with fs shutdown doesn't work if submounts are + * used. + */ + fuse_file_put(ff, ff->fm->fc->auto_submounts); +} + +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_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, true); + fuse_file_put(ff, true); +} +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 list_head queue_entry; + struct inode *inode; + struct fuse_sync_bucket *bucket; +}; + +/* + * 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; + + 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, ssize_t nres, + bool should_dirty) +{ + unsigned int i; + + for (i = 0; i < ap->num_folios; i++) { + if (should_dirty) + folio_mark_dirty_lock(ap->folios[i]); + if (ap->args.is_pinned) + unpin_folio(ap->folios[i]); + } + + if (nres > 0 && ap->args.invalidate_vmap) + invalidate_kernel_vmap_range(ap->args.vmap_base, nres); +} + +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; +} + +static void fuse_aio_invalidate_worker(struct work_struct *work) +{ + struct fuse_io_priv *io = container_of(work, struct fuse_io_priv, work); + struct address_space *mapping = io->iocb->ki_filp->f_mapping; + ssize_t res = fuse_get_res_by_io(io); + pgoff_t start = io->offset >> PAGE_SHIFT; + pgoff_t end = (io->offset + res - 1) >> PAGE_SHIFT; + + invalidate_inode_pages2_range(mapping, start, end); + io->iocb->ki_complete(io->iocb, res); + kref_put(&io->refcnt, fuse_io_release); +} + +/* + * 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) { + struct inode *inode = file_inode(io->iocb->ki_filp); + struct address_space *mapping = io->iocb->ki_filp->f_mapping; + ssize_t res = fuse_get_res_by_io(io); + + if (res >= 0) { + 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); + } + + if (io->write && res > 0 && mapping->nrpages) { + /* + * As in generic_file_direct_write(), invalidate after the + * write, to invalidate read-ahead cache that may have competed + * with the write. + */ + INIT_WORK(&io->work, fuse_aio_invalidate_worker); + queue_work(inode->i_sb->s_dio_done_wq, &io->work); + return; + } + + 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 nfolios) +{ + struct fuse_io_args *ia; + + ia = kzalloc_obj(*ia); + if (ia) { + ia->io = io; + ia->ap.folios = fuse_folios_alloc(nfolios, GFP_KERNEL, + &ia->ap.descs); + if (!ia->ap.folios) { + kfree(ia); + ia = NULL; + } + } + return ia; +} + +static void fuse_io_free(struct fuse_io_args *ia) +{ + kfree(ia->ap.folios); + kfree(ia); +} + +static void fuse_aio_complete_req(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; + size_t nres; + + if (err) { + /* Nothing */ + } else if (io->write) { + if (ia->write.out.size > ia->write.in.size) { + err = -EIO; + } else { + nres = ia->write.out.size; + 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; + + nres = outsize; + if (ia->read.in.size != outsize) + pos = ia->read.in.offset - io->offset + outsize; + } + + fuse_release_user_pages(&ia->ap, err ?: nres, io->should_dirty); + + 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(&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 = folio_pos(ap->folios[0]) + num_read; + fuse_read_update_size(inode, pos, attr_ver); + } +} + +static int fuse_do_readfolio(struct file *file, struct folio *folio, + size_t off, size_t len) +{ + struct inode *inode = folio->mapping->host; + struct fuse_mount *fm = get_fuse_mount(inode); + loff_t pos = folio_pos(folio) + off; + struct fuse_folio_desc desc = { + .offset = off, + .length = len, + }; + struct fuse_io_args ia = { + .ap.args.page_zeroing = true, + .ap.args.out_pages = true, + .ap.num_folios = 1, + .ap.folios = &folio, + .ap.descs = &desc, + }; + ssize_t res; + u64 attr_ver; + + 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); + + return 0; +} + +static int fuse_iomap_begin(struct inode *inode, loff_t offset, loff_t length, + unsigned int flags, struct iomap *iomap, + struct iomap *srcmap) +{ + iomap->type = IOMAP_MAPPED; + iomap->length = length; + iomap->offset = offset; + return 0; +} + +static DEFINE_IOMAP_ITER_NEXT(fuse_iomap_next, fuse_iomap_begin); + +static const struct iomap_ops fuse_iomap_ops = { + .iomap_next = fuse_iomap_next, +}; + +struct fuse_fill_read_data { + struct file *file; + + /* Fields below are used if sending the read request asynchronously */ + struct fuse_conn *fc; + struct fuse_io_args *ia; + unsigned int nr_bytes; +}; + +/* forward declarations */ +static bool fuse_folios_need_send(struct fuse_conn *fc, loff_t pos, + unsigned len, struct fuse_args_pages *ap, + unsigned cur_bytes, bool write); +static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file, + unsigned int count, bool async); + +static int fuse_handle_readahead(struct folio *folio, + struct readahead_control *rac, + struct fuse_fill_read_data *data, loff_t pos, + size_t len) +{ + struct fuse_io_args *ia = data->ia; + size_t off = offset_in_folio(folio, pos); + struct fuse_conn *fc = data->fc; + struct fuse_args_pages *ap; + unsigned int nr_pages; + + if (ia && fuse_folios_need_send(fc, pos, len, &ia->ap, data->nr_bytes, + false)) { + fuse_send_readpages(ia, data->file, data->nr_bytes, + fc->async_read); + data->nr_bytes = 0; + data->ia = NULL; + ia = NULL; + } + if (!ia) { + if (fuse_chan_num_background(fc->chan) >= fc->congestion_threshold && + rac->ra->async_size >= readahead_count(rac)) + /* + * Congested and only async pages left, so skip the + * rest. + */ + return -EAGAIN; + + nr_pages = min(fc->max_pages, readahead_count(rac)); + data->ia = fuse_io_alloc(NULL, nr_pages); + if (!data->ia) + return -ENOMEM; + ia = data->ia; + } + folio_get(folio); + ap = &ia->ap; + ap->folios[ap->num_folios] = folio; + ap->descs[ap->num_folios].offset = off; + ap->descs[ap->num_folios].length = len; + data->nr_bytes += len; + ap->num_folios++; + + return 0; +} + +static int fuse_iomap_read_folio_range_async(const struct iomap_iter *iter, + struct iomap_read_folio_ctx *ctx, + size_t len) +{ + struct fuse_fill_read_data *data = ctx->read_ctx; + struct folio *folio = ctx->cur_folio; + loff_t pos = iter->pos; + size_t off = offset_in_folio(folio, pos); + struct file *file = data->file; + int ret; + + if (ctx->rac) { + ret = fuse_handle_readahead(folio, ctx->rac, data, pos, len); + } else { + /* + * for non-readahead read requests, do reads synchronously + * since it's not guaranteed that the server can handle + * out-of-order reads + */ + ret = fuse_do_readfolio(file, folio, off, len); + if (!ret) + iomap_finish_folio_read(folio, off, len, ret); + } + return ret; +} + +static const struct iomap_read_ops fuse_iomap_read_ops = { + .read_folio_range = fuse_iomap_read_folio_range_async, +}; + +static int fuse_read_folio(struct file *file, struct folio *folio) +{ + struct inode *inode = folio->mapping->host; + struct fuse_fill_read_data data = { + .file = file, + }; + struct iomap_read_folio_ctx ctx = { + .cur_folio = folio, + .ops = &fuse_iomap_read_ops, + .read_ctx = &data, + + }; + + if (fuse_is_bad(inode)) { + folio_unlock(folio); + return -EIO; + } + + iomap_read_folio(&fuse_iomap_ops, &ctx, NULL); + fuse_invalidate_atime(inode); + return 0; +} + +static int fuse_iomap_read_folio_range(const struct iomap_iter *iter, + struct folio *folio, loff_t pos, + size_t len) +{ + struct file *file = iter->private; + size_t off = offset_in_folio(folio, pos); + + return fuse_do_readfolio(file, folio, off, len); +} + +static void fuse_readpages_end(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; + struct inode *inode; + + WARN_ON_ONCE(!ap->num_folios); + mapping = ap->folios[0]->mapping; + 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_folios; i++) { + iomap_finish_folio_read(ap->folios[i], ap->descs[i].offset, + ap->descs[i].length, err); + folio_put(ap->folios[i]); + } + if (ia->ff) + fuse_file_put(ia->ff, false); + + fuse_io_free(ia); +} + +static void fuse_send_readpages(struct fuse_io_args *ia, struct file *file, + unsigned int count, bool async) +{ + struct fuse_file *ff = file->private_data; + struct fuse_mount *fm = ff->fm; + struct fuse_args_pages *ap = &ia->ap; + loff_t pos = folio_pos(ap->folios[0]); + 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_folios - 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 (async) { + 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(&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); + struct fuse_fill_read_data data = { + .file = rac->file, + .fc = fc, + }; + struct iomap_read_folio_ctx ctx = { + .ops = &fuse_iomap_read_ops, + .rac = rac, + .read_ctx = &data + }; + + if (fuse_is_bad(inode)) + return; + + iomap_readahead(&fuse_iomap_ops, &ctx, NULL); + if (data.ia) + fuse_send_readpages(data.ia, data.file, data.nr_bytes, + fc->async_read); +} + +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 i; + int err; + + for (i = 0; i < ap->num_folios; i++) + folio_wait_writeback(ap->folios[i]); + + 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; + + for (i = 0; i < ap->num_folios; i++) { + struct folio *folio = ap->folios[i]; + + if (ia->write.folio_locked && (i == ap->num_folios - 1)) + folio_unlock(folio); + folio_put(folio); + } + + 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_folios) +{ + struct fuse_args_pages *ap = &ia->ap; + struct fuse_conn *fc = get_fuse_conn(mapping->host); + size_t count = 0; + unsigned int num; + int err = 0; + + num = min(iov_iter_count(ii), fc->max_write); + + ap->args.in_pages = true; + + while (num && ap->num_folios < max_folios) { + size_t tmp; + struct folio *folio; + pgoff_t index = pos >> PAGE_SHIFT; + unsigned int bytes; + unsigned int folio_offset; + + again: + folio = __filemap_get_folio(mapping, index, FGP_WRITEBEGIN, + mapping_gfp_mask(mapping)); + if (IS_ERR(folio)) { + err = PTR_ERR(folio); + break; + } + + if (mapping_writably_mapped(mapping)) + flush_dcache_folio(folio); + + folio_offset = offset_in_folio(folio, pos); + bytes = min(folio_size(folio) - folio_offset, num); + + tmp = copy_folio_from_iter_atomic(folio, folio_offset, bytes, ii); + flush_dcache_folio(folio); + + if (!tmp) { + folio_unlock(folio); + folio_put(folio); + + /* + * Ensure forward progress by faulting in + * while not holding the folio lock: + */ + if (fault_in_iov_iter_readable(ii, bytes)) { + err = -EFAULT; + break; + } + + goto again; + } + + ap->folios[ap->num_folios] = folio; + ap->descs[ap->num_folios].offset = folio_offset; + ap->descs[ap->num_folios].length = tmp; + ap->num_folios++; + + count += tmp; + pos += tmp; + num -= tmp; + + /* If we copied full folio, mark it uptodate */ + if (tmp == folio_size(folio)) + iomap_folio_mark_uptodate(folio); + + if (folio_test_uptodate(folio)) { + folio_unlock(folio); + } else { + ia->write.folio_locked = true; + break; + } + if (!fc->big_writes) + break; + if (folio_offset + tmp != folio_size(folio)) + break; + } + + return count > 0 ? count : err; +} + +static inline unsigned int fuse_wr_pages(loff_t pos, size_t len, + unsigned int max_pages) +{ + unsigned int pages = ((pos + len - 1) >> PAGE_SHIFT) - + (pos >> PAGE_SHIFT) + 1; + + return min(pages, max_pages); +} + +static ssize_t fuse_perform_write(struct kiocb *iocb, struct iov_iter *ii) +{ + struct address_space *mapping = iocb->ki_filp->f_mapping; + struct inode *inode = mapping->host; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_inode *fi = get_fuse_inode(inode); + loff_t pos = iocb->ki_pos; + 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->folios = fuse_folios_alloc(nr_pages, GFP_KERNEL, &ap->descs); + if (!ap->folios) { + 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->folios); + } while (!err && iov_iter_count(ii)); + + fuse_write_update_attr(inode, pos, res); + clear_bit(FUSE_I_SIZE_UNSTABLE, &fi->state); + + if (!res) + return err; + iocb->ki_pos += res; + return res; +} + +static bool fuse_io_past_eof(struct kiocb *iocb, struct iov_iter *iter) +{ + struct inode *inode = file_inode(iocb->ki_filp); + + return iocb->ki_pos + iov_iter_count(iter) > i_size_read(inode); +} + +/* + * @return true if an exclusive lock for direct IO writes is needed + */ +static bool fuse_dio_wr_exclusive_lock(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(iocb->ki_filp); + struct fuse_inode *fi = get_fuse_inode(inode); + + /* Server side has to advise that it supports parallel dio writes. */ + if (!(ff->open_flags & FOPEN_PARALLEL_DIRECT_WRITES)) + return true; + + /* + * Append will need to know the eventual EOF - always needs an + * exclusive lock. + */ + if (iocb->ki_flags & IOCB_APPEND) + return true; + + /* shared locks are not allowed with parallel page cache IO */ + if (test_bit(FUSE_I_CACHE_IO_MODE, &fi->state)) + return true; + + /* Parallel dio beyond EOF is not supported, at least for now. */ + if (fuse_io_past_eof(iocb, from)) + return true; + + return false; +} + +static void fuse_dio_lock(struct kiocb *iocb, struct iov_iter *from, + bool *exclusive) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct fuse_inode *fi = get_fuse_inode(inode); + + *exclusive = fuse_dio_wr_exclusive_lock(iocb, from); + if (*exclusive) { + inode_lock(inode); + } else { + inode_lock_shared(inode); + /* + * New parallal dio allowed only if inode is not in caching + * mode and denies new opens in caching mode. This check + * should be performed only after taking shared inode lock. + * Previous past eof check was without inode lock and might + * have raced, so check it again. + */ + if (fuse_io_past_eof(iocb, from) || + fuse_inode_uncached_io_start(fi, NULL) != 0) { + inode_unlock_shared(inode); + inode_lock(inode); + *exclusive = true; + } + } +} + +static void fuse_dio_unlock(struct kiocb *iocb, bool exclusive) +{ + struct inode *inode = file_inode(iocb->ki_filp); + struct fuse_inode *fi = get_fuse_inode(inode); + + if (exclusive) { + inode_unlock(inode); + } else { + /* Allow opens in caching mode after last parallel dio end */ + fuse_inode_uncached_io_end(fi); + inode_unlock_shared(inode); + } +} + +static const struct iomap_write_ops fuse_iomap_write_ops = { + .read_folio_range = fuse_iomap_read_folio_range, +}; + +static ssize_t fuse_cache_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct mnt_idmap *idmap = file_mnt_idmap(file); + struct address_space *mapping = file->f_mapping; + ssize_t written = 0; + struct inode *inode = mapping->host; + ssize_t err, count; + struct fuse_conn *fc = get_fuse_conn(inode); + bool writeback = false; + + 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(idmap, file_inode(file))) + writeback = true; + } + + inode_lock(inode); + + err = count = generic_write_checks(iocb, from); + if (err <= 0) + goto out; + + task_io_account_write(count); + + err = kiocb_modified(iocb); + if (err) + goto out; + + if (iocb->ki_flags & IOCB_DIRECT) { + written = generic_file_direct_write(iocb, from); + if (written < 0 || !iov_iter_count(from)) + goto out; + written = direct_write_fallback(iocb, from, written, + fuse_perform_write(iocb, from)); + } else if (writeback) { + /* + * Use iomap so that we can do granular uptodate reads + * and granular dirty tracking for large folios. + */ + written = iomap_file_buffered_write(iocb, from, + &fuse_iomap_ops, + &fuse_iomap_write_ops, + file); + } else { + written = fuse_perform_write(iocb, from); + } +out: + 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)iter_iov(ii)->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, + bool use_pages_for_kvec_io) +{ + bool flush_or_invalidate = false; + unsigned int nr_pages = 0; + 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. + * However if the implementation of fuse_conn requires pages instead of + * pointer (e.g., virtio-fs), use iov_iter_extract_pages() instead. + */ + if (iov_iter_is_kvec(ii)) { + void *user_addr = (void *)fuse_get_user_addr(ii); + + if (!use_pages_for_kvec_io) { + size_t frag_size = fuse_get_frag_size(ii, *nbytesp); + + if (write) + ap->args.in_args[1].value = user_addr; + else + ap->args.out_args[0].value = user_addr; + + iov_iter_advance(ii, frag_size); + *nbytesp = frag_size; + return 0; + } + + if (is_vmalloc_addr(user_addr)) { + ap->args.vmap_base = user_addr; + flush_or_invalidate = true; + } + } + + /* + * Until there is support for iov_iter_extract_folios(), we have to + * manually extract pages using iov_iter_extract_pages() and then + * copy that to a folios array. + */ + struct page **pages = kcalloc(max_pages, sizeof(struct page *), + GFP_KERNEL); + if (!pages) { + ret = -ENOMEM; + goto out; + } + + while (nbytes < *nbytesp && nr_pages < max_pages) { + unsigned nfolios, i; + size_t start; + + ret = iov_iter_extract_pages(ii, &pages, + *nbytesp - nbytes, + max_pages - nr_pages, + 0, &start); + if (ret < 0) + break; + + nbytes += ret; + + nfolios = DIV_ROUND_UP(ret + start, PAGE_SIZE); + + for (i = 0; i < nfolios; i++) { + struct folio *folio = page_folio(pages[i]); + unsigned int offset = start + + (folio_page_idx(folio, pages[i]) << PAGE_SHIFT); + unsigned int len = umin(ret, PAGE_SIZE - start); + + ap->descs[ap->num_folios].offset = offset; + ap->descs[ap->num_folios].length = len; + ap->folios[ap->num_folios] = folio; + start = 0; + ret -= len; + ap->num_folios++; + } + + nr_pages += nfolios; + } + kfree(pages); + + if (write && flush_or_invalidate) + flush_kernel_vmap_range(ap->args.vmap_base, nbytes); + + ap->args.invalidate_vmap = !write && flush_or_invalidate; + ap->args.is_pinned = iov_iter_extract_will_pin(ii); + ap->args.user_pages = true; + if (write) + ap->args.in_pages = true; + else + ap->args.out_pages = true; + +out: + *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 address_space *mapping = file->f_mapping; + struct inode *inode = 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; + bool fopen_direct_io = ff->open_flags & FOPEN_DIRECT_IO; + + max_pages = iov_iter_npages(iter, fc->max_pages); + ia = fuse_io_alloc(io, max_pages); + if (!ia) + return -ENOMEM; + + if (fopen_direct_io) { + res = filemap_write_and_wait_range(mapping, pos, pos + count - 1); + if (res) { + fuse_io_free(ia); + return res; + } + } + if (!cuse && filemap_range_has_writeback(mapping, pos, (pos + count - 1))) { + if (!write) + inode_lock(inode); + fuse_sync_writes(inode); + if (!write) + inode_unlock(inode); + } + + if (fopen_direct_io && write) { + res = invalidate_inode_pages2_range(mapping, idx_from, idx_to); + if (res) { + fuse_io_free(ia); + return res; + } + } + + 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, fc->use_pages_for_kvec_io); + 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, nres, 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)) { + 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 address_space *mapping = inode->i_mapping; + loff_t pos = iocb->ki_pos; + ssize_t res; + bool exclusive; + + fuse_dio_lock(iocb, from, &exclusive); + res = generic_write_checks(iocb, from); + if (res > 0) { + task_io_account_write(res); + if (!is_sync_kiocb(iocb)) { + res = fuse_direct_IO(iocb, from); + } else { + struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb); + + res = fuse_direct_io(&io, from, &iocb->ki_pos, + FUSE_DIO_WRITE); + fuse_write_update_attr(inode, iocb->ki_pos, res); + } + if (res > 0 && mapping->nrpages) { + /* + * As in generic_file_direct_write(), invalidate after + * write, to invalidate read-ahead cache that may have + * with the write. + */ + invalidate_inode_pages2_range(mapping, + pos >> PAGE_SHIFT, + (pos + res - 1) >> PAGE_SHIFT); + } + } + fuse_dio_unlock(iocb, exclusive); + + 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); + + /* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */ + if (ff->open_flags & FOPEN_DIRECT_IO) + return fuse_direct_read_iter(iocb, to); + else if (fuse_file_passthrough(ff)) + return fuse_passthrough_read_iter(iocb, to); + else + return fuse_cache_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); + + /* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */ + if (ff->open_flags & FOPEN_DIRECT_IO) + return fuse_direct_write_iter(iocb, from); + else if (fuse_file_passthrough(ff)) + return fuse_passthrough_write_iter(iocb, from); + else + return fuse_cache_write_iter(iocb, from); +} + +static ssize_t fuse_splice_read(struct file *in, loff_t *ppos, + struct pipe_inode_info *pipe, size_t len, + unsigned int flags) +{ + struct fuse_file *ff = in->private_data; + + /* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */ + if (fuse_file_passthrough(ff) && !(ff->open_flags & FOPEN_DIRECT_IO)) + return fuse_passthrough_splice_read(in, ppos, pipe, len, flags); + else + return filemap_splice_read(in, ppos, pipe, len, flags); +} + +static ssize_t fuse_splice_write(struct pipe_inode_info *pipe, struct file *out, + loff_t *ppos, size_t len, unsigned int flags) +{ + struct fuse_file *ff = out->private_data; + + /* FOPEN_DIRECT_IO overrides FOPEN_PASSTHROUGH */ + if (fuse_file_passthrough(ff) && !(ff->open_flags & FOPEN_DIRECT_IO)) + return fuse_passthrough_splice_write(pipe, out, ppos, len, flags); + else + return iter_file_splice_write(pipe, out, ppos, len, flags); +} + +static void fuse_writepage_free(struct fuse_writepage_args *wpa) +{ + struct fuse_args_pages *ap = &wpa->ia.ap; + + if (wpa->bucket) + fuse_sync_bucket_dec(wpa->bucket); + + fuse_file_put(wpa->ia.ff, false); + + kfree(ap->folios); + kfree(wpa); +} + +static void fuse_writepage_finish(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); + int i; + + for (i = 0; i < ap->num_folios; i++) + /* + * Benchmarks showed that ending writeback within the + * scope of the fi->lock alleviates xarray lock + * contention and noticeably improves performance. + */ + iomap_finish_folio_write(inode, ap->folios[i], + ap->descs[i].length); + + 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_inode *fi = get_fuse_inode(wpa->inode); + struct fuse_args_pages *ap = &wpa->ia.ap; + struct fuse_write_in *inarg = &wpa->ia.write.in; + struct fuse_args *args = &ap->args; + __u64 data_size = 0; + int err, i; + + for (i = 0; i < ap->num_folios; i++) + data_size += ap->descs[i].length; + + 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--; + fuse_writepage_finish(wpa); + spin_unlock(&fi->lock); + 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 void fuse_writepage_end(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); + fi->writectr--; + fuse_writepage_finish(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; + + ff = __fuse_write_file_get(fi); + err = fuse_flush_times(inode, ff); + if (ff) + fuse_file_put(ff, 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_obj(*wpa, GFP_NOFS); + if (wpa) { + ap = &wpa->ia.ap; + ap->num_folios = 0; + ap->folios = fuse_folios_alloc(1, GFP_NOFS, &ap->descs); + if (!ap->folios) { + 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 void fuse_writepage_args_page_fill(struct fuse_writepage_args *wpa, struct folio *folio, + uint32_t folio_index, loff_t offset, unsigned len) +{ + struct fuse_args_pages *ap = &wpa->ia.ap; + + ap->folios[folio_index] = folio; + ap->descs[folio_index].offset = offset; + ap->descs[folio_index].length = len; +} + +static struct fuse_writepage_args *fuse_writepage_args_setup(struct folio *folio, + size_t offset, + struct fuse_file *ff) +{ + struct inode *inode = folio->mapping->host; + struct fuse_conn *fc = get_fuse_conn(inode); + struct fuse_writepage_args *wpa; + struct fuse_args_pages *ap; + + wpa = fuse_writepage_args_alloc(); + if (!wpa) + return NULL; + + fuse_writepage_add_to_bucket(fc, wpa); + fuse_write_args_fill(&wpa->ia, ff, folio_pos(folio) + offset, 0); + wpa->ia.write.in.write_flags |= FUSE_WRITE_CACHE; + wpa->inode = inode; + wpa->ia.ff = ff; + + ap = &wpa->ia.ap; + ap->args.in_pages = true; + ap->args.end = fuse_writepage_end; + + return wpa; +} + +struct fuse_fill_wb_data { + struct fuse_writepage_args *wpa; + struct fuse_file *ff; + unsigned int max_folios; + /* + * nr_bytes won't overflow since fuse_folios_need_send() caps + * wb requests to never exceed fc->max_pages (which has an upper bound + * of U16_MAX). + */ + unsigned int nr_bytes; +}; + +static bool fuse_pages_realloc(struct fuse_fill_wb_data *data, + unsigned int max_pages) +{ + struct fuse_args_pages *ap = &data->wpa->ia.ap; + struct folio **folios; + struct fuse_folio_desc *descs; + unsigned int nfolios = min_t(unsigned int, + max_t(unsigned int, data->max_folios * 2, + FUSE_DEFAULT_MAX_PAGES_PER_REQ), + max_pages); + WARN_ON(nfolios <= data->max_folios); + + folios = fuse_folios_alloc(nfolios, GFP_NOFS, &descs); + if (!folios) + return false; + + memcpy(folios, ap->folios, sizeof(struct folio *) * ap->num_folios); + memcpy(descs, ap->descs, sizeof(struct fuse_folio_desc) * ap->num_folios); + kfree(ap->folios); + ap->folios = folios; + ap->descs = descs; + data->max_folios = nfolios; + + return true; +} + +static void fuse_writepages_send(struct inode *inode, + struct fuse_fill_wb_data *data) +{ + struct fuse_writepage_args *wpa = data->wpa; + struct fuse_inode *fi = get_fuse_inode(inode); + + spin_lock(&fi->lock); + list_add_tail(&wpa->queue_entry, &fi->queued_writes); + fuse_flush_writepages(inode); + spin_unlock(&fi->lock); +} + +static bool fuse_folios_need_send(struct fuse_conn *fc, loff_t pos, + unsigned len, struct fuse_args_pages *ap, + unsigned cur_bytes, bool write) +{ + struct folio *prev_folio; + struct fuse_folio_desc prev_desc; + unsigned bytes = cur_bytes + len; + loff_t prev_pos; + size_t max_bytes = write ? fc->max_write : fc->max_read; + + WARN_ON(!ap->num_folios); + + /* Reached max pages or max folio slots */ + if (ap->num_folios >= fc->max_pages) + return true; + + if (DIV_ROUND_UP(bytes, PAGE_SIZE) > fc->max_pages) + return true; + + if (bytes > max_bytes) + return true; + + /* Discontinuity */ + prev_folio = ap->folios[ap->num_folios - 1]; + prev_desc = ap->descs[ap->num_folios - 1]; + prev_pos = folio_pos(prev_folio) + prev_desc.offset + prev_desc.length; + if (prev_pos != pos) + return true; + + return false; +} + +static ssize_t fuse_iomap_writeback_range(struct iomap_writepage_ctx *wpc, + struct folio *folio, u64 pos, + unsigned len, u64 end_pos) +{ + struct fuse_fill_wb_data *data = wpc->wb_ctx; + struct fuse_writepage_args *wpa = data->wpa; + struct fuse_args_pages *ap = &wpa->ia.ap; + struct inode *inode = wpc->inode; + struct fuse_inode *fi = get_fuse_inode(inode); + struct fuse_conn *fc = get_fuse_conn(inode); + loff_t offset = offset_in_folio(folio, pos); + + WARN_ON_ONCE(!data); + + if (!data->ff) { + data->ff = fuse_write_file_get(fi); + if (!data->ff) + return -EIO; + } + + if (wpa) { + bool send = fuse_folios_need_send(fc, pos, len, ap, + data->nr_bytes, true); + + if (!send) { + /* + * Need to grow the pages array? If so, did the + * expansion fail? + */ + send = (ap->num_folios == data->max_folios) && + !fuse_pages_realloc(data, fc->max_pages); + } + + if (send) { + fuse_writepages_send(inode, data); + data->wpa = NULL; + data->nr_bytes = 0; + } + } + + if (data->wpa == NULL) { + wpa = fuse_writepage_args_setup(folio, offset, data->ff); + if (!wpa) + return -ENOMEM; + fuse_file_get(wpa->ia.ff); + data->max_folios = 1; + ap = &wpa->ia.ap; + } + + fuse_writepage_args_page_fill(wpa, folio, ap->num_folios, + offset, len); + data->nr_bytes += len; + + ap->num_folios++; + if (!data->wpa) + data->wpa = wpa; + + return len; +} + +static int fuse_iomap_writeback_submit(struct iomap_writepage_ctx *wpc, + int error) +{ + struct fuse_fill_wb_data *data = wpc->wb_ctx; + + WARN_ON_ONCE(!data); + + if (data->wpa) { + WARN_ON(!data->wpa->ia.ap.num_folios); + fuse_writepages_send(wpc->inode, data); + } + + if (data->ff) + fuse_file_put(data->ff, false); + + return error; +} + +static const struct iomap_writeback_ops fuse_writeback_ops = { + .writeback_range = fuse_iomap_writeback_range, + .writeback_submit = fuse_iomap_writeback_submit, +}; + +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 = {}; + struct iomap_writepage_ctx wpc = { + .inode = inode, + .iomap.type = IOMAP_MAPPED, + .wbc = wbc, + .ops = &fuse_writeback_ops, + .wb_ctx = &data, + }; + + if (fuse_is_bad(inode)) + return -EIO; + + if (wbc->sync_mode == WB_SYNC_NONE && + fuse_chan_num_background(fc->chan) >= fc->congestion_threshold) + return 0; + + return iomap_writepages(&wpc); +} + +static int fuse_launder_folio(struct folio *folio) +{ + int err = 0; + struct fuse_fill_wb_data data = {}; + struct iomap_writepage_ctx wpc = { + .inode = folio->mapping->host, + .iomap.type = IOMAP_MAPPED, + .ops = &fuse_writeback_ops, + .wb_ctx = &data, + }; + + if (folio_clear_dirty_for_io(folio)) { + err = iomap_writeback_folio(&wpc, folio); + err = fuse_iomap_writeback_submit(&wpc, err); + if (!err) + folio_wait_writeback(folio); + } + 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 folio *folio = page_folio(vmf->page); + struct inode *inode = file_inode(vmf->vma->vm_file); + + file_update_time(vmf->vma->vm_file); + folio_lock(folio); + if (folio->mapping != inode->i_mapping) { + folio_unlock(folio); + return VM_FAULT_NOPAGE; + } + + folio_wait_writeback(folio); + 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; + struct fuse_conn *fc = ff->fm->fc; + struct inode *inode = file_inode(file); + int rc; + + /* DAX mmap is superior to direct_io mmap */ + if (FUSE_IS_DAX(inode)) + return fuse_dax_mmap(file, vma); + + /* + * If inode is in passthrough io mode, because it has some file open + * in passthrough mode, either mmap to backing file or fail mmap, + * because mixing cached mmap and passthrough io mode is not allowed. + */ + if (fuse_file_passthrough(ff)) + return fuse_passthrough_mmap(file, vma); + else if (fuse_inode_backing(get_fuse_inode(inode))) + return -ENODEV; + + /* + * FOPEN_DIRECT_IO handling is special compared to O_DIRECT, + * as does not allow MAP_SHARED mmap without FUSE_DIRECT_IO_ALLOW_MMAP. + */ + if (ff->open_flags & FOPEN_DIRECT_IO) { + /* + * Can't provide the coherency needed for MAP_SHARED + * if FUSE_DIRECT_IO_ALLOW_MMAP isn't set. + */ + if ((vma->vm_flags & VM_MAYSHARE) && !fc->direct_io_allow_mmap) + return -ENODEV; + + invalidate_inode_pages2(file->f_mapping); + + if (!(vma->vm_flags & VM_MAYSHARE)) { + /* MAP_PRIVATE */ + return generic_file_mmap(file, vma); + } + + /* + * First mmap of direct_io file enters caching inode io mode. + * Also waits for parallel dio writers to go into serial mode + * (exclusive instead of shared lock). + * After first mmap, the inode stays in caching io mode until + * the direct_io file release. + */ + rc = fuse_file_cached_io_open(inode, ff); + if (rc) + return rc; + } + + 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->c.flc_pid = pid_nr_ns(find_pid_ns(ffl->pid, fc->pid_ns), &init_pid_ns); + rcu_read_unlock(); + break; + + default: + return -EIO; + } + fl->c.flc_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->c.flc_owner); + inarg->lk.start = fl->fl_start; + inarg->lk.end = fl->fl_end; + inarg->lk.type = fl->c.flc_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->c.flc_flags & FL_SLEEP) ? FUSE_SETLKW : FUSE_SETLK; + struct pid *pid = fl->c.flc_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; + } + + 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 */ + err = fuse_setlk(file, fl, 1); + if (!err) + ff->flock = true; + } + + 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; +} + +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_mnt_idmap(file), 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; + bool async = ff->fm->fc->async_dio; + + pos = offset; + inode = file->f_mapping->host; + i_size = i_size_read(inode); + + if ((iov_iter_rw(iter) == READ) && (offset >= i_size)) + return 0; + + if ((iov_iter_rw(iter) == WRITE) && async && !inode->i_sb->s_dio_done_wq) { + ret = sb_init_dio_done_wq(inode->i_sb); + if (ret < 0) + return ret; + } + + io = kmalloc_obj(struct fuse_io_priv); + 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 = async; + 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); + /* For extending writes we already hold exclusive lock */ + 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, -1); + 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; + struct fuse_copy_file_range_out outarg_64; + u64 bytes_copied; + 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_64; + 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_64); + args.out_args[0].value = &outarg_64; + if (fc->no_copy_file_range_64) { +fallback: + /* Fall back to old op that can't handle large copy length */ + args.opcode = FUSE_COPY_FILE_RANGE; + args.out_args[0].size = sizeof(outarg); + args.out_args[0].value = &outarg; + inarg.len = len = min_t(size_t, len, UINT_MAX & PAGE_MASK); + } + err = fuse_simple_request(fm, &args); + if (err == -ENOSYS) { + if (fc->no_copy_file_range_64) { + fc->no_copy_file_range = 1; + err = -EOPNOTSUPP; + } else { + fc->no_copy_file_range_64 = 1; + goto fallback; + } + } + if (err) + goto out; + + bytes_copied = fc->no_copy_file_range_64 ? + outarg.size : outarg_64.bytes_copied; + + if (bytes_copied > len) { + err = -EIO; + goto out; + } + + truncate_inode_pages_range(inode_out->i_mapping, + ALIGN_DOWN(pos_out, PAGE_SIZE), + ALIGN(pos_out + bytes_copied, PAGE_SIZE) - 1); + + file_update_time(file_out); + fuse_write_update_attr(inode_out, pos_out + bytes_copied, bytes_copied); + + err = bytes_copied; +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 = splice_copy_file_range(src_file, src_off, dst_file, + dst_off, len); + 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 = fuse_splice_read, + .splice_write = fuse_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, + .setlease = generic_setlease, +}; + +static const struct address_space_operations fuse_file_aops = { + .read_folio = fuse_read_folio, + .readahead = fuse_readahead, + .writepages = fuse_writepages, + .launder_folio = fuse_launder_folio, + .dirty_folio = iomap_dirty_folio, + .release_folio = iomap_release_folio, + .invalidate_folio = iomap_invalidate_folio, + .is_partially_uptodate = iomap_is_partially_uptodate, + .migrate_folio = filemap_migrate_folio, + .bmap = fuse_bmap, + .direct_IO = fuse_direct_IO, +}; + +void fuse_init_file_inode(struct inode *inode, unsigned int flags) +{ + struct fuse_inode *fi = get_fuse_inode(inode); + struct fuse_conn *fc = get_fuse_conn(inode); + + inode->i_fop = &fuse_file_operations; + inode->i_data.a_ops = &fuse_file_aops; + if (fc->writeback_cache) + mapping_set_writeback_may_deadlock_on_reclaim(&inode->i_data); + + INIT_LIST_HEAD(&fi->write_files); + INIT_LIST_HEAD(&fi->queued_writes); + fi->writectr = 0; + fi->iocachectr = 0; + init_waitqueue_head(&fi->page_waitq); + init_waitqueue_head(&fi->direct_io_waitq); + + if (IS_ENABLED(CONFIG_FUSE_DAX)) + fuse_dax_inode_init(inode, flags); +} |