6.12-stable review patch. If anyone has any objections, please let me know.
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From: Mark Harmstone maharmstone@fb.com
[ Upstream commit 26efd44796c6dd7a64f039a0dda6d558eac97a3e ]
Change the behaviour of btrfs_encoded_read() so that if it needs to read an extent from disk, it leaves the extent and inode locked and returns -EIOCBQUEUED. The caller is then responsible for doing the I/O via btrfs_encoded_read_regular() and unlocking the extent and inode.
Signed-off-by: Mark Harmstone maharmstone@fb.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Stable-dep-of: 05b36b04d74a ("btrfs: fix use-after-free in btrfs_encoded_read_endio()") Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/btrfs_inode.h | 9 ++++++- fs/btrfs/inode.c | 57 ++++++++++++++++++++---------------------- fs/btrfs/ioctl.c | 32 +++++++++++++++++++++++- 3 files changed, 66 insertions(+), 32 deletions(-)
diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h index 5e2d93c2dfb5a..db53a3263fbd0 100644 --- a/fs/btrfs/btrfs_inode.h +++ b/fs/btrfs/btrfs_inode.h @@ -616,7 +616,14 @@ int btrfs_encoded_read_regular_fill_pages(struct btrfs_inode *inode, u64 disk_bytenr, u64 disk_io_size, struct page **pages); ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter, - struct btrfs_ioctl_encoded_io_args *encoded); + struct btrfs_ioctl_encoded_io_args *encoded, + struct extent_state **cached_state, + u64 *disk_bytenr, u64 *disk_io_size); +ssize_t btrfs_encoded_read_regular(struct kiocb *iocb, struct iov_iter *iter, + u64 start, u64 lockend, + struct extent_state **cached_state, + u64 disk_bytenr, u64 disk_io_size, + size_t count, bool compressed, bool *unlocked); ssize_t btrfs_do_encoded_write(struct kiocb *iocb, struct iov_iter *from, const struct btrfs_ioctl_encoded_io_args *encoded);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 753e9cb0c3717..9c4f1a3742f3f 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -9177,13 +9177,11 @@ int btrfs_encoded_read_regular_fill_pages(struct btrfs_inode *inode, return blk_status_to_errno(READ_ONCE(priv.status)); }
-static ssize_t btrfs_encoded_read_regular(struct kiocb *iocb, - struct iov_iter *iter, - u64 start, u64 lockend, - struct extent_state **cached_state, - u64 disk_bytenr, u64 disk_io_size, - size_t count, bool compressed, - bool *unlocked) +ssize_t btrfs_encoded_read_regular(struct kiocb *iocb, struct iov_iter *iter, + u64 start, u64 lockend, + struct extent_state **cached_state, + u64 disk_bytenr, u64 disk_io_size, + size_t count, bool compressed, bool *unlocked) { struct btrfs_inode *inode = BTRFS_I(file_inode(iocb->ki_filp)); struct extent_io_tree *io_tree = &inode->io_tree; @@ -9244,15 +9242,16 @@ static ssize_t btrfs_encoded_read_regular(struct kiocb *iocb, }
ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter, - struct btrfs_ioctl_encoded_io_args *encoded) + struct btrfs_ioctl_encoded_io_args *encoded, + struct extent_state **cached_state, + u64 *disk_bytenr, u64 *disk_io_size) { struct btrfs_inode *inode = BTRFS_I(file_inode(iocb->ki_filp)); struct btrfs_fs_info *fs_info = inode->root->fs_info; struct extent_io_tree *io_tree = &inode->io_tree; ssize_t ret; size_t count = iov_iter_count(iter); - u64 start, lockend, disk_bytenr, disk_io_size; - struct extent_state *cached_state = NULL; + u64 start, lockend; struct extent_map *em; bool unlocked = false;
@@ -9278,13 +9277,13 @@ ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter, lockend - start + 1); if (ret) goto out_unlock_inode; - lock_extent(io_tree, start, lockend, &cached_state); + lock_extent(io_tree, start, lockend, cached_state); ordered = btrfs_lookup_ordered_range(inode, start, lockend - start + 1); if (!ordered) break; btrfs_put_ordered_extent(ordered); - unlock_extent(io_tree, start, lockend, &cached_state); + unlock_extent(io_tree, start, lockend, cached_state); cond_resched(); }
@@ -9304,7 +9303,7 @@ ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter, free_extent_map(em); em = NULL; ret = btrfs_encoded_read_inline(iocb, iter, start, lockend, - &cached_state, extent_start, + cached_state, extent_start, count, encoded, &unlocked); goto out; } @@ -9317,12 +9316,12 @@ ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter, inode->vfs_inode.i_size) - iocb->ki_pos; if (em->disk_bytenr == EXTENT_MAP_HOLE || (em->flags & EXTENT_FLAG_PREALLOC)) { - disk_bytenr = EXTENT_MAP_HOLE; + *disk_bytenr = EXTENT_MAP_HOLE; count = min_t(u64, count, encoded->len); encoded->len = count; encoded->unencoded_len = count; } else if (extent_map_is_compressed(em)) { - disk_bytenr = em->disk_bytenr; + *disk_bytenr = em->disk_bytenr; /* * Bail if the buffer isn't large enough to return the whole * compressed extent. @@ -9331,7 +9330,7 @@ ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter, ret = -ENOBUFS; goto out_em; } - disk_io_size = em->disk_num_bytes; + *disk_io_size = em->disk_num_bytes; count = em->disk_num_bytes; encoded->unencoded_len = em->ram_bytes; encoded->unencoded_offset = iocb->ki_pos - (em->start - em->offset); @@ -9341,35 +9340,32 @@ ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter, goto out_em; encoded->compression = ret; } else { - disk_bytenr = extent_map_block_start(em) + (start - em->start); + *disk_bytenr = extent_map_block_start(em) + (start - em->start); if (encoded->len > count) encoded->len = count; /* * Don't read beyond what we locked. This also limits the page * allocations that we'll do. */ - disk_io_size = min(lockend + 1, iocb->ki_pos + encoded->len) - start; - count = start + disk_io_size - iocb->ki_pos; + *disk_io_size = min(lockend + 1, iocb->ki_pos + encoded->len) - start; + count = start + *disk_io_size - iocb->ki_pos; encoded->len = count; encoded->unencoded_len = count; - disk_io_size = ALIGN(disk_io_size, fs_info->sectorsize); + *disk_io_size = ALIGN(*disk_io_size, fs_info->sectorsize); } free_extent_map(em); em = NULL;
- if (disk_bytenr == EXTENT_MAP_HOLE) { - unlock_extent(io_tree, start, lockend, &cached_state); + if (*disk_bytenr == EXTENT_MAP_HOLE) { + unlock_extent(io_tree, start, lockend, cached_state); btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED); unlocked = true; ret = iov_iter_zero(count, iter); if (ret != count) ret = -EFAULT; } else { - ret = btrfs_encoded_read_regular(iocb, iter, start, lockend, - &cached_state, disk_bytenr, - disk_io_size, count, - encoded->compression, - &unlocked); + ret = -EIOCBQUEUED; + goto out_em; }
out: @@ -9378,10 +9374,11 @@ ssize_t btrfs_encoded_read(struct kiocb *iocb, struct iov_iter *iter, out_em: free_extent_map(em); out_unlock_extent: - if (!unlocked) - unlock_extent(io_tree, start, lockend, &cached_state); + /* Leave inode and extent locked if we need to do a read. */ + if (!unlocked && ret != -EIOCBQUEUED) + unlock_extent(io_tree, start, lockend, cached_state); out_unlock_inode: - if (!unlocked) + if (!unlocked && ret != -EIOCBQUEUED) btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED); return ret; } diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 226c91fe31a70..3e3722a732393 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -4514,12 +4514,17 @@ static int btrfs_ioctl_encoded_read(struct file *file, void __user *argp, size_t copy_end_kernel = offsetofend(struct btrfs_ioctl_encoded_io_args, flags); size_t copy_end; + struct btrfs_inode *inode = BTRFS_I(file_inode(file)); + struct btrfs_fs_info *fs_info = inode->root->fs_info; + struct extent_io_tree *io_tree = &inode->io_tree; struct iovec iovstack[UIO_FASTIOV]; struct iovec *iov = iovstack; struct iov_iter iter; loff_t pos; struct kiocb kiocb; ssize_t ret; + u64 disk_bytenr, disk_io_size; + struct extent_state *cached_state = NULL;
if (!capable(CAP_SYS_ADMIN)) { ret = -EPERM; @@ -4572,7 +4577,32 @@ static int btrfs_ioctl_encoded_read(struct file *file, void __user *argp, init_sync_kiocb(&kiocb, file); kiocb.ki_pos = pos;
- ret = btrfs_encoded_read(&kiocb, &iter, &args); + ret = btrfs_encoded_read(&kiocb, &iter, &args, &cached_state, + &disk_bytenr, &disk_io_size); + + if (ret == -EIOCBQUEUED) { + bool unlocked = false; + u64 start, lockend, count; + + start = ALIGN_DOWN(kiocb.ki_pos, fs_info->sectorsize); + lockend = start + BTRFS_MAX_UNCOMPRESSED - 1; + + if (args.compression) + count = disk_io_size; + else + count = args.len; + + ret = btrfs_encoded_read_regular(&kiocb, &iter, start, lockend, + &cached_state, disk_bytenr, + disk_io_size, count, + args.compression, &unlocked); + + if (!unlocked) { + unlock_extent(io_tree, start, lockend, &cached_state); + btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED); + } + } + if (ret >= 0) { fsnotify_access(file); if (copy_to_user(argp + copy_end,