When we write some data to the place that is beyond the end of the file in direct I/O mode, a data hole will be created. And Btrfs should insert a file extent item that point to this hole into the fs tree. But unfortunately Btrfs forgets doing it.
The following is a simple way to reproduce it: # mkfs.btrfs /dev/sdc2 # mount /dev/sdc2 /test4 # touch /test4/a # dd if=/dev/zero of=/test4/a seek=8 count=1 bs=4K oflag=direct conv=nocreat,notrunc # umount /test4 # btrfsck /dev/sdc2 root 5 inode 257 errors 100 Reported-by: Tsutomu Itoh <[email protected]> Signed-off-by: Miao Xie <[email protected]> Tested-by: Tsutomu Itoh <[email protected]> --- fs/btrfs/file.c | 16 ++++++++++------ 1 files changed, 10 insertions(+), 6 deletions(-) diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 010aec8..a9c4636 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1073,12 +1073,6 @@ static noinline int prepare_pages(struct btrfs_root *root, struct file *file, start_pos = pos & ~((u64)root->sectorsize - 1); last_pos = ((u64)index + num_pages) << PAGE_CACHE_SHIFT; - if (start_pos > inode->i_size) { - err = btrfs_cont_expand(inode, i_size_read(inode), start_pos); - if (err) - return err; - } - again: for (i = 0; i < num_pages; i++) { pages[i] = find_or_create_page(inode->i_mapping, index + i, @@ -1336,6 +1330,7 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb, struct inode *inode = fdentry(file)->d_inode; struct btrfs_root *root = BTRFS_I(inode)->root; loff_t *ppos = &iocb->ki_pos; + u64 start_pos; ssize_t num_written = 0; ssize_t err = 0; size_t count, ocount; @@ -1384,6 +1379,15 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb, file_update_time(file); BTRFS_I(inode)->sequence++; + start_pos = round_down(pos, root->sectorsize); + if (start_pos > i_size_read(inode)) { + err = btrfs_cont_expand(inode, i_size_read(inode), start_pos); + if (err) { + mutex_unlock(&inode->i_mutex); + goto out; + } + } + if (unlikely(file->f_flags & O_DIRECT)) { num_written = __btrfs_direct_write(iocb, iov, nr_segs, pos, ppos, count, ocount); -- 1.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
