Btrfs: fix the file extent gap when doing direct IO (0c1a98c8) · Commits · 戴 / test

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 <t-itoh@jp.fujitsu.com> Signed-off-by:

Miao Xie <miaox@cn.fujitsu.com> Tested-by:

Tsutomu Itoh <t-itoh@jp.fujitsu.com> Signed-off-by:

Chris Mason <chris.mason@oracle.com>

fs/btrfs/file.c

+10 −6

Original line number	Diff line number	Diff line
		@@ -1075,12 +1075,6 @@ 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,
		@@ -1338,6 +1332,7 @@ 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;
		@@ -1386,6 +1381,15 @@ 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);

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