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Commit 3d850dd4 authored by Filipe Manana's avatar Filipe Manana Committed by Chris Mason
Browse files

Btrfs: add missing inode item update in fallocate() 



If we fallocate(), without the keep size flag, into an area already covered
by an extent previously fallocated, we were updating the inode's i_size but
we weren't updating the inode item in the fs/subvol tree. A following umount
+ mount would result in a loss of the inode's size (and an fsync would miss
too the fact that the inode changed).

Reproducer:

  $ mkfs.btrfs -f /dev/sdd
  $ mount /dev/sdd /mnt
  $ fallocate -n -l 1M /mnt/foobar
  $ fallocate -l 512K /mnt/foobar
  $ umount /mnt
  $ mount /dev/sdd /mnt
  $ od -t x1 /mnt/foobar
  0000000

The expected result is:

  $ od -t x1 /mnt/foobar
  0000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  *
  2000000

A test case for fstests follows soon.

Signed-off-by: default avatarFilipe Manana <fdmanana@suse.com>
Reviewed-by: default avatarLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: default avatarChris Mason <clm@fb.com>
parent 5f806c3a

fs/btrfs/file.c

+20 −9
Original line number Original line Diff line number Diff line
@@ -2669,23 +2669,34 @@ static long btrfs_fallocate(struct file *file, int mode, 
							1 << inode->i_blkbits,

							1 << inode->i_blkbits,

							offset + len,

							offset + len,

							&alloc_hint);

							&alloc_hint);



			if (ret < 0) {

				free_extent_map(em);

				break;

			}

		} else if (actual_end > inode->i_size &&

		} else if (actual_end > inode->i_size &&

			   !(mode & FALLOC_FL_KEEP_SIZE)) {

			   !(mode & FALLOC_FL_KEEP_SIZE)) {

			struct btrfs_trans_handle *trans;



			/*

			/*

			 * We didn't need to allocate any more space, but we

			 * We didn't need to allocate any more space, but we

			 * still extended the size of the file so we need to

			 * still extended the size of the file so we need to

			 * update i_size.

			 * update i_size and the inode item.

			 */

			 */

			trans = btrfs_start_transaction(root, 1);

			if (IS_ERR(trans)) {

				ret = PTR_ERR(trans);

			} else {

				inode->i_ctime = CURRENT_TIME;

				inode->i_ctime = CURRENT_TIME;

				i_size_write(inode, actual_end);

				i_size_write(inode, actual_end);

			btrfs_ordered_update_i_size(inode, actual_end, NULL);

				btrfs_ordered_update_i_size(inode, actual_end,

							    NULL);

				ret = btrfs_update_inode(trans, root, inode);

				if (ret)

					btrfs_end_transaction(trans, root);

				else

					ret = btrfs_end_transaction(trans,

								    root);

			}

		}

		}

		free_extent_map(em);

		free_extent_map(em);

		if (ret < 0)

			break;





		cur_offset = last_byte;

		cur_offset = last_byte;

		if (cur_offset >= alloc_end) {

		if (cur_offset >= alloc_end) {