From: Filipe Manana Date: Thu, 18 Jan 2018 11:34:20 +0000 (+0000) Subject: Btrfs: fix missing inode i_size update after zero range operation X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=9f13ce743b1bd4e764193980e6311bfcdf424bb2;p=openwrt%2Fstaging%2Fblogic.git Btrfs: fix missing inode i_size update after zero range operation For a fallocate's zero range operation that targets a range with an end that is not aligned to the sector size, we can end up not updating the inode's i_size. This happens when the last page of the range maps to an unwritten (prealloc) extent and before that last page we have either a hole or a written extent. This is because in this scenario we relied on a call to btrfs_prealloc_file_range() to update the inode's i_size, however it can only update the i_size to the "down aligned" end of the range. Example: $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt $ xfs_io -f -c "pwrite -S 0xff 0 428K" /mnt/foobar $ xfs_io -c "falloc -k 428K 4K" /mnt/foobar $ xfs_io -c "fzero 0 430K" /mnt/foobar $ du --bytes /mnt/foobar 438272 /mnt/foobar The inode's i_size was left as 428Kb (438272 bytes) when it should have been updated to 430Kb (440320 bytes). Fix this by always updating the inode's i_size explicitly after zeroing the range. Fixes: ba6d5887946ff86d93dc ("Btrfs: add support for fallocate's zero range operation") Signed-off-by: Filipe Manana Signed-off-by: David Sterba --- diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index cba2ac371ce0..baad81c1f9a3 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -3026,9 +3026,12 @@ reserve_space: unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend, &cached_state); /* btrfs_prealloc_file_range releases reserved space on error */ - if (ret) + if (ret) { space_reserved = false; + goto out; + } } + ret = btrfs_fallocate_update_isize(inode, offset + len, mode); out: if (ret && space_reserved) btrfs_free_reserved_data_space(inode, data_reserved,