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authorQu Wenruo <wqu@suse.com>2019-09-16 20:02:38 +0800
committerDavid Sterba <dsterba@suse.com>2019-09-27 15:24:28 +0200
commitbab32fc069ce8829c416e8737c119f62a57970f9 (patch)
treeaf6b046ff374a309ad974bf68ab4ea586d391856 /fs
parentfab273595507a9ec7035df6d5512a955d80a80ba (diff)
btrfs: qgroup: Fix the wrong target io_tree when freeing reserved data space
[BUG] Under the following case with qgroup enabled, if some error happened after we have reserved delalloc space, then in error handling path, we could cause qgroup data space leakage: From btrfs_truncate_block() in inode.c: ret = btrfs_delalloc_reserve_space(inode, &data_reserved, block_start, blocksize); if (ret) goto out; again: page = find_or_create_page(mapping, index, mask); if (!page) { btrfs_delalloc_release_space(inode, data_reserved, block_start, blocksize, true); btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, true); ret = -ENOMEM; goto out; } [CAUSE] In the above case, btrfs_delalloc_reserve_space() will call btrfs_qgroup_reserve_data() and mark the io_tree range with EXTENT_QGROUP_RESERVED flag. In the error handling path, we have the following call stack: btrfs_delalloc_release_space() |- btrfs_free_reserved_data_space() |- btrsf_qgroup_free_data() |- __btrfs_qgroup_release_data(reserved=@reserved, free=1) |- qgroup_free_reserved_data(reserved=@reserved) |- clear_record_extent_bits(); |- freed += changeset.bytes_changed; However due to a completion bug, qgroup_free_reserved_data() will clear EXTENT_QGROUP_RESERVED flag in BTRFS_I(inode)->io_failure_tree, other than the correct BTRFS_I(inode)->io_tree. Since io_failure_tree is never marked with that flag, btrfs_qgroup_free_data() will not free any data reserved space at all, causing a leakage. This type of error handling can only be triggered by errors outside of qgroup code. So EDQUOT error from qgroup can't trigger it. [FIX] Fix the wrong target io_tree. Reported-by: Josef Bacik <josef@toxicpanda.com> Fixes: bc42bda22345 ("btrfs: qgroup: Fix qgroup reserved space underflow by only freeing reserved ranges") CC: stable@vger.kernel.org # 4.14+ Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/qgroup.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 52701c1be109..4ab85555a947 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -3486,7 +3486,7 @@ static int qgroup_free_reserved_data(struct inode *inode,
* EXTENT_QGROUP_RESERVED, we won't double free.
* So not need to rush.
*/
- ret = clear_record_extent_bits(&BTRFS_I(inode)->io_failure_tree,
+ ret = clear_record_extent_bits(&BTRFS_I(inode)->io_tree,
free_start, free_start + free_len - 1,
EXTENT_QGROUP_RESERVED, &changeset);
if (ret < 0)

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