On 08/11/2019 05.08, Ritesh Harjani wrote:
On 10/29/19 12:47 PM, Konstantin Khlebnikov wrote:
If inode->i_blocks is zero then ext4_evict_inode() skips ext4_truncate().
Delayed allocation extents are freed later in ext4_clear_inode() but this
happens when quota reference is already dropped. This leads to leak of
reserved space in quota block, which disappears after umount-mount.
This seems broken for a long time but worked somehow until recent changes
in delayed allocation.
Sorry, I may have missed it, but could you please help understand
what recent changes in delayed allocation make this break or worse?
I don't see problem for 4.19. Haven't bisected yet.
Most likely this is around 'reserved cluster accounting'.
I suspect before these changes something always triggered da before unlink and
space usage committed and then truncated at eviction.
A silly query, since I couldn't figure it out. Maybe the code has been
there ever since like this:-
So why can't we just move drop_dquot later after the ext4_es_remove_extent() (in function ext4_clear_inode)? Any known
problems around that?
Clear_inode is called also when inode evicts from cache while it has nlinks
and stays at disk. I'm not sure how this must interact with reserves.
-ritesh
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
---
fs/ext4/inode.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 516faa280ced..580898145e8f 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -293,6 +293,15 @@ void ext4_evict_inode(struct inode *inode)
inode->i_ino, err);
goto stop_handle;
}
+ } else if (EXT4_I(inode)->i_reserved_data_blocks) {
+ /* Deaccount reserve if inode has only delayed allocations. */
+ err = ext4_es_remove_extent(inode, 0, EXT_MAX_BLOCKS);
+ if (err) {
+ ext4_warning(inode->i_sb,
+ "couldn't remove extents %lu (err %d)",
+ inode->i_ino, err);
+ goto stop_handle;
+ }
}
/* Remove xattr references. */
