[04/22] ext4: Fix credit estimate for final inode freeing
diff mbox series

Message ID 20191003220613.10791-4-jack@suse.cz
State Superseded
Headers show
Series
  • ext4: Fix transaction overflow due to revoke descriptors
Related show

Commit Message

Jan Kara Oct. 3, 2019, 10:05 p.m. UTC
Estimate for the number of credits needed for final freeing of inode in
ext4_evict_inode() was to small. We may modify 4 blocks (inode & sb for
orphan deletion, bitmap & group descriptor for inode freeing) and not
just 3.

Fixes: e50e5129f384 ("ext4: xattr-in-inode support")
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/ext4/inode.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

Comments

Theodore Y. Ts'o Oct. 21, 2019, 1:07 a.m. UTC | #1
On Fri, Oct 04, 2019 at 12:05:50AM +0200, Jan Kara wrote:
> Estimate for the number of credits needed for final freeing of inode in
> ext4_evict_inode() was to small. We may modify 4 blocks (inode & sb for
> orphan deletion, bitmap & group descriptor for inode freeing) and not
> just 3.

The modification for the inode should already be included in the
calculation for ext4_blocks_for_truncate(), no?  So we only need 3
extra blocks (sb, inode bitmap, and bg descriptor for the inode).

      	     	  		    - Ted
Jan Kara Oct. 24, 2019, 10:30 a.m. UTC | #2
On Sun 20-10-19 21:07:23, Theodore Y. Ts'o wrote:
> On Fri, Oct 04, 2019 at 12:05:50AM +0200, Jan Kara wrote:
> > Estimate for the number of credits needed for final freeing of inode in
> > ext4_evict_inode() was to small. We may modify 4 blocks (inode & sb for
> > orphan deletion, bitmap & group descriptor for inode freeing) and not
> > just 3.
> 
> The modification for the inode should already be included in the
> calculation for ext4_blocks_for_truncate(), no?  So we only need 3
> extra blocks (sb, inode bitmap, and bg descriptor for the inode).

Yes, but 'extra_credits' is also passed to ext4_xattr_delete_inode() and if
that needs to restart a transaction, it needs to reserve enough for inode
modification in that new transaction. This patch is actually a result of
assertion checks I was getting with more accurate transaction restart
handling implemented later in this series...

I agree we can actually subtract 3 from
ext4_blocks_for_truncate(inode)+extra_credits when starting the initial
transaction as inode changes get double-accounted there. I can do that
and I'll also update the changelog to explain this better.

								Honza

Patch
diff mbox series

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 516faa280ced..e6b631d50c26 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -196,7 +196,12 @@  void ext4_evict_inode(struct inode *inode)
 {
 	handle_t *handle;
 	int err;
-	int extra_credits = 3;
+	/*
+	 * Credits for final inode cleanup and freeing:
+	 * sb + inode (ext4_orphan_del()), block bitmap, group descriptor
+	 * (xattr block freeind), bitmap, group descriptor (inode freeing)
+	 */
+	int extra_credits = 6;
 	struct ext4_xattr_inode_array *ea_inode_array = NULL;
 
 	trace_ext4_evict_inode(inode);