This is a note to let you know that I've just added the patch titled
ext4: don't let i_reserved_meta_blocks go negative
to the 3.5-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ext4-don-t-let-i_reserved_meta_blocks-go-negative.patch
and it can be found in the queue-3.5 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 97795d2a5b8d3c8dc4365d4bd3404191840453ba Mon Sep 17 00:00:00 2001
From: Brian Foster <[email protected]>
Date: Sun, 22 Jul 2012 23:59:40 -0400
Subject: ext4: don't let i_reserved_meta_blocks go negative
From: Brian Foster <[email protected]>
commit 97795d2a5b8d3c8dc4365d4bd3404191840453ba upstream.
If we hit a condition where we have allocated metadata blocks that
were not appropriately reserved, we risk underflow of
ei->i_reserved_meta_blocks. In turn, this can throw
sbi->s_dirtyclusters_counter significantly out of whack and undermine
the nondelalloc fallback logic in ext4_nonda_switch(). Warn if this
occurs and set i_allocated_meta_blocks to avoid this problem.
This condition is reproduced by xfstests 270 against ext2 with
delalloc enabled:
Mar 28 08:58:02 localhost kernel: [ 171.526344] EXT4-fs (loop1): delayed block
allocation failed for inode 14 at logical offset 64486 with max blocks 64 with
error -28
Mar 28 08:58:02 localhost kernel: [ 171.526346] EXT4-fs (loop1): This should
not happen!! Data will be lost
270 ultimately fails with an inconsistent filesystem and requires an
fsck to repair. The cause of the error is an underflow in
ext4_da_update_reserve_space() due to an unreserved meta block
allocation.
Signed-off-by: Brian Foster <[email protected]>
Signed-off-by: "Theodore Ts'o" <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/ext4/inode.c | 9 +++++++++
1 file changed, 9 insertions(+)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -346,6 +346,15 @@ void ext4_da_update_reserve_space(struct
used = ei->i_reserved_data_blocks;
}
+ if (unlikely(ei->i_allocated_meta_blocks > ei->i_reserved_meta_blocks))
{
+ ext4_msg(inode->i_sb, KERN_NOTICE, "%s: ino %lu, allocated %d "
+ "with only %d reserved metadata blocks\n", __func__,
+ inode->i_ino, ei->i_allocated_meta_blocks,
+ ei->i_reserved_meta_blocks);
+ WARN_ON(1);
+ ei->i_allocated_meta_blocks = ei->i_reserved_meta_blocks;
+ }
+
/* Update per-inode reservations */
ei->i_reserved_data_blocks -= used;
ei->i_reserved_meta_blocks -= ei->i_allocated_meta_blocks;
Patches currently in stable-queue which might be from [email protected] are
queue-3.5/ext4-undo-ext4_calc_metadata_amount-if-we-fail-to-claim-space.patch
queue-3.5/ext4-don-t-let-i_reserved_meta_blocks-go-negative.patch
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