This is a note to let you know that I've just added the patch titled
ext4: don't allow ext4_free_blocks() to fail due to ENOMEM
to the 3.4-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-allow-ext4_free_blocks-to-fail-due-to-enomem.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From e7676a704ee0a1ef71a6b23760b5a8f6896cb1a1 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@xxxxxxx>
Date: Sat, 13 Jul 2013 00:40:35 -0400
Subject: ext4: don't allow ext4_free_blocks() to fail due to ENOMEM
From: Theodore Ts'o <tytso@xxxxxxx>
commit e7676a704ee0a1ef71a6b23760b5a8f6896cb1a1 upstream.
The filesystem should not be marked inconsistent if ext4_free_blocks()
is not able to allocate memory. Unfortunately some callers (most
notably ext4_truncate) don't have a way to reflect an error back up to
the VFS. And even if we did, most userspace applications won't deal
with most system calls returning ENOMEM anyway.
Reported-by: Nagachandra P <nagachandra@xxxxxxxxx>
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/mballoc.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4639,11 +4639,16 @@ do_more:
* blocks being freed are metadata. these blocks shouldn't
* be used until this transaction is committed
*/
+ retry:
new_entry = kmem_cache_alloc(ext4_free_data_cachep, GFP_NOFS);
if (!new_entry) {
- ext4_mb_unload_buddy(&e4b);
- err = -ENOMEM;
- goto error_return;
+ /*
+ * We use a retry loop because
+ * ext4_free_blocks() is not allowed to fail.
+ */
+ cond_resched();
+ congestion_wait(BLK_RW_ASYNC, HZ/50);
+ goto retry;
}
new_entry->efd_start_cluster = bit;
new_entry->efd_group = block_group;
Patches currently in stable-queue which might be from tytso@xxxxxxx are
queue-3.4/jbd2-fix-theoretical-race-in-jbd2__journal_restart.patch
queue-3.4/ext4-don-t-allow-ext4_free_blocks-to-fail-due-to-enomem.patch
queue-3.4/ext4-fix-data-offset-overflow-in-ext4_xattr_fiemap-on-32-bit-archs.patch
queue-3.4/ext4-fix-overflow-when-counting-used-blocks-on-32-bit-architectures.patch
queue-3.4/ext3-ext4-don-t-mess-with-dir_file-f_pos-in-htree_dirblock_to_tree.patch
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