From: Theodore Ts'o <tytso@mit.edu>
Date: Mon, 15 Jul 2013 04:09:19 +0000 (-0400)
Subject: ext4: fix error handling in ext4_ext_truncate()
X-Git-Tag: v3.11-rc2~5^2~4
X-Git-Url: http://pileus.org/git/?p=~andy%2Flinux;a=commitdiff_plain;h=8acd5e9b1217e58a57124d9e225afa12efeae20d

ext4: fix error handling in ext4_ext_truncate()

Previously ext4_ext_truncate() was ignoring potential error returns
from ext4_es_remove_extent() and ext4_ext_remove_space().  This can
lead to the on-diks extent tree and the extent status tree cache
getting out of sync, which is particuarlly bad, and can lead to file
system corruption and potential data loss.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
---

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 7097b0f680e..f57cc0e7f1b 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4405,9 +4405,20 @@ void ext4_ext_truncate(handle_t *handle, struct inode *inode)
 
 	last_block = (inode->i_size + sb->s_blocksize - 1)
 			>> EXT4_BLOCK_SIZE_BITS(sb);
+retry:
 	err = ext4_es_remove_extent(inode, last_block,
 				    EXT_MAX_BLOCKS - last_block);
+	if (err == ENOMEM) {
+		cond_resched();
+		congestion_wait(BLK_RW_ASYNC, HZ/50);
+		goto retry;
+	}
+	if (err) {
+		ext4_std_error(inode->i_sb, err);
+		return;
+	}
 	err = ext4_ext_remove_space(inode, last_block, EXT_MAX_BLOCKS - 1);
+	ext4_std_error(inode->i_sb, err);
 }
 
 static void ext4_falloc_update_inode(struct inode *inode,