[Bug 14472] EXT4 corruption

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http://bugzilla.kernel.org/show_bug.cgi?id=14472


Parag Warudkar <parag.warudkar@gmail.com> changed:

           What    |Removed                     |Added
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                 CC|                            |parag.warudkar@gmail.com




--- Comment #2 from Parag Warudkar <parag.warudkar@gmail.com>  2009-10-29 21:38:47 ---
I looked at the fsck pics - I have gone through this a few days ago. 

Aneesh suggested to apply the below patch and after applying it and crashing
the machine couple times I have not observed the corruption. So I have reason
to hope this patch below on top of today's git should improve things. Please
try.

commit a8836b1d6f92273e001012c7705ae8f4c3d5fb65
Author: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date:   Tue Oct 27 15:36:38 2009 +0530

   ext4: discard preallocation during truncate

   We need to make sure when we drop and reacquire the inode's
   i_data_sem we discard the inode preallocation. Otherwise we
   could have blocks marked as free in bitmap but still belonging
   to prealloc space.

   Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 5c5bc5d..a1ef1c3 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -209,6 +209,12 @@ static int try_to_extend_transaction(handle_t *handle,
struct inode *inode)
       up_write(&EXT4_I(inode)->i_data_sem);
       ret = ext4_journal_restart(handle, blocks_for_truncate(inode));
       down_write(&EXT4_I(inode)->i_data_sem);
+       /*
+        * We have dropped i_data_sem. So somebody else could have done
+        * block allocation. So discard the prealloc space created as a
+        * part of block allocation
+        */
+       ext4_discard_preallocations(inode);

       return ret;
 }

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