The patch titled
fs: truncate blocks outside i_size after O_DIRECT write error
has been added to the -mm tree. Its filename is
fs-truncate-blocks-outside-i_size-after-o_direct-write-error.patch
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------------------------------------------------------
Subject: fs: truncate blocks outside i_size after O_DIRECT write error
From: Dmitri Monakhov <dmonakhov@xxxxxxxxxx>
In case of error extending write may have instantiated a few blocks
outside i_size. We need to trim these blocks. We have to do it
*regardless* to blocksize. At least ext2, ext3 and reiserfs interpret
(i_size < biggest block) condition as error. Fsck will complain about
wrong i_size. Then fsck will fix the error by changing i_size according
to the biggest block. This is bad because this blocks contain garbage
from previous write attempt. And result in data corruption.
####TESTCASE_BEGIN
$touch /mnt/test/BIG_FILE
## at this moment /mnt/test/BIG_FILE size and blocks equal to zero
open("/mnt/test/BIG_FILE", O_WRONLY|O_CREAT|O_DIRECT, 0666) = 3
write(3, "aaaaaaaaaaaa"..., 104857600) = -1 ENOSPC (No space left on device)
## size and block sould't be changed because write op failed.
$stat /mnt/test/BIG_FILE
File: `/mnt/test/BIG_FILE'
Size: 0 Blocks: 110896 IO Block: 1024 regular empty file
<<<<<<<<^^^^^^^^^^^^^^^^^^^^^^^^^^^^^file size is less than biggest block idx
Device: fe07h/65031d Inode: 14 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2007-01-24 20:03:38.000000000 +0300
Modify: 2007-01-24 20:03:38.000000000 +0300
Change: 2007-01-24 20:03:39.000000000 +0300
#fsck.ext3 -f /dev/VG/test
e2fsck 1.39 (29-May-2006)
Pass 1: Checking inodes, blocks, and sizes
Inode 14, i_size is 0, should be 56556544. Fix<y>? yes
Pass 2: Checking directory structure
....
#####TESTCASE_ENDdiff --git a/fs/direct-io.c b/fs/direct-io.c
index af0558d..4e88bea 100644
Signed-off-by: Dmitri Monakhov <dmonakhov@xxxxxxxxxx>
Cc: Zach Brown <zach.brown@xxxxxxxxxx>
Cc: Nick Piggin <npiggin@xxxxxxx>
Cc: Badari Pulavarty <pbadari@xxxxxxxxxx>
Cc: Chris Mason <chris.mason@xxxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/direct-io.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff -puN fs/direct-io.c~fs-truncate-blocks-outside-i_size-after-o_direct-write-error fs/direct-io.c
--- a/fs/direct-io.c~fs-truncate-blocks-outside-i_size-after-o_direct-write-error
+++ a/fs/direct-io.c
@@ -1209,6 +1209,16 @@ __blockdev_direct_IO(int rw, struct kioc
retval = direct_io_worker(rw, iocb, inode, iov, offset,
nr_segs, blkbits, get_block, end_io, dio);
+ /*
+ * In case of error extending write may have instantiated a few
+ * blocks outside i_size. Trim these off again for DIO_LOCKING.
+ * NOTE: DIO_NO_LOCK/DIO_OWN_LOCK callers have to handle this by
+ * it's own meaner.
+ */
+ if (unlikely(retval < 0 && (rw & WRITE) && (end > i_size_read(inode))
+ && dio_lock_type == DIO_LOCKING))
+ vmtruncate(inode, inode->i_size);
+
if (rw == READ && dio_lock_type == DIO_LOCKING)
release_i_mutex = 0;
_
Patches currently in -mm which might be from dmonakhov@xxxxxxxxxx are
kill-suid-bit-only-for-regular-files.patch
fs-truncate-blocks-outside-i_size-after-o_direct-write-error.patch
fs-truncate-blocks-outside-i_size-after-o_direct-write-error-fix.patch
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