Hi Rich,
On Wed 13-06-07 15:48:03, Rich Coe wrote:
> This patch fixes directory and missing files corruption in fs/udf which
> occurs on all known 2.6 releases.
>
> The corruption occurs because blocks which were pre-alloc'd for a directory
> are released back to the fs freelist, but the inode's alloc block information
> is not updated to reflect this.
>
> You would not see corruption if the number of files in any directory is
> less than 41, because the pre-alloc routine does not allocate blocks for the
> directory until the number of files is over 40.
>
> The problem occurs during unmounting because fs/udf incorrectly calls
> udf_discard_prealloc() from udf_clear_inode(). udf_discard_prealloc() will
> update the inode and schedule it for write, but no write will ever occur
> because the fs is in the process of being umount'd.
>
> The solution is to add a put_inode routine to update the inode contents
> and release the pre-alloc'd blocks to disk prior to clearing the inode
> from the kernel.
>
> Test case:
> mkuddfs /dev/scd0
> mount -o sync /dev/scd0 /mnt/cdrom
> mkdir /mnt/cdrom/A /mnt/cdrom/B
> cp A/* /mnt/cdrom/A [ A contains 90 files of various sizes ]
> cp B/* /mnt/cdrom/B [ B contains 20 or fewer files ]
> umount /mnt/cdrom
>
> Here you can see how 7 blocks starting at sector 139 are free and listed in the
> directory entry for 'A'. I used udfdump to get the following information:
> [ ... ]
> Free space found on this partition
> [00000139 - 00000159] [00000161 - 00000191] [00000193 - 00000223]
> [00004464 - 00004475] [00004485 - 00524286] [00524287 - 01048573]
> [01048574 - 01572860] [01572861 - 02097147] [02097148 - 02235039]
> [ ... ]
> Filename `A`
> [ ... ]
> [ blob at sector 2038 for 2048 bytes in logical partion 0 ]
> [ blob at sector 137 for 4096 bytes in logical partion 0 ]
> [ blob at sector 139 for 14336 bytes in logical partion 0 flags 1 ]
>
> --
> Rich Coe [email protected]
> Virtual Principle Engineer General Electric Healthcare Technologies
> Global Software Platforms, Computer Technology Team
>
> Signed-off-by: Rich Coe <[email protected]>
> ---
> diff -urNp linux-2.6.20.orig/fs/udf/inode.c linux-2.6.20/fs/udf/inode.c
> --- linux-2.6.20.orig/fs/udf/inode.c 2007-02-04 12:44:54.000000000 -0600
> +++ linux-2.6.20/fs/udf/inode.c 2007-06-13 11:32:41.930983471 -0500
> @@ -102,14 +102,17 @@ no_delete:
>
> void udf_clear_inode(struct inode *inode)
> {
> + kfree(UDF_I_DATA(inode));
> + UDF_I_DATA(inode) = NULL;
> +}
> +
> +void udf_put_inode(struct inode *inode)
> +{
> if (!(inode->i_sb->s_flags & MS_RDONLY)) {
> lock_kernel();
> udf_discard_prealloc(inode);
> unlock_kernel();
> }
Calling udf_discard_preallloc() from put_inode() has the problem that you
truncate the last extent too early - see the comments in the patch Chuck
pointed too (http://lkml.org/lkml/2007/6/11/79).
Can you try whether that patch fixes your problems?
Thanks
Honza
--
Jan Kara <[email protected]>
SuSE CR Labs
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