Re: [PATCH 26/31] libext2fs: openfs() musn't allow bigalloc without EXT2_FLAGS_64BITS

Lukáš Czerner
2013-10-07T12:51:00Z

On Mon, 30 Sep 2013, Darrick J. Wong wrote:

> Date: Mon, 30 Sep 2013 18:29:28 -0700
> From: Darrick J. Wong <darrick.wong@oracle.com>
> To: tytso@mit.edu, darrick.wong@oracle.com
> Cc: linux-ext4@vger.kernel.org
> Subject: [PATCH 26/31] libext2fs: openfs() musn't allow bigalloc without
> EXT2_FLAGS_64BITS
>
> Currently, only the 64-bit bitmap implementation supports the block<->cluster
> conversions that bigalloc requires. Therefore, if we have a bigalloc
> filesystem, require EXT2_FLAGS_64BITS be passed in to ext2fs_open().
>
> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
> ---
> lib/ext2fs/openfs.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)

Looks good.

Reviewed-by: Lukas Czerner <lczerner@redhat.com>

>
>
> diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c
> index 3c0bf14..f486a35 100644
> --- a/lib/ext2fs/openfs.c
> +++ b/lib/ext2fs/openfs.c
> @@ -272,6 +272,18 @@ errcode_t ext2fs_open3(const char *name, const char *io_options,
> retval = EXT2_ET_CORRUPT_SUPERBLOCK;
> goto cleanup;
> }
> +
> + /*
> + * bigalloc requires cluster-aware bitfield operations, which at the
> + * moment means we need EXT2_FLAG_64BITS.
> + */
> + if (EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
> + EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
> + !(flags & EXT2_FLAG_64BITS)) {
> + retval = EXT2_ET_CANT_USE_LEGACY_BITMAPS;
> + goto cleanup;
> + }
> +
> if (!EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
> EXT4_FEATURE_RO_COMPAT_BIGALLOC) &&
> (fs->super->s_log_block_size != fs->super->s_log_cluster_size)) {
>
> --
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