On Wed 25-09-24 09:56:24, Hongbo Li wrote:
> The `fs_lookup_param` did not consider the relative path for
> block device. When we mount ext4 with `journal_path` option using
> relative path, `param->dirfd` was not set which will cause mounting
> error.
>
> This can be reproduced easily like this:
>
> mke2fs -F -O journal_dev $JOURNAL_DEV -b 4096 100M
> mkfs.ext4 -F -J device=$JOURNAL_DEV -b 4096 $FS_DEV
> cd /dev; mount -t ext4 -o journal_path=`basename $JOURNAL_DEV` $FS_DEV $MNT
>
> Fixes: 461c3af045d3 ("ext4: Change handle_mount_opt() to use fs_parameter")
> Suggested-by: Christian Brauner <brauner@xxxxxxxxxx>
> Signed-off-by: Hongbo Li <lihongbo22@xxxxxxxxxx>
> ---
> v2:
> - Change the journal_path parameter as string not bdev, and
> determine the relative path situation inside fs_lookup_param.
> - Add Suggested-by.
>
> v1: https://lore.kernel.org/all/20240527-mahlen-packung-3fe035ab390d@brauner/
> ---
> fs/ext4/super.c | 4 ++--
> fs/fs_parser.c | 3 +++
> 2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 16a4ce704460..cd23536ce46e 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -1744,7 +1744,7 @@ static const struct fs_parameter_spec ext4_param_specs[] = {
> fsparam_u32 ("min_batch_time", Opt_min_batch_time),
> fsparam_u32 ("max_batch_time", Opt_max_batch_time),
> fsparam_u32 ("journal_dev", Opt_journal_dev),
> - fsparam_bdev ("journal_path", Opt_journal_path),
> + fsparam_string ("journal_path", Opt_journal_path),
Why did you change this? As far as I can see the only effect would be that
empty path will not be allowed (which makes sense) but that seems like an
independent change which would deserve a comment in the changelog? Or am I
missing something?
> fsparam_flag ("journal_checksum", Opt_journal_checksum),
> fsparam_flag ("nojournal_checksum", Opt_nojournal_checksum),
> fsparam_flag ("journal_async_commit",Opt_journal_async_commit),
> @@ -2301,7 +2301,7 @@ static int ext4_parse_param(struct fs_context *fc, struct fs_parameter *param)
> return -EINVAL;
> }
>
> - error = fs_lookup_param(fc, param, 1, LOOKUP_FOLLOW, &path);
> + error = fs_lookup_param(fc, param, true, LOOKUP_FOLLOW, &path);
> if (error) {
> ext4_msg(NULL, KERN_ERR, "error: could not find "
> "journal device path");
> diff --git a/fs/fs_parser.c b/fs/fs_parser.c
> index 24727ec34e5a..2ae296764b69 100644
> --- a/fs/fs_parser.c
> +++ b/fs/fs_parser.c
> @@ -156,6 +156,9 @@ int fs_lookup_param(struct fs_context *fc,
> f = getname_kernel(param->string);
> if (IS_ERR(f))
> return PTR_ERR(f);
> + /* for relative path */
> + if (f->name[0] != '/')
> + param->dirfd = AT_FDCWD;
What Al meant is that you can do simply:
param->dirfd = AT_FDCWD;
and everything will work the same because 'dfd' is ignored for absolute
pathnames in path_init().
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
