On Tue, Oct 04, 2022 at 03:58:03PM +0200, Lukas Czerner wrote:
> Before the commit 461c3af045d3 ("ext4: Change handle_mount_opt() to use
> fs_parameter") ext4 mount option journal_path did follow links in the
> provided path.
>
> Bring this behavior back by allowing to pass pathwalk flags to
> fs_lookup_param().
>
> Fixes: 461c3af045d3 ("ext4: Change handle_mount_opt() to use fs_parameter")
> Signed-off-by: Lukas Czerner <lczerner@xxxxxxxxxx>
This bit me recently when I was debugging an old system that used an
external journal on an LVM LV and I wanted to know if the bug I was
chasing also reproduced on upstream. Thanks for fixing this before I
got around to making a patch:
Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx>
--D
> ---
> Documentation/filesystems/mount_api.rst | 1 +
> fs/ext4/super.c | 2 +-
> fs/fs_parser.c | 3 ++-
> include/linux/fs_parser.h | 1 +
> 4 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/filesystems/mount_api.rst b/Documentation/filesystems/mount_api.rst
> index eb358a00be27..1d16787a00e9 100644
> --- a/Documentation/filesystems/mount_api.rst
> +++ b/Documentation/filesystems/mount_api.rst
> @@ -814,6 +814,7 @@ process the parameters it is given.
> int fs_lookup_param(struct fs_context *fc,
> struct fs_parameter *value,
> bool want_bdev,
> + unsigned int flags,
> struct path *_path);
>
> This takes a parameter that carries a string or filename type and attempts
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 9a66abcca1a8..4c1b3972d53f 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -2271,7 +2271,7 @@ static int ext4_parse_param(struct fs_context *fc, struct fs_parameter *param)
> return -EINVAL;
> }
>
> - error = fs_lookup_param(fc, param, 1, &path);
> + error = fs_lookup_param(fc, param, 1, 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 ed40ce5742fd..edb3712dcfa5 100644
> --- a/fs/fs_parser.c
> +++ b/fs/fs_parser.c
> @@ -138,15 +138,16 @@ EXPORT_SYMBOL(__fs_parse);
> * @fc: The filesystem context to log errors through.
> * @param: The parameter.
> * @want_bdev: T if want a blockdev
> + * @flags: Pathwalk flags passed to filename_lookup()
> * @_path: The result of the lookup
> */
> int fs_lookup_param(struct fs_context *fc,
> struct fs_parameter *param,
> bool want_bdev,
> + unsigned int flags,
> struct path *_path)
> {
> struct filename *f;
> - unsigned int flags = 0;
> bool put_f;
> int ret;
>
> diff --git a/include/linux/fs_parser.h b/include/linux/fs_parser.h
> index f103c91139d4..01542c4b87a2 100644
> --- a/include/linux/fs_parser.h
> +++ b/include/linux/fs_parser.h
> @@ -76,6 +76,7 @@ static inline int fs_parse(struct fs_context *fc,
> extern int fs_lookup_param(struct fs_context *fc,
> struct fs_parameter *param,
> bool want_bdev,
> + unsigned int flags,
> struct path *_path);
>
> extern int lookup_constant(const struct constant_table tbl[], const char *name, int not_found);
> --
> 2.37.3
>
