2022-10-04 14:10:28

by Lukas Czerner

[permalink] [raw]
Subject: [PATCH] ext4: journal_path mount options should follow links

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 <[email protected]>
---
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


2022-10-04 18:48:51

by Darrick J. Wong

[permalink] [raw]
Subject: Re: [PATCH] ext4: journal_path mount options should follow links

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 <[email protected]>

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 <[email protected]>

--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
>

2022-11-29 21:13:38

by Theodore Ts'o

[permalink] [raw]
Subject: Re: [PATCH] ext4: journal_path mount options should follow links

On Tue, 4 Oct 2022 15:58:03 +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().
>
> [...]

Applied, thanks!

[1/1] ext4: journal_path mount options should follow links
commit: c5d6c14eac604c4ef551e2751726f665b3f09e32

Best regards,
--
Theodore Ts'o <[email protected]>