[PATCH] vfs: replace WARN(down_read_trylock, ...) abuse with proper asserts

[PATCH] vfs: replace WARN(down_read_trylock, ...) abuse with proper asserts

[Mateusz Guzik]

Note the macro used here works regardless of LOCKDEP.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
---
 fs/dcache.c      | 2 +-
 fs/quota/dquot.c | 8 ++------
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/fs/dcache.c b/fs/dcache.c
index 407095188f83..a0a944fd3a1c 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1548,7 +1548,7 @@ void shrink_dcache_for_umount(struct super_block *sb)
 {
 	struct dentry *dentry;
 
-	WARN(down_read_trylock(&sb->s_umount), "s_umount should've been locked");
+	rwsem_assert_held_write(&sb->s_umount);
 
 	dentry = sb->s_root;
 	sb->s_root = NULL;
diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 627eb2f72ef3..a2b256dac36e 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -2246,9 +2246,7 @@ int dquot_disable(struct super_block *sb, int type, unsigned int flags)
 	int cnt;
 	struct quota_info *dqopt = sb_dqopt(sb);
 
-	/* s_umount should be held in exclusive mode */
-	if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
-		up_read(&sb->s_umount);
+	rwsem_assert_held_write(&sb->s_umount);
 
 	/* Cannot turn off usage accounting without turning off limits, or
 	 * suspend quotas and simultaneously turn quotas off. */
@@ -2510,9 +2508,7 @@ int dquot_resume(struct super_block *sb, int type)
 	int ret = 0, cnt;
 	unsigned int flags;
 
-	/* s_umount should be held in exclusive mode */
-	if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
-		up_read(&sb->s_umount);
+	rwsem_assert_held_write(&sb->s_umount);
 
 	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
 		if (type != -1 && cnt != type)
-- 
2.39.2

Re: [PATCH] vfs: replace WARN(down_read_trylock, ...) abuse with proper asserts

[Jan Kara]

On Sun 02-06-24 14:37:19, Mateusz Guzik wrote:
> Note the macro used here works regardless of LOCKDEP.
> 
> Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>

Nice cleanup. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/dcache.c      | 2 +-
>  fs/quota/dquot.c | 8 ++------
>  2 files changed, 3 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/dcache.c b/fs/dcache.c
> index 407095188f83..a0a944fd3a1c 100644
> --- a/fs/dcache.c
> +++ b/fs/dcache.c
> @@ -1548,7 +1548,7 @@ void shrink_dcache_for_umount(struct super_block *sb)
>  {
>  	struct dentry *dentry;
>  
> -	WARN(down_read_trylock(&sb->s_umount), "s_umount should've been locked");
> +	rwsem_assert_held_write(&sb->s_umount);
>  
>  	dentry = sb->s_root;
>  	sb->s_root = NULL;
> diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
> index 627eb2f72ef3..a2b256dac36e 100644
> --- a/fs/quota/dquot.c
> +++ b/fs/quota/dquot.c
> @@ -2246,9 +2246,7 @@ int dquot_disable(struct super_block *sb, int type, unsigned int flags)
>  	int cnt;
>  	struct quota_info *dqopt = sb_dqopt(sb);
>  
> -	/* s_umount should be held in exclusive mode */
> -	if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
> -		up_read(&sb->s_umount);
> +	rwsem_assert_held_write(&sb->s_umount);
>  
>  	/* Cannot turn off usage accounting without turning off limits, or
>  	 * suspend quotas and simultaneously turn quotas off. */
> @@ -2510,9 +2508,7 @@ int dquot_resume(struct super_block *sb, int type)
>  	int ret = 0, cnt;
>  	unsigned int flags;
>  
> -	/* s_umount should be held in exclusive mode */
> -	if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
> -		up_read(&sb->s_umount);
> +	rwsem_assert_held_write(&sb->s_umount);
>  
>  	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
>  		if (type != -1 && cnt != type)
> -- 
> 2.39.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH] vfs: replace WARN(down_read_trylock, ...) abuse with proper asserts

[Christian Brauner]

On Sun, 02 Jun 2024 14:37:19 +0200, Mateusz Guzik wrote:
> Note the macro used here works regardless of LOCKDEP.
> 
> 

Applied to the vfs.misc branch of the vfs/vfs.git tree.
Patches in the vfs.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs.misc

[1/1] vfs: replace WARN(down_read_trylock, ...) abuse with proper asserts
      https://git.kernel.org/vfs/vfs/c/43bcd0a6aa46