Re: [PATCH 02/11] fs: provide unlocked helper thaw_super()

[Jan Kara]

On Wed 29-11-17 15:23:47, Luis R. Rodriguez wrote:
> thaw_super() hold a write lock, however we wish to also enable
> callers which already hold the write lock. To do this provide a helper
> and make thaw_super() use it. This way, all that thaw_super() does
> now is lock handling and active count management.
> 
> This change has no functional changes.
> 
> Suggested-by: Dave Chinner 
> Signed-off-by: Luis R. Rodriguez 

Looks good to me. You can add:

Reviewed-by: Jan Kara 

Honza

> ---
>  fs/super.c | 39 ++-
>  1 file changed, 26 insertions(+), 13 deletions(-)
> 
> diff --git a/fs/super.c b/fs/super.c
> index a7650ff22f0e..cecc279beecd 100644
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -1493,21 +1493,13 @@ int freeze_super(struct super_block *sb)
>  }
>  EXPORT_SYMBOL(freeze_super);
>  
> -/**
> - * thaw_super -- unlock filesystem
> - * @sb: the super to thaw
> - *
> - * Unlocks the filesystem and marks it writeable again after freeze_super().
> - */
> -int thaw_super(struct super_block *sb)
> +/* Caller takes lock and handles active count */
> +static int thaw_locked_super(struct super_block *sb)
>  {
>   int error;
>  
> - down_write(>s_umount);
> - if (sb->s_writers.frozen != SB_FREEZE_COMPLETE) {
> - up_write(>s_umount);
> + if (sb->s_writers.frozen != SB_FREEZE_COMPLETE)
>   return -EINVAL;
> - }
>  
>   if (sb_rdonly(sb)) {
>   sb->s_writers.frozen = SB_UNFROZEN;
> @@ -1522,7 +1514,6 @@ int thaw_super(struct super_block *sb)
>   printk(KERN_ERR
>   "VFS:Filesystem thaw failed\n");
>   lockdep_sb_freeze_release(sb);
> - up_write(>s_umount);
>   return error;
>   }
>   }
> @@ -1531,7 +1522,29 @@ int thaw_super(struct super_block *sb)
>   sb_freeze_unlock(sb);
>  out:
>   wake_up(>s_writers.wait_unfrozen);
> - deactivate_locked_super(sb);
>   return 0;
>  }
> +
> +/**
> + * thaw_super -- unlock filesystem
> + * @sb: the super to thaw
> + *
> + * Unlocks the filesystem and marks it writeable again after freeze_super().
> + */
> +int thaw_super(struct super_block *sb)
> +{
> + int error;
> +
> + down_write(>s_umount);
> + error = thaw_locked_super(sb);
> + if (error) {
> + up_write(>s_umount);
> + goto out;
> + }
> +
> + deactivate_locked_super(sb);
> +
> +out:
> + return error;
> +}
>  EXPORT_SYMBOL(thaw_super);
> -- 
> 2.15.0
> 
-- 
Jan Kara 
SUSE Labs, CR

Re: [PATCH 02/11] fs: provide unlocked helper thaw_super()

[Jan Kara]

On Wed 29-11-17 15:23:47, Luis R. Rodriguez wrote:
> thaw_super() hold a write lock, however we wish to also enable
> callers which already hold the write lock. To do this provide a helper
> and make thaw_super() use it. This way, all that thaw_super() does
> now is lock handling and active count management.
> 
> This change has no functional changes.
> 
> Suggested-by: Dave Chinner 
> Signed-off-by: Luis R. Rodriguez 

Looks good to me. You can add:

Reviewed-by: Jan Kara 

Honza

> ---
>  fs/super.c | 39 ++-
>  1 file changed, 26 insertions(+), 13 deletions(-)
> 
> diff --git a/fs/super.c b/fs/super.c
> index a7650ff22f0e..cecc279beecd 100644
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -1493,21 +1493,13 @@ int freeze_super(struct super_block *sb)
>  }
>  EXPORT_SYMBOL(freeze_super);
>  
> -/**
> - * thaw_super -- unlock filesystem
> - * @sb: the super to thaw
> - *
> - * Unlocks the filesystem and marks it writeable again after freeze_super().
> - */
> -int thaw_super(struct super_block *sb)
> +/* Caller takes lock and handles active count */
> +static int thaw_locked_super(struct super_block *sb)
>  {
>   int error;
>  
> - down_write(>s_umount);
> - if (sb->s_writers.frozen != SB_FREEZE_COMPLETE) {
> - up_write(>s_umount);
> + if (sb->s_writers.frozen != SB_FREEZE_COMPLETE)
>   return -EINVAL;
> - }
>  
>   if (sb_rdonly(sb)) {
>   sb->s_writers.frozen = SB_UNFROZEN;
> @@ -1522,7 +1514,6 @@ int thaw_super(struct super_block *sb)
>   printk(KERN_ERR
>   "VFS:Filesystem thaw failed\n");
>   lockdep_sb_freeze_release(sb);
> - up_write(>s_umount);
>   return error;
>   }
>   }
> @@ -1531,7 +1522,29 @@ int thaw_super(struct super_block *sb)
>   sb_freeze_unlock(sb);
>  out:
>   wake_up(>s_writers.wait_unfrozen);
> - deactivate_locked_super(sb);
>   return 0;
>  }
> +
> +/**
> + * thaw_super -- unlock filesystem
> + * @sb: the super to thaw
> + *
> + * Unlocks the filesystem and marks it writeable again after freeze_super().
> + */
> +int thaw_super(struct super_block *sb)
> +{
> + int error;
> +
> + down_write(>s_umount);
> + error = thaw_locked_super(sb);
> + if (error) {
> + up_write(>s_umount);
> + goto out;
> + }
> +
> + deactivate_locked_super(sb);
> +
> +out:
> + return error;
> +}
>  EXPORT_SYMBOL(thaw_super);
> -- 
> 2.15.0
> 
-- 
Jan Kara 
SUSE Labs, CR

[PATCH 02/11] fs: provide unlocked helper thaw_super()

[Luis R. Rodriguez]

thaw_super() hold a write lock, however we wish to also enable
callers which already hold the write lock. To do this provide a helper
and make thaw_super() use it. This way, all that thaw_super() does
now is lock handling and active count management.

This change has no functional changes.

Suggested-by: Dave Chinner 
Signed-off-by: Luis R. Rodriguez 
---
 fs/super.c | 39 ++-
 1 file changed, 26 insertions(+), 13 deletions(-)

diff --git a/fs/super.c b/fs/super.c
index a7650ff22f0e..cecc279beecd 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1493,21 +1493,13 @@ int freeze_super(struct super_block *sb)
 }
 EXPORT_SYMBOL(freeze_super);
 
-/**
- * thaw_super -- unlock filesystem
- * @sb: the super to thaw
- *
- * Unlocks the filesystem and marks it writeable again after freeze_super().
- */
-int thaw_super(struct super_block *sb)
+/* Caller takes lock and handles active count */
+static int thaw_locked_super(struct super_block *sb)
 {
int error;
 
-   down_write(>s_umount);
-   if (sb->s_writers.frozen != SB_FREEZE_COMPLETE) {
-   up_write(>s_umount);
+   if (sb->s_writers.frozen != SB_FREEZE_COMPLETE)
return -EINVAL;
-   }
 
if (sb_rdonly(sb)) {
sb->s_writers.frozen = SB_UNFROZEN;
@@ -1522,7 +1514,6 @@ int thaw_super(struct super_block *sb)
printk(KERN_ERR
"VFS:Filesystem thaw failed\n");
lockdep_sb_freeze_release(sb);
-   up_write(>s_umount);
return error;
}
}
@@ -1531,7 +1522,29 @@ int thaw_super(struct super_block *sb)
sb_freeze_unlock(sb);
 out:
wake_up(>s_writers.wait_unfrozen);
-   deactivate_locked_super(sb);
return 0;
 }
+
+/**
+ * thaw_super -- unlock filesystem
+ * @sb: the super to thaw
+ *
+ * Unlocks the filesystem and marks it writeable again after freeze_super().
+ */
+int thaw_super(struct super_block *sb)
+{
+   int error;
+
+   down_write(>s_umount);
+   error = thaw_locked_super(sb);
+   if (error) {
+   up_write(>s_umount);
+   goto out;
+   }
+
+   deactivate_locked_super(sb);
+
+out:
+   return error;
+}
 EXPORT_SYMBOL(thaw_super);
-- 
2.15.0

[PATCH 02/11] fs: provide unlocked helper thaw_super()

[Luis R. Rodriguez]

thaw_super() hold a write lock, however we wish to also enable
callers which already hold the write lock. To do this provide a helper
and make thaw_super() use it. This way, all that thaw_super() does
now is lock handling and active count management.

This change has no functional changes.

Suggested-by: Dave Chinner 
Signed-off-by: Luis R. Rodriguez 
---
 fs/super.c | 39 ++-
 1 file changed, 26 insertions(+), 13 deletions(-)

diff --git a/fs/super.c b/fs/super.c
index a7650ff22f0e..cecc279beecd 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -1493,21 +1493,13 @@ int freeze_super(struct super_block *sb)
 }
 EXPORT_SYMBOL(freeze_super);
 
-/**
- * thaw_super -- unlock filesystem
- * @sb: the super to thaw
- *
- * Unlocks the filesystem and marks it writeable again after freeze_super().
- */
-int thaw_super(struct super_block *sb)
+/* Caller takes lock and handles active count */
+static int thaw_locked_super(struct super_block *sb)
 {
int error;
 
-   down_write(>s_umount);
-   if (sb->s_writers.frozen != SB_FREEZE_COMPLETE) {
-   up_write(>s_umount);
+   if (sb->s_writers.frozen != SB_FREEZE_COMPLETE)
return -EINVAL;
-   }
 
if (sb_rdonly(sb)) {
sb->s_writers.frozen = SB_UNFROZEN;
@@ -1522,7 +1514,6 @@ int thaw_super(struct super_block *sb)
printk(KERN_ERR
"VFS:Filesystem thaw failed\n");
lockdep_sb_freeze_release(sb);
-   up_write(>s_umount);
return error;
}
}
@@ -1531,7 +1522,29 @@ int thaw_super(struct super_block *sb)
sb_freeze_unlock(sb);
 out:
wake_up(>s_writers.wait_unfrozen);
-   deactivate_locked_super(sb);
return 0;
 }
+
+/**
+ * thaw_super -- unlock filesystem
+ * @sb: the super to thaw
+ *
+ * Unlocks the filesystem and marks it writeable again after freeze_super().
+ */
+int thaw_super(struct super_block *sb)
+{
+   int error;
+
+   down_write(>s_umount);
+   error = thaw_locked_super(sb);
+   if (error) {
+   up_write(>s_umount);
+   goto out;
+   }
+
+   deactivate_locked_super(sb);
+
+out:
+   return error;
+}
 EXPORT_SYMBOL(thaw_super);
-- 
2.15.0