diff mbox series

[4/4] locks: map correct ino/dev pairs when exporting to userspace

Message ID 20180731211045.5671-5-mfasheh@suse.de (mailing list archive)
State New, archived
Headers show
Series vfs: map unique ino/dev pairs for user space | expand

Commit Message

Mark Fasheh July 31, 2018, 9:10 p.m. UTC 
/proc/locks does not always print the correct inode number/device pair.
Update lock_get_status() to use vfs_map_unique_ino_dev() to get the real,
unique values for userspace.

Signed-off-by: Mark Fasheh <mfasheh@suse.de>
---
 fs/locks.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

Comments

Amir Goldstein Aug. 1, 2018, 5:37 a.m. UTC | #1 
On Wed, Aug 1, 2018 at 12:10 AM, Mark Fasheh <mfasheh@suse.de> wrote:
> /proc/locks does not always print the correct inode number/device pair.
> Update lock_get_status() to use vfs_map_unique_ino_dev() to get the real,
> unique values for userspace.
>
> Signed-off-by: Mark Fasheh <mfasheh@suse.de>
> ---
>  fs/locks.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/fs/locks.c b/fs/locks.c
> index db7b6917d9c5..3a012df87fd8 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -2621,6 +2621,7 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
>                             loff_t id, char *pfx)
>  {
>         struct inode *inode = NULL;
> +       struct dentry *dentry;
>         unsigned int fl_pid;
>         struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
>
> @@ -2633,8 +2634,10 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
>         if (fl_pid == 0)
>                 return;
>
> -       if (fl->fl_file != NULL)
> +       if (fl->fl_file != NULL) {
>                 inode = locks_inode(fl->fl_file);
> +               dentry = file_dentry(fl->fl_file);
> +       }
>
>         seq_printf(f, "%lld:%s ", id, pfx);
>         if (IS_POSIX(fl)) {
> @@ -2681,10 +2684,13 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
>                                : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
>         }
>         if (inode) {
> +               __u64 ino;
> +               dev_t dev;
> +
> +               vfs_map_unique_ino_dev(dentry, &ino, &dev);
>                 /* userspace relies on this representation of dev_t */
>                 seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
> -                               MAJOR(inode->i_sb->s_dev),
> -                               MINOR(inode->i_sb->s_dev), inode->i_ino);
> +                               MAJOR(dev), MINOR(dev), inode->i_ino);

Don't you mean ,ino); ?

Thanks,
Amir.
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Jeff Layton Aug. 1, 2018, 11:03 a.m. UTC | #2 
On Tue, 2018-07-31 at 14:10 -0700, Mark Fasheh wrote:
> /proc/locks does not always print the correct inode number/device pair.
> Update lock_get_status() to use vfs_map_unique_ino_dev() to get the real,
> unique values for userspace.
> 
> Signed-off-by: Mark Fasheh <mfasheh@suse.de>
> ---
>  fs/locks.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/locks.c b/fs/locks.c
> index db7b6917d9c5..3a012df87fd8 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -2621,6 +2621,7 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
>  			    loff_t id, char *pfx)
>  {
>  	struct inode *inode = NULL;
> +	struct dentry *dentry;
>  	unsigned int fl_pid;
>  	struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
>  
> @@ -2633,8 +2634,10 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
>  	if (fl_pid == 0)
>  		return;
>  
> -	if (fl->fl_file != NULL)
> +	if (fl->fl_file != NULL) {
>  		inode = locks_inode(fl->fl_file);
> +		dentry = file_dentry(fl->fl_file);
> +	}
>  
>  	seq_printf(f, "%lld:%s ", id, pfx);
>  	if (IS_POSIX(fl)) {
> @@ -2681,10 +2684,13 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
>  			       : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
>  	}
>  	if (inode) {
> +		__u64 ino;
> +		dev_t dev;
> +
> +		vfs_map_unique_ino_dev(dentry, &ino, &dev);

This code is under a spinlock (blocked_locks_lock or ctx->flc_lock). I
don't think it'll be ok to call ->getattr while holding a spinlock.

>  		/* userspace relies on this representation of dev_t */
>  		seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
> -				MAJOR(inode->i_sb->s_dev),
> -				MINOR(inode->i_sb->s_dev), inode->i_ino);
> +				MAJOR(dev), MINOR(dev), inode->i_ino);
>  	} else {
>  		seq_printf(f, "%d <none>:0 ", fl_pid);
>  	}
Mark Fasheh Aug. 1, 2018, 5:45 p.m. UTC | #3 
On Wed, Aug 01, 2018 at 08:37:31AM +0300, Amir Goldstein wrote:
> >         if (inode) {
> > +               __u64 ino;
> > +               dev_t dev;
> > +
> > +               vfs_map_unique_ino_dev(dentry, &ino, &dev);
> >                 /* userspace relies on this representation of dev_t */
> >                 seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
> > -                               MAJOR(inode->i_sb->s_dev),
> > -                               MINOR(inode->i_sb->s_dev), inode->i_ino);
> > +                               MAJOR(dev), MINOR(dev), inode->i_ino);
> 
> Don't you mean ,ino); ?

Indeed I do, thanks for catching that one Amir.
	--Mark
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Mark Fasheh Aug. 1, 2018, 8:38 p.m. UTC | #4 
Hi Jeff,

On Wed, Aug 01, 2018 at 07:03:54AM -0400, Jeff Layton wrote:
> On Tue, 2018-07-31 at 14:10 -0700, Mark Fasheh wrote:
> > /proc/locks does not always print the correct inode number/device pair.
> > Update lock_get_status() to use vfs_map_unique_ino_dev() to get the real,
> > unique values for userspace.
> > 
> > Signed-off-by: Mark Fasheh <mfasheh@suse.de>
> > ---
> >  fs/locks.c | 12 +++++++++---
> >  1 file changed, 9 insertions(+), 3 deletions(-)
> > 
> > diff --git a/fs/locks.c b/fs/locks.c
> > index db7b6917d9c5..3a012df87fd8 100644
> > --- a/fs/locks.c
> > +++ b/fs/locks.c
> > @@ -2621,6 +2621,7 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
> >  			    loff_t id, char *pfx)
> >  {
> >  	struct inode *inode = NULL;
> > +	struct dentry *dentry;
> >  	unsigned int fl_pid;
> >  	struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
> >  
> > @@ -2633,8 +2634,10 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
> >  	if (fl_pid == 0)
> >  		return;
> >  
> > -	if (fl->fl_file != NULL)
> > +	if (fl->fl_file != NULL) {
> >  		inode = locks_inode(fl->fl_file);
> > +		dentry = file_dentry(fl->fl_file);
> > +	}
> >  
> >  	seq_printf(f, "%lld:%s ", id, pfx);
> >  	if (IS_POSIX(fl)) {
> > @@ -2681,10 +2684,13 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
> >  			       : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
> >  	}
> >  	if (inode) {
> > +		__u64 ino;
> > +		dev_t dev;
> > +
> > +		vfs_map_unique_ino_dev(dentry, &ino, &dev);
> 
> This code is under a spinlock (blocked_locks_lock or ctx->flc_lock). I
> don't think it'll be ok to call ->getattr while holding a spinlock.

Hmm, indeed it does call under spinlock. I'll hve to rethink how to approach
this in fs/locks.c

Thanks,
	--Mark
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diff mbox series

Patch

diff --git a/fs/locks.c b/fs/locks.c
index db7b6917d9c5..3a012df87fd8 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2621,6 +2621,7 @@  static void lock_get_status(struct seq_file *f, struct file_lock *fl,
 			    loff_t id, char *pfx)
 {
 	struct inode *inode = NULL;
+	struct dentry *dentry;
 	unsigned int fl_pid;
 	struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
 
@@ -2633,8 +2634,10 @@  static void lock_get_status(struct seq_file *f, struct file_lock *fl,
 	if (fl_pid == 0)
 		return;
 
-	if (fl->fl_file != NULL)
+	if (fl->fl_file != NULL) {
 		inode = locks_inode(fl->fl_file);
+		dentry = file_dentry(fl->fl_file);
+	}
 
 	seq_printf(f, "%lld:%s ", id, pfx);
 	if (IS_POSIX(fl)) {
@@ -2681,10 +2684,13 @@  static void lock_get_status(struct seq_file *f, struct file_lock *fl,
 			       : (fl->fl_type == F_WRLCK) ? "WRITE" : "READ ");
 	}
 	if (inode) {
+		__u64 ino;
+		dev_t dev;
+
+		vfs_map_unique_ino_dev(dentry, &ino, &dev);
 		/* userspace relies on this representation of dev_t */
 		seq_printf(f, "%d %02x:%02x:%ld ", fl_pid,
-				MAJOR(inode->i_sb->s_dev),
-				MINOR(inode->i_sb->s_dev), inode->i_ino);
+				MAJOR(dev), MINOR(dev), inode->i_ino);
 	} else {
 		seq_printf(f, "%d <none>:0 ", fl_pid);
 	}