RE: jffs2 umount

["Koeller, T." <Thomas dot Koeller at baslerweb dot com>]

You are right. I assumed the superblock would be deleted when
unmounting the file system, so its contents didn't matter. But
after checking again I found that it is actually reused if the
file system is re-mounted later.

In this case, that patch could take a simpler form where the
mount count is unconditionally decremented at the end, outside
the 'if' statement.

tk

----------------------------------------------- 
Thomas Koeller, Software Development 

Basler Vision Technologies 
An der Strusbek 60-62 
22926 Ahrensburg 
Germany 

Tel +49 (4102) 463-390 
Fax +49 (4102) 463-46390

mailto:Thomas.Koeller@baslerweb.com 
http://www.baslerweb.com 




> -----Original Message-----
> From: Andrew Lunn [mailto:andrew@lunn.ch]
> Sent: Tuesday, September 23, 2003 12:21 PM
> To: Thomas Koeller
> Cc: ecos-patches@sources.redhat.com
> Subject: Re: jffs2 umount
> 
> 
> On Sun, Sep 21, 2003 at 10:38:13PM +0200, Thomas Koeller wrote:
> > The jffs2_umount() function always decrements the mount count
> > for the file system, even if the umount attempt fails with
> > EBUSY. This means the umount can never be retried. Patch
> > attached.
> 
> It was not quite correct. You didn't decrement the mount count for
> successful umount's. This may not actually be necessary, but the old
> code would do it. Here i what i've committed.
> 
>      Andrew
> 
> Index: packages/fs/jffs2/current//ChangeLog
> ===================================================================
> RCS file: /cvs/ecos/ecos/packages/fs/jffs2/current/ChangeLog,v
> retrieving revision 1.12
> diff -u -r1.12 ChangeLog
> --- packages/fs/jffs2/current//ChangeLog        19 Sep 2003 
> 00:21:46 -0000      1.12+++ 
> packages/fs/jffs2/current//ChangeLog        23 Sep 2003 10:20:07 -0000
> @@ -1,3 +1,9 @@
> +2003-09-21  Thomas Koeller  <thomas.koeller@baslerweb.com>
> +           Andrew Lunn     <andrew.lunn@ascom.ch>
> +
> +       * src/fs-ecos.c: Do not decrement mount count for unsuccessful
> +       umount attempts.
> +
>  2003-09-19  Thomas Koeller  <thomas.koeller@baslerweb.com>
>   
>         * src/fs-ecos.c: Another inode number fix.
> Index: packages/fs/jffs2/current//src/fs-ecos.c
> ===================================================================
> RCS file: /cvs/ecos/ecos/packages/fs/jffs2/current/src/fs-ecos.c,v
> retrieving revision 1.7
> diff -u -r1.7 fs-ecos.c
> --- packages/fs/jffs2/current//src/fs-ecos.c    19 Sep 2003 
> 00:21:46 -0000      1.7
> +++ packages/fs/jffs2/current//src/fs-ecos.c    23 Sep 2003 
> 10:20:10 -0000
> @@ -584,17 +584,15 @@
>   
>         D2(printf("jffs2_umount\n"));
>   
> -       // Decrement the mount count
> -       jffs2_sb->s_mount_count--;
> -
>         // Only really umount if this is the only mount
> -       if (jffs2_sb->s_mount_count == 0) {
> +       if (jffs2_sb->s_mount_count == 1) {
>   
>                 // Check for open/inuse root or any cached inodes
>  //if( root->i_count != 1 || root->i_cache_next != NULL) // 
> root icount was set to 1 on mount
>                 if (root->i_cache_next != NULL) // root 
> icount was set to 1 on mount                        return EBUSY;
> -
> +
> +               jffs2_sb->s_mount_count--;
>                 dec_refcnt(root);       // Time to free the root inode
>   
>                 //Clear root inode
> @@ -611,7 +609,8 @@
>                 mte->fs->data = 0;      // fstab entry, 
> visible to all mounts. No current mount
>                 // That's all folks.
>                 D2(printf("jffs2_umount No current mounts\n"));
> -       }
> +       } else
> +               jffs2_sb->s_mount_count--;
>   
>         return ENOERR;
>  }
>