subdirs trying to be mounted when using ghosting

subdirs trying to be mounted when using ghosting

[Johan van den Dorpe]

Hi guys

We're having a problem when trying to access a subdir of an automount 
directory that isn't mounted. Instead of looking up the mount entry for 
the directory, a subdir is looked up instead. If the exact dir of the 
entry is accessed, then it mounts fine.

i.e.

ls /net/alpha/job/xmen3 -> no such file or directory
ls /net/alpha -> lists OK

We use a yp map for auto.net, it's not -host based mounting, heres the 
line from auto.master

/net yp:auto.net --ghost


Here's the entry from auto.net for /net/alpha which seems to be causing 
the problem (but I understand we experienced this for other mount 
points, including nfs servers. alpha is a lustre cluster)

alpha -fstype=lustre mds1a://mdt1a/alpha


We're running autofs 4.1.4-8 from RHEL4 RHN repo rebuilt for Fedora Core 
3. Also kernel-2.6.12-1.1381 from FC3 updates.

We've got debugging turned on the automounter so here you can see the 
logs when running the commands listed above


Jan 24 15:38:49 rj081 automount[3186]: handle_packet: type = 0
Jan 24 15:38:49 rj081 automount[3186]: handle_packet_missing: token 269, 
name alpha/job
Jan 24 15:38:49 rj081 automount[3186]: attempting to mount entry 
/net/alpha/job
Jan 24 15:38:49 rj081 automount[25673]: lookup(yp): looking up alpha/job
Jan 24 15:38:49 rj081 automount[25673]: ret = 8
Jan 24 15:38:49 rj081 automount[25673]: failed to mount /net/alpha/job
Jan 24 15:38:49 rj081 automount[25673]: umount_multi: 
path=/net/alpha/job incl=1
Jan 24 15:38:49 rj081 automount[25673]: umount_multi: no mounts found 
under /net/alpha/job
Jan 24 15:38:51 rj081 automount[3137]: sig 14 switching from 1 to 2
Jan 24 15:38:51 rj081 automount[3137]: get_pkt: state 1, next 2
Jan 24 15:38:51 rj081 automount[3137]: st_expire(): state = 1
Jan 24 15:38:51 rj081 automount[3137]: expire_proc: exp_proc=25674
Jan 24 15:38:51 rj081 automount[3292]: sig 14 switching from 1 to 2
Jan 24 15:38:51 rj081 automount[3292]: get_pkt: state 1, next 2
Jan 24 15:38:51 rj081 automount[3292]: st_expire(): state = 1
Jan 24 15:38:51 rj081 automount[3292]: expire_proc: exp_proc=25675
Jan 24 15:38:51 rj081 automount[3137]: handle_child: got pid 25674, sig 
0 (0), stat 0
Jan 24 15:38:51 rj081 automount[3137]: sigchld: exp 25674 finished, 
switching from 2 to 1
Jan 24 15:38:51 rj081 automount[3137]: get_pkt: state 2, next 1
Jan 24 15:38:51 rj081 automount[3137]: st_ready(): state = 2
Jan 24 15:38:51 rj081 automount[3292]: handle_child: got pid 25675, sig 
0 (0), stat 0
Jan 24 15:38:51 rj081 automount[3292]: sigchld: exp 25675 finished, 
switching from 2 to 1
Jan 24 15:38:51 rj081 automount[3292]: get_pkt: state 2, next 1
Jan 24 15:38:51 rj081 automount[3292]: st_ready(): state = 2
Jan 24 15:38:51 rj081 automount[3186]: handle_child: got pid 25673, sig 
0 (0), stat 1
Jan 24 15:38:51 rj081 automount[3186]: sig_child: found pending iop pid 
25673: signalled 0 (sig 0), exit status 1
Jan 24 15:38:51 rj081 automount[3186]: send_fail: token=269
Jan 24 15:38:51 rj081 automount[3186]: handle_packet: type = 0
Jan 24 15:38:51 rj081 automount[3186]: handle_packet_missing: token 270, 
name alpha
Jan 24 15:38:51 rj081 automount[3186]: attempting to mount entry /net/alpha
Jan 24 15:38:51 rj081 automount[25677]: lookup(yp): looking up alpha
Jan 24 15:38:51 rj081 automount[25677]: ret = 1
Jan 24 15:38:51 rj081 automount[25677]: lookup(yp): alpha -> 
-fstype=lustre mds1a://mdt1a/alpha
Jan 24 15:38:51 rj081 automount[25677]: parse(sun): expanded entry: 
-fstype=lustre mds1a://mdt1a/alpha
Jan 24 15:38:51 rj081 automount[25677]: parse(sun): 
dequote("fstype=lustre") -> fstype=lustre
Jan 24 15:38:51 rj081 automount[25677]: parse(sun): gathered options: 
fstype=lustre
Jan 24 15:38:51 rj081 automount[25677]: parse(sun): 
dequote("mds1a://mdt1a/alpha") -> mds1a://mdt1a/alpha
Jan 24 15:38:51 rj081 automount[25677]: parse(sun): core of entry: 
options=fstype=lustre, loc=mds1a://mdt1a/alpha
Jan 24 15:38:51 rj081 automount[25677]: parse(sun): mounting root /net, 
mountpoint alpha, what mds1a://mdt1a/alpha, fstype lustre, options
Jan 24 15:38:51 rj081 automount[25677]: do_mount mds1a://mdt1a/alpha 
/net/alpha type lustre options  using module generic
Jan 24 15:38:51 rj081 automount[25677]: mount(generic): calling 
mkdir_path /net/alpha
Jan 24 15:38:51 rj081 automount[25677]: mount(generic): calling mount -t 
lustre mds1a://mdt1a/alpha /net/alpha
Jan 24 15:38:52 rj081 automount[25677]: mount(generic): mounted 
mds1a://mdt1a/alpha type lustre on /net/alpha
Jan 24 15:39:31 rj081 automount[3186]: handle_child: got pid 25677, sig 
0 (0), stat 0
Jan 24 15:39:31 rj081 automount[3186]: sig_child: found pending iop pid 
25677: signalled 0 (sig 0), exit status 0



-- 
Johan van den Dorpe
Systems Administrator, Framestore CFC
020 7106 2441

Re: subdirs trying to be mounted when using ghosting

[Jeff Moyer]

==> Regarding [autofs] subdirs trying to be mounted when using ghosting; Johan van den Dorpe <johan.vandendorpe@framestore-cfc.com> adds:

johan.vandendorpe> Hi guys We're having a problem when trying to access a
johan.vandendorpe> subdir of an automount directory that isn't
johan.vandendorpe> mounted. Instead of looking up the mount entry for the
johan.vandendorpe> directory, a subdir is looked up instead. If the exact
johan.vandendorpe> dir of the entry is accessed, then it mounts fine.

Fixed by Ian in more recent kernels.  Patch was something like the
attached, though you'd do better to drop this part, I think:

-		return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
+		return (dentry->d_time - jiffies <= 0);


-Jeff

diff -Nurp linux-2.6.12.orig/fs/autofs4/expire.c linux-2.6.12/fs/autofs4/expire.c
--- linux-2.6.12.orig/fs/autofs4/expire.c	2005-06-18 03:48:29.000000000 +0800
+++ linux-2.6.12/fs/autofs4/expire.c	2005-10-09 15:11:37.000000000 +0800
@@ -177,7 +177,7 @@ resume:
 		DPRINTK("dentry %p %.*s",
 			dentry, (int)dentry->d_name.len, dentry->d_name.name);
 
-		if (!list_empty(&dentry->d_subdirs)) {
+		if (!simple_empty_nolock(dentry)) {
 			this_parent = dentry;
 			goto repeat;
 		}
@@ -269,7 +269,7 @@ static struct dentry *autofs4_expire(str
 			goto next;
 		}
 
-		if ( simple_empty(dentry) )
+		if (simple_empty(dentry))
 			goto next;
 
 		/* Case 2: tree mount, expire iff entire tree is not busy */
diff -Nurp linux-2.6.12.orig/fs/autofs4/root.c linux-2.6.12/fs/autofs4/root.c
--- linux-2.6.12.orig/fs/autofs4/root.c	2005-06-18 03:48:29.000000000 +0800
+++ linux-2.6.12/fs/autofs4/root.c	2005-10-09 15:52:04.000000000 +0800
@@ -386,13 +386,13 @@ static int autofs4_revalidate(struct den
 
 	/* Negative dentry.. invalidate if "old" */
 	if (dentry->d_inode == NULL)
-		return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
+		return (dentry->d_time - jiffies <= 0);
 
 	/* Check for a non-mountpoint directory with no contents */
 	spin_lock(&dcache_lock);
 	if (S_ISDIR(dentry->d_inode->i_mode) &&
 	    !d_mountpoint(dentry) && 
-	    list_empty(&dentry->d_subdirs)) {
+	    simple_empty_nolock(dentry)) {
 		DPRINTK("dentry=%p %.*s, emptydir",
 			 dentry, dentry->d_name.len, dentry->d_name.name);
 		spin_unlock(&dcache_lock);

Re: subdirs trying to be mounted when using ghosting

[Johan van den Dorpe]

Jeff Moyer wrote:
> ==> Regarding [autofs] subdirs trying to be mounted when using ghosting; Johan van den Dorpe <johan.vandendorpe@framestore-cfc.com> adds:
> 
> johan.vandendorpe> Hi guys We're having a problem when trying to access a
> johan.vandendorpe> subdir of an automount directory that isn't
> johan.vandendorpe> mounted. Instead of looking up the mount entry for the
> johan.vandendorpe> directory, a subdir is looked up instead. If the exact
> johan.vandendorpe> dir of the entry is accessed, then it mounts fine.
> 
> Fixed by Ian in more recent kernels.  Patch was something like the
> attached...

Thanks very much Jeff, Ian. No errors this morning, but after the last 
kernel change it was a couple of days before they cropped up... so we'll 
see how we go.

Thanks again.

-- 
Johan van den Dorpe
Systems Administrator, Framestore CFC
020 7106 2441

Re: subdirs trying to be mounted when using ghosting

[James Pearson]

I'm seeing a very similar problem on clients using a 2.4.30 kernel (with 
the 20041227 autofs4 patch) - do you (or anyone else) know if this patch 
will work on 2.4.x clients? The code this patch touches appears to be 
identical in the 2.4.x autofs4 source.

Thanks

James Pearson

Jeff Moyer wrote:
> ==> Regarding [autofs] subdirs trying to be mounted when using ghosting; Johan van den Dorpe <johan.vandendorpe@framestore-cfc.com> adds:
> 
> johan.vandendorpe> Hi guys We're having a problem when trying to access a
> johan.vandendorpe> subdir of an automount directory that isn't
> johan.vandendorpe> mounted. Instead of looking up the mount entry for the
> johan.vandendorpe> directory, a subdir is looked up instead. If the exact
> johan.vandendorpe> dir of the entry is accessed, then it mounts fine.
> 
> Fixed by Ian in more recent kernels.  Patch was something like the
> attached, though you'd do better to drop this part, I think:
> 
> -		return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
> +		return (dentry->d_time - jiffies <= 0);
> 
> 
> -Jeff
> 
> diff -Nurp linux-2.6.12.orig/fs/autofs4/expire.c linux-2.6.12/fs/autofs4/expire.c
> --- linux-2.6.12.orig/fs/autofs4/expire.c	2005-06-18 03:48:29.000000000 +0800
> +++ linux-2.6.12/fs/autofs4/expire.c	2005-10-09 15:11:37.000000000 +0800
> @@ -177,7 +177,7 @@ resume:
>  		DPRINTK("dentry %p %.*s",
>  			dentry, (int)dentry->d_name.len, dentry->d_name.name);
>  
> -		if (!list_empty(&dentry->d_subdirs)) {
> +		if (!simple_empty_nolock(dentry)) {
>  			this_parent = dentry;
>  			goto repeat;
>  		}
> @@ -269,7 +269,7 @@ static struct dentry *autofs4_expire(str
>  			goto next;
>  		}
>  
> -		if ( simple_empty(dentry) )
> +		if (simple_empty(dentry))
>  			goto next;
>  
>  		/* Case 2: tree mount, expire iff entire tree is not busy */
> diff -Nurp linux-2.6.12.orig/fs/autofs4/root.c linux-2.6.12/fs/autofs4/root.c
> --- linux-2.6.12.orig/fs/autofs4/root.c	2005-06-18 03:48:29.000000000 +0800
> +++ linux-2.6.12/fs/autofs4/root.c	2005-10-09 15:52:04.000000000 +0800
> @@ -386,13 +386,13 @@ static int autofs4_revalidate(struct den
>  
>  	/* Negative dentry.. invalidate if "old" */
>  	if (dentry->d_inode == NULL)
> -		return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
> +		return (dentry->d_time - jiffies <= 0);
>  
>  	/* Check for a non-mountpoint directory with no contents */
>  	spin_lock(&dcache_lock);
>  	if (S_ISDIR(dentry->d_inode->i_mode) &&
>  	    !d_mountpoint(dentry) && 
> -	    list_empty(&dentry->d_subdirs)) {
> +	    simple_empty_nolock(dentry)) {
>  		DPRINTK("dentry=%p %.*s, emptydir",
>  			 dentry, dentry->d_name.len, dentry->d_name.name);
>  		spin_unlock(&dcache_lock);
> 
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