autofs4: fix indirect mount pending expire race

[linux-2.6-omap-h63xx.git] / fs / autofs4 / root.c

diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index 61d1dca1688446b9d26c741cc6542972af020b58..1c2579de1f2e902499ec70f1bcd5f0fc5ba7f74c 100644 (file)
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -133,7 +133,10 @@ static int try_to_fill_dentry(struct dentry *dentry, int flags)
        /* Block on any pending expiry here; invalidate the dentry
            when expiration is done to trigger mount request with a new
            dentry */
-       if (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
+       spin_lock(&sbi->fs_lock);
+       if (ino->flags & AUTOFS_INF_EXPIRING) {
+               spin_unlock(&sbi->fs_lock);
+
                DPRINTK("waiting for expire %p name=%.*s",
                         dentry, dentry->d_name.len, dentry->d_name.name);
 
@@ -149,8 +152,11 @@ static int try_to_fill_dentry(struct dentry *dentry, int flags)
                status = d_invalidate(dentry);
                if (status != -EBUSY)
                        return -EAGAIN;
-       }
 
+               goto cont;
+       }
+       spin_unlock(&sbi->fs_lock);
+cont:
        DPRINTK("dentry=%p %.*s ino=%p",
                 dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
 
@@ -229,15 +235,21 @@ static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd)
                goto done;
 
        /* If an expire request is pending wait for it. */
-       if (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
+       spin_lock(&sbi->fs_lock);
+       if (ino->flags & AUTOFS_INF_EXPIRING) {
+               spin_unlock(&sbi->fs_lock);
+
                DPRINTK("waiting for active request %p name=%.*s",
                        dentry, dentry->d_name.len, dentry->d_name.name);
 
                status = autofs4_wait(sbi, dentry, NFY_NONE);
 
                DPRINTK("request done status=%d", status);
-       }
 
+               goto cont;
+       }
+       spin_unlock(&sbi->fs_lock);
+cont:
        /*
         * If the dentry contains directories then it is an
         * autofs multi-mount with no root mount offset. So
@@ -292,8 +304,11 @@ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
        int status = 1;
 
        /* Pending dentry */
+       spin_lock(&sbi->fs_lock);
        if (autofs4_ispending(dentry)) {
                /* The daemon never causes a mount to trigger */
+               spin_unlock(&sbi->fs_lock);
+
                if (oz_mode)
                        return 1;
 
@@ -316,6 +331,7 @@ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
 
                return status;
        }
+       spin_unlock(&sbi->fs_lock);
 
        /* Negative dentry.. invalidate if "old" */
        if (dentry->d_inode == NULL)
@@ -329,6 +345,7 @@ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
                DPRINTK("dentry=%p %.*s, emptydir",
                         dentry, dentry->d_name.len, dentry->d_name.name);
                spin_unlock(&dcache_lock);
+
                /* The daemon never causes a mount to trigger */
                if (oz_mode)
                        return 1;
@@ -521,13 +538,18 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s
                 * so it must have been successful, so just wait for it.
                 */
                ino = autofs4_dentry_ino(expiring);
-               while (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
+               spin_lock(&sbi->fs_lock);
+               if (ino->flags & AUTOFS_INF_EXPIRING) {
+                       spin_unlock(&sbi->fs_lock);
                        DPRINTK("wait for incomplete expire %p name=%.*s",
                                expiring, expiring->d_name.len,
                                expiring->d_name.name);
                        autofs4_wait(sbi, expiring, NFY_NONE);
                        DPRINTK("request completed");
+                       goto cont;
                }
+               spin_unlock(&sbi->fs_lock);
+cont:
                spin_lock(&sbi->lookup_lock);
                if (!list_empty(&ino->expiring))
                        list_del_init(&ino->expiring);