autofs4 - reinstate last used update on access

When direct (and offset) mounts were introduced the the last used
timeout could no longer be updated in ->d_revalidate(). This is
because covered direct mounts would be followed over without calling
the autofs file system. As a result the definition of the busyness
check for all entries was changed to be "actually busy" being an open
file or working directory within the automount. But now we have a call
back in the follow so the last used update on any access can be
re-instated. This requires DCACHE_MANAGE_TRANSIT to always be set.

Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 14 insertions, 34 deletions

diff --git a/fs/autofs4/expire.c b/fs/autofs4/expire.c
index f43100b9662b..c896dd6c1ea9 100644
--- a/fs/autofs4/expire.c
+++ b/fs/autofs4/expire.c
@@ -294,7 +294,6 @@ struct dentry *autofs4_expire_direct(struct super_block *sb,
                 spin_unlock(&sbi->fs_lock);
                 return NULL;
         }
-        managed_dentry_set_transit(root);
         if (!autofs4_direct_busy(mnt, root, timeout, do_now)) {
                 struct autofs_info *ino = autofs4_dentry_ino(root);
                 ino->flags |= AUTOFS_INF_EXPIRING;
@@ -302,7 +301,6 @@ struct dentry *autofs4_expire_direct(struct super_block *sb,
                 spin_unlock(&sbi->fs_lock);
                 return root;
         }
-        managed_dentry_clear_transit(root);
         spin_unlock(&sbi->fs_lock);
         dput(root);
 
@@ -341,8 +339,7 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
                 ino = autofs4_dentry_ino(dentry);
                 /* No point expiring a pending mount */
                 if (ino->flags & AUTOFS_INF_PENDING)
-                        goto cont;
-                managed_dentry_set_transit(dentry);
+                        goto next;
 
                 /*
                  * Case 1: (i) indirect mount or top level pseudo direct mount
@@ -402,8 +399,6 @@ struct dentry *autofs4_expire_indirect(struct super_block *sb,
                         }
                 }
 next:
-                managed_dentry_clear_transit(dentry);
-cont:
                 spin_unlock(&sbi->fs_lock);
         }
         return NULL;
@@ -484,8 +479,6 @@ int autofs4_expire_run(struct super_block *sb,
         spin_lock(&sbi->fs_lock);
         ino = autofs4_dentry_ino(dentry);
         ino->flags &= ~AUTOFS_INF_EXPIRING;
-        if (!d_unhashed(dentry))
-                managed_dentry_clear_transit(dentry);
         complete_all(&ino->expire_complete);
         spin_unlock(&sbi->fs_lock);
 
@@ -513,9 +506,7 @@ int autofs4_do_expire_multi(struct super_block *sb, struct vfsmount *mnt,
                 spin_lock(&sbi->fs_lock);
                 ino->flags &= ~AUTOFS_INF_EXPIRING;
                 spin_lock(&dentry->d_lock);
-                if (ret)
-                        __managed_dentry_clear_transit(dentry);
-                else {
+                if (!ret) {
                         if ((IS_ROOT(dentry) ||
                             (autofs_type_indirect(sbi->type) &&
                              IS_ROOT(dentry->d_parent))) &&
diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index e6f84d26f4cf..3a93d3552486 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -275,17 +275,16 @@ static int autofs4_mount_wait(struct dentry *dentry)
 {
         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
         struct autofs_info *ino = autofs4_dentry_ino(dentry);
-        int status;
+        int status = 0;
 
         if (ino->flags & AUTOFS_INF_PENDING) {
                 DPRINTK("waiting for mount name=%.*s",
                         dentry->d_name.len, dentry->d_name.name);
                 status = autofs4_wait(sbi, dentry, NFY_MOUNT);
                 DPRINTK("mount wait done status=%d", status);
-                ino->last_used = jiffies;
-                return status;
         }
-        return 0;
+        ino->last_used = jiffies;
+        return status;
 }
 
 static int do_expire_wait(struct dentry *dentry)
@@ -319,9 +318,12 @@ static struct dentry *autofs4_mountpoint_changed(struct path *path)
          */
         if (autofs_type_indirect(sbi->type) && d_unhashed(dentry)) {
                 struct dentry *parent = dentry->d_parent;
+                struct autofs_info *ino;
                 struct dentry *new = d_lookup(parent, &dentry->d_name);
                 if (!new)
                         return NULL;
+                ino = autofs4_dentry_ino(new);
+                ino->last_used = jiffies;
                 dput(path->dentry);
                 path->dentry = new;
         }
@@ -338,18 +340,6 @@ static struct vfsmount *autofs4_d_automount(struct path *path)
         DPRINTK("dentry=%p %.*s",
                 dentry, dentry->d_name.len, dentry->d_name.name);
 
-        /*
-         * Someone may have manually umounted this or it was a submount
-         * that has gone away.
-         */
-        spin_lock(&dentry->d_lock);
-        if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) {
-                if (!(dentry->d_flags & DCACHE_MANAGE_TRANSIT) &&
-                     (dentry->d_flags & DCACHE_NEED_AUTOMOUNT))
-                        __managed_dentry_set_transit(path->dentry);
-        }
-        spin_unlock(&dentry->d_lock);
-
         /* The daemon never triggers a mount. */
         if (autofs4_oz_mode(sbi))
                 return NULL;
@@ -418,18 +408,17 @@ static struct vfsmount *autofs4_d_automount(struct path *path)
 done:
         if (!(ino->flags & AUTOFS_INF_EXPIRING)) {
                 /*
-                 * Any needed mounting has been completed and the path updated
-                 * so turn this into a normal dentry so we don't continually
-                 * call ->d_automount() and ->d_manage().
-                 */
-                spin_lock(&dentry->d_lock);
-                __managed_dentry_clear_transit(dentry);
-                /*
+                 * Any needed mounting has been completed and the path
+                 * updated so clear DCACHE_NEED_AUTOMOUNT so we don't
+                 * call ->d_automount() on rootless multi-mounts since
+                 * it can lead to an incorrect ELOOP error return.
+                 *
                  * Only clear DMANAGED_AUTOMOUNT for rootless multi-mounts and
                  * symlinks as in all other cases the dentry will be covered by
                  * an actual mount so ->d_automount() won't be called during
                  * the follow.
                  */
+                spin_lock(&dentry->d_lock);
                 if ((!d_mountpoint(dentry) &&
                     !list_empty(&dentry->d_subdirs)) ||
                     (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode)))