Merge branch 'mpi-master' into wip-k-fmlpwip-k-fmlp

Conflicts:
	litmus/sched_cedf.c

1 files changed, 328 insertions, 444 deletions

diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index cb1bd38dc08c..f55ae23b137e 100644
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -19,7 +19,7 @@
 #include <linux/param.h>
 #include <linux/time.h>
 #include <linux/compat.h>
-#include <linux/smp_lock.h>
+#include <linux/mutex.h>
 
 #include "autofs_i.h"
 
@@ -28,13 +28,14 @@ static int autofs4_dir_unlink(struct inode *,struct dentry *);
 static int autofs4_dir_rmdir(struct inode *,struct dentry *);
 static int autofs4_dir_mkdir(struct inode *,struct dentry *,int);
 static long autofs4_root_ioctl(struct file *,unsigned int,unsigned long);
+#ifdef CONFIG_COMPAT
 static long autofs4_root_compat_ioctl(struct file *,unsigned int,unsigned long);
+#endif
 static int autofs4_dir_open(struct inode *inode, struct file *file);
 static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
-static void *autofs4_follow_link(struct dentry *, struct nameidata *);
-
-#define TRIGGER_FLAGS   (LOOKUP_CONTINUE | LOOKUP_DIRECTORY)
-#define TRIGGER_INTENTS (LOOKUP_OPEN | LOOKUP_CREATE)
+static struct vfsmount *autofs4_d_automount(struct path *);
+static int autofs4_d_manage(struct dentry *, bool);
+static void autofs4_dentry_release(struct dentry *);
 
 const struct file_operations autofs4_root_operations = {
         .open           = dcache_dir_open,
@@ -56,7 +57,7 @@ const struct file_operations autofs4_dir_operations = {
         .llseek         = dcache_dir_lseek,
 };
 
-const struct inode_operations autofs4_indirect_root_inode_operations = {
+const struct inode_operations autofs4_dir_inode_operations = {
         .lookup         = autofs4_lookup,
         .unlink         = autofs4_dir_unlink,
         .symlink        = autofs4_dir_symlink,
@@ -64,20 +65,10 @@ const struct inode_operations autofs4_indirect_root_inode_operations = {
         .rmdir          = autofs4_dir_rmdir,
 };
 
-const struct inode_operations autofs4_direct_root_inode_operations = {
-        .lookup         = autofs4_lookup,
-        .unlink         = autofs4_dir_unlink,
-        .mkdir          = autofs4_dir_mkdir,
-        .rmdir          = autofs4_dir_rmdir,
-        .follow_link    = autofs4_follow_link,
-};
-
-const struct inode_operations autofs4_dir_inode_operations = {
-        .lookup         = autofs4_lookup,
-        .unlink         = autofs4_dir_unlink,
-        .symlink        = autofs4_dir_symlink,
-        .mkdir          = autofs4_dir_mkdir,
-        .rmdir          = autofs4_dir_rmdir,
+const struct dentry_operations autofs4_dentry_operations = {
+        .d_automount    = autofs4_d_automount,
+        .d_manage       = autofs4_d_manage,
+        .d_release      = autofs4_dentry_release,
 };
 
 static void autofs4_add_active(struct dentry *dentry)
@@ -112,14 +103,6 @@ static void autofs4_del_active(struct dentry *dentry)
         return;
 }
 
-static unsigned int autofs4_need_mount(unsigned int flags)
-{
-        unsigned int res = 0;
-        if (flags & (TRIGGER_FLAGS | TRIGGER_INTENTS))
-                res = 1;
-        return res;
-}
-
 static int autofs4_dir_open(struct inode *inode, struct file *file)
 {
         struct dentry *dentry = file->f_path.dentry;
@@ -140,275 +123,41 @@ static int autofs4_dir_open(struct inode *inode, struct file *file)
          * autofs file system so just let the libfs routines handle
          * it.
          */
-        spin_lock(&dcache_lock);
+        spin_lock(&sbi->lookup_lock);
+        spin_lock(&dentry->d_lock);
         if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) {
-                spin_unlock(&dcache_lock);
+                spin_unlock(&dentry->d_lock);
+                spin_unlock(&sbi->lookup_lock);
                 return -ENOENT;
         }
-        spin_unlock(&dcache_lock);
+        spin_unlock(&dentry->d_lock);
+        spin_unlock(&sbi->lookup_lock);
 
 out:
         return dcache_dir_open(inode, file);
 }
 
-static int try_to_fill_dentry(struct dentry *dentry, int flags)
+static void autofs4_dentry_release(struct dentry *de)
 {
-        struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
-        struct autofs_info *ino = autofs4_dentry_ino(dentry);
-        int status;
-
-        DPRINTK("dentry=%p %.*s ino=%p",
-                 dentry, dentry->d_name.len, dentry->d_name.name, dentry->d_inode);
-
-        /*
-         * Wait for a pending mount, triggering one if there
-         * isn't one already
-         */
-        if (dentry->d_inode == NULL) {
-                DPRINTK("waiting for mount name=%.*s",
-                         dentry->d_name.len, dentry->d_name.name);
-
-                status = autofs4_wait(sbi, dentry, NFY_MOUNT);
-
-                DPRINTK("mount done status=%d", status);
-
-                /* Turn this into a real negative dentry? */
-                if (status == -ENOENT) {
-                        spin_lock(&sbi->fs_lock);
-                        ino->flags &= ~AUTOFS_INF_PENDING;
-                        spin_unlock(&sbi->fs_lock);
-                        return status;
-                } else if (status) {
-                        /* Return a negative dentry, but leave it "pending" */
-                        return status;
-                }
-        /* Trigger mount for path component or follow link */
-        } else if (ino->flags & AUTOFS_INF_PENDING ||
-                        autofs4_need_mount(flags)) {
-                DPRINTK("waiting for mount name=%.*s",
-                        dentry->d_name.len, dentry->d_name.name);
-
-                spin_lock(&sbi->fs_lock);
-                ino->flags |= AUTOFS_INF_PENDING;
-                spin_unlock(&sbi->fs_lock);
-                status = autofs4_wait(sbi, dentry, NFY_MOUNT);
-
-                DPRINTK("mount done status=%d", status);
-
-                if (status) {
-                        spin_lock(&sbi->fs_lock);
-                        ino->flags &= ~AUTOFS_INF_PENDING;
-                        spin_unlock(&sbi->fs_lock);
-                        return status;
-                }
-        }
-
-        /* Initialize expiry counter after successful mount */
-        ino->last_used = jiffies;
-
-        spin_lock(&sbi->fs_lock);
-        ino->flags &= ~AUTOFS_INF_PENDING;
-        spin_unlock(&sbi->fs_lock);
-
-        return 0;
-}
-
-/* For autofs direct mounts the follow link triggers the mount */
-static void *autofs4_follow_link(struct dentry *dentry, struct nameidata *nd)
-{
-        struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
-        struct autofs_info *ino = autofs4_dentry_ino(dentry);
-        int oz_mode = autofs4_oz_mode(sbi);
-        unsigned int lookup_type;
-        int status;
-
-        DPRINTK("dentry=%p %.*s oz_mode=%d nd->flags=%d",
-                dentry, dentry->d_name.len, dentry->d_name.name, oz_mode,
-                nd->flags);
-        /*
-         * For an expire of a covered direct or offset mount we need
-         * to break out of follow_down() at the autofs mount trigger
-         * (d_mounted--), so we can see the expiring flag, and manage
-         * the blocking and following here until the expire is completed.
-         */
-        if (oz_mode) {
-                spin_lock(&sbi->fs_lock);
-                if (ino->flags & AUTOFS_INF_EXPIRING) {
-                        spin_unlock(&sbi->fs_lock);
-                        /* Follow down to our covering mount. */
-                        if (!follow_down(&nd->path))
-                                goto done;
-                        goto follow;
-                }
-                spin_unlock(&sbi->fs_lock);
-                goto done;
-        }
-
-        /* If an expire request is pending everyone must wait. */
-        autofs4_expire_wait(dentry);
-
-        /* We trigger a mount for almost all flags */
-        lookup_type = autofs4_need_mount(nd->flags);
-        spin_lock(&sbi->fs_lock);
-        spin_lock(&dcache_lock);
-        if (!(lookup_type || ino->flags & AUTOFS_INF_PENDING)) {
-                spin_unlock(&dcache_lock);
-                spin_unlock(&sbi->fs_lock);
-                goto follow;
-        }
-
-        /*
-         * If the dentry contains directories then it is an autofs
-         * multi-mount with no root mount offset. So don't try to
-         * mount it again.
-         */
-        if (ino->flags & AUTOFS_INF_PENDING ||
-            (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs))) {
-                spin_unlock(&dcache_lock);
-                spin_unlock(&sbi->fs_lock);
-
-                status = try_to_fill_dentry(dentry, nd->flags);
-                if (status)
-                        goto out_error;
-
-                goto follow;
-        }
-        spin_unlock(&dcache_lock);
-        spin_unlock(&sbi->fs_lock);
-follow:
-        /*
-         * If there is no root mount it must be an autofs
-         * multi-mount with no root offset so we don't need
-         * to follow it.
-         */
-        if (d_mountpoint(dentry)) {
-                if (!autofs4_follow_mount(&nd->path)) {
-                        status = -ENOENT;
-                        goto out_error;
-                }
-        }
-
-done:
-        return NULL;
-
-out_error:
-        path_put(&nd->path);
-        return ERR_PTR(status);
-}
-
-/*
- * Revalidate is called on every cache lookup.  Some of those
- * cache lookups may actually happen while the dentry is not
- * yet completely filled in, and revalidate has to delay such
- * lookups..
- */
-static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
-{
-        struct inode *dir = dentry->d_parent->d_inode;
-        struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
-        int oz_mode = autofs4_oz_mode(sbi);
-        int flags = nd ? nd->flags : 0;
-        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;
-
-                /*
-                 * If the directory has gone away due to an expire
-                 * we have been called as ->d_revalidate() and so
-                 * we need to return false and proceed to ->lookup().
-                 */
-                if (autofs4_expire_wait(dentry) == -EAGAIN)
-                        return 0;
-
-                /*
-                 * A zero status is success otherwise we have a
-                 * negative error code.
-                 */
-                status = try_to_fill_dentry(dentry, flags);
-                if (status == 0)
-                        return 1;
-
-                return status;
-        }
-        spin_unlock(&sbi->fs_lock);
-
-        /* Negative dentry.. invalidate if "old" */
-        if (dentry->d_inode == NULL)
-                return 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)) {
-                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;
-
-                /*
-                 * A zero status is success otherwise we have a
-                 * negative error code.
-                 */
-                status = try_to_fill_dentry(dentry, flags);
-                if (status == 0)
-                        return 1;
-
-                return status;
-        }
-        spin_unlock(&dcache_lock);
-
-        return 1;
-}
-
-void autofs4_dentry_release(struct dentry *de)
-{
-        struct autofs_info *inf;
+        struct autofs_info *ino = autofs4_dentry_ino(de);
+        struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb);
 
         DPRINTK("releasing %p", de);
 
-        inf = autofs4_dentry_ino(de);
-        de->d_fsdata = NULL;
-
-        if (inf) {
-                struct autofs_sb_info *sbi = autofs4_sbi(de->d_sb);
-
-                if (sbi) {
-                        spin_lock(&sbi->lookup_lock);
-                        if (!list_empty(&inf->active))
-                                list_del(&inf->active);
-                        if (!list_empty(&inf->expiring))
-                                list_del(&inf->expiring);
-                        spin_unlock(&sbi->lookup_lock);
-                }
-
-                inf->dentry = NULL;
-                inf->inode = NULL;
+        if (!ino)
+                return;
 
-                autofs4_free_ino(inf);
+        if (sbi) {
+                spin_lock(&sbi->lookup_lock);
+                if (!list_empty(&ino->active))
+                        list_del(&ino->active);
+                if (!list_empty(&ino->expiring))
+                        list_del(&ino->expiring);
+                spin_unlock(&sbi->lookup_lock);
         }
-}
 
-/* For dentries of directories in the root dir */
-static const struct dentry_operations autofs4_root_dentry_operations = {
-        .d_revalidate   = autofs4_revalidate,
-        .d_release      = autofs4_dentry_release,
-};
-
-/* For other dentries */
-static const struct dentry_operations autofs4_dentry_operations = {
-        .d_revalidate   = autofs4_revalidate,
-        .d_release      = autofs4_dentry_release,
-};
+        autofs4_free_ino(ino);
+}
 
 static struct dentry *autofs4_lookup_active(struct dentry *dentry)
 {
@@ -420,7 +169,6 @@ static struct dentry *autofs4_lookup_active(struct dentry *dentry)
         const unsigned char *str = name->name;
         struct list_head *p, *head;
 
-        spin_lock(&dcache_lock);
         spin_lock(&sbi->lookup_lock);
         head = &sbi->active_list;
         list_for_each(p, head) {
@@ -434,7 +182,7 @@ static struct dentry *autofs4_lookup_active(struct dentry *dentry)
                 spin_lock(&active->d_lock);
 
                 /* Already gone? */
-                if (atomic_read(&active->d_count) == 0)
+                if (active->d_count == 0)
                         goto next;
 
                 qstr = &active->d_name;
@@ -450,17 +198,15 @@ static struct dentry *autofs4_lookup_active(struct dentry *dentry)
                         goto next;
 
                 if (d_unhashed(active)) {
-                        dget(active);
+                        dget_dlock(active);
                         spin_unlock(&active->d_lock);
                         spin_unlock(&sbi->lookup_lock);
-                        spin_unlock(&dcache_lock);
                         return active;
                 }
 next:
                 spin_unlock(&active->d_lock);
         }
         spin_unlock(&sbi->lookup_lock);
-        spin_unlock(&dcache_lock);
 
         return NULL;
 }
@@ -475,7 +221,6 @@ static struct dentry *autofs4_lookup_expiring(struct dentry *dentry)
         const unsigned char *str = name->name;
         struct list_head *p, *head;
 
-        spin_lock(&dcache_lock);
         spin_lock(&sbi->lookup_lock);
         head = &sbi->expiring_list;
         list_for_each(p, head) {
@@ -505,66 +250,250 @@ static struct dentry *autofs4_lookup_expiring(struct dentry *dentry)
                         goto next;
 
                 if (d_unhashed(expiring)) {
-                        dget(expiring);
+                        dget_dlock(expiring);
                         spin_unlock(&expiring->d_lock);
                         spin_unlock(&sbi->lookup_lock);
-                        spin_unlock(&dcache_lock);
                         return expiring;
                 }
 next:
                 spin_unlock(&expiring->d_lock);
         }
         spin_unlock(&sbi->lookup_lock);
-        spin_unlock(&dcache_lock);
 
         return NULL;
 }
 
+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 = 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;
+}
+
+static int do_expire_wait(struct dentry *dentry)
+{
+        struct dentry *expiring;
+
+        expiring = autofs4_lookup_expiring(dentry);
+        if (!expiring)
+                return autofs4_expire_wait(dentry);
+        else {
+                /*
+                 * If we are racing with expire the request might not
+                 * be quite complete, but the directory has been removed
+                 * so it must have been successful, just wait for it.
+                 */
+                autofs4_expire_wait(expiring);
+                autofs4_del_expiring(expiring);
+                dput(expiring);
+        }
+        return 0;
+}
+
+static struct dentry *autofs4_mountpoint_changed(struct path *path)
+{
+        struct dentry *dentry = path->dentry;
+        struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+
+        /*
+         * If this is an indirect mount the dentry could have gone away
+         * as a result of an expire and a new one created.
+         */
+        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;
+        }
+        return path->dentry;
+}
+
+static struct vfsmount *autofs4_d_automount(struct path *path)
+{
+        struct dentry *dentry = path->dentry;
+        struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+        struct autofs_info *ino = autofs4_dentry_ino(dentry);
+        int status;
+
+        DPRINTK("dentry=%p %.*s",
+                dentry, dentry->d_name.len, dentry->d_name.name);
+
+        /* The daemon never triggers a mount. */
+        if (autofs4_oz_mode(sbi))
+                return NULL;
+
+        /*
+         * If an expire request is pending everyone must wait.
+         * If the expire fails we're still mounted so continue
+         * the follow and return. A return of -EAGAIN (which only
+         * happens with indirect mounts) means the expire completed
+         * and the directory was removed, so just go ahead and try
+         * the mount.
+         */
+        status = do_expire_wait(dentry);
+        if (status && status != -EAGAIN)
+                return NULL;
+
+        /* Callback to the daemon to perform the mount or wait */
+        spin_lock(&sbi->fs_lock);
+        if (ino->flags & AUTOFS_INF_PENDING) {
+                spin_unlock(&sbi->fs_lock);
+                status = autofs4_mount_wait(dentry);
+                if (status)
+                        return ERR_PTR(status);
+                spin_lock(&sbi->fs_lock);
+                goto done;
+        }
+
+        /*
+         * If the dentry is a symlink it's equivalent to a directory
+         * having d_mountpoint() true, so there's no need to call back
+         * to the daemon.
+         */
+        if (dentry->d_inode && S_ISLNK(dentry->d_inode->i_mode))
+                goto done;
+        if (!d_mountpoint(dentry)) {
+                /*
+                 * It's possible that user space hasn't removed directories
+                 * after umounting a rootless multi-mount, although it
+                 * should. For v5 have_submounts() is sufficient to handle
+                 * this because the leaves of the directory tree under the
+                 * mount never trigger mounts themselves (they have an autofs
+                 * trigger mount mounted on them). But v4 pseudo direct mounts
+                 * do need the leaves to to trigger mounts. In this case we
+                 * have no choice but to use the list_empty() check and
+                 * require user space behave.
+                 */
+                if (sbi->version > 4) {
+                        if (have_submounts(dentry))
+                                goto done;
+                } else {
+                        spin_lock(&dentry->d_lock);
+                        if (!list_empty(&dentry->d_subdirs)) {
+                                spin_unlock(&dentry->d_lock);
+                                goto done;
+                        }
+                        spin_unlock(&dentry->d_lock);
+                }
+                ino->flags |= AUTOFS_INF_PENDING;
+                spin_unlock(&sbi->fs_lock);
+                status = autofs4_mount_wait(dentry);
+                if (status)
+                        return ERR_PTR(status);
+                spin_lock(&sbi->fs_lock);
+                ino->flags &= ~AUTOFS_INF_PENDING;
+        }
+done:
+        if (!(ino->flags & AUTOFS_INF_EXPIRING)) {
+                /*
+                 * 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)))
+                        __managed_dentry_clear_automount(dentry);
+                spin_unlock(&dentry->d_lock);
+        }
+        spin_unlock(&sbi->fs_lock);
+
+        /* Mount succeeded, check if we ended up with a new dentry */
+        dentry = autofs4_mountpoint_changed(path);
+        if (!dentry)
+                return ERR_PTR(-ENOENT);
+
+        return NULL;
+}
+
+int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
+{
+        struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+
+        DPRINTK("dentry=%p %.*s",
+                dentry, dentry->d_name.len, dentry->d_name.name);
+
+        /* The daemon never waits. */
+        if (autofs4_oz_mode(sbi)) {
+                if (rcu_walk)
+                        return 0;
+                if (!d_mountpoint(dentry))
+                        return -EISDIR;
+                return 0;
+        }
+
+        /* We need to sleep, so we need pathwalk to be in ref-mode */
+        if (rcu_walk)
+                return -ECHILD;
+
+        /* Wait for pending expires */
+        do_expire_wait(dentry);
+
+        /*
+         * This dentry may be under construction so wait on mount
+         * completion.
+         */
+        return autofs4_mount_wait(dentry);
+}
+
 /* Lookups in the root directory */
 static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
 {
         struct autofs_sb_info *sbi;
         struct autofs_info *ino;
-        struct dentry *expiring, *active;
-        int oz_mode;
+        struct dentry *active;
 
-        DPRINTK("name = %.*s",
-                dentry->d_name.len, dentry->d_name.name);
+        DPRINTK("name = %.*s", dentry->d_name.len, dentry->d_name.name);
 
         /* File name too long to exist */
         if (dentry->d_name.len > NAME_MAX)
                 return ERR_PTR(-ENAMETOOLONG);
 
         sbi = autofs4_sbi(dir->i_sb);
-        oz_mode = autofs4_oz_mode(sbi);
 
         DPRINTK("pid = %u, pgrp = %u, catatonic = %d, oz_mode = %d",
-                 current->pid, task_pgrp_nr(current), sbi->catatonic, oz_mode);
+                current->pid, task_pgrp_nr(current), sbi->catatonic,
+                autofs4_oz_mode(sbi));
 
         active = autofs4_lookup_active(dentry);
         if (active) {
-                dentry = active;
-                ino = autofs4_dentry_ino(dentry);
+                return active;
         } else {
                 /*
-                 * Mark the dentry incomplete but don't hash it. We do this
-                 * to serialize our inode creation operations (symlink and
-                 * mkdir) which prevents deadlock during the callback to
-                 * the daemon. Subsequent user space lookups for the same
-                 * dentry are placed on the wait queue while the daemon
-                 * itself is allowed passage unresticted so the create
-                 * operation itself can then hash the dentry. Finally,
-                 * we check for the hashed dentry and return the newly
-                 * hashed dentry.
+                 * A dentry that is not within the root can never trigger a
+                 * mount operation, unless the directory already exists, so we
+                 * can return fail immediately.  The daemon however does need
+                 * to create directories within the file system.
                  */
-                dentry->d_op = &autofs4_root_dentry_operations;
+                if (!autofs4_oz_mode(sbi) && !IS_ROOT(dentry->d_parent))
+                        return ERR_PTR(-ENOENT);
 
-                /*
-                 * And we need to ensure that the same dentry is used for
-                 * all following lookup calls until it is hashed so that
-                 * the dentry flags are persistent throughout the request.
-                 */
-                ino = autofs4_init_ino(NULL, sbi, 0555);
+                /* Mark entries in the root as mount triggers */
+                if (autofs_type_indirect(sbi->type) && IS_ROOT(dentry->d_parent))
+                        __managed_dentry_set_managed(dentry);
+
+                ino = autofs4_new_ino(sbi);
                 if (!ino)
                         return ERR_PTR(-ENOMEM);
 
@@ -575,82 +504,6 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s
 
                 d_instantiate(dentry, NULL);
         }
-
-        if (!oz_mode) {
-                mutex_unlock(&dir->i_mutex);
-                expiring = autofs4_lookup_expiring(dentry);
-                if (expiring) {
-                        /*
-                         * If we are racing with expire the request might not
-                         * be quite complete but the directory has been removed
-                         * so it must have been successful, so just wait for it.
-                         */
-                        autofs4_expire_wait(expiring);
-                        autofs4_del_expiring(expiring);
-                        dput(expiring);
-                }
-
-                spin_lock(&sbi->fs_lock);
-                ino->flags |= AUTOFS_INF_PENDING;
-                spin_unlock(&sbi->fs_lock);
-                if (dentry->d_op && dentry->d_op->d_revalidate)
-                        (dentry->d_op->d_revalidate)(dentry, nd);
-                mutex_lock(&dir->i_mutex);
-        }
-
-        /*
-         * If we are still pending, check if we had to handle
-         * a signal. If so we can force a restart..
-         */
-        if (ino->flags & AUTOFS_INF_PENDING) {
-                /* See if we were interrupted */
-                if (signal_pending(current)) {
-                        sigset_t *sigset = &current->pending.signal;
-                        if (sigismember (sigset, SIGKILL) ||
-                            sigismember (sigset, SIGQUIT) ||
-                            sigismember (sigset, SIGINT)) {
-                            if (active)
-                                dput(active);
-                            return ERR_PTR(-ERESTARTNOINTR);
-                        }
-                }
-                if (!oz_mode) {
-                        spin_lock(&sbi->fs_lock);
-                        ino->flags &= ~AUTOFS_INF_PENDING;
-                        spin_unlock(&sbi->fs_lock);
-                }
-        }
-
-        /*
-         * If this dentry is unhashed, then we shouldn't honour this
-         * lookup.  Returning ENOENT here doesn't do the right thing
-         * for all system calls, but it should be OK for the operations
-         * we permit from an autofs.
-         */
-        if (!oz_mode && d_unhashed(dentry)) {
-                /*
-                 * A user space application can (and has done in the past)
-                 * remove and re-create this directory during the callback.
-                 * This can leave us with an unhashed dentry, but a
-                 * successful mount!  So we need to perform another
-                 * cached lookup in case the dentry now exists.
-                 */
-                struct dentry *parent = dentry->d_parent;
-                struct dentry *new = d_lookup(parent, &dentry->d_name);
-                if (new != NULL)
-                        dentry = new;
-                else
-                        dentry = ERR_PTR(-ENOENT);
-
-                if (active)
-                        dput(active);
-
-                return dentry;
-        }
-
-        if (active)
-                return active;
-
         return NULL;
 }
 
@@ -662,6 +515,7 @@ static int autofs4_dir_symlink(struct inode *dir,
         struct autofs_info *ino = autofs4_dentry_ino(dentry);
         struct autofs_info *p_ino;
         struct inode *inode;
+        size_t size = strlen(symname);
         char *cp;
 
         DPRINTK("%s <- %.*s", symname,
@@ -670,45 +524,35 @@ static int autofs4_dir_symlink(struct inode *dir,
         if (!autofs4_oz_mode(sbi))
                 return -EACCES;
 
-        ino = autofs4_init_ino(ino, sbi, S_IFLNK | 0555);
-        if (!ino)
-                return -ENOMEM;
+        BUG_ON(!ino);
+
+        autofs4_clean_ino(ino);
 
         autofs4_del_active(dentry);
 
-        ino->size = strlen(symname);
-        cp = kmalloc(ino->size + 1, GFP_KERNEL);
-        if (!cp) {
-                if (!dentry->d_fsdata)
-                        kfree(ino);
+        cp = kmalloc(size + 1, GFP_KERNEL);
+        if (!cp)
                 return -ENOMEM;
-        }
 
         strcpy(cp, symname);
 
-        inode = autofs4_get_inode(dir->i_sb, ino);
+        inode = autofs4_get_inode(dir->i_sb, S_IFLNK | 0555);
         if (!inode) {
                 kfree(cp);
                 if (!dentry->d_fsdata)
                         kfree(ino);
                 return -ENOMEM;
         }
+        inode->i_private = cp;
+        inode->i_size = size;
         d_add(dentry, inode);
 
-        if (dir == dir->i_sb->s_root->d_inode)
-                dentry->d_op = &autofs4_root_dentry_operations;
-        else
-                dentry->d_op = &autofs4_dentry_operations;
-
-        dentry->d_fsdata = ino;
-        ino->dentry = dget(dentry);
+        dget(dentry);
         atomic_inc(&ino->count);
         p_ino = autofs4_dentry_ino(dentry->d_parent);
         if (p_ino && dentry->d_parent != dentry)
                 atomic_inc(&p_ino->count);
-        ino->inode = inode;
 
-        ino->u.symlink = cp;
         dir->i_mtime = CURRENT_TIME;
 
         return 0;
@@ -751,16 +595,68 @@ static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
 
         dir->i_mtime = CURRENT_TIME;
 
-        spin_lock(&dcache_lock);
-        autofs4_add_expiring(dentry);
+        spin_lock(&sbi->lookup_lock);
+        __autofs4_add_expiring(dentry);
         spin_lock(&dentry->d_lock);
         __d_drop(dentry);
         spin_unlock(&dentry->d_lock);
-        spin_unlock(&dcache_lock);
+        spin_unlock(&sbi->lookup_lock);
 
         return 0;
 }
 
+/*
+ * Version 4 of autofs provides a pseudo direct mount implementation
+ * that relies on directories at the leaves of a directory tree under
+ * an indirect mount to trigger mounts. To allow for this we need to
+ * set the DMANAGED_AUTOMOUNT and DMANAGED_TRANSIT flags on the leaves
+ * of the directory tree. There is no need to clear the automount flag
+ * following a mount or restore it after an expire because these mounts
+ * are always covered. However, it is necessary to ensure that these
+ * flags are clear on non-empty directories to avoid unnecessary calls
+ * during path walks.
+ */
+static void autofs_set_leaf_automount_flags(struct dentry *dentry)
+{
+        struct dentry *parent;
+
+        /* root and dentrys in the root are already handled */
+        if (IS_ROOT(dentry->d_parent))
+                return;
+
+        managed_dentry_set_managed(dentry);
+
+        parent = dentry->d_parent;
+        /* only consider parents below dentrys in the root */
+        if (IS_ROOT(parent->d_parent))
+                return;
+        managed_dentry_clear_managed(parent);
+        return;
+}
+
+static void autofs_clear_leaf_automount_flags(struct dentry *dentry)
+{
+        struct list_head *d_child;
+        struct dentry *parent;
+
+        /* flags for dentrys in the root are handled elsewhere */
+        if (IS_ROOT(dentry->d_parent))
+                return;
+
+        managed_dentry_clear_managed(dentry);
+
+        parent = dentry->d_parent;
+        /* only consider parents below dentrys in the root */
+        if (IS_ROOT(parent->d_parent))
+                return;
+        d_child = &dentry->d_u.d_child;
+        /* Set parent managed if it's becoming empty */
+        if (d_child->next == &parent->d_subdirs &&
+            d_child->prev == &parent->d_subdirs)
+                managed_dentry_set_managed(parent);
+        return;
+}
+
 static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
 {
         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
@@ -773,16 +669,20 @@ static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
         if (!autofs4_oz_mode(sbi))
                 return -EACCES;
 
-        spin_lock(&dcache_lock);
+        spin_lock(&sbi->lookup_lock);
+        spin_lock(&dentry->d_lock);
         if (!list_empty(&dentry->d_subdirs)) {
-                spin_unlock(&dcache_lock);
+                spin_unlock(&dentry->d_lock);
+                spin_unlock(&sbi->lookup_lock);
                 return -ENOTEMPTY;
         }
-        autofs4_add_expiring(dentry);
-        spin_lock(&dentry->d_lock);
+        __autofs4_add_expiring(dentry);
         __d_drop(dentry);
         spin_unlock(&dentry->d_lock);
-        spin_unlock(&dcache_lock);
+        spin_unlock(&sbi->lookup_lock);
+
+        if (sbi->version < 5)
+                autofs_clear_leaf_automount_flags(dentry);
 
         if (atomic_dec_and_test(&ino->count)) {
                 p_ino = autofs4_dentry_ino(dentry->d_parent);
@@ -812,32 +712,25 @@ static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
         DPRINTK("dentry %p, creating %.*s",
                 dentry, dentry->d_name.len, dentry->d_name.name);
 
-        ino = autofs4_init_ino(ino, sbi, S_IFDIR | 0555);
-        if (!ino)
-                return -ENOMEM;
+        BUG_ON(!ino);
+
+        autofs4_clean_ino(ino);
 
         autofs4_del_active(dentry);
 
-        inode = autofs4_get_inode(dir->i_sb, ino);
-        if (!inode) {
-                if (!dentry->d_fsdata)
-                        kfree(ino);
+        inode = autofs4_get_inode(dir->i_sb, S_IFDIR | 0555);
+        if (!inode)
                 return -ENOMEM;
-        }
         d_add(dentry, inode);
 
-        if (dir == dir->i_sb->s_root->d_inode)
-                dentry->d_op = &autofs4_root_dentry_operations;
-        else
-                dentry->d_op = &autofs4_dentry_operations;
+        if (sbi->version < 5)
+                autofs_set_leaf_automount_flags(dentry);
 
-        dentry->d_fsdata = ino;
-        ino->dentry = dget(dentry);
+        dget(dentry);
         atomic_inc(&ino->count);
         p_ino = autofs4_dentry_ino(dentry->d_parent);
         if (p_ino && dentry->d_parent != dentry)
                 atomic_inc(&p_ino->count);
-        ino->inode = inode;
         inc_nlink(dir);
         dir->i_mtime = CURRENT_TIME;
 
@@ -919,8 +812,7 @@ static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
 int is_autofs4_dentry(struct dentry *dentry)
 {
         return dentry && dentry->d_inode &&
-                (dentry->d_op == &autofs4_root_dentry_operations ||
-                 dentry->d_op == &autofs4_dentry_operations) &&
+                dentry->d_op == &autofs4_dentry_operations &&
                 dentry->d_fsdata != NULL;
 }
 
@@ -981,14 +873,8 @@ static int autofs4_root_ioctl_unlocked(struct inode *inode, struct file *filp,
 static long autofs4_root_ioctl(struct file *filp,
                                unsigned int cmd, unsigned long arg)
 {
-        long ret;
         struct inode *inode = filp->f_dentry->d_inode;
-
-        lock_kernel();
-        ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, arg);
-        unlock_kernel();
-
-        return ret;
+        return autofs4_root_ioctl_unlocked(inode, filp, cmd, arg);
 }
 
 #ifdef CONFIG_COMPAT
@@ -998,13 +884,11 @@ static long autofs4_root_compat_ioctl(struct file *filp,
         struct inode *inode = filp->f_path.dentry->d_inode;
         int ret;
 
-        lock_kernel();
         if (cmd == AUTOFS_IOC_READY || cmd == AUTOFS_IOC_FAIL)
                 ret = autofs4_root_ioctl_unlocked(inode, filp, cmd, arg);
         else
                 ret = autofs4_root_ioctl_unlocked(inode, filp, cmd,
                         (unsigned long)compat_ptr(arg));
-        unlock_kernel();
 
         return ret;
 }