Merge tag 'platform-drivers-x86-v3.19-1' of git://git.infradead.org/users/dvhart...

[karo-tx-linux.git] / fs / autofs4 / root.c

diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index cdb25ebccc4c49c2ac2f4a4c17d998ae99f14941..dbb5b7212ce162130727256d49351e3f2d2677c9 100644 (file)
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -108,8 +108,7 @@ static int autofs4_dir_open(struct inode *inode, struct file *file)
        struct dentry *dentry = file->f_path.dentry;
        struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
 
-       DPRINTK("file=%p dentry=%p %.*s",
-               file, dentry, dentry->d_name.len, dentry->d_name.name);
+       DPRINTK("file=%p dentry=%p %pD", file, dentry, dentry);
 
        if (autofs4_oz_mode(sbi))
                goto out;
@@ -210,7 +209,8 @@ next:
        return NULL;
 }
 
-static struct dentry *autofs4_lookup_expiring(struct dentry *dentry)
+static struct dentry *autofs4_lookup_expiring(struct dentry *dentry,
+                                             bool rcu_walk)
 {
        struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
        struct dentry *parent = dentry->d_parent;
@@ -229,6 +229,11 @@ static struct dentry *autofs4_lookup_expiring(struct dentry *dentry)
                struct dentry *expiring;
                struct qstr *qstr;
 
+               if (rcu_walk) {
+                       spin_unlock(&sbi->lookup_lock);
+                       return ERR_PTR(-ECHILD);
+               }
+
                ino = list_entry(p, struct autofs_info, expiring);
                expiring = ino->dentry;
 
@@ -264,15 +269,16 @@ next:
        return NULL;
 }
 
-static int autofs4_mount_wait(struct dentry *dentry)
+static int autofs4_mount_wait(struct dentry *dentry, bool rcu_walk)
 {
        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);
+               if (rcu_walk)
+                       return -ECHILD;
+               DPRINTK("waiting for mount name=%pd", dentry);
                status = autofs4_wait(sbi, dentry, NFY_MOUNT);
                DPRINTK("mount wait done status=%d", status);
        }
@@ -280,20 +286,22 @@ static int autofs4_mount_wait(struct dentry *dentry)
        return status;
 }
 
-static int do_expire_wait(struct dentry *dentry)
+static int do_expire_wait(struct dentry *dentry, bool rcu_walk)
 {
        struct dentry *expiring;
 
-       expiring = autofs4_lookup_expiring(dentry);
+       expiring = autofs4_lookup_expiring(dentry, rcu_walk);
+       if (IS_ERR(expiring))
+               return PTR_ERR(expiring);
        if (!expiring)
-               return autofs4_expire_wait(dentry);
+               return autofs4_expire_wait(dentry, rcu_walk);
        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_expire_wait(expiring, 0);
                autofs4_del_expiring(expiring);
                dput(expiring);
        }
@@ -330,8 +338,7 @@ static struct vfsmount *autofs4_d_automount(struct path *path)
        struct autofs_info *ino = autofs4_dentry_ino(dentry);
        int status;
 
-       DPRINTK("dentry=%p %.*s",
-               dentry, dentry->d_name.len, dentry->d_name.name);
+       DPRINTK("dentry=%p %pd", dentry, dentry);
 
        /* The daemon never triggers a mount. */
        if (autofs4_oz_mode(sbi))
@@ -345,7 +352,7 @@ static struct vfsmount *autofs4_d_automount(struct path *path)
         * and the directory was removed, so just go ahead and try
         * the mount.
         */
-       status = do_expire_wait(dentry);
+       status = do_expire_wait(dentry, 0);
        if (status && status != -EAGAIN)
                return NULL;
 
@@ -353,7 +360,7 @@ static struct vfsmount *autofs4_d_automount(struct path *path)
        spin_lock(&sbi->fs_lock);
        if (ino->flags & AUTOFS_INF_PENDING) {
                spin_unlock(&sbi->fs_lock);
-               status = autofs4_mount_wait(dentry);
+               status = autofs4_mount_wait(dentry, 0);
                if (status)
                        return ERR_PTR(status);
                goto done;
@@ -394,7 +401,7 @@ static struct vfsmount *autofs4_d_automount(struct path *path)
                }
                ino->flags |= AUTOFS_INF_PENDING;
                spin_unlock(&sbi->fs_lock);
-               status = autofs4_mount_wait(dentry);
+               status = autofs4_mount_wait(dentry, 0);
                spin_lock(&sbi->fs_lock);
                ino->flags &= ~AUTOFS_INF_PENDING;
                if (status) {
@@ -418,33 +425,50 @@ static int autofs4_d_manage(struct dentry *dentry, bool rcu_walk)
        struct autofs_info *ino = autofs4_dentry_ino(dentry);
        int status;
 
-       DPRINTK("dentry=%p %.*s",
-               dentry, dentry->d_name.len, dentry->d_name.name);
+       DPRINTK("dentry=%p %pd", dentry, dentry);
 
        /* 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);
+       if (do_expire_wait(dentry, rcu_walk) == -ECHILD)
+               return -ECHILD;
 
        /*
         * This dentry may be under construction so wait on mount
         * completion.
         */
-       status = autofs4_mount_wait(dentry);
+       status = autofs4_mount_wait(dentry, rcu_walk);
        if (status)
                return status;
 
+       if (rcu_walk) {
+               /* We don't need fs_lock in rcu_walk mode,
+                * just testing 'AUTOFS_INFO_NO_RCU' is enough.
+                * simple_empty() takes a spinlock, so leave it
+                * to last.
+                * We only return -EISDIR when certain this isn't
+                * a mount-trap.
+                */
+               struct inode *inode;
+               if (ino->flags & (AUTOFS_INF_EXPIRING | AUTOFS_INF_NO_RCU))
+                       return 0;
+               if (d_mountpoint(dentry))
+                       return 0;
+               inode = ACCESS_ONCE(dentry->d_inode);
+               if (inode && S_ISLNK(inode->i_mode))
+                       return -EISDIR;
+               if (list_empty(&dentry->d_subdirs))
+                       return 0;
+               if (!simple_empty(dentry))
+                       return -EISDIR;
+               return 0;
+       }
+
        spin_lock(&sbi->fs_lock);
        /*
         * If the dentry has been selected for expire while we slept
@@ -476,7 +500,7 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, u
        struct autofs_info *ino;
        struct dentry *active;
 
-       DPRINTK("name = %.*s", dentry->d_name.len, dentry->d_name.name);
+       DPRINTK("name = %pd", dentry);
 
        /* File name too long to exist */
        if (dentry->d_name.len > NAME_MAX)
@@ -530,8 +554,7 @@ static int autofs4_dir_symlink(struct inode *dir,
        size_t size = strlen(symname);
        char *cp;
 
-       DPRINTK("%s <- %.*s", symname,
-               dentry->d_name.len, dentry->d_name.name);
+       DPRINTK("%s <- %pd", symname, dentry);
 
        if (!autofs4_oz_mode(sbi))
                return -EACCES;
@@ -659,7 +682,7 @@ static void autofs_clear_leaf_automount_flags(struct dentry *dentry)
        /* only consider parents below dentrys in the root */
        if (IS_ROOT(parent->d_parent))
                return;
-       d_child = &dentry->d_u.d_child;
+       d_child = &dentry->d_child;
        /* Set parent managed if it's becoming empty */
        if (d_child->next == &parent->d_subdirs &&
            d_child->prev == &parent->d_subdirs)
@@ -673,8 +696,7 @@ static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
        struct autofs_info *ino = autofs4_dentry_ino(dentry);
        struct autofs_info *p_ino;
        
-       DPRINTK("dentry %p, removing %.*s",
-               dentry, dentry->d_name.len, dentry->d_name.name);
+       DPRINTK("dentry %p, removing %pd", dentry, dentry);
 
        if (!autofs4_oz_mode(sbi))
                return -EACCES;
@@ -716,8 +738,7 @@ static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, umode_t m
        if (!autofs4_oz_mode(sbi))
                return -EACCES;
 
-       DPRINTK("dentry %p, creating %.*s",
-               dentry, dentry->d_name.len, dentry->d_name.name);
+       DPRINTK("dentry %p, creating %pd", dentry, dentry);
 
        BUG_ON(!ino);