[PATCH] autofs4: add v5 follow_link mount trigger method

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

diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index 26eb1f0248667598d79cb126df83098ab9deefac..3f0048582248cad53bf930206e7bf6b0e888ed2d 100644 (file)
--- a/fs/autofs4/root.c
+++ b/fs/autofs4/root.c
@@ -4,7 +4,7 @@
  *
  *  Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
  *  Copyright 1999-2000 Jeremy Fitzhardinge <jeremy@goop.org>
- *  Copyright 2001-2003 Ian Kent <raven@themaw.net>
+ *  Copyright 2001-2006 Ian Kent <raven@themaw.net>
  *
  * This file is part of the Linux kernel and is made available under
  * the terms of the GNU General Public License, version 2, or at your
@@ -30,6 +30,7 @@ static int autofs4_dir_close(struct inode *inode, struct file *file);
 static int autofs4_dir_readdir(struct file * filp, void * dirent, filldir_t filldir);
 static int autofs4_root_readdir(struct file * filp, void * dirent, filldir_t filldir);
 static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *);
+static void *autofs4_follow_link(struct dentry *, struct nameidata *);
 
 struct file_operations autofs4_root_operations = {
        .open           = dcache_dir_open,
@@ -46,7 +47,7 @@ struct file_operations autofs4_dir_operations = {
        .readdir        = autofs4_dir_readdir,
 };
 
-struct inode_operations autofs4_root_inode_operations = {
+struct inode_operations autofs4_indirect_root_inode_operations = {
        .lookup         = autofs4_lookup,
        .unlink         = autofs4_dir_unlink,
        .symlink        = autofs4_dir_symlink,
@@ -54,6 +55,11 @@ struct inode_operations autofs4_root_inode_operations = {
        .rmdir          = autofs4_dir_rmdir,
 };
 
+struct inode_operations autofs4_direct_root_inode_operations = {
+       .lookup         = autofs4_lookup,
+       .follow_link    = autofs4_follow_link,
+};
+
 struct inode_operations autofs4_dir_inode_operations = {
        .lookup         = autofs4_lookup,
        .unlink         = autofs4_dir_unlink,
@@ -252,7 +258,7 @@ static int try_to_fill_dentry(struct dentry *dentry, int flags)
                 */
                status = d_invalidate(dentry);
                if (status != -EBUSY)
-                       return 0;
+                       return -ENOENT;
        }
 
        DPRINTK("dentry=%p %.*s ino=%p",
@@ -271,17 +277,17 @@ static int try_to_fill_dentry(struct dentry *dentry, int flags)
                DPRINTK("mount done status=%d", status);
 
                if (status && dentry->d_inode)
-                       return 0; /* Try to get the kernel to invalidate this dentry */
+                       return status; /* Try to get the kernel to invalidate this dentry */
 
                /* Turn this into a real negative dentry? */
                if (status == -ENOENT) {
                        spin_lock(&dentry->d_lock);
                        dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
                        spin_unlock(&dentry->d_lock);
-                       return 0;
+                       return status;
                } else if (status) {
                        /* Return a negative dentry, but leave it "pending" */
-                       return 0;
+                       return status;
                }
        /* Trigger mount for path component or follow link */
        } else if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) ||
@@ -300,7 +306,7 @@ static int try_to_fill_dentry(struct dentry *dentry, int flags)
                        spin_lock(&dentry->d_lock);
                        dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
                        spin_unlock(&dentry->d_lock);
-                       return 0;
+                       return status;
                }
        }
 
@@ -311,7 +317,41 @@ static int try_to_fill_dentry(struct dentry *dentry, int flags)
        spin_lock(&dentry->d_lock);
        dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
        spin_unlock(&dentry->d_lock);
-       return 1;
+       return status;
+}
+
+/* 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);
+       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);
+
+       /* If it's our master or we shouldn't trigger a mount we're done */
+       lookup_type = nd->flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY);
+       if (oz_mode || !lookup_type)
+               goto done;
+
+       status = try_to_fill_dentry(dentry, 0);
+       if (status)
+               goto out_error;
+
+       if (!autofs4_follow_mount(&nd->mnt, &nd->dentry)) {
+               status = -ENOENT;
+               goto out_error;
+       }
+
+done:
+       return NULL;
+
+out_error:
+       path_release(nd);
+       return ERR_PTR(status);
 }
 
 /*
@@ -326,13 +366,13 @@ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
        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;
+       int status = 0;
 
        /* Pending dentry */
        if (autofs4_ispending(dentry)) {
                if (!oz_mode)
                        status = try_to_fill_dentry(dentry, flags);
-               return status;
+               return !status;
        }
 
        /* Negative dentry.. invalidate if "old" */
@@ -349,14 +389,14 @@ static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
                spin_unlock(&dcache_lock);
                if (!oz_mode)
                        status = try_to_fill_dentry(dentry, flags);
-               return status;
+               return !status;
        }
        spin_unlock(&dcache_lock);
 
        return 1;
 }
 
-static void autofs4_dentry_release(struct dentry *de)
+void autofs4_dentry_release(struct dentry *de)
 {
        struct autofs_info *inf;