1 files changed, 180 insertions, 148 deletions

diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c
index 62d8d4acb8bb..84e030c8ddd0 100644
--- 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
@@ -30,9 +30,9 @@ 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 int autofs4_dcache_readdir(struct file *, void *, filldir_t);
+static void *autofs4_follow_link(struct dentry *, struct nameidata *);
 
-struct file_operations autofs4_root_operations = {
+const struct file_operations autofs4_root_operations = {
         .open           = dcache_dir_open,
         .release        = dcache_dir_close,
         .read           = generic_read_dir,
@@ -40,14 +40,14 @@ struct file_operations autofs4_root_operations = {
         .ioctl          = autofs4_root_ioctl,
 };
 
-struct file_operations autofs4_dir_operations = {
+const struct file_operations autofs4_dir_operations = {
         .open           = autofs4_dir_open,
         .release        = autofs4_dir_close,
         .read           = generic_read_dir,
         .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,
@@ -55,6 +55,14 @@ struct inode_operations autofs4_root_inode_operations = {
         .rmdir          = autofs4_dir_rmdir,
 };
 
+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,
+};
+
 struct inode_operations autofs4_dir_inode_operations = {
         .lookup         = autofs4_lookup,
         .unlink         = autofs4_dir_unlink,
@@ -82,87 +90,7 @@ static int autofs4_root_readdir(struct file *file, void *dirent,
 
         DPRINTK("needs_reghost = %d", sbi->needs_reghost);
 
-        return autofs4_dcache_readdir(file, dirent, filldir);
-}
-
-/* Update usage from here to top of tree, so that scan of
-   top-level directories will give a useful result */
-static void autofs4_update_usage(struct vfsmount *mnt, struct dentry *dentry)
-{
-        struct dentry *top = dentry->d_sb->s_root;
-
-        spin_lock(&dcache_lock);
-        for(; dentry != top; dentry = dentry->d_parent) {
-                struct autofs_info *ino = autofs4_dentry_ino(dentry);
-
-                if (ino) {
-                        touch_atime(mnt, dentry);
-                        ino->last_used = jiffies;
-                }
-        }
-        spin_unlock(&dcache_lock);
-}
-
-/*
- * From 2.4 kernel readdir.c
- */
-static int autofs4_dcache_readdir(struct file * filp, void * dirent, filldir_t filldir)
-{
-        int i;
-        struct dentry *dentry = filp->f_dentry;
-
-        i = filp->f_pos;
-        switch (i) {
-                case 0:
-                        if (filldir(dirent, ".", 1, i, dentry->d_inode->i_ino, DT_DIR) < 0)
-                                break;
-                        i++;
-                        filp->f_pos++;
-                        /* fallthrough */
-                case 1:
-                        if (filldir(dirent, "..", 2, i, dentry->d_parent->d_inode->i_ino, DT_DIR) < 0)
-                                break;
-                        i++;
-                        filp->f_pos++;
-                        /* fallthrough */
-                default: {
-                        struct list_head *list;
-                        int j = i-2;
-
-                        spin_lock(&dcache_lock);
-                        list = dentry->d_subdirs.next;
-
-                        for (;;) {
-                                if (list == &dentry->d_subdirs) {
-                                        spin_unlock(&dcache_lock);
-                                        return 0;
-                                }
-                                if (!j)
-                                        break;
-                                j--;
-                                list = list->next;
-                        }
-
-                        while(1) {
-                                struct dentry *de = list_entry(list,
-                                                struct dentry, d_u.d_child);
-
-                                if (!d_unhashed(de) && de->d_inode) {
-                                        spin_unlock(&dcache_lock);
-                                        if (filldir(dirent, de->d_name.name, de->d_name.len, filp->f_pos, de->d_inode->i_ino, DT_UNKNOWN) < 0)
-                                                break;
-                                        spin_lock(&dcache_lock);
-                                }
-                                filp->f_pos++;
-                                list = list->next;
-                                if (list != &dentry->d_subdirs)
-                                        continue;
-                                spin_unlock(&dcache_lock);
-                                break;
-                        }
-                }
-        }
-        return 0;
+        return dcache_readdir(file, dirent, filldir);
 }
 
 static int autofs4_dir_open(struct inode *inode, struct file *file)
@@ -170,8 +98,16 @@ static int autofs4_dir_open(struct inode *inode, struct file *file)
         struct dentry *dentry = file->f_dentry;
         struct vfsmount *mnt = file->f_vfsmnt;
         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+        struct dentry *cursor;
         int status;
 
+        status = dcache_dir_open(inode, file);
+        if (status)
+                goto out;
+
+        cursor = file->private_data;
+        cursor->d_fsdata = NULL;
+
         DPRINTK("file=%p dentry=%p %.*s",
                 file, dentry, dentry->d_name.len, dentry->d_name.name);
 
@@ -180,12 +116,15 @@ static int autofs4_dir_open(struct inode *inode, struct file *file)
 
         if (autofs4_ispending(dentry)) {
                 DPRINTK("dentry busy");
-                return -EBUSY;
+                dcache_dir_close(inode, file);
+                status = -EBUSY;
+                goto out;
         }
 
+        status = -ENOENT;
         if (!d_mountpoint(dentry) && dentry->d_op && dentry->d_op->d_revalidate) {
                 struct nameidata nd;
-                int empty;
+                int empty, ret;
 
                 /* In case there are stale directory dentrys from a failed mount */
                 spin_lock(&dcache_lock);
@@ -195,13 +134,13 @@ static int autofs4_dir_open(struct inode *inode, struct file *file)
                 if (!empty)
                         d_invalidate(dentry);
 
-                nd.dentry = dentry;
-                nd.mnt = mnt;
                 nd.flags = LOOKUP_DIRECTORY;
-                status = (dentry->d_op->d_revalidate)(dentry, &nd);
+                ret = (dentry->d_op->d_revalidate)(dentry, &nd);
 
-                if (!status)
-                        return -ENOENT;
+                if (!ret) {
+                        dcache_dir_close(inode, file);
+                        goto out;
+                }
         }
 
         if (d_mountpoint(dentry)) {
@@ -212,25 +151,29 @@ static int autofs4_dir_open(struct inode *inode, struct file *file)
                 if (!autofs4_follow_mount(&fp_mnt, &fp_dentry)) {
                         dput(fp_dentry);
                         mntput(fp_mnt);
-                        return -ENOENT;
+                        dcache_dir_close(inode, file);
+                        goto out;
                 }
 
                 fp = dentry_open(fp_dentry, fp_mnt, file->f_flags);
                 status = PTR_ERR(fp);
                 if (IS_ERR(fp)) {
-                        file->private_data = NULL;
-                        return status;
+                        dcache_dir_close(inode, file);
+                        goto out;
                 }
-                file->private_data = fp;
+                cursor->d_fsdata = fp;
         }
-out:
         return 0;
+out:
+        return status;
 }
 
 static int autofs4_dir_close(struct inode *inode, struct file *file)
 {
         struct dentry *dentry = file->f_dentry;
         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+        struct dentry *cursor = file->private_data;
+        int status = 0;
 
         DPRINTK("file=%p dentry=%p %.*s",
                 file, dentry, dentry->d_name.len, dentry->d_name.name);
@@ -240,26 +183,28 @@ static int autofs4_dir_close(struct inode *inode, struct file *file)
 
         if (autofs4_ispending(dentry)) {
                 DPRINTK("dentry busy");
-                return -EBUSY;
+                status = -EBUSY;
+                goto out;
         }
 
         if (d_mountpoint(dentry)) {
-                struct file *fp = file->private_data;
-
-                if (!fp)
-                        return -ENOENT;
-
+                struct file *fp = cursor->d_fsdata;
+                if (!fp) {
+                        status = -ENOENT;
+                        goto out;
+                }
                 filp_close(fp, current->files);
-                file->private_data = NULL;
         }
 out:
-        return 0;
+        dcache_dir_close(inode, file);
+        return status;
 }
 
 static int autofs4_dir_readdir(struct file *file, void *dirent, filldir_t filldir)
 {
         struct dentry *dentry = file->f_dentry;
         struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+        struct dentry *cursor = file->private_data;
         int status;
 
         DPRINTK("file=%p dentry=%p %.*s",
@@ -274,7 +219,7 @@ static int autofs4_dir_readdir(struct file *file, void *dirent, filldir_t filldi
         }
 
         if (d_mountpoint(dentry)) {
-                struct file *fp = file->private_data;
+                struct file *fp = cursor->d_fsdata;
 
                 if (!fp)
                         return -ENOENT;
@@ -289,27 +234,26 @@ static int autofs4_dir_readdir(struct file *file, void *dirent, filldir_t filldi
                 return status;
         }
 out:
-        return autofs4_dcache_readdir(file, dirent, filldir);
+        return dcache_readdir(file, dirent, filldir);
 }
 
-static int try_to_fill_dentry(struct vfsmount *mnt, struct dentry *dentry, int flags)
+static int try_to_fill_dentry(struct dentry *dentry, int flags)
 {
-        struct super_block *sb = mnt->mnt_sb;
-        struct autofs_sb_info *sbi = autofs4_sbi(sb);
-        struct autofs_info *de_info = autofs4_dentry_ino(dentry);
+        struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
+        struct autofs_info *ino = autofs4_dentry_ino(dentry);
         int status = 0;
 
         /* Block on any pending expiry here; invalidate the dentry
            when expiration is done to trigger mount request with a new
            dentry */
-        if (de_info && (de_info->flags & AUTOFS_INF_EXPIRING)) {
+        if (ino && (ino->flags & AUTOFS_INF_EXPIRING)) {
                 DPRINTK("waiting for expire %p name=%.*s",
                          dentry, dentry->d_name.len, dentry->d_name.name);
 
                 status = autofs4_wait(sbi, dentry, NFY_NONE);
-                
+
                 DPRINTK("expire done status=%d", status);
-                
+
                 /*
                  * If the directory still exists the mount request must
                  * continue otherwise it can't be followed at the right
@@ -317,34 +261,36 @@ static int try_to_fill_dentry(struct vfsmount *mnt, struct dentry *dentry, int f
                  */
                 status = d_invalidate(dentry);
                 if (status != -EBUSY)
-                        return 0;
+                        return -ENOENT;
         }
 
         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 */
+        /*
+         * 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);
 
                 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) {
-                        dentry->d_time = jiffies + AUTOFS_NEGATIVE_TIMEOUT;
                         spin_lock(&dentry->d_lock);
                         dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
                         spin_unlock(&dentry->d_lock);
-                        return 1;
+                        return status;
                 } else if (status) {
                         /* Return a negative dentry, but leave it "pending" */
-                        return 1;
+                        return status;
                 }
         /* Trigger mount for path component or follow link */
         } else if (flags & (LOOKUP_CONTINUE | LOOKUP_DIRECTORY) ||
@@ -363,19 +309,87 @@ static int try_to_fill_dentry(struct vfsmount *mnt, struct dentry *dentry, int f
                         spin_lock(&dentry->d_lock);
                         dentry->d_flags &= ~DCACHE_AUTOFS_PENDING;
                         spin_unlock(&dentry->d_lock);
-                        return 0;
+                        return status;
                 }
         }
 
-        /* We don't update the usages for the autofs daemon itself, this
-           is necessary for recursive autofs mounts */
-        if (!autofs4_oz_mode(sbi))
-                autofs4_update_usage(mnt, dentry);
+        /* Initialize expiry counter after successful mount */
+        if (ino)
+                ino->last_used = jiffies;
 
         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;
+
+        /*
+         * If a request is pending wait for it.
+         * If it's a mount then it won't be expired till at least
+         * a liitle later and if it's an expire then we might need
+         * to mount it again.
+         */
+        if (autofs4_ispending(dentry)) {
+                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);
+        }
+
+        /*
+         * 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.
+         */
+        spin_lock(&dcache_lock);
+        if (!d_mountpoint(dentry) && list_empty(&dentry->d_subdirs)) {
+                spin_unlock(&dcache_lock);
+
+                status = try_to_fill_dentry(dentry, 0);
+                if (status)
+                        goto out_error;
+
+                /*
+                 * The mount succeeded but if there is no root mount
+                 * it must be an autofs multi-mount with no root offset
+                 * so we don't need to follow the mount.
+                 */
+                if (d_mountpoint(dentry)) {
+                        if (!autofs4_follow_mount(&nd->mnt, &nd->dentry)) {
+                                status = -ENOENT;
+                                goto out_error;
+                        }
+                }
+
+                goto done;
+        }
+        spin_unlock(&dcache_lock);
+
+done:
+        return NULL;
+
+out_error:
+        path_release(nd);
+        return ERR_PTR(status);
 }
 
 /*
@@ -384,47 +398,43 @@ static int try_to_fill_dentry(struct vfsmount *mnt, struct dentry *dentry, int f
  * yet completely filled in, and revalidate has to delay such
  * lookups..
  */
-static int autofs4_revalidate(struct dentry * dentry, struct nameidata *nd)
+static int autofs4_revalidate(struct dentry *dentry, struct nameidata *nd)
 {
-        struct inode * dir = dentry->d_parent->d_inode;
+        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;
+        int status = 0;
 
         /* Pending dentry */
         if (autofs4_ispending(dentry)) {
                 if (!oz_mode)
-                        status = try_to_fill_dentry(nd->mnt, dentry, flags);
-                return status;
+                        status = try_to_fill_dentry(dentry, flags);
+                return !status;
         }
 
         /* Negative dentry.. invalidate if "old" */
         if (dentry->d_inode == NULL)
-                return (dentry->d_time - jiffies <= AUTOFS_NEGATIVE_TIMEOUT);
+                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)) {
+            __simple_empty(dentry)) {
                 DPRINTK("dentry=%p %.*s, emptydir",
                          dentry, dentry->d_name.len, dentry->d_name.name);
                 spin_unlock(&dcache_lock);
                 if (!oz_mode)
-                        status = try_to_fill_dentry(nd->mnt, dentry, flags);
-                return status;
+                        status = try_to_fill_dentry(dentry, flags);
+                return !status;
         }
         spin_unlock(&dcache_lock);
 
-        /* Update the usage list */
-        if (!oz_mode)
-                autofs4_update_usage(nd->mnt, dentry);
-
         return 1;
 }
 
-static void autofs4_dentry_release(struct dentry *de)
+void autofs4_dentry_release(struct dentry *de)
 {
         struct autofs_info *inf;
 
@@ -462,12 +472,13 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s
         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);/* File name too long to exist */
+                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, process_group(current), sbi->catatonic, oz_mode);
 
@@ -519,7 +530,7 @@ static struct dentry *autofs4_lookup(struct inode *dir, struct dentry *dentry, s
          * doesn't do the right thing for all system calls, but it should
          * be OK for the operations we permit from an autofs.
          */
-        if ( dentry->d_inode && d_unhashed(dentry) )
+        if (dentry->d_inode && d_unhashed(dentry))
                 return ERR_PTR(-ENOENT);
 
         return NULL;
@@ -531,6 +542,7 @@ static int autofs4_dir_symlink(struct inode *dir,
 {
         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
         struct autofs_info *ino = autofs4_dentry_ino(dentry);
+        struct autofs_info *p_ino;
         struct inode *inode;
         char *cp;
 
@@ -564,6 +576,10 @@ static int autofs4_dir_symlink(struct inode *dir,
 
         dentry->d_fsdata = ino;
         ino->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;
 
         dir->i_mtime = CURRENT_TIME;
@@ -590,11 +606,17 @@ static int autofs4_dir_unlink(struct inode *dir, struct dentry *dentry)
 {
         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
         struct autofs_info *ino = autofs4_dentry_ino(dentry);
+        struct autofs_info *p_ino;
         
         /* This allows root to remove symlinks */
         if ( !autofs4_oz_mode(sbi) && !capable(CAP_SYS_ADMIN) )
                 return -EACCES;
 
+        if (atomic_dec_and_test(&ino->count)) {
+                p_ino = autofs4_dentry_ino(dentry->d_parent);
+                if (p_ino && dentry->d_parent != dentry)
+                        atomic_dec(&p_ino->count);
+        }
         dput(ino->dentry);
 
         dentry->d_inode->i_size = 0;
@@ -611,6 +633,7 @@ static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
 {
         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
         struct autofs_info *ino = autofs4_dentry_ino(dentry);
+        struct autofs_info *p_ino;
         
         if (!autofs4_oz_mode(sbi))
                 return -EACCES;
@@ -625,8 +648,12 @@ static int autofs4_dir_rmdir(struct inode *dir, struct dentry *dentry)
         spin_unlock(&dentry->d_lock);
         spin_unlock(&dcache_lock);
 
+        if (atomic_dec_and_test(&ino->count)) {
+                p_ino = autofs4_dentry_ino(dentry->d_parent);
+                if (p_ino && dentry->d_parent != dentry)
+                        atomic_dec(&p_ino->count);
+        }
         dput(ino->dentry);
-
         dentry->d_inode->i_size = 0;
         dentry->d_inode->i_nlink = 0;
 
@@ -640,6 +667,7 @@ static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 {
         struct autofs_sb_info *sbi = autofs4_sbi(dir->i_sb);
         struct autofs_info *ino = autofs4_dentry_ino(dentry);
+        struct autofs_info *p_ino;
         struct inode *inode;
 
         if ( !autofs4_oz_mode(sbi) )
@@ -662,6 +690,10 @@ static int autofs4_dir_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 
         dentry->d_fsdata = ino;
         ino->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;
         dir->i_nlink++;
         dir->i_mtime = CURRENT_TIME;
@@ -745,7 +777,7 @@ static inline int autofs4_ask_umount(struct vfsmount *mnt, int __user *p)
 {
         int status = 0;
 
-        if (may_umount(mnt) == 0)
+        if (may_umount(mnt))
                 status = 1;
 
         DPRINTK("returning %d", status);