Merge branch 'stable-3.2' into pandora-3.2

[pandora-kernel.git] / fs / namei.c

diff --git a/fs/namei.c b/fs/namei.c
index ac6d214..8fc6f57 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -554,24 +554,22 @@ static int complete_walk(struct nameidata *nd)
 
 static __always_inline void set_root(struct nameidata *nd)
 {
-       if (!nd->root.mnt)
-               get_fs_root(current->fs, &nd->root);
+       get_fs_root(current->fs, &nd->root);
 }
 
 static int link_path_walk(const char *, struct nameidata *);
 
-static __always_inline void set_root_rcu(struct nameidata *nd)
+static __always_inline unsigned set_root_rcu(struct nameidata *nd)
 {
-       if (!nd->root.mnt) {
-               struct fs_struct *fs = current->fs;
-               unsigned seq;
+       struct fs_struct *fs = current->fs;
+       unsigned seq, res;
 
-               do {
-                       seq = read_seqcount_begin(&fs->seq);
-                       nd->root = fs->root;
-                       nd->seq = __read_seqcount_begin(&nd->root.dentry->d_seq);
-               } while (read_seqcount_retry(&fs->seq, seq));
-       }
+       do {
+               seq = read_seqcount_begin(&fs->seq);
+               nd->root = fs->root;
+               res = __read_seqcount_begin(&nd->root.dentry->d_seq);
+       } while (read_seqcount_retry(&fs->seq, seq));
+       return res;
 }
 
 static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link)
@@ -582,7 +580,8 @@ static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *l
                goto fail;
 
        if (*link == '/') {
-               set_root(nd);
+               if (!nd->root.mnt)
+                       set_root(nd);
                path_put(&nd->path);
                nd->path = nd->root;
                path_get(&nd->root);
@@ -852,7 +851,7 @@ static int follow_managed(struct path *path, unsigned flags)
                mntput(path->mnt);
        if (ret == -EISDIR)
                ret = 0;
-       return ret;
+       return ret < 0 ? ret : need_mntput;
 }
 
 int follow_down_one(struct path *path)
@@ -900,6 +899,7 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
                        break;
                path->mnt = mounted;
                path->dentry = mounted->mnt_root;
+               nd->flags |= LOOKUP_JUMPED;
                nd->seq = read_seqcount_begin(&path->dentry->d_seq);
                /*
                 * Update the inode too. We don't need to re-check the
@@ -911,22 +911,11 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path,
        return true;
 }
 
-static void follow_mount_rcu(struct nameidata *nd)
-{
-       while (d_mountpoint(nd->path.dentry)) {
-               struct vfsmount *mounted;
-               mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry, 1);
-               if (!mounted)
-                       break;
-               nd->path.mnt = mounted;
-               nd->path.dentry = mounted->mnt_root;
-               nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
-       }
-}
-
 static int follow_dotdot_rcu(struct nameidata *nd)
 {
-       set_root_rcu(nd);
+       struct inode *inode = nd->inode;
+       if (!nd->root.mnt)
+               set_root_rcu(nd);
 
        while (1) {
                if (nd->path.dentry == nd->root.dentry &&
@@ -938,6 +927,7 @@ static int follow_dotdot_rcu(struct nameidata *nd)
                        struct dentry *parent = old->d_parent;
                        unsigned seq;
 
+                       inode = parent->d_inode;
                        seq = read_seqcount_begin(&parent->d_seq);
                        if (read_seqcount_retry(&old->d_seq, nd->seq))
                                goto failed;
@@ -947,10 +937,20 @@ static int follow_dotdot_rcu(struct nameidata *nd)
                }
                if (!follow_up_rcu(&nd->path))
                        break;
+               inode = nd->path.dentry->d_inode;
                nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
        }
-       follow_mount_rcu(nd);
-       nd->inode = nd->path.dentry->d_inode;
+       while (d_mountpoint(nd->path.dentry)) {
+               struct vfsmount *mounted;
+               mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry, 1);
+               if (!mounted)
+                       break;
+               nd->path.mnt = mounted;
+               nd->path.dentry = mounted->mnt_root;
+               inode = nd->path.dentry->d_inode;
+               nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq);
+       }
+       nd->inode = inode;
        return 0;
 
 failed:
@@ -1029,7 +1029,8 @@ static void follow_mount(struct path *path)
 
 static void follow_dotdot(struct nameidata *nd)
 {
-       set_root(nd);
+       if (!nd->root.mnt)
+               set_root(nd);
 
        while(1) {
                struct dentry *old = nd->path.dentry;
@@ -1093,8 +1094,10 @@ static struct dentry *d_inode_lookup(struct dentry *parent, struct dentry *dentr
        struct dentry *old;
 
        /* Don't create child dentry for a dead directory. */
-       if (unlikely(IS_DEADDIR(inode)))
+       if (unlikely(IS_DEADDIR(inode))) {
+               dput(dentry);
                return ERR_PTR(-ENOENT);
+       }
 
        old = inode->i_op->lookup(inode, dentry, nd);
        if (unlikely(old)) {
@@ -1213,6 +1216,8 @@ retry:
                path_put_conditional(path, nd);
                return err;
        }
+       if (err)
+               nd->flags |= LOOKUP_JUMPED;
        *inode = path->dentry->d_inode;
        return 0;
 }
@@ -1499,7 +1504,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
                if (flags & LOOKUP_RCU) {
                        br_read_lock(vfsmount_lock);
                        rcu_read_lock();
-                       set_root_rcu(nd);
+                       nd->seq = set_root_rcu(nd);
                } else {
                        set_root(nd);
                        path_get(&nd->root);
@@ -1555,7 +1560,14 @@ static int path_init(int dfd, const char *name, unsigned int flags,
        }
 
        nd->inode = nd->path.dentry->d_inode;
-       return 0;
+       if (!(flags & LOOKUP_RCU))
+               return 0;
+       if (likely(!read_seqcount_retry(&nd->path.dentry->d_seq, nd->seq)))
+               return 0;
+       if (!(nd->flags & LOOKUP_ROOT))
+               nd->root.mnt = NULL;
+       rcu_read_unlock();
+       return -ECHILD;
 
 fput_fail:
        fput_light(file, fput_needed);
@@ -1750,10 +1762,11 @@ static struct dentry *__lookup_hash(struct qstr *name,
  * needs parent already locked. Doesn't follow mounts.
  * SMP-safe.
  */
-static struct dentry *lookup_hash(struct nameidata *nd)
+struct dentry *lookup_hash(struct nameidata *nd)
 {
        return __lookup_hash(&nd->last, nd->path.dentry, nd);
 }
+EXPORT_SYMBOL(lookup_hash);
 
 /**
  * lookup_one_len - filesystem helper to lookup single pathname component
@@ -2134,7 +2147,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
                /* sayonara */
                error = complete_walk(nd);
                if (error)
-                       return ERR_PTR(-ECHILD);
+                       return ERR_PTR(error);
 
                error = -ENOTDIR;
                if (nd->flags & LOOKUP_DIRECTORY) {
@@ -2146,6 +2159,10 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
        }
 
        /* create side of things */
+       /*
+        * This will *only* deal with leaving RCU mode - LOOKUP_JUMPED has been
+        * cleared when we got to the last component we are about to look up
+        */
        error = complete_walk(nd);
        if (error)
                return ERR_PTR(error);
@@ -2214,6 +2231,9 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
        if (error < 0)
                goto exit_dput;
 
+       if (error)
+               nd->flags |= LOOKUP_JUMPED;
+
        error = -ENOENT;
        if (!path->dentry->d_inode)
                goto exit_dput;
@@ -2223,6 +2243,10 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 
        path_to_nameidata(path, nd);
        nd->inode = path->dentry->d_inode;
+       /* Why this, you ask?  _Now_ we might have grown LOOKUP_JUMPED... */
+       error = complete_walk(nd);
+       if (error)
+               return ERR_PTR(error);
        error = -EISDIR;
        if (S_ISDIR(nd->inode->i_mode))
                goto exit;