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 5008f01..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);
@@ -912,22 +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 &&
@@ -939,6 +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;
@@ -948,10 +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:
@@ -1030,7 +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;
@@ -1094,8 +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)) {
@@ -1502,7 +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);
@@ -1558,7 +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);
@@ -1753,10 +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
@@ -2137,7 +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) {
@@ -2236,7 +2246,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
        /* Why this, you ask?  _Now_ we might have grown LOOKUP_JUMPED... */
        error = complete_walk(nd);
        if (error)
-               goto exit;
+               return ERR_PTR(error);
        error = -EISDIR;
        if (S_ISDIR(nd->inode->i_mode))
                goto exit;