X-Git-Url: http://review.tizen.org/git/?a=blobdiff_plain;f=fs%2Fnamei.c;h=fad7117dbb28577e5688f206a454602b6e34fe4f;hb=d58ffd35c1e595df2cf8ac4803f178c8be95ca7a;hp=90210b46b4614bd03bc27252905f065a55cf0e6f;hpb=050ac841ea90610067fec26150574be8c6077738;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git

diff --git a/fs/namei.c b/fs/namei.c
index 90210b4..fad7117 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -605,7 +605,7 @@ static inline void path_to_nameidata(const struct path *path,
 static inline void put_link(struct nameidata *nd, struct path *link, void *cookie)
 {
 	struct inode *inode = link->dentry->d_inode;
-	if (!IS_ERR(cookie) && inode->i_op->put_link)
+	if (inode->i_op->put_link)
 		inode->i_op->put_link(link->dentry, nd, cookie);
 	path_put(link);
 }
@@ -613,19 +613,19 @@ static inline void put_link(struct nameidata *nd, struct path *link, void *cooki
 static __always_inline int
 follow_link(struct path *link, struct nameidata *nd, void **p)
 {
-	int error;
 	struct dentry *dentry = link->dentry;
+	int error;
+	char *s;
 
 	BUG_ON(nd->flags & LOOKUP_RCU);
 
 	if (link->mnt == nd->path.mnt)
 		mntget(link->mnt);
 
-	if (unlikely(current->total_link_count >= 40)) {
-		*p = ERR_PTR(-ELOOP); /* no ->put_link(), please */
-		path_put(&nd->path);
-		return -ELOOP;
-	}
+	error = -ELOOP;
+	if (unlikely(current->total_link_count >= 40))
+		goto out_put_nd_path;
+
 	cond_resched();
 	current->total_link_count++;
 
@@ -633,30 +633,37 @@ follow_link(struct path *link, struct nameidata *nd, void **p)
 	nd_set_link(nd, NULL);
 
 	error = security_inode_follow_link(link->dentry, nd);
-	if (error) {
-		*p = ERR_PTR(error); /* no ->put_link(), please */
-		path_put(&nd->path);
-		return error;
-	}
+	if (error)
+		goto out_put_nd_path;
 
 	nd->last_type = LAST_BIND;
 	*p = dentry->d_inode->i_op->follow_link(dentry, nd);
 	error = PTR_ERR(*p);
-	if (!IS_ERR(*p)) {
-		char *s = nd_get_link(nd);
-		error = 0;
-		if (s)
-			error = __vfs_follow_link(nd, s);
-		else if (nd->last_type == LAST_BIND) {
-			nd->flags |= LOOKUP_JUMPED;
-			nd->inode = nd->path.dentry->d_inode;
-			if (nd->inode->i_op->follow_link) {
-				/* stepped on a _really_ weird one */
-				path_put(&nd->path);
-				error = -ELOOP;
-			}
+	if (IS_ERR(*p))
+		goto out_put_link;
+
+	error = 0;
+	s = nd_get_link(nd);
+	if (s) {
+		error = __vfs_follow_link(nd, s);
+	} else if (nd->last_type == LAST_BIND) {
+		nd->flags |= LOOKUP_JUMPED;
+		nd->inode = nd->path.dentry->d_inode;
+		if (nd->inode->i_op->follow_link) {
+			/* stepped on a _really_ weird one */
+			path_put(&nd->path);
+			error = -ELOOP;
 		}
 	}
+	if (unlikely(error))
+		put_link(nd, link, *p);
+
+	return error;
+
+out_put_nd_path:
+	path_put(&nd->path);
+out_put_link:
+	path_put(link);
 	return error;
 }
 
@@ -1383,9 +1390,10 @@ static inline int nested_symlink(struct path *path, struct nameidata *nd)
 		void *cookie;
 
 		res = follow_link(&link, nd, &cookie);
-		if (!res)
-			res = walk_component(nd, path, &nd->last,
-					     nd->last_type, LOOKUP_FOLLOW);
+		if (res)
+			break;
+		res = walk_component(nd, path, &nd->last,
+				     nd->last_type, LOOKUP_FOLLOW);
 		put_link(nd, &link, cookie);
 	} while (res > 0);
 
@@ -1777,8 +1785,9 @@ static int path_lookupat(int dfd, const char *name,
 			struct path link = path;
 			nd->flags |= LOOKUP_PARENT;
 			err = follow_link(&link, nd, &cookie);
-			if (!err)
-				err = lookup_last(nd, &path);
+			if (err)
+				break;
+			err = lookup_last(nd, &path);
 			put_link(nd, &link, cookie);
 		}
 	}
@@ -2188,20 +2197,76 @@ static inline int open_to_namei_flags(int flag)
 }
 
 /*
+ * Lookup, maybe create and open the last component
+ *
+ * Must be called with i_mutex held on parent.
+ *
+ * Returns open file or NULL on success, error otherwise.  NULL means no open
+ * was performed, only lookup.
+ */
+static struct file *lookup_open(struct nameidata *nd, struct path *path,
+				const struct open_flags *op,
+				int *want_write, bool *created)
+{
+	struct dentry *dir = nd->path.dentry;
+	struct dentry *dentry;
+	int error;
+
+	*created = false;
+	dentry = lookup_hash(nd);
+	if (IS_ERR(dentry))
+		return ERR_CAST(dentry);
+
+	/* Negative dentry, just create the file */
+	if (!dentry->d_inode && (op->open_flag & O_CREAT)) {
+		umode_t mode = op->mode;
+		if (!IS_POSIXACL(dir->d_inode))
+			mode &= ~current_umask();
+		/*
+		 * This write is needed to ensure that a
+		 * rw->ro transition does not occur between
+		 * the time when the file is created and when
+		 * a permanent write count is taken through
+		 * the 'struct file' in nameidata_to_filp().
+		 */
+		error = mnt_want_write(nd->path.mnt);
+		if (error)
+			goto out_dput;
+		*want_write = 1;
+		*created = true;
+		error = security_path_mknod(&nd->path, dentry, mode, 0);
+		if (error)
+			goto out_dput;
+		error = vfs_create(dir->d_inode, dentry, mode, nd);
+		if (error)
+			goto out_dput;
+	}
+	path->dentry = dentry;
+	path->mnt = nd->path.mnt;
+	return NULL;
+
+out_dput:
+	dput(dentry);
+	return ERR_PTR(error);
+}
+
+/*
  * Handle the last step of open()
  */
 static struct file *do_last(struct nameidata *nd, struct path *path,
 			    const struct open_flags *op, const char *pathname)
 {
 	struct dentry *dir = nd->path.dentry;
-	struct dentry *dentry;
 	int open_flag = op->open_flag;
 	int will_truncate = open_flag & O_TRUNC;
 	int want_write = 0;
 	int acc_mode = op->acc_mode;
 	struct file *filp;
 	struct inode *inode;
+	bool created;
 	int symlink_ok = 0;
+	struct path save_parent = { .dentry = NULL, .mnt = NULL };
+	bool retried = false;
 	int error;
 
 	nd->flags &= ~LOOKUP_PARENT;
@@ -2239,112 +2304,51 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 			symlink_ok = 1;
 		/* we _can_ be in RCU mode here */
 		error = lookup_fast(nd, &nd->last, path, &inode);
-		if (unlikely(error)) {
-			if (error < 0)
-				goto exit;
+		if (likely(!error))
+			goto finish_lookup;
 
-			error = lookup_slow(nd, &nd->last, path);
-			if (error < 0)
-				goto exit;
-
-			inode = path->dentry->d_inode;
-		}
-		error = -ENOENT;
-		if (!inode) {
-			path_to_nameidata(path, nd);
+		if (error < 0)
 			goto exit;
-		}
 
-		if (should_follow_link(inode, !symlink_ok)) {
-			if (nd->flags & LOOKUP_RCU) {
-				if (unlikely(unlazy_walk(nd, path->dentry))) {
-					error = -ECHILD;
-					goto exit;
-				}
-			}
-			BUG_ON(inode != path->dentry->d_inode);
-			return NULL;
-		}
-		path_to_nameidata(path, nd);
-		nd->inode = inode;
-
-		/* sayonara */
+		BUG_ON(nd->inode != dir->d_inode);
+	} else {
+		/* 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);
 
-		error = -ENOTDIR;
-		if (nd->flags & LOOKUP_DIRECTORY) {
-			if (!nd->inode->i_op->lookup)
-				goto exit;
-		}
-		audit_inode(pathname, nd->path.dentry);
-		goto ok;
+		audit_inode(pathname, dir);
+		error = -EISDIR;
+		/* trailing slashes? */
+		if (nd->last.name[nd->last.len])
+			goto exit;
 	}
 
-	/* 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);
-
-	audit_inode(pathname, dir);
-	error = -EISDIR;
-	/* trailing slashes? */
-	if (nd->last.name[nd->last.len])
-		goto exit;
-
+retry_lookup:
 	mutex_lock(&dir->d_inode->i_mutex);
+	filp = lookup_open(nd, path, op, &want_write, &created);
+	mutex_unlock(&dir->d_inode->i_mutex);
 
-	dentry = lookup_hash(nd);
-	error = PTR_ERR(dentry);
-	if (IS_ERR(dentry)) {
-		mutex_unlock(&dir->d_inode->i_mutex);
-		goto exit;
-	}
-
-	path->dentry = dentry;
-	path->mnt = nd->path.mnt;
+	if (IS_ERR(filp))
+		goto out;
 
-	/* Negative dentry, just create the file */
-	if (!dentry->d_inode) {
-		umode_t mode = op->mode;
-		if (!IS_POSIXACL(dir->d_inode))
-			mode &= ~current_umask();
-		/*
-		 * This write is needed to ensure that a
-		 * rw->ro transition does not occur between
-		 * the time when the file is created and when
-		 * a permanent write count is taken through
-		 * the 'struct file' in nameidata_to_filp().
-		 */
-		error = mnt_want_write(nd->path.mnt);
-		if (error)
-			goto exit_mutex_unlock;
-		want_write = 1;
+	if (created) {
 		/* Don't check for write permission, don't truncate */
 		open_flag &= ~O_TRUNC;
 		will_truncate = 0;
 		acc_mode = MAY_OPEN;
-		error = security_path_mknod(&nd->path, dentry, mode, 0);
-		if (error)
-			goto exit_mutex_unlock;
-		error = vfs_create(dir->d_inode, dentry, mode, nd);
-		if (error)
-			goto exit_mutex_unlock;
-		mutex_unlock(&dir->d_inode->i_mutex);
-		dput(nd->path.dentry);
-		nd->path.dentry = dentry;
+		path_to_nameidata(path, nd);
 		goto common;
 	}
 
 	/*
 	 * It already exists.
 	 */
-	mutex_unlock(&dir->d_inode->i_mutex);
 	audit_inode(pathname, path->dentry);
 
 	error = -EEXIST;
@@ -2360,6 +2364,8 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 
 	BUG_ON(nd->flags & LOOKUP_RCU);
 	inode = path->dentry->d_inode;
+finish_lookup:
+	/* we _can_ be in RCU mode here */
 	error = -ENOENT;
 	if (!inode) {
 		path_to_nameidata(path, nd);
@@ -2377,18 +2383,28 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
 		return NULL;
 	}
 
-	path_to_nameidata(path, nd);
+	if ((nd->flags & LOOKUP_RCU) || nd->path.mnt != path->mnt) {
+		path_to_nameidata(path, nd);
+	} else {
+		save_parent.dentry = nd->path.dentry;
+		save_parent.mnt = mntget(path->mnt);
+		nd->path.dentry = path->dentry;
+
+	}
 	nd->inode = inode;
 	/* Why this, you ask?  _Now_ we might have grown LOOKUP_JUMPED... */
 	error = complete_walk(nd);
-	if (error)
+	if (error) {
+		path_put(&save_parent);
 		return ERR_PTR(error);
+	}
 	error = -EISDIR;
 	if ((open_flag & O_CREAT) && S_ISDIR(nd->inode->i_mode))
 		goto exit;
 	error = -ENOTDIR;
 	if ((nd->flags & LOOKUP_DIRECTORY) && !nd->inode->i_op->lookup)
 		goto exit;
+	audit_inode(pathname, nd->path.dentry);
 ok:
 	if (!S_ISREG(nd->inode->i_mode))
 		will_truncate = 0;
@@ -2404,6 +2420,20 @@ common:
 	if (error)
 		goto exit;
 	filp = nameidata_to_filp(nd);
+	if (filp == ERR_PTR(-EOPENSTALE) && save_parent.dentry && !retried) {
+		BUG_ON(save_parent.dentry != dir);
+		path_put(&nd->path);
+		nd->path = save_parent;
+		nd->inode = dir->d_inode;
+		save_parent.mnt = NULL;
+		save_parent.dentry = NULL;
+		if (want_write) {
+			mnt_drop_write(nd->path.mnt);
+			want_write = 0;
+		}
+		retried = true;
+		goto retry_lookup;
+	}
 	if (!IS_ERR(filp)) {
 		error = ima_file_check(filp, op->acc_mode);
 		if (error) {
@@ -2423,11 +2453,10 @@ common:
 out:
 	if (want_write)
 		mnt_drop_write(nd->path.mnt);
+	path_put(&save_parent);
 	terminate_walk(nd);
 	return filp;
 
-exit_mutex_unlock:
-	mutex_unlock(&dir->d_inode->i_mutex);
 exit_dput:
 	path_put_conditional(path, nd);
 exit:
@@ -2475,9 +2504,8 @@ static struct file *path_openat(int dfd, const char *pathname,
 		nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL);
 		error = follow_link(&link, nd, &cookie);
 		if (unlikely(error))
-			filp = ERR_PTR(error);
-		else
-			filp = do_last(nd, &path, op, pathname);
+			goto out_filp;
+		filp = do_last(nd, &path, op, pathname);
 		put_link(nd, &link, cookie);
 	}
 out:
@@ -2486,6 +2514,12 @@ out:
 	if (base)
 		fput(base);
 	release_open_intent(nd);
+	if (filp == ERR_PTR(-EOPENSTALE)) {
+		if (flags & LOOKUP_RCU)
+			filp = ERR_PTR(-ECHILD);
+		else
+			filp = ERR_PTR(-ESTALE);
+	}
 	return filp;
 
 out_filp: