[PATCH -V14 04/11] vfs: Allow handle based open on symlinks

From: Aneesh Kumar K.V
Date: Tue Jun 15 2010 - 13:15:19 EST


The patch update may_open to allow handle based open on symlinks.
The file handle based API use file descritor returned from open_by_handle_at
to do different file system operations. To find the link target name we
need to get a file descriptor on symlinks.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
---
fs/namei.c | 17 ++++++++++++++---
1 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index c2d19c7..417bf53 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1422,7 +1422,7 @@ int vfs_create(struct inode *dir, struct dentry *dentry, int mode,
return error;
}

-int may_open(struct path *path, int acc_mode, int flag)
+static int __may_open(struct path *path, int acc_mode, int flag, int handle)
{
struct dentry *dentry = path->dentry;
struct inode *inode = dentry->d_inode;
@@ -1433,7 +1433,13 @@ int may_open(struct path *path, int acc_mode, int flag)

switch (inode->i_mode & S_IFMT) {
case S_IFLNK:
- return -ELOOP;
+ /*
+ * For file handle based open we should allow
+ * open of symlink.
+ */
+ if (!handle)
+ return -ELOOP;
+ break;
case S_IFDIR:
if (acc_mode & MAY_WRITE)
return -EISDIR;
@@ -1473,6 +1479,11 @@ int may_open(struct path *path, int acc_mode, int flag)
return break_lease(inode, flag);
}

+int may_open(struct path *path, int acc_mode, int flag)
+{
+ return __may_open(path, acc_mode, flag, 0);
+}
+
static int handle_truncate(struct path *path)
{
struct inode *inode = path->dentry->d_inode;
@@ -1570,7 +1581,7 @@ struct file *finish_open_handle(struct path *path,
if (error)
goto exit;
}
- error = may_open(path, acc_mode, open_flag);
+ error = __may_open(path, acc_mode, open_flag, 1);
if (error) {
if (will_truncate)
mnt_drop_write(path->mnt);
--
1.7.1.331.ga5080

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