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authorMiklos Szeredi <mszeredi@suse.cz>2012-05-21 17:30:09 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2012-06-01 12:11:58 -0400
commitd45ea86792db9679ed010b2c3df3db32b2ce5bde (patch)
tree573f99f16911ce9e14087a5559a11e876d676859
parentvfs: do_last(): use inode variable (diff)
downloadlinux-dev-d45ea86792db9679ed010b2c3df3db32b2ce5bde.tar.xz
linux-dev-d45ea86792db9679ed010b2c3df3db32b2ce5bde.zip
vfs: make follow_link check RCU safe
This will allow this code to be used in RCU mode. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/namei.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/fs/namei.c b/fs/namei.c
index 41445e7fd339..c6b996817bb3 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2201,6 +2201,7 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
int acc_mode = op->acc_mode;
struct file *filp;
struct inode *inode;
+ int symlink_ok = 0;
int error;
nd->flags &= ~LOOKUP_PARENT;
@@ -2232,7 +2233,6 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
}
if (!(open_flag & O_CREAT)) {
- int symlink_ok = 0;
if (nd->last.name[nd->last.len])
nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
if (open_flag & O_PATH && !(nd->flags & LOOKUP_FOLLOW))
@@ -2364,8 +2364,16 @@ static struct file *do_last(struct nameidata *nd, struct path *path,
if (!inode)
goto exit_dput;
- if (inode->i_op->follow_link)
+ 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;