vfs: add helpers to get root and pwd
Add three helpers that retrieve a refcounted copy of the root and cwd
from the supplied fs_struct.
get_fs_root()
get_fs_pwd()
get_fs_root_and_pwd()
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/cachefiles/daemon.c b/fs/cachefiles/daemon.c
index 72d4d00..727caed 100644
--- a/fs/cachefiles/daemon.c
+++ b/fs/cachefiles/daemon.c
@@ -552,7 +552,6 @@
*/
static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args)
{
- struct fs_struct *fs;
struct path path;
const struct cred *saved_cred;
int ret;
@@ -573,11 +572,7 @@
}
/* extract the directory dentry from the cwd */
- fs = current->fs;
- read_lock(&fs->lock);
- path = fs->pwd;
- path_get(&path);
- read_unlock(&fs->lock);
+ get_fs_pwd(current->fs, &path);
if (!S_ISDIR(path.dentry->d_inode->i_mode))
goto notdir;
@@ -629,7 +624,6 @@
*/
static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args)
{
- struct fs_struct *fs;
struct path path;
const struct cred *saved_cred;
int ret;
@@ -650,11 +644,7 @@
}
/* extract the directory dentry from the cwd */
- fs = current->fs;
- read_lock(&fs->lock);
- path = fs->pwd;
- path_get(&path);
- read_unlock(&fs->lock);
+ get_fs_pwd(current->fs, &path);
if (!S_ISDIR(path.dentry->d_inode->i_mode))
goto notdir;
diff --git a/fs/dcache.c b/fs/dcache.c
index 9f2c134..995d080 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2014,10 +2014,7 @@
if (path->dentry->d_op && path->dentry->d_op->d_dname)
return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
- read_lock(¤t->fs->lock);
- root = current->fs->root;
- path_get(&root);
- read_unlock(¤t->fs->lock);
+ get_fs_root(current->fs, &root);
spin_lock(&dcache_lock);
tmp = root;
res = __d_path(path, &tmp, buf, buflen);
@@ -2129,12 +2126,7 @@
if (!page)
return -ENOMEM;
- read_lock(¤t->fs->lock);
- pwd = current->fs->pwd;
- path_get(&pwd);
- root = current->fs->root;
- path_get(&root);
- read_unlock(¤t->fs->lock);
+ get_fs_root_and_pwd(current->fs, &root, &pwd);
error = -ENOENT;
spin_lock(&dcache_lock);
diff --git a/fs/fs_struct.c b/fs/fs_struct.c
index eee0590..1ee40eb 100644
--- a/fs/fs_struct.c
+++ b/fs/fs_struct.c
@@ -106,12 +106,7 @@
fs->in_exec = 0;
rwlock_init(&fs->lock);
fs->umask = old->umask;
- read_lock(&old->lock);
- fs->root = old->root;
- path_get(&old->root);
- fs->pwd = old->pwd;
- path_get(&old->pwd);
- read_unlock(&old->lock);
+ get_fs_root_and_pwd(old, &fs->root, &fs->pwd);
}
return fs;
}
diff --git a/fs/namei.c b/fs/namei.c
index 13ff4ab..17ea76b 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -483,13 +483,8 @@
static __always_inline void set_root(struct nameidata *nd)
{
- if (!nd->root.mnt) {
- struct fs_struct *fs = current->fs;
- read_lock(&fs->lock);
- nd->root = fs->root;
- path_get(&nd->root);
- read_unlock(&fs->lock);
- }
+ if (!nd->root.mnt)
+ get_fs_root(current->fs, &nd->root);
}
static int link_path_walk(const char *, struct nameidata *);
@@ -1015,11 +1010,7 @@
nd->path = nd->root;
path_get(&nd->root);
} else if (dfd == AT_FDCWD) {
- struct fs_struct *fs = current->fs;
- read_lock(&fs->lock);
- nd->path = fs->pwd;
- path_get(&fs->pwd);
- read_unlock(&fs->lock);
+ get_fs_pwd(current->fs, &nd->path);
} else {
struct dentry *dentry;
diff --git a/fs/namespace.c b/fs/namespace.c
index 66c4f7e..7972e51 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2213,10 +2213,7 @@
goto out1;
}
- read_lock(¤t->fs->lock);
- root = current->fs->root;
- path_get(¤t->fs->root);
- read_unlock(¤t->fs->lock);
+ get_fs_root(current->fs, &root);
down_write(&namespace_sem);
mutex_lock(&old.dentry->d_inode->i_mutex);
error = -EINVAL;
diff --git a/fs/proc/base.c b/fs/proc/base.c
index c806dfb..4cf5abf 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -149,18 +149,13 @@
return count;
}
-static int get_fs_path(struct task_struct *task, struct path *path, bool root)
+static int get_task_root(struct task_struct *task, struct path *root)
{
- struct fs_struct *fs;
int result = -ENOENT;
task_lock(task);
- fs = task->fs;
- if (fs) {
- read_lock(&fs->lock);
- *path = root ? fs->root : fs->pwd;
- path_get(path);
- read_unlock(&fs->lock);
+ if (task->fs) {
+ get_fs_root(task->fs, root);
result = 0;
}
task_unlock(task);
@@ -173,7 +168,12 @@
int result = -ENOENT;
if (task) {
- result = get_fs_path(task, path, 0);
+ task_lock(task);
+ if (task->fs) {
+ get_fs_pwd(task->fs, path);
+ result = 0;
+ }
+ task_unlock(task);
put_task_struct(task);
}
return result;
@@ -185,7 +185,7 @@
int result = -ENOENT;
if (task) {
- result = get_fs_path(task, path, 1);
+ result = get_task_root(task, path);
put_task_struct(task);
}
return result;
@@ -597,7 +597,7 @@
get_mnt_ns(ns);
}
rcu_read_unlock();
- if (ns && get_fs_path(task, &root, 1) == 0)
+ if (ns && get_task_root(task, &root) == 0)
ret = 0;
put_task_struct(task);
}
diff --git a/include/linux/fs_struct.h b/include/linux/fs_struct.h
index 78a05bf..eca3d52 100644
--- a/include/linux/fs_struct.h
+++ b/include/linux/fs_struct.h
@@ -21,4 +21,31 @@
extern void daemonize_fs_struct(void);
extern int unshare_fs_struct(void);
+static inline void get_fs_root(struct fs_struct *fs, struct path *root)
+{
+ read_lock(&fs->lock);
+ *root = fs->root;
+ path_get(root);
+ read_unlock(&fs->lock);
+}
+
+static inline void get_fs_pwd(struct fs_struct *fs, struct path *pwd)
+{
+ read_lock(&fs->lock);
+ *pwd = fs->pwd;
+ path_get(pwd);
+ read_unlock(&fs->lock);
+}
+
+static inline void get_fs_root_and_pwd(struct fs_struct *fs, struct path *root,
+ struct path *pwd)
+{
+ read_lock(&fs->lock);
+ *root = fs->root;
+ path_get(root);
+ *pwd = fs->pwd;
+ path_get(pwd);
+ read_unlock(&fs->lock);
+}
+
#endif /* _LINUX_FS_STRUCT_H */
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index b87a63b..1b31c13 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1835,13 +1835,8 @@
context->names[context->name_count].ino = (unsigned long)-1;
context->names[context->name_count].osid = 0;
++context->name_count;
- if (!context->pwd.dentry) {
- read_lock(¤t->fs->lock);
- context->pwd = current->fs->pwd;
- path_get(¤t->fs->pwd);
- read_unlock(¤t->fs->lock);
- }
-
+ if (!context->pwd.dentry)
+ get_fs_pwd(current->fs, &context->pwd);
}
/* audit_putname - intercept a putname request