From f7ad3c6be90809b53b7f0ae9d4eaa45ce2564a79 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Tue, 10 Aug 2010 11:41:36 +0200 Subject: [PATCH] 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 Signed-off-by: Al Viro --- fs/cachefiles/daemon.c | 14 ++------------ fs/dcache.c | 12 ++---------- fs/fs_struct.c | 7 +------ fs/namei.c | 15 +++------------ fs/namespace.c | 5 +---- fs/proc/base.c | 22 +++++++++++----------- include/linux/fs_struct.h | 27 +++++++++++++++++++++++++++ kernel/auditsc.c | 9 ++------- 8 files changed, 49 insertions(+), 62 deletions(-) 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_tag(struct cachefiles_cache *cache, char *args) */ 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 @@ static int cachefiles_daemon_cull(struct cachefiles_cache *cache, char *args) } /* 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 @@ inval: */ 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 @@ static int cachefiles_daemon_inuse(struct cachefiles_cache *cache, char *args) } /* 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 @@ char *d_path(const struct path *path, char *buf, int buflen) 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 @@ SYSCALL_DEFINE2(getcwd, char __user *, buf, unsigned long, size) 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 @@ struct fs_struct *copy_fs_struct(struct fs_struct *old) 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 @@ ok: 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 @@ static int path_init(int dfd, const char *name, unsigned int flags, struct namei 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 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, 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 @@ static unsigned int pid_entry_count_dirs(const struct pid_entry *entries, 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 @@ static int proc_cwd_link(struct inode *inode, struct path *path) 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 @@ static int proc_root_link(struct inode *inode, struct path *path) 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 @@ static int mounts_open_common(struct inode *inode, struct file *file, 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 free_fs_struct(struct fs_struct *); 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 @@ void __audit_getname(const char *name) 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 -- 2.7.4