diff options
Diffstat (limited to 'fs/namei.c')
| -rw-r--r-- | fs/namei.c | 52 |
1 files changed, 32 insertions, 20 deletions
@@ -644,24 +644,22 @@ static int complete_walk(struct nameidata *nd) static __always_inline void set_root(struct nameidata *nd) { - if (!nd->root.mnt) - get_fs_root(current->fs, &nd->root); + get_fs_root(current->fs, &nd->root); } static int link_path_walk(const char *, struct nameidata *); -static __always_inline void set_root_rcu(struct nameidata *nd) +static __always_inline unsigned set_root_rcu(struct nameidata *nd) { - if (!nd->root.mnt) { - struct fs_struct *fs = current->fs; - unsigned seq; + struct fs_struct *fs = current->fs; + unsigned seq, res; - do { - seq = read_seqcount_begin(&fs->seq); - nd->root = fs->root; - nd->seq = __read_seqcount_begin(&nd->root.dentry->d_seq); - } while (read_seqcount_retry(&fs->seq, seq)); - } + do { + seq = read_seqcount_begin(&fs->seq); + nd->root = fs->root; + res = __read_seqcount_begin(&nd->root.dentry->d_seq); + } while (read_seqcount_retry(&fs->seq, seq)); + return res; } static void path_put_conditional(struct path *path, struct nameidata *nd) @@ -861,7 +859,8 @@ follow_link(struct path *link, struct nameidata *nd, void **p) return PTR_ERR(s); } if (*s == '/') { - set_root(nd); + if (!nd->root.mnt) + set_root(nd); path_put(&nd->path); nd->path = nd->root; path_get(&nd->root); @@ -1138,13 +1137,15 @@ static bool __follow_mount_rcu(struct nameidata *nd, struct path *path, */ *inode = path->dentry->d_inode; } - return read_seqretry(&mount_lock, nd->m_seq) && + return !read_seqretry(&mount_lock, nd->m_seq) && !(path->dentry->d_flags & DCACHE_NEED_AUTOMOUNT); } static int follow_dotdot_rcu(struct nameidata *nd) { - set_root_rcu(nd); + struct inode *inode = nd->inode; + if (!nd->root.mnt) + set_root_rcu(nd); while (1) { if (nd->path.dentry == nd->root.dentry && @@ -1156,6 +1157,7 @@ static int follow_dotdot_rcu(struct nameidata *nd) struct dentry *parent = old->d_parent; unsigned seq; + inode = parent->d_inode; seq = read_seqcount_begin(&parent->d_seq); if (read_seqcount_retry(&old->d_seq, nd->seq)) goto failed; @@ -1165,6 +1167,7 @@ static int follow_dotdot_rcu(struct nameidata *nd) } if (!follow_up_rcu(&nd->path)) break; + inode = nd->path.dentry->d_inode; nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq); } while (d_mountpoint(nd->path.dentry)) { @@ -1174,11 +1177,12 @@ static int follow_dotdot_rcu(struct nameidata *nd) break; nd->path.mnt = &mounted->mnt; nd->path.dentry = mounted->mnt.mnt_root; + inode = nd->path.dentry->d_inode; nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq); - if (!read_seqretry(&mount_lock, nd->m_seq)) + if (read_seqretry(&mount_lock, nd->m_seq)) goto failed; } - nd->inode = nd->path.dentry->d_inode; + nd->inode = inode; return 0; failed: @@ -1257,7 +1261,8 @@ static void follow_mount(struct path *path) static void follow_dotdot(struct nameidata *nd) { - set_root(nd); + if (!nd->root.mnt) + set_root(nd); while(1) { struct dentry *old = nd->path.dentry; @@ -1853,7 +1858,7 @@ static int path_init(int dfd, const char *name, unsigned int flags, if (*name=='/') { if (flags & LOOKUP_RCU) { rcu_read_lock(); - set_root_rcu(nd); + nd->seq = set_root_rcu(nd); } else { set_root(nd); path_get(&nd->root); @@ -1904,7 +1909,14 @@ static int path_init(int dfd, const char *name, unsigned int flags, } nd->inode = nd->path.dentry->d_inode; - return 0; + if (!(flags & LOOKUP_RCU)) + return 0; + if (likely(!read_seqcount_retry(&nd->path.dentry->d_seq, nd->seq))) + return 0; + if (!(nd->flags & LOOKUP_ROOT)) + nd->root.mnt = NULL; + rcu_read_unlock(); + return -ECHILD; } static inline int lookup_last(struct nameidata *nd, struct path *path) |
