diff options
| -rw-r--r-- | fs/fs_struct.c | 10 | ||||
| -rw-r--r-- | fs/namei.c | 34 | ||||
| -rw-r--r-- | include/linux/fs_struct.h | 3 |
3 files changed, 34 insertions, 13 deletions
diff --git a/fs/fs_struct.c b/fs/fs_struct.c index ed45a9cf5f3d..60b8531f41c5 100644 --- a/fs/fs_struct.c +++ b/fs/fs_struct.c @@ -14,9 +14,11 @@ void set_fs_root(struct fs_struct *fs, struct path *path) struct path old_root; spin_lock(&fs->lock); + write_seqcount_begin(&fs->seq); old_root = fs->root; fs->root = *path; path_get(path); + write_seqcount_end(&fs->seq); spin_unlock(&fs->lock); if (old_root.dentry) path_put(&old_root); @@ -31,9 +33,11 @@ void set_fs_pwd(struct fs_struct *fs, struct path *path) struct path old_pwd; spin_lock(&fs->lock); + write_seqcount_begin(&fs->seq); old_pwd = fs->pwd; fs->pwd = *path; path_get(path); + write_seqcount_end(&fs->seq); spin_unlock(&fs->lock); if (old_pwd.dentry) @@ -52,6 +56,7 @@ void chroot_fs_refs(struct path *old_root, struct path *new_root) fs = p->fs; if (fs) { spin_lock(&fs->lock); + write_seqcount_begin(&fs->seq); if (fs->root.dentry == old_root->dentry && fs->root.mnt == old_root->mnt) { path_get(new_root); @@ -64,6 +69,7 @@ void chroot_fs_refs(struct path *old_root, struct path *new_root) fs->pwd = *new_root; count++; } + write_seqcount_end(&fs->seq); spin_unlock(&fs->lock); } task_unlock(p); @@ -88,8 +94,10 @@ void exit_fs(struct task_struct *tsk) int kill; task_lock(tsk); spin_lock(&fs->lock); + write_seqcount_begin(&fs->seq); tsk->fs = NULL; kill = !--fs->users; + write_seqcount_end(&fs->seq); spin_unlock(&fs->lock); task_unlock(tsk); if (kill) @@ -105,6 +113,7 @@ struct fs_struct *copy_fs_struct(struct fs_struct *old) fs->users = 1; fs->in_exec = 0; spin_lock_init(&fs->lock); + seqcount_init(&fs->seq); fs->umask = old->umask; get_fs_root_and_pwd(old, &fs->root, &fs->pwd); } @@ -144,6 +153,7 @@ EXPORT_SYMBOL(current_umask); struct fs_struct init_fs = { .users = 1, .lock = __SPIN_LOCK_UNLOCKED(init_fs.lock), + .seq = SEQCNT_ZERO, .umask = 0022, }; diff --git a/fs/namei.c b/fs/namei.c index 8d3f15b3a541..c731b50a6184 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -684,9 +684,12 @@ static __always_inline void set_root_rcu(struct nameidata *nd) { if (!nd->root.mnt) { struct fs_struct *fs = current->fs; - spin_lock(&fs->lock); - nd->root = fs->root; - spin_unlock(&fs->lock); + unsigned seq; + + do { + seq = read_seqcount_begin(&fs->seq); + nd->root = fs->root; + } while (read_seqcount_retry(&fs->seq, seq)); } } @@ -1369,26 +1372,31 @@ static int path_init_rcu(int dfd, const char *name, unsigned int flags, struct n if (*name=='/') { struct fs_struct *fs = current->fs; + unsigned seq; br_read_lock(vfsmount_lock); rcu_read_lock(); - spin_lock(&fs->lock); - nd->root = fs->root; - nd->path = nd->root; - nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq); - spin_unlock(&fs->lock); + do { + seq = read_seqcount_begin(&fs->seq); + nd->root = fs->root; + nd->path = nd->root; + nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); + } while (read_seqcount_retry(&fs->seq, seq)); } else if (dfd == AT_FDCWD) { struct fs_struct *fs = current->fs; + unsigned seq; br_read_lock(vfsmount_lock); rcu_read_lock(); - spin_lock(&fs->lock); - nd->path = fs->pwd; - nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq); - spin_unlock(&fs->lock); + do { + seq = read_seqcount_begin(&fs->seq); + nd->path = fs->pwd; + nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); + } while (read_seqcount_retry(&fs->seq, seq)); + } else { struct dentry *dentry; @@ -1411,7 +1419,7 @@ static int path_init_rcu(int dfd, const char *name, unsigned int flags, struct n if (fput_needed) nd->file = file; - nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq); + nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); br_read_lock(vfsmount_lock); rcu_read_lock(); } diff --git a/include/linux/fs_struct.h b/include/linux/fs_struct.h index a42b5bf02f8b..003dc0fd7347 100644 --- a/include/linux/fs_struct.h +++ b/include/linux/fs_struct.h @@ -2,10 +2,13 @@ #define _LINUX_FS_STRUCT_H #include <linux/path.h> +#include <linux/spinlock.h> +#include <linux/seqlock.h> struct fs_struct { int users; spinlock_t lock; + seqcount_t seq; int umask; int in_exec; struct path root, pwd; |