Merge tag 'v2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

[mv-sheeva.git] / fs / fs_struct.c

diff --git a/fs/fs_struct.c b/fs/fs_struct.c
index ed45a9cf5f3de46ae08e90d581a500bed9eb4dbf..78b519c135365fb02d533441377ac4785abcb3ed 100644 (file)
--- a/fs/fs_struct.c
+++ b/fs/fs_struct.c
@@ -4,6 +4,19 @@
 #include <linux/path.h>
 #include <linux/slab.h>
 #include <linux/fs_struct.h>
+#include "internal.h"
+
+static inline void path_get_longterm(struct path *path)
+{
+       path_get(path);
+       mnt_make_longterm(path->mnt);
+}
+
+static inline void path_put_longterm(struct path *path)
+{
+       mnt_make_shortterm(path->mnt);
+       path_put(path);
+}
 
 /*
  * Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values.
@@ -14,12 +27,14 @@ 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);
+       path_get_longterm(path);
+       write_seqcount_end(&fs->seq);
        spin_unlock(&fs->lock);
        if (old_root.dentry)
-               path_put(&old_root);
+               path_put_longterm(&old_root);
 }
 
 /*
@@ -31,13 +46,15 @@ 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);
+       path_get_longterm(path);
+       write_seqcount_end(&fs->seq);
        spin_unlock(&fs->lock);
 
        if (old_pwd.dentry)
-               path_put(&old_pwd);
+               path_put_longterm(&old_pwd);
 }
 
 void chroot_fs_refs(struct path *old_root, struct path *new_root)
@@ -52,31 +69,33 @@ 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);
+                               path_get_longterm(new_root);
                                fs->root = *new_root;
                                count++;
                        }
                        if (fs->pwd.dentry == old_root->dentry
                            && fs->pwd.mnt == old_root->mnt) {
-                               path_get(new_root);
+                               path_get_longterm(new_root);
                                fs->pwd = *new_root;
                                count++;
                        }
+                       write_seqcount_end(&fs->seq);
                        spin_unlock(&fs->lock);
                }
                task_unlock(p);
        } while_each_thread(g, p);
        read_unlock(&tasklist_lock);
        while (count--)
-               path_put(old_root);
+               path_put_longterm(old_root);
 }
 
 void free_fs_struct(struct fs_struct *fs)
 {
-       path_put(&fs->root);
-       path_put(&fs->pwd);
+       path_put_longterm(&fs->root);
+       path_put_longterm(&fs->pwd);
        kmem_cache_free(fs_cachep, fs);
 }
 
@@ -88,8 +107,10 @@ 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)
@@ -105,8 +126,15 @@ 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);
+
+               spin_lock(&old->lock);
+               fs->root = old->root;
+               path_get_longterm(&fs->root);
+               fs->pwd = old->pwd;
+               path_get_longterm(&fs->pwd);
+               spin_unlock(&old->lock);
        }
        return fs;
 }
@@ -144,6 +172,7 @@ EXPORT_SYMBOL(current_umask);
 struct fs_struct init_fs = {
        .users          = 1,
        .lock           = __SPIN_LOCK_UNLOCKED(init_fs.lock),
+       .seq            = SEQCNT_ZERO,
        .umask          = 0022,
 };