Merge commit 'v2.6.30' into for-2.6.31

[safe/jmp/linux-2.6] / fs / namespace.c

diff --git a/fs/namespace.c b/fs/namespace.c
index 228d8c4..134d494 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -27,6 +27,7 @@
 #include <linux/ramfs.h>
 #include <linux/log2.h>
 #include <linux/idr.h>
+#include <linux/fs_struct.h>
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
 #include "pnode.h"
@@ -397,11 +398,10 @@ static void __mnt_unmake_readonly(struct vfsmount *mnt)
        spin_unlock(&vfsmount_lock);
 }
 
-int simple_set_mnt(struct vfsmount *mnt, struct super_block *sb)
+void simple_set_mnt(struct vfsmount *mnt, struct super_block *sb)
 {
        mnt->mnt_sb = sb;
        mnt->mnt_root = dget(sb->s_root);
-       return 0;
 }
 
 EXPORT_SYMBOL(simple_set_mnt);
@@ -614,9 +614,11 @@ static inline void __mntput(struct vfsmount *mnt)
         */
        for_each_possible_cpu(cpu) {
                struct mnt_writer *cpu_writer = &per_cpu(mnt_writers, cpu);
-               if (cpu_writer->mnt != mnt)
-                       continue;
                spin_lock(&cpu_writer->lock);
+               if (cpu_writer->mnt != mnt) {
+                       spin_unlock(&cpu_writer->lock);
+                       continue;
+               }
                atomic_add(cpu_writer->count, &mnt->__mnt_writers);
                cpu_writer->count = 0;
                /*
@@ -693,12 +695,16 @@ static inline void mangle(struct seq_file *m, const char *s)
  */
 int generic_show_options(struct seq_file *m, struct vfsmount *mnt)
 {
-       const char *options = mnt->mnt_sb->s_options;
+       const char *options;
+
+       rcu_read_lock();
+       options = rcu_dereference(mnt->mnt_sb->s_options);
 
        if (options != NULL && options[0]) {
                seq_putc(m, ',');
                mangle(m, options);
        }
+       rcu_read_unlock();
 
        return 0;
 }
@@ -719,11 +725,22 @@ EXPORT_SYMBOL(generic_show_options);
  */
 void save_mount_options(struct super_block *sb, char *options)
 {
-       kfree(sb->s_options);
-       sb->s_options = kstrdup(options, GFP_KERNEL);
+       BUG_ON(sb->s_options);
+       rcu_assign_pointer(sb->s_options, kstrdup(options, GFP_KERNEL));
 }
 EXPORT_SYMBOL(save_mount_options);
 
+void replace_mount_options(struct super_block *sb, char *options)
+{
+       char *old = sb->s_options;
+       rcu_assign_pointer(sb->s_options, options);
+       if (old) {
+               synchronize_rcu();
+               kfree(old);
+       }
+}
+EXPORT_SYMBOL(replace_mount_options);
+
 #ifdef CONFIG_PROC_FS
 /* iterator */
 static void *m_start(struct seq_file *m, loff_t *pos)
@@ -778,6 +795,7 @@ static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
                { MNT_NOATIME, ",noatime" },
                { MNT_NODIRATIME, ",nodiratime" },
                { MNT_RELATIME, ",relatime" },
+               { MNT_STRICTATIME, ",strictatime" },
                { 0, NULL }
        };
        const struct proc_fs_info *fs_infop;
@@ -1070,9 +1088,7 @@ static int do_umount(struct vfsmount *mnt, int flags)
         */
 
        if (flags & MNT_FORCE && sb->s_op->umount_begin) {
-               lock_kernel();
                sb->s_op->umount_begin(sb);
-               unlock_kernel();
        }
 
        /*
@@ -1374,7 +1390,7 @@ static int attach_recursive_mnt(struct vfsmount *source_mnt,
        if (parent_path) {
                detach_mnt(source_mnt, parent_path);
                attach_mnt(source_mnt, path);
-               touch_mnt_namespace(current->nsproxy->mnt_ns);
+               touch_mnt_namespace(parent_path->mnt->mnt_ns);
        } else {
                mnt_set_mountpoint(dest_mnt, dest_dentry, source_mnt);
                commit_tree(source_mnt);
@@ -1917,6 +1933,10 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
        if (data_page)
                ((char *)data_page)[PAGE_SIZE - 1] = 0;
 
+       /* Default to relatime unless overriden */
+       if (!(flags & MS_NOATIME))
+               mnt_flags |= MNT_RELATIME;
+
        /* Separate the per-mountpoint flags */
        if (flags & MS_NOSUID)
                mnt_flags |= MNT_NOSUID;
@@ -1928,13 +1948,14 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
                mnt_flags |= MNT_NOATIME;
        if (flags & MS_NODIRATIME)
                mnt_flags |= MNT_NODIRATIME;
-       if (flags & MS_RELATIME)
-               mnt_flags |= MNT_RELATIME;
+       if (flags & MS_STRICTATIME)
+               mnt_flags &= ~(MNT_RELATIME | MNT_NOATIME);
        if (flags & MS_RDONLY)
                mnt_flags |= MNT_READONLY;
 
        flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE |
-                  MS_NOATIME | MS_NODIRATIME | MS_RELATIME| MS_KERNMOUNT);
+                  MS_NOATIME | MS_NODIRATIME | MS_RELATIME| MS_KERNMOUNT |
+                  MS_STRICTATIME);
 
        /* ... and get the mountpoint */
        retval = kern_path(dir_name, LOOKUP_FOLLOW, &path);
@@ -2087,66 +2108,6 @@ out1:
 }
 
 /*
- * Replace the fs->{rootmnt,root} with {mnt,dentry}. Put the old values.
- * It can block. Requires the big lock held.
- */
-void set_fs_root(struct fs_struct *fs, struct path *path)
-{
-       struct path old_root;
-
-       write_lock(&fs->lock);
-       old_root = fs->root;
-       fs->root = *path;
-       path_get(path);
-       write_unlock(&fs->lock);
-       if (old_root.dentry)
-               path_put(&old_root);
-}
-
-/*
- * Replace the fs->{pwdmnt,pwd} with {mnt,dentry}. Put the old values.
- * It can block. Requires the big lock held.
- */
-void set_fs_pwd(struct fs_struct *fs, struct path *path)
-{
-       struct path old_pwd;
-
-       write_lock(&fs->lock);
-       old_pwd = fs->pwd;
-       fs->pwd = *path;
-       path_get(path);
-       write_unlock(&fs->lock);
-
-       if (old_pwd.dentry)
-               path_put(&old_pwd);
-}
-
-static void chroot_fs_refs(struct path *old_root, struct path *new_root)
-{
-       struct task_struct *g, *p;
-       struct fs_struct *fs;
-
-       read_lock(&tasklist_lock);
-       do_each_thread(g, p) {
-               task_lock(p);
-               fs = p->fs;
-               if (fs) {
-                       atomic_inc(&fs->count);
-                       task_unlock(p);
-                       if (fs->root.dentry == old_root->dentry
-                           && fs->root.mnt == old_root->mnt)
-                               set_fs_root(fs, new_root);
-                       if (fs->pwd.dentry == old_root->dentry
-                           && fs->pwd.mnt == old_root->mnt)
-                               set_fs_pwd(fs, new_root);
-                       put_fs_struct(fs);
-               } else
-                       task_unlock(p);
-       } while_each_thread(g, p);
-       read_unlock(&tasklist_lock);
-}
-
-/*
  * pivot_root Semantics:
  * Moves the root file system of the current process to the directory put_old,
  * makes new_root as the new root file system of the current process, and sets