fs: sdfat: Update to version 2.4.5
[GitHub/LineageOS/android_kernel_samsung_universal7580.git] / fs / super.c
index 7465d4364208a2e751d2d3a7c8a8c1cc10d2d7c3..81cdbe57d2ec9dab081ba94c57ca3b8e1d5cdc75 100644 (file)
@@ -76,6 +76,8 @@ static int prune_super(struct shrinker *shrink, struct shrink_control *sc)
 
        total_objects = sb->s_nr_dentry_unused +
                        sb->s_nr_inodes_unused + fs_objects + 1;
+       if (!total_objects)
+               total_objects = 1;
 
        if (sc->nr_to_scan) {
                int     dentries;
@@ -161,19 +163,6 @@ static struct super_block *alloc_super(struct file_system_type *type, int flags)
                        s = NULL;
                        goto out;
                }
-#ifdef CONFIG_SMP
-               s->s_files = alloc_percpu(struct list_head);
-               if (!s->s_files)
-                       goto err_out;
-               else {
-                       int i;
-
-                       for_each_possible_cpu(i)
-                               INIT_LIST_HEAD(per_cpu_ptr(s->s_files, i));
-               }
-#else
-               INIT_LIST_HEAD(&s->s_files);
-#endif
                if (init_sb_writers(s, type))
                        goto err_out;
                s->s_flags = flags;
@@ -223,10 +212,6 @@ out:
        return s;
 err_out:
        security_sb_free(s);
-#ifdef CONFIG_SMP
-       if (s->s_files)
-               free_percpu(s->s_files);
-#endif
        destroy_sb_writers(s);
        kfree(s);
        s = NULL;
@@ -241,9 +226,6 @@ err_out:
  */
 static inline void destroy_super(struct super_block *s)
 {
-#ifdef CONFIG_SMP
-       free_percpu(s->s_files);
-#endif
        destroy_sb_writers(s);
        security_sb_free(s);
        WARN_ON(!list_empty(&s->s_mounts));
@@ -336,19 +318,19 @@ EXPORT_SYMBOL(deactivate_super);
  *     and want to turn it into a full-blown active reference.  grab_super()
  *     is called with sb_lock held and drops it.  Returns 1 in case of
  *     success, 0 if we had failed (superblock contents was already dead or
- *     dying when grab_super() had been called).
+ *     dying when grab_super() had been called).  Note that this is only
+ *     called for superblocks not in rundown mode (== ones still on ->fs_supers
+ *     of their type), so increment of ->s_count is OK here.
  */
 static int grab_super(struct super_block *s) __releases(sb_lock)
 {
-       if (atomic_inc_not_zero(&s->s_active)) {
-               spin_unlock(&sb_lock);
-               return 1;
-       }
-       /* it's going away */
        s->s_count++;
        spin_unlock(&sb_lock);
-       /* wait for it to die */
        down_write(&s->s_umount);
+       if ((s->s_flags & MS_BORN) && atomic_inc_not_zero(&s->s_active)) {
+               put_super(s);
+               return 1;
+       }
        up_write(&s->s_umount);
        put_super(s);
        return 0;
@@ -463,11 +445,6 @@ retry:
                                destroy_super(s);
                                s = NULL;
                        }
-                       down_write(&old->s_umount);
-                       if (unlikely(!(old->s_flags & MS_BORN))) {
-                               deactivate_locked_super(old);
-                               goto retry;
-                       }
                        return old;
                }
        }
@@ -660,10 +637,10 @@ restart:
                if (hlist_unhashed(&sb->s_instances))
                        continue;
                if (sb->s_bdev == bdev) {
-                       if (grab_super(sb)) /* drops sb_lock */
-                               return sb;
-                       else
+                       if (!grab_super(sb))
                                goto restart;
+                       up_write(&sb->s_umount);
+                       return sb;
                }
        }
        spin_unlock(&sb_lock);
@@ -698,7 +675,8 @@ rescan:
 }
 
 /**
- *     do_remount_sb - asks filesystem to change mount options.
+ *     do_remount_sb2 - asks filesystem to change mount options.
+ *     @mnt:   mount we are looking at
  *     @sb:    superblock in question
  *     @flags: numeric part of options
  *     @data:  the rest of options
@@ -706,7 +684,7 @@ rescan:
  *
  *     Alters the mount options of a mounted file system.
  */
-int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
+int do_remount_sb2(struct vfsmount *mnt, struct super_block *sb, int flags, void *data, int force)
 {
        int retval;
        int remount_ro;
@@ -730,7 +708,8 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
           make sure there are no rw files opened */
        if (remount_ro) {
                if (force) {
-                       mark_files_ro(sb);
+                       sb->s_readonly_remount = 1;
+                       smp_wmb();
                } else {
                        retval = sb_prepare_remount_readonly(sb);
                        if (retval)
@@ -738,7 +717,16 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
                }
        }
 
-       if (sb->s_op->remount_fs) {
+       if (mnt && sb->s_op->remount_fs2) {
+               retval = sb->s_op->remount_fs2(mnt, sb, &flags, data);
+               if (retval) {
+                       if (!force)
+                               goto cancel_readonly;
+                       /* If forced remount, go ahead despite any errors */
+                       WARN(1, "forced remount of a %s fs returned %i\n",
+                            sb->s_type->name, retval);
+               }
+       } else if (sb->s_op->remount_fs) {
                retval = sb->s_op->remount_fs(sb, &flags, data);
                if (retval) {
                        if (!force)
@@ -770,12 +758,17 @@ cancel_readonly:
        return retval;
 }
 
-static void do_emergency_remount(struct work_struct *work)
+int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
+{
+       return do_remount_sb2(NULL, sb, flags, data, force);
+}
+
+void do_emergency_remount(struct work_struct *work)
 {
        struct super_block *sb, *p = NULL;
 
        spin_lock(&sb_lock);
-       list_for_each_entry(sb, &super_blocks, s_list) {
+       list_for_each_entry_reverse(sb, &super_blocks, s_list) {
                if (hlist_unhashed(&sb->s_instances))
                        continue;
                sb->s_count++;
@@ -1089,7 +1082,7 @@ struct dentry *mount_single(struct file_system_type *fs_type,
 EXPORT_SYMBOL(mount_single);
 
 struct dentry *
-mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
+mount_fs(struct file_system_type *type, int flags, const char *name, struct vfsmount *mnt, void *data)
 {
        struct dentry *root;
        struct super_block *sb;
@@ -1106,7 +1099,10 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data)
                        goto out_free_secdata;
        }
 
-       root = type->mount(type, flags, name, data);
+       if (type->mount2)
+               root = type->mount2(mnt, type, flags, name, data);
+       else
+               root = type->mount(type, flags, name, data);
        if (IS_ERR(root)) {
                error = PTR_ERR(root);
                goto out_free_secdata;
@@ -1349,8 +1345,8 @@ int freeze_super(struct super_block *sb)
                }
        }
        /*
-        * This is just for debugging purposes so that fs can warn if it
-        * sees write activity when frozen is set to SB_FREEZE_COMPLETE.
+        * For debugging purposes so that fs can warn if it sees write activity
+        * when frozen is set to SB_FREEZE_COMPLETE, and for thaw_super().
         */
        sb->s_writers.frozen = SB_FREEZE_COMPLETE;
        up_write(&sb->s_umount);
@@ -1369,7 +1365,7 @@ int thaw_super(struct super_block *sb)
        int error;
 
        down_write(&sb->s_umount);
-       if (sb->s_writers.frozen == SB_UNFROZEN) {
+       if (sb->s_writers.frozen != SB_FREEZE_COMPLETE) {
                up_write(&sb->s_umount);
                return -EINVAL;
        }