* Drops a temporary reference, frees superblock if there's no
* references left.
*/
-static void put_super(struct super_block *sb)
+void put_super(struct super_block *sb)
{
spin_lock(&sb_lock);
__put_super(sb);
EXPORT_SYMBOL(iterate_supers_type);
-static struct super_block *__get_super(struct block_device *bdev, bool excl)
+/**
+ * get_super - get the superblock of a device
+ * @bdev: device to get the superblock for
+ *
+ * Scans the superblock list and finds the superblock of the file system
+ * mounted on the device given. %NULL is returned if no match is found.
+ */
+struct super_block *get_super(struct block_device *bdev)
{
struct super_block *sb;
if (sb->s_bdev == bdev) {
sb->s_count++;
spin_unlock(&sb_lock);
- if (!excl)
- down_read(&sb->s_umount);
- else
- down_write(&sb->s_umount);
+ down_read(&sb->s_umount);
/* still alive? */
if (sb->s_root && (sb->s_flags & SB_BORN))
return sb;
- if (!excl)
- up_read(&sb->s_umount);
- else
- up_write(&sb->s_umount);
+ up_read(&sb->s_umount);
/* nope, got unmounted */
spin_lock(&sb_lock);
__put_super(sb);
return NULL;
}
-/**
- * get_super - get the superblock of a device
- * @bdev: device to get the superblock for
- *
- * Scans the superblock list and finds the superblock of the file system
- * mounted on the device given. %NULL is returned if no match is found.
- */
-struct super_block *get_super(struct block_device *bdev)
-{
- return __get_super(bdev, false);
-}
-EXPORT_SYMBOL(get_super);
-
-static struct super_block *__get_super_thawed(struct block_device *bdev,
- bool excl)
-{
- while (1) {
- struct super_block *s = __get_super(bdev, excl);
- if (!s || s->s_writers.frozen == SB_UNFROZEN)
- return s;
- if (!excl)
- up_read(&s->s_umount);
- else
- up_write(&s->s_umount);
- wait_event(s->s_writers.wait_unfrozen,
- s->s_writers.frozen == SB_UNFROZEN);
- put_super(s);
- }
-}
-
-/**
- * get_super_thawed - get thawed superblock of a device
- * @bdev: device to get the superblock for
- *
- * Scans the superblock list and finds the superblock of the file system
- * mounted on the device. The superblock is returned once it is thawed
- * (or immediately if it was not frozen). %NULL is returned if no match
- * is found.
- */
-struct super_block *get_super_thawed(struct block_device *bdev)
-{
- return __get_super_thawed(bdev, false);
-}
-EXPORT_SYMBOL(get_super_thawed);
-
-/**
- * get_super_exclusive_thawed - get thawed superblock of a device
- * @bdev: device to get the superblock for
- *
- * Scans the superblock list and finds the superblock of the file system
- * mounted on the device. The superblock is returned once it is thawed
- * (or immediately if it was not frozen) and s_umount semaphore is held
- * in exclusive mode. %NULL is returned if no match is found.
- */
-struct super_block *get_super_exclusive_thawed(struct block_device *bdev)
-{
- return __get_super_thawed(bdev, true);
-}
-EXPORT_SYMBOL(get_super_exclusive_thawed);
-
/**
* get_active_super - get an active reference to the superblock of a device
* @bdev: device to get the superblock for
return NULL;
}
-struct super_block *user_get_super(dev_t dev)
+struct super_block *user_get_super(dev_t dev, bool excl)
{
struct super_block *sb;
if (sb->s_dev == dev) {
sb->s_count++;
spin_unlock(&sb_lock);
- down_read(&sb->s_umount);
+ if (excl)
+ down_write(&sb->s_umount);
+ else
+ down_read(&sb->s_umount);
/* still alive? */
if (sb->s_root && (sb->s_flags & SB_BORN))
return sb;
- up_read(&sb->s_umount);
+ if (excl)
+ up_write(&sb->s_umount);
+ else
+ up_read(&sb->s_umount);
/* nope, got unmounted */
spin_lock(&sb_lock);
__put_super(sb);
}
EXPORT_SYMBOL(super_setup_bdi);
-/*
- * This is an internal function, please use sb_end_{write,pagefault,intwrite}
- * instead.
- */
-void __sb_end_write(struct super_block *sb, int level)
-{
- percpu_up_read(sb->s_writers.rw_sem + level-1);
-}
-EXPORT_SYMBOL(__sb_end_write);
-
-/*
- * This is an internal function, please use sb_start_{write,pagefault,intwrite}
- * instead.
- */
-int __sb_start_write(struct super_block *sb, int level, bool wait)
-{
- bool force_trylock = false;
- int ret = 1;
-
-#ifdef CONFIG_LOCKDEP
- /*
- * We want lockdep to tell us about possible deadlocks with freezing
- * but it's it bit tricky to properly instrument it. Getting a freeze
- * protection works as getting a read lock but there are subtle
- * problems. XFS for example gets freeze protection on internal level
- * twice in some cases, which is OK only because we already hold a
- * freeze protection also on higher level. Due to these cases we have
- * to use wait == F (trylock mode) which must not fail.
- */
- if (wait) {
- int i;
-
- for (i = 0; i < level - 1; i++)
- if (percpu_rwsem_is_held(sb->s_writers.rw_sem + i)) {
- force_trylock = true;
- break;
- }
- }
-#endif
- if (wait && !force_trylock)
- percpu_down_read(sb->s_writers.rw_sem + level-1);
- else
- ret = percpu_down_read_trylock(sb->s_writers.rw_sem + level-1);
-
- WARN_ON(force_trylock && !ret);
- return ret;
-}
-EXPORT_SYMBOL(__sb_start_write);
-
/**
* sb_wait_write - wait until all writers to given file system finish
* @sb: the super for which we wait
projects / linux-2.6-microblaze.git / blobdiff