#include <linux/module.h>
#include <linux/slab.h>
-#include <linux/init.h>
-#include <linux/smp_lock.h>
#include <linux/acct.h>
#include <linux/blkdev.h>
-#include <linux/quotaops.h>
-#include <linux/namei.h>
#include <linux/mount.h>
#include <linux/security.h>
-#include <linux/syscalls.h>
-#include <linux/vfs.h>
#include <linux/writeback.h> /* for the emergency remount stuff */
#include <linux/idr.h>
-#include <linux/kobject.h>
#include <linux/mutex.h>
-#include <linux/file.h>
#include <linux/backing-dev.h>
-#include <asm/uaccess.h>
#include "internal.h"
s->s_count = 1;
atomic_set(&s->s_active, 1);
mutex_init(&s->s_vfs_rename_mutex);
+ lockdep_set_class(&s->s_vfs_rename_mutex, &type->s_vfs_rename_key);
mutex_init(&s->s_dquot.dqio_mutex);
mutex_init(&s->s_dquot.dqonoff_mutex);
init_rwsem(&s->s_dquot.dqptr_sem);
init_waitqueue_head(&s->s_wait_unfrozen);
s->s_maxbytes = MAX_NON_LFS;
- s->dq_op = sb_dquot_ops;
- s->s_qcop = sb_quotactl_ops;
s->s_op = &default_op;
s->s_time_gran = 1000000000;
}
/* Superblock refcounting */
/*
- * Drop a superblock's refcount. Returns non-zero if the superblock was
- * destroyed. The caller must hold sb_lock.
+ * Drop a superblock's refcount. The caller must hold sb_lock.
*/
-int __put_super(struct super_block *sb)
+void __put_super(struct super_block *sb)
{
- int ret = 0;
-
if (!--sb->s_count) {
list_del_init(&sb->s_list);
destroy_super(sb);
- ret = 1;
}
- return ret;
-}
-
-/*
- * Drop a superblock's refcount.
- * Returns non-zero if the superblock is about to be destroyed and
- * at least is already removed from super_blocks list, so if we are
- * making a loop through super blocks then we need to restart.
- * The caller must hold sb_lock.
- */
-int __put_super_and_need_restart(struct super_block *sb)
-{
- /* check for race with generic_shutdown_super() */
- if (list_empty(&sb->s_instances)) {
- /* super block is removed, need to restart... */
- __put_super(sb);
- return 1;
- }
- /* can't be the last, since s_list is still in use */
- sb->s_count--;
- BUG_ON(sb->s_count == 0);
- return 0;
}
/**
{
struct file_system_type *fs = s->s_type;
if (atomic_dec_and_test(&s->s_active)) {
- vfs_dq_off(s, 0);
fs->kill_sb(s);
put_filesystem(fs);
put_super(s);
{
if (atomic_inc_not_zero(&s->s_active)) {
spin_unlock(&sb_lock);
- down_write(&s->s_umount);
return 1;
}
/* it's going away */
up_write(&s->s_umount);
destroy_super(s);
}
+ down_write(&old->s_umount);
return old;
}
}
*/
void sync_supers(void)
{
- struct super_block *sb;
+ struct super_block *sb, *n;
spin_lock(&sb_lock);
-restart:
- list_for_each_entry(sb, &super_blocks, s_list) {
+ list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
if (list_empty(&sb->s_instances))
continue;
if (sb->s_op->write_super && sb->s_dirt) {
up_read(&sb->s_umount);
spin_lock(&sb_lock);
- if (__put_super_and_need_restart(sb))
- goto restart;
+ __put_super(sb);
}
}
spin_unlock(&sb_lock);
}
+/**
+ * iterate_supers - call function for all active superblocks
+ * @f: function to call
+ * @arg: argument to pass to it
+ *
+ * Scans the superblock list and calls given function, passing it
+ * locked superblock and given argument.
+ */
+void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
+{
+ struct super_block *sb, *n;
+
+ spin_lock(&sb_lock);
+ list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
+ if (list_empty(&sb->s_instances))
+ continue;
+ sb->s_count++;
+ spin_unlock(&sb_lock);
+
+ down_read(&sb->s_umount);
+ if (sb->s_root)
+ f(sb, arg);
+ up_read(&sb->s_umount);
+
+ spin_lock(&sb_lock);
+ __put_super(sb);
+ }
+ spin_unlock(&sb_lock);
+}
+
/**
* get_super - get the superblock of a device
* @bdev: device to get the superblock for
* 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 *get_super(struct block_device *bdev)
{
struct super_block *sb;
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
+ /* still alive? */
if (sb->s_root)
return sb;
up_read(&sb->s_umount);
- /* restart only when sb is no longer on the list */
+ /* nope, got unmounted */
spin_lock(&sb_lock);
- if (__put_super_and_need_restart(sb))
- goto rescan;
+ __put_super(sb);
+ goto rescan;
}
}
spin_unlock(&sb_lock);
*
* Scans the superblock list and finds the superblock of the file system
* mounted on the device given. Returns the superblock with an active
- * reference and s_umount held exclusively or %NULL if none was found.
+ * reference or %NULL if none was found.
*/
struct super_block *get_active_super(struct block_device *bdev)
{
if (!bdev)
return NULL;
+restart:
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
if (list_empty(&sb->s_instances))
continue;
- if (sb->s_bdev != bdev)
- continue;
-
- if (grab_super(sb)) /* drops sb_lock */
- return sb;
-
- spin_lock(&sb_lock);
+ if (sb->s_bdev == bdev) {
+ if (grab_super(sb)) /* drops sb_lock */
+ return sb;
+ else
+ goto restart;
+ }
}
spin_unlock(&sb_lock);
return NULL;
}
-struct super_block * user_get_super(dev_t dev)
+struct super_block *user_get_super(dev_t dev)
{
struct super_block *sb;
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
+ /* still alive? */
if (sb->s_root)
return sb;
up_read(&sb->s_umount);
- /* restart only when sb is no longer on the list */
+ /* nope, got unmounted */
spin_lock(&sb_lock);
- if (__put_super_and_need_restart(sb))
- goto rescan;
+ __put_super(sb);
+ goto rescan;
}
}
spin_unlock(&sb_lock);
return NULL;
}
-SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
-{
- struct super_block *s;
- struct ustat tmp;
- struct kstatfs sbuf;
- int err = -EINVAL;
-
- s = user_get_super(new_decode_dev(dev));
- if (s == NULL)
- goto out;
- err = vfs_statfs(s->s_root, &sbuf);
- drop_super(s);
- if (err)
- goto out;
-
- memset(&tmp,0,sizeof(struct ustat));
- tmp.f_tfree = sbuf.f_bfree;
- tmp.f_tinode = sbuf.f_ffree;
-
- err = copy_to_user(ubuf,&tmp,sizeof(struct ustat)) ? -EFAULT : 0;
-out:
- return err;
-}
-
/**
* do_remount_sb - asks filesystem to change mount options.
* @sb: superblock in question
int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
{
int retval;
- int remount_rw, remount_ro;
+ int remount_ro;
if (sb->s_frozen != SB_UNFROZEN)
return -EBUSY;
sync_filesystem(sb);
remount_ro = (flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY);
- remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY);
/* If we are remounting RDONLY and current sb is read/write,
make sure there are no rw files opened */
mark_files_ro(sb);
else if (!fs_may_remount_ro(sb))
return -EBUSY;
- retval = vfs_dq_off(sb, 1);
- if (retval < 0 && retval != -ENOSYS)
- return -EBUSY;
}
if (sb->s_op->remount_fs) {
return retval;
}
sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
- if (remount_rw)
- vfs_dq_quota_on_remount(sb);
+
/*
* Some filesystems modify their metadata via some other path than the
* bdev buffer cache (eg. use a private mapping, or directories in
static void do_emergency_remount(struct work_struct *work)
{
- struct super_block *sb;
+ struct super_block *sb, *n;
spin_lock(&sb_lock);
- list_for_each_entry(sb, &super_blocks, s_list) {
+ list_for_each_entry_safe(sb, n, &super_blocks, s_list) {
if (list_empty(&sb->s_instances))
continue;
sb->s_count++;
do_remount_sb(sb, MS_RDONLY, NULL, 1);
}
up_write(&sb->s_umount);
- put_super(sb);
spin_lock(&sb_lock);
+ __put_super(sb);
}
spin_unlock(&sb_lock);
kfree(work);
EXPORT_SYMBOL_GPL(vfs_kern_mount);
+/**
+ * freeze_super - lock the filesystem and force it into a consistent state
+ * @sb: the super to lock
+ *
+ * Syncs the super to make sure the filesystem is consistent and calls the fs's
+ * freeze_fs. Subsequent calls to this without first thawing the fs will return
+ * -EBUSY.
+ */
+int freeze_super(struct super_block *sb)
+{
+ int ret;
+
+ atomic_inc(&sb->s_active);
+ down_write(&sb->s_umount);
+ if (sb->s_frozen) {
+ deactivate_locked_super(sb);
+ return -EBUSY;
+ }
+
+ if (sb->s_flags & MS_RDONLY) {
+ sb->s_frozen = SB_FREEZE_TRANS;
+ smp_wmb();
+ up_write(&sb->s_umount);
+ return 0;
+ }
+
+ sb->s_frozen = SB_FREEZE_WRITE;
+ smp_wmb();
+
+ sync_filesystem(sb);
+
+ sb->s_frozen = SB_FREEZE_TRANS;
+ smp_wmb();
+
+ sync_blockdev(sb->s_bdev);
+ if (sb->s_op->freeze_fs) {
+ ret = sb->s_op->freeze_fs(sb);
+ if (ret) {
+ printk(KERN_ERR
+ "VFS:Filesystem freeze failed\n");
+ sb->s_frozen = SB_UNFROZEN;
+ deactivate_locked_super(sb);
+ return ret;
+ }
+ }
+ up_write(&sb->s_umount);
+ return 0;
+}
+EXPORT_SYMBOL(freeze_super);
+
+/**
+ * thaw_super -- unlock filesystem
+ * @sb: the super to thaw
+ *
+ * Unlocks the filesystem and marks it writeable again after freeze_super().
+ */
+int thaw_super(struct super_block *sb)
+{
+ int error;
+
+ down_write(&sb->s_umount);
+ if (sb->s_frozen == SB_UNFROZEN) {
+ up_write(&sb->s_umount);
+ return -EINVAL;
+ }
+
+ if (sb->s_flags & MS_RDONLY)
+ goto out;
+
+ if (sb->s_op->unfreeze_fs) {
+ error = sb->s_op->unfreeze_fs(sb);
+ if (error) {
+ printk(KERN_ERR
+ "VFS:Filesystem thaw failed\n");
+ sb->s_frozen = SB_FREEZE_TRANS;
+ up_write(&sb->s_umount);
+ return error;
+ }
+ }
+
+out:
+ sb->s_frozen = SB_UNFROZEN;
+ smp_wmb();
+ wake_up(&sb->s_wait_unfrozen);
+ deactivate_locked_super(sb);
+
+ return 0;
+}
+EXPORT_SYMBOL(thaw_super);
+
static struct vfsmount *fs_set_subtype(struct vfsmount *mnt, const char *fstype)
{
int err;
projects / linux.git / blobdiff