Commit 7214dd4e authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'work.thaw' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 

Pull vfs thaw updates from Al Viro:
 "An ancient series that has fallen through the cracks in the previous
  cycle"

* 'work.thaw' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  buffer.c: call thaw_super during emergency thaw
  vfs: factor sb iteration out of do_emergency_remount
parents 19e8a2f8 08fdc8a0

fs/buffer.c

+1 −24
Original line number Diff line number Diff line
@@ -494,35 +494,12 @@ repeat: 
	return err;

}



static void do_thaw_one(struct super_block *sb, void *unused)

void emergency_thaw_bdev(struct super_block *sb)

{

	while (sb->s_bdev && !thaw_bdev(sb->s_bdev, sb))

		printk(KERN_WARNING "Emergency Thaw on %pg\n", sb->s_bdev);

}



static void do_thaw_all(struct work_struct *work)

{

	iterate_supers(do_thaw_one, NULL);

	kfree(work);

	printk(KERN_WARNING "Emergency Thaw complete\n");

}



/**

 * emergency_thaw_all -- forcibly thaw every frozen filesystem

 *

 * Used for emergency unfreeze of all filesystems via SysRq

 */

void emergency_thaw_all(void)

{

	struct work_struct *work;



	work = kmalloc(sizeof(*work), GFP_ATOMIC);

	if (work) {

		INIT_WORK(work, do_thaw_all);

		schedule_work(work);

	}

}



/**

 * sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers

 * @mapping: the mapping which wants those buffers written

fs/super.c

+78 −27
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
#include <linux/user_namespace.h>

#include "internal.h"



static int thaw_super_locked(struct super_block *sb);



static LIST_HEAD(super_blocks);

static DEFINE_SPINLOCK(sb_lock);
@@ -574,6 +575,28 @@ void drop_super_exclusive(struct super_block *sb) 
}

EXPORT_SYMBOL(drop_super_exclusive);



static void __iterate_supers(void (*f)(struct super_block *))

{

	struct super_block *sb, *p = NULL;



	spin_lock(&sb_lock);

	list_for_each_entry(sb, &super_blocks, s_list) {

		if (hlist_unhashed(&sb->s_instances))

			continue;

		sb->s_count++;

		spin_unlock(&sb_lock);



		f(sb);



		spin_lock(&sb_lock);

		if (p)

			__put_super(p);

		p = sb;

	}

	if (p)

		__put_super(p);

	spin_unlock(&sb_lock);

}

/**

 *	iterate_supers - call function for all active superblocks

 *	@f: function to call
@@ -881,16 +904,8 @@ cancel_readonly: 
	return retval;

}



static void do_emergency_remount(struct work_struct *work)

static void do_emergency_remount_callback(struct super_block *sb)

{

	struct super_block *sb, *p = NULL;



	spin_lock(&sb_lock);

	list_for_each_entry(sb, &super_blocks, s_list) {

		if (hlist_unhashed(&sb->s_instances))

			continue;

		sb->s_count++;

		spin_unlock(&sb_lock);

	down_write(&sb->s_umount);

	if (sb->s_root && sb->s_bdev && (sb->s_flags & SB_BORN) &&

	    !sb_rdonly(sb)) {
@@ -900,14 +915,11 @@ static void do_emergency_remount(struct work_struct *work) 
		do_remount_sb(sb, SB_RDONLY, NULL, 1);

	}

	up_write(&sb->s_umount);

		spin_lock(&sb_lock);

		if (p)

			__put_super(p);

		p = sb;

}

	if (p)

		__put_super(p);

	spin_unlock(&sb_lock);



static void do_emergency_remount(struct work_struct *work)

{

	__iterate_supers(do_emergency_remount_callback);

	kfree(work);

	printk("Emergency Remount complete\n");

}
@@ -923,6 +935,40 @@ void emergency_remount(void) 
	}

}



static void do_thaw_all_callback(struct super_block *sb)

{

	down_write(&sb->s_umount);

	if (sb->s_root && sb->s_flags & MS_BORN) {

		emergency_thaw_bdev(sb);

		thaw_super_locked(sb);

	} else {

		up_write(&sb->s_umount);

	}

}



static void do_thaw_all(struct work_struct *work)

{

	__iterate_supers(do_thaw_all_callback);

	kfree(work);

	printk(KERN_WARNING "Emergency Thaw complete\n");

}



/**

 * emergency_thaw_all -- forcibly thaw every frozen filesystem

 *

 * Used for emergency unfreeze of all filesystems via SysRq

 */

void emergency_thaw_all(void)

{

	struct work_struct *work;



	work = kmalloc(sizeof(*work), GFP_ATOMIC);

	if (work) {

		INIT_WORK(work, do_thaw_all);

		schedule_work(work);

	}

}



/*

 * Unnamed block devices are dummy devices used by virtual

 * filesystems which don't use real block-devices.  -- jrs
@@ -1492,11 +1538,10 @@ EXPORT_SYMBOL(freeze_super); 
 *

 * Unlocks the filesystem and marks it writeable again after freeze_super().

 */

int thaw_super(struct super_block *sb)

static int thaw_super_locked(struct super_block *sb)

{

	int error;



	down_write(&sb->s_umount);

	if (sb->s_writers.frozen != SB_FREEZE_COMPLETE) {

		up_write(&sb->s_umount);

		return -EINVAL;
@@ -1527,4 +1572,10 @@ out: 
	deactivate_locked_super(sb);

	return 0;

}



int thaw_super(struct super_block *sb)

{

	down_write(&sb->s_umount);

	return thaw_super_locked(sb);

}

EXPORT_SYMBOL(thaw_super);

include/linux/fs.h

+6 −0
Original line number Diff line number Diff line
@@ -2445,6 +2445,7 @@ extern int sync_blockdev(struct block_device *bdev); 
extern void kill_bdev(struct block_device *);

extern struct super_block *freeze_bdev(struct block_device *);

extern void emergency_thaw_all(void);

extern void emergency_thaw_bdev(struct super_block *sb);

extern int thaw_bdev(struct block_device *bdev, struct super_block *sb);

extern int fsync_bdev(struct block_device *);
@@ -2470,6 +2471,11 @@ static inline int thaw_bdev(struct block_device *bdev, struct super_block *sb) 
	return 0;

}



static inline int emergency_thaw_bdev(struct super_block *sb)

{

	return 0;

}



static inline void iterate_bdevs(void (*f)(struct block_device *, void *), void *arg)

{

}

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