Commit aa7dfb89 authored by Ryusuke Konishi's avatar Ryusuke Konishi Committed by Al Viro
Browse files

nilfs2: get rid of bd_mount_sem use from nilfs 



This will remove every bd_mount_sem use in nilfs.

The intended exclusion control was replaced by the previous patch
("nilfs2: correct exclusion control in nilfs_remount function") for
nilfs_remount(), and this patch will replace remains with a new mutex
that this inserts in nilfs object.

Signed-off-by: default avatarRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent e59399d0

fs/nilfs2/cpfile.c

+3 −3
Original line number Diff line number Diff line
@@ -864,11 +864,11 @@ int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode) 
	case NILFS_CHECKPOINT:

		/*

		 * Check for protecting existing snapshot mounts:

		 * bd_mount_sem is used to make this operation atomic and

		 * ns_mount_mutex is used to make this operation atomic and

		 * exclusive with a new mount job.  Though it doesn't cover

		 * umount, it's enough for the purpose.

		 */

		down(&nilfs->ns_bdev->bd_mount_sem);

		mutex_lock(&nilfs->ns_mount_mutex);

		if (nilfs_checkpoint_is_mounted(nilfs, cno, 1)) {

			/* Current implementation does not have to protect

			   plain read-only mounts since they are exclusive
@@ -877,7 +877,7 @@ int nilfs_cpfile_change_cpmode(struct inode *cpfile, __u64 cno, int mode) 
			ret = -EBUSY;

		} else

			ret = nilfs_cpfile_clear_snapshot(cpfile, cno);

		up(&nilfs->ns_bdev->bd_mount_sem);

		mutex_unlock(&nilfs->ns_mount_mutex);

		return ret;

	case NILFS_SNAPSHOT:

		return nilfs_cpfile_set_snapshot(cpfile, cno);

fs/nilfs2/super.c

+6 −6
Original line number Diff line number Diff line
@@ -764,7 +764,7 @@ int nilfs_store_magic_and_option(struct super_block *sb, 
 * @silent: silent mode flag

 * @nilfs: the_nilfs struct

 *

 * This function is called exclusively by bd_mount_mutex.

 * This function is called exclusively by nilfs->ns_mount_mutex.

 * So, the recovery process is protected from other simultaneous mounts.

 */

static int
@@ -1105,7 +1105,7 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, 
		goto failed;

	}



	down(&sd.bdev->bd_mount_sem);

	mutex_lock(&nilfs->ns_mount_mutex);



	if (!sd.cno) {

		/*
@@ -1164,7 +1164,7 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, 
		need_to_close = 0;

	}



	up(&sd.bdev->bd_mount_sem);

	mutex_unlock(&nilfs->ns_mount_mutex);

	put_nilfs(nilfs);

	if (need_to_close)

		close_bdev_exclusive(sd.bdev, flags);
@@ -1172,7 +1172,7 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, 
	return 0;



 failed_unlock:

	up(&sd.bdev->bd_mount_sem);

	mutex_unlock(&nilfs->ns_mount_mutex);

	put_nilfs(nilfs);

 failed:

	close_bdev_exclusive(sd.bdev, flags);
@@ -1181,14 +1181,14 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags, 


 cancel_new:

	/* Abandoning the newly allocated superblock */

	up(&sd.bdev->bd_mount_sem);

	mutex_unlock(&nilfs->ns_mount_mutex);

	put_nilfs(nilfs);

	up_write(&s->s_umount);

	deactivate_super(s);

	/*

	 * deactivate_super() invokes close_bdev_exclusive().

	 * We must finish all post-cleaning before this call;

	 * put_nilfs() and unlocking bd_mount_sem need the block device.

	 * put_nilfs() needs the block device.

	 */

	return err;

}

fs/nilfs2/the_nilfs.c

+1 −0
Original line number Diff line number Diff line
@@ -73,6 +73,7 @@ static struct the_nilfs *alloc_nilfs(struct block_device *bdev) 
	atomic_set(&nilfs->ns_ndirtyblks, 0);

	init_rwsem(&nilfs->ns_sem);

	init_rwsem(&nilfs->ns_super_sem);

	mutex_init(&nilfs->ns_mount_mutex);

	mutex_init(&nilfs->ns_writer_mutex);

	INIT_LIST_HEAD(&nilfs->ns_list);

	INIT_LIST_HEAD(&nilfs->ns_supers);

fs/nilfs2/the_nilfs.h

+2 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ enum { 
 * @ns_writer: back pointer to writable nilfs_sb_info

 * @ns_sem: semaphore for shared states

 * @ns_super_sem: semaphore for global operations across super block instances

 * @ns_mount_mutex: mutex protecting mount process of nilfs

 * @ns_writer_mutex: mutex protecting ns_writer attach/detach

 * @ns_writer_refcount: number of referrers on ns_writer

 * @ns_current: back pointer to current mount
@@ -98,6 +99,7 @@ struct the_nilfs { 
	struct nilfs_sb_info   *ns_writer;

	struct rw_semaphore	ns_sem;

	struct rw_semaphore	ns_super_sem;

	struct mutex		ns_mount_mutex;

	struct mutex		ns_writer_mutex;

	atomic_t		ns_writer_refcount;

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