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Commit fca39346 authored by Jan Kara's avatar Jan Kara Committed by Jens Axboe
Browse files

fs: Provide infrastructure for dynamic BDIs in filesystems 



Provide helper functions for setting up dynamically allocated
backing_dev_info structures for filesystems and cleaning them up on
superblock destruction.

CC: linux-mtd@lists.infradead.org
CC: linux-nfs@vger.kernel.org
CC: Petr Vandrovec <petr@vandrovec.name>
CC: linux-nilfs@vger.kernel.org
CC: cluster-devel@redhat.com
CC: osd-dev@open-osd.org
CC: codalist@coda.cs.cmu.edu
CC: linux-afs@lists.infradead.org
CC: ecryptfs@vger.kernel.org
CC: linux-cifs@vger.kernel.org
CC: ceph-devel@vger.kernel.org
CC: linux-btrfs@vger.kernel.org
CC: v9fs-developer@lists.sourceforge.net
CC: lustre-devel@lists.lustre.org
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 62bf42ad

fs/super.c

+49 −0
Original line number Diff line number Diff line
@@ -446,6 +446,11 @@ void generic_shutdown_super(struct super_block *sb) 
	hlist_del_init(&sb->s_instances);

	spin_unlock(&sb_lock);

	up_write(&sb->s_umount);

	if (sb->s_iflags & SB_I_DYNBDI) {

		bdi_put(sb->s_bdi);

		sb->s_bdi = &noop_backing_dev_info;

		sb->s_iflags &= ~SB_I_DYNBDI;

	}

}



EXPORT_SYMBOL(generic_shutdown_super);
@@ -1255,6 +1260,50 @@ mount_fs(struct file_system_type *type, int flags, const char *name, void *data) 
	return ERR_PTR(error);

}



/*

 * Setup private BDI for given superblock. It gets automatically cleaned up

 * in generic_shutdown_super().

 */

int super_setup_bdi_name(struct super_block *sb, char *fmt, ...)

{

	struct backing_dev_info *bdi;

	int err;

	va_list args;



	bdi = bdi_alloc(GFP_KERNEL);

	if (!bdi)

		return -ENOMEM;



	bdi->name = sb->s_type->name;



	va_start(args, fmt);

	err = bdi_register_va(bdi, NULL, fmt, args);

	va_end(args);

	if (err) {

		bdi_put(bdi);

		return err;

	}

	WARN_ON(sb->s_bdi != &noop_backing_dev_info);

	sb->s_bdi = bdi;

	sb->s_iflags |= SB_I_DYNBDI;



	return 0;

}

EXPORT_SYMBOL(super_setup_bdi_name);



/*

 * Setup private BDI for given superblock. I gets automatically cleaned up

 * in generic_shutdown_super().

 */

int super_setup_bdi(struct super_block *sb)

{

	static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);



	return super_setup_bdi_name(sb, "%.28s-%ld", sb->s_type->name,

				    atomic_long_inc_return(&bdi_seq));

}

EXPORT_SYMBOL(super_setup_bdi);



/*

 * This is an internal function, please use sb_end_{write,pagefault,intwrite}

 * instead.

include/linux/backing-dev-defs.h

+1 −1
Original line number Diff line number Diff line
@@ -146,7 +146,7 @@ struct backing_dev_info { 
	congested_fn *congested_fn; /* Function pointer if device is md/dm */

	void *congested_data;	/* Pointer to aux data for congested func */



	char *name;

	const char *name;



	struct kref refcnt;	/* Reference counter for the structure */

	unsigned int capabilities; /* Device capabilities */

include/linux/fs.h

+6 −0
Original line number Diff line number Diff line
@@ -1272,6 +1272,9 @@ struct mm_struct; 
/* sb->s_iflags to limit user namespace mounts */

#define SB_I_USERNS_VISIBLE		0x00000010 /* fstype already mounted */



/* Temporary flag until all filesystems are converted to dynamic bdis */

#define SB_I_DYNBDI	0x00000100



/* Possible states of 'frozen' field */

enum {

	SB_UNFROZEN = 0,		/* FS is unfrozen */
@@ -2121,6 +2124,9 @@ extern int vfs_ustat(dev_t, struct kstatfs *); 
extern int freeze_super(struct super_block *super);

extern int thaw_super(struct super_block *super);

extern bool our_mnt(struct vfsmount *mnt);

extern __printf(2, 3)

int super_setup_bdi_name(struct super_block *sb, char *fmt, ...);

extern int super_setup_bdi(struct super_block *sb);



extern int current_umask(void);