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Commit dd70edbd authored by Vyacheslav Dubeyko's avatar Vyacheslav Dubeyko Committed by Linus Torvalds
Browse files

nilfs2: integrate sysfs support into driver 



This patch integrates creation of sysfs groups and
attributes into NILFS file system driver.

It was found the issue with nilfs_sysfs_{create/delete}_snapshot_group
functions by Michael L Semon <mlsemon35@gmail.com> in the first
version of the patch:

  BUG: sleeping function called from invalid context at kernel/locking/mutex.c:579
  in_atomic(): 1, irqs_disabled(): 0, pid: 32676, name: umount.nilfs2
  2 locks held by umount.nilfs2/32676:
   #0:  (&type->s_umount_key#21){++++..}, at: [<790c18e2>] deactivate_super+0x37/0x58
   #1:  (&(&nilfs->ns_cptree_lock)->rlock){+.+...}, at: [<791bf659>] nilfs_put_root+0x23/0x5a
  Preemption disabled at:[<791bf659>] nilfs_put_root+0x23/0x5a

  CPU: 0 PID: 32676 Comm: umount.nilfs2 Not tainted 3.14.0+ #2
  Hardware name: Dell Computer Corporation Dimension 2350/07W080, BIOS A01 12/17/2002
  Call Trace:
    dump_stack+0x4b/0x75
    __might_sleep+0x111/0x16f
    mutex_lock_nested+0x1e/0x3ad
    kernfs_remove+0x12/0x26
    sysfs_remove_dir+0x3d/0x62
    kobject_del+0x13/0x38
    nilfs_sysfs_delete_snapshot_group+0xb/0xd
    nilfs_put_root+0x2a/0x5a
    nilfs_detach_log_writer+0x1ab/0x2c1
    nilfs_put_super+0x13/0x68
    generic_shutdown_super+0x60/0xd1
    kill_block_super+0x1d/0x60
    deactivate_locked_super+0x22/0x3f
    deactivate_super+0x3e/0x58
    mntput_no_expire+0xe2/0x141
    SyS_oldumount+0x70/0xa5
    syscall_call+0x7/0xb

The reason of the issue was placement of
nilfs_sysfs_{create/delete}_snapshot_group() call under
nilfs->ns_cptree_lock protection.  But this protection is unnecessary and
wrong solution.  The second version of the patch fixes this issue.

[fengguang.wu@intel.com: nilfs_sysfs_create_mounted_snapshots_group can be static]
Reported-by: default avatarMichael L. Semon <mlsemon35@gmail.com>
Signed-off-by: default avatarVyacheslav Dubeyko <Vyacheslav.Dubeyko@hgst.com>
Cc: Vyacheslav Dubeyko <slava@dubeyko.com>
Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Tested-by: default avatarMichael L. Semon <mlsemon35@gmail.com>
Signed-off-by: default avatarFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a5a7332a

fs/nilfs2/Makefile

+1 −1
Original line number Original line Diff line number Diff line
@@ -2,4 +2,4 @@ obj-$(CONFIG_NILFS2_FS) += nilfs2.o 
nilfs2-y := inode.o file.o dir.o super.o namei.o page.o mdt.o \

nilfs2-y := inode.o file.o dir.o super.o namei.o page.o mdt.o \

	btnode.o bmap.o btree.o direct.o dat.o recovery.o \

	btnode.o bmap.o btree.o direct.o dat.o recovery.o \

	the_nilfs.o segbuf.o segment.o cpfile.o sufile.o \

	the_nilfs.o segbuf.o segment.o cpfile.o sufile.o \

	ifile.o alloc.o gcinode.o ioctl.o
 
	ifile.o alloc.o gcinode.o ioctl.o sysfs.o

fs/nilfs2/nilfs.h

+8 −0
Original line number Original line Diff line number Diff line
@@ -320,6 +320,14 @@ int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *); 
int nilfs_init_gcinode(struct inode *inode);

int nilfs_init_gcinode(struct inode *inode);

void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs);

void nilfs_remove_all_gcinodes(struct the_nilfs *nilfs);





/* sysfs.c */

int __init nilfs_sysfs_init(void);

void nilfs_sysfs_exit(void);

int nilfs_sysfs_create_device_group(struct super_block *);

void nilfs_sysfs_delete_device_group(struct the_nilfs *);

int nilfs_sysfs_create_snapshot_group(struct nilfs_root *);

void nilfs_sysfs_delete_snapshot_group(struct nilfs_root *);



/*

/*

 * Inodes and files operations

 * Inodes and files operations

 */

 */

fs/nilfs2/super.c

+8 −1
Original line number Original line Diff line number Diff line
@@ -1452,13 +1452,19 @@ static int __init init_nilfs_fs(void) 
	if (err)

	if (err)

		goto fail;

		goto fail;





	err = register_filesystem(&nilfs_fs_type);

	err = nilfs_sysfs_init();

	if (err)

	if (err)

		goto free_cachep;

		goto free_cachep;





	err = register_filesystem(&nilfs_fs_type);

	if (err)

		goto deinit_sysfs_entry;



	printk(KERN_INFO "NILFS version 2 loaded\n");

	printk(KERN_INFO "NILFS version 2 loaded\n");

	return 0;

	return 0;





deinit_sysfs_entry:

	nilfs_sysfs_exit();

free_cachep:

free_cachep:

	nilfs_destroy_cachep();

	nilfs_destroy_cachep();

fail:

fail:
@@ -1468,6 +1474,7 @@ static int __init init_nilfs_fs(void) 
static void __exit exit_nilfs_fs(void)

static void __exit exit_nilfs_fs(void)

{

{

	nilfs_destroy_cachep();

	nilfs_destroy_cachep();

	nilfs_sysfs_exit();

	unregister_filesystem(&nilfs_fs_type);

	unregister_filesystem(&nilfs_fs_type);

}

}

fs/nilfs2/sysfs.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -87,7 +87,7 @@ static struct kobj_type nilfs_##name##_ktype = { \ 
};

};





#define NILFS_DEV_INT_GROUP_FNS(name, parent_name) \

#define NILFS_DEV_INT_GROUP_FNS(name, parent_name) \

int nilfs_sysfs_create_##name##_group(struct the_nilfs *nilfs) \

static int nilfs_sysfs_create_##name##_group(struct the_nilfs *nilfs) \

{ \

{ \

	struct kobject *parent; \

	struct kobject *parent; \

	struct kobject *kobj; \

	struct kobject *kobj; \
@@ -106,7 +106,7 @@ int nilfs_sysfs_create_##name##_group(struct the_nilfs *nilfs) \ 
		return err; \

		return err; \

	return 0; \

	return 0; \

} \

} \

void nilfs_sysfs_delete_##name##_group(struct the_nilfs *nilfs) \

static void nilfs_sysfs_delete_##name##_group(struct the_nilfs *nilfs) \

{ \

{ \

	kobject_del(&nilfs->ns_##parent_name##_subgroups->sg_##name##_kobj); \

	kobject_del(&nilfs->ns_##parent_name##_subgroups->sg_##name##_kobj); \

}

}

fs/nilfs2/the_nilfs.c

+15 −1
Original line number Original line Diff line number Diff line
@@ -98,6 +98,7 @@ void destroy_nilfs(struct the_nilfs *nilfs) 
{

{

	might_sleep();

	might_sleep();

	if (nilfs_init(nilfs)) {

	if (nilfs_init(nilfs)) {

		nilfs_sysfs_delete_device_group(nilfs);

		brelse(nilfs->ns_sbh[0]);

		brelse(nilfs->ns_sbh[0]);

		brelse(nilfs->ns_sbh[1]);

		brelse(nilfs->ns_sbh[1]);

	}

	}
@@ -641,6 +642,10 @@ int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data) 
	if (err)

	if (err)

		goto failed_sbh;

		goto failed_sbh;





	err = nilfs_sysfs_create_device_group(sb);

	if (err)

		goto failed_sbh;



	set_nilfs_init(nilfs);

	set_nilfs_init(nilfs);

	err = 0;

	err = 0;

 out:

 out:
@@ -741,12 +746,13 @@ nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno) 
{

{

	struct rb_node **p, *parent;

	struct rb_node **p, *parent;

	struct nilfs_root *root, *new;

	struct nilfs_root *root, *new;

	int err;





	root = nilfs_lookup_root(nilfs, cno);

	root = nilfs_lookup_root(nilfs, cno);

	if (root)

	if (root)

		return root;

		return root;





	new = kmalloc(sizeof(*root), GFP_KERNEL);

	new = kzalloc(sizeof(*root), GFP_KERNEL);

	if (!new)

	if (!new)

		return NULL;

		return NULL;
@@ -783,6 +789,12 @@ nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno) 




	spin_unlock(&nilfs->ns_cptree_lock);

	spin_unlock(&nilfs->ns_cptree_lock);





	err = nilfs_sysfs_create_snapshot_group(new);

	if (err) {

		kfree(new);

		new = NULL;

	}



	return new;

	return new;

}

}
@@ -791,6 +803,8 @@ void nilfs_put_root(struct nilfs_root *root) 
	if (atomic_dec_and_test(&root->count)) {

	if (atomic_dec_and_test(&root->count)) {

		struct the_nilfs *nilfs = root->nilfs;

		struct the_nilfs *nilfs = root->nilfs;





		nilfs_sysfs_delete_snapshot_group(root);



		spin_lock(&nilfs->ns_cptree_lock);

		spin_lock(&nilfs->ns_cptree_lock);

		rb_erase(&root->rb_node, &nilfs->ns_cptree);

		rb_erase(&root->rb_node, &nilfs->ns_cptree);

		spin_unlock(&nilfs->ns_cptree_lock);

		spin_unlock(&nilfs->ns_cptree_lock);