Commit bce8d112 authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: avoid deadlock on init_inode_metadata 



Previously, init_inode_metadata does not hold any parent directory's inode
page. So, f2fs_init_acl can grab its parent inode page without any problem.
But, when we use inline_dentry, that page is grabbed during f2fs_add_link,
so that we can fall into deadlock condition like below.

INFO: task mknod:11006 blocked for more than 120 seconds.
      Tainted: G           OE  3.17.0-rc1+ #13
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
mknod           D ffff88003fc94580     0 11006  11004 0x00000000
 ffff880007717b10 0000000000000002 ffff88003c323220 ffff880007717fd8
 0000000000014580 0000000000014580 ffff88003daecb30 ffff88003c323220
 ffff88003fc94e80 ffff88003ffbb4e8 ffff880007717ba0 0000000000000002
Call Trace:
 [<ffffffff8173dc40>] ? bit_wait+0x50/0x50
 [<ffffffff8173d4cd>] io_schedule+0x9d/0x130
 [<ffffffff8173dc6c>] bit_wait_io+0x2c/0x50
 [<ffffffff8173da3b>] __wait_on_bit_lock+0x4b/0xb0
 [<ffffffff811640a7>] __lock_page+0x67/0x70
 [<ffffffff810acf50>] ? autoremove_wake_function+0x40/0x40
 [<ffffffff811652cc>] pagecache_get_page+0x14c/0x1e0
 [<ffffffffa029afa9>] get_node_page+0x59/0x130 [f2fs]
 [<ffffffffa02a63ad>] read_all_xattrs+0x24d/0x430 [f2fs]
 [<ffffffffa02a6ca2>] f2fs_getxattr+0x52/0xe0 [f2fs]
 [<ffffffffa02a7481>] f2fs_get_acl+0x41/0x2d0 [f2fs]
 [<ffffffff8122d847>] get_acl+0x47/0x70
 [<ffffffff8122db5a>] posix_acl_create+0x5a/0x150
 [<ffffffffa02a7759>] f2fs_init_acl+0x29/0xcb [f2fs]
 [<ffffffffa0286a8d>] init_inode_metadata+0x5d/0x340 [f2fs]
 [<ffffffffa029253a>] f2fs_add_inline_entry+0x12a/0x2e0 [f2fs]
 [<ffffffffa0286ea5>] __f2fs_add_link+0x45/0x4a0 [f2fs]
 [<ffffffffa028b5b6>] ? f2fs_new_inode+0x146/0x220 [f2fs]
 [<ffffffffa028b816>] f2fs_mknod+0x86/0xf0 [f2fs]
 [<ffffffff811e3ec1>] vfs_mknod+0xe1/0x160
 [<ffffffff811e4b26>] SyS_mknod+0x1f6/0x200
 [<ffffffff81741d7f>] tracesys+0xe1/0xe6

Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 59a06155

fs/f2fs/acl.c

+138 −6
Original line number Diff line number Diff line
@@ -162,7 +162,8 @@ static void *f2fs_acl_to_disk(const struct posix_acl *acl, size_t *size) 
	return ERR_PTR(-EINVAL);

}



struct posix_acl *f2fs_get_acl(struct inode *inode, int type)

static struct posix_acl *__f2fs_get_acl(struct inode *inode, int type,

						struct page *dpage)

{

	int name_index = F2FS_XATTR_INDEX_POSIX_ACL_DEFAULT;

	void *value = NULL;
@@ -172,12 +173,13 @@ struct posix_acl *f2fs_get_acl(struct inode *inode, int type) 
	if (type == ACL_TYPE_ACCESS)

		name_index = F2FS_XATTR_INDEX_POSIX_ACL_ACCESS;



	retval = f2fs_getxattr(inode, name_index, "", NULL, 0);

	retval = f2fs_getxattr(inode, name_index, "", NULL, 0, dpage);

	if (retval > 0) {

		value = kmalloc(retval, GFP_F2FS_ZERO);

		if (!value)

			return ERR_PTR(-ENOMEM);

		retval = f2fs_getxattr(inode, name_index, "", value, retval);

		retval = f2fs_getxattr(inode, name_index, "", value,

							retval, dpage);

	}



	if (retval > 0)
@@ -194,6 +196,11 @@ struct posix_acl *f2fs_get_acl(struct inode *inode, int type) 
	return acl;

}



struct posix_acl *f2fs_get_acl(struct inode *inode, int type)

{

	return __f2fs_get_acl(inode, type, NULL);

}



static int __f2fs_set_acl(struct inode *inode, int type,

			struct posix_acl *acl, struct page *ipage)

{
@@ -249,12 +256,137 @@ int f2fs_set_acl(struct inode *inode, struct posix_acl *acl, int type) 
	return __f2fs_set_acl(inode, type, acl, NULL);

}



int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage)

/*

 * Most part of f2fs_acl_clone, f2fs_acl_create_masq, f2fs_acl_create

 * are copied from posix_acl.c

 */

static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl,

							gfp_t flags)

{

	struct posix_acl *clone = NULL;



	if (acl) {

		int size = sizeof(struct posix_acl) + acl->a_count *

				sizeof(struct posix_acl_entry);

		clone = kmemdup(acl, size, flags);

		if (clone)

			atomic_set(&clone->a_refcount, 1);

	}

	return clone;

}



static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)

{

	struct posix_acl_entry *pa, *pe;

	struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;

	umode_t mode = *mode_p;

	int not_equiv = 0;



	/* assert(atomic_read(acl->a_refcount) == 1); */



	FOREACH_ACL_ENTRY(pa, acl, pe) {

		switch(pa->e_tag) {

		case ACL_USER_OBJ:

			pa->e_perm &= (mode >> 6) | ~S_IRWXO;

			mode &= (pa->e_perm << 6) | ~S_IRWXU;

			break;



		case ACL_USER:

		case ACL_GROUP:

			not_equiv = 1;

			break;



		case ACL_GROUP_OBJ:

			group_obj = pa;

			break;



		case ACL_OTHER:

			pa->e_perm &= mode | ~S_IRWXO;

			mode &= pa->e_perm | ~S_IRWXO;

			break;



		case ACL_MASK:

			mask_obj = pa;

			not_equiv = 1;

			break;



		default:

			return -EIO;

		}

	}



	if (mask_obj) {

		mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO;

		mode &= (mask_obj->e_perm << 3) | ~S_IRWXG;

	} else {

		if (!group_obj)

			return -EIO;

		group_obj->e_perm &= (mode >> 3) | ~S_IRWXO;

		mode &= (group_obj->e_perm << 3) | ~S_IRWXG;

	}



	*mode_p = (*mode_p & ~S_IRWXUGO) | mode;

        return not_equiv;

}



static int f2fs_acl_create(struct inode *dir, umode_t *mode,

		struct posix_acl **default_acl, struct posix_acl **acl,

		struct page *dpage)

{

	struct posix_acl *p;

	int ret;



	if (S_ISLNK(*mode) || !IS_POSIXACL(dir))

		goto no_acl;



	p = __f2fs_get_acl(dir, ACL_TYPE_DEFAULT, dpage);

	if (IS_ERR(p)) {

		if (p == ERR_PTR(-EOPNOTSUPP))

			goto apply_umask;

		return PTR_ERR(p);

	}



	if (!p)

		goto apply_umask;



	*acl = f2fs_acl_clone(p, GFP_NOFS);

	if (!*acl)

		return -ENOMEM;



	ret = f2fs_acl_create_masq(*acl, mode);

	if (ret < 0) {

		posix_acl_release(*acl);

		return -ENOMEM;

	}



	if (ret == 0) {

		posix_acl_release(*acl);

		*acl = NULL;

	}



	if (!S_ISDIR(*mode)) {

		posix_acl_release(p);

		*default_acl = NULL;

	} else {

		*default_acl = p;

	}

	return 0;



apply_umask:

	*mode &= ~current_umask();

no_acl:

	*default_acl = NULL;

	*acl = NULL;

	return 0;

}



int f2fs_init_acl(struct inode *inode, struct inode *dir, struct page *ipage,

							struct page *dpage)

{

	struct posix_acl *default_acl, *acl;

	struct posix_acl *default_acl = NULL, *acl = NULL;

	int error = 0;



	error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);

	error = f2fs_acl_create(dir, &inode->i_mode, &default_acl, &acl, dpage);

	if (error)

		return error;

fs/f2fs/acl.h

+3 −2
Original line number Diff line number Diff line
@@ -38,14 +38,15 @@ struct f2fs_acl_header { 


extern struct posix_acl *f2fs_get_acl(struct inode *, int);

extern int f2fs_set_acl(struct inode *inode, struct posix_acl *acl, int type);

extern int f2fs_init_acl(struct inode *, struct inode *, struct page *);

extern int f2fs_init_acl(struct inode *, struct inode *, struct page *,

							struct page *);

#else

#define f2fs_check_acl	NULL

#define f2fs_get_acl	NULL

#define f2fs_set_acl	NULL



static inline int f2fs_init_acl(struct inode *inode, struct inode *dir,

							struct page *page)

				struct page *ipage, struct page *dpage)

{

	return 0;

}

fs/f2fs/dir.c

+5 −5
Original line number Diff line number Diff line
@@ -363,8 +363,8 @@ static int make_empty_dir(struct inode *inode, 
	return 0;

}



struct page *init_inode_metadata(struct inode *inode,

		struct inode *dir, const struct qstr *name)

struct page *init_inode_metadata(struct inode *inode, struct inode *dir,

			const struct qstr *name, struct page *dpage)

{

	struct page *page;

	int err;
@@ -380,7 +380,7 @@ struct page *init_inode_metadata(struct inode *inode, 
				goto error;

		}



		err = f2fs_init_acl(inode, dir, page);

		err = f2fs_init_acl(inode, dir, page, dpage);

		if (err)

			goto put_error;
@@ -541,7 +541,7 @@ int __f2fs_add_link(struct inode *dir, const struct qstr *name, 
	f2fs_wait_on_page_writeback(dentry_page, DATA);



	down_write(&F2FS_I(inode)->i_sem);

	page = init_inode_metadata(inode, dir, name);

	page = init_inode_metadata(inode, dir, name, NULL);

	if (IS_ERR(page)) {

		err = PTR_ERR(page);

		goto fail;
@@ -580,7 +580,7 @@ int f2fs_do_tmpfile(struct inode *inode, struct inode *dir) 
	int err = 0;



	down_write(&F2FS_I(inode)->i_sem);

	page = init_inode_metadata(inode, dir, NULL);

	page = init_inode_metadata(inode, dir, NULL, NULL);

	if (IS_ERR(page)) {

		err = PTR_ERR(page);

		goto fail;

fs/f2fs/f2fs.h

+1 −1
Original line number Diff line number Diff line
@@ -1247,7 +1247,7 @@ void set_de_type(struct f2fs_dir_entry *, struct inode *); 
struct f2fs_dir_entry *find_target_dentry(struct qstr *, int *, const void *,

			struct f2fs_dir_entry *, __u8 (*)[F2FS_SLOT_LEN]);

struct page *init_inode_metadata(struct inode *, struct inode *,

							const struct qstr *);

			const struct qstr *, struct page *);

void update_parent_metadata(struct inode *, struct inode *, unsigned int);

int room_for_filename(const void *, int, int);

void f2fs_drop_nlink(struct inode *, struct inode *, struct page *);

fs/f2fs/inline.c

+3 −3
Original line number Diff line number Diff line
@@ -427,14 +427,14 @@ int f2fs_add_inline_entry(struct inode *dir, const struct qstr *name, 
		goto out;

	}



	f2fs_wait_on_page_writeback(ipage, NODE);



	down_write(&F2FS_I(inode)->i_sem);

	page = init_inode_metadata(inode, dir, name);

	page = init_inode_metadata(inode, dir, name, ipage);

	if (IS_ERR(page)) {

		err = PTR_ERR(page);

		goto fail;

	}



	f2fs_wait_on_page_writeback(ipage, NODE);

	de = &dentry_blk->dentry[bit_pos];

	de->hash_code = name_hash;

	de->name_len = cpu_to_le16(namelen);