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Commit 52ab9560 authored by Russ Knize's avatar Russ Knize Committed by Jaegeuk Kim
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f2fs: don't GC or take an fs_lock from f2fs_initxattrs() 



f2fs_initxattrs() is called internally from within F2FS and should
not call functions that are used by VFS handlers.  This avoids
certain deadlocks:

- vfs_create()
 - f2fs_create() <-- takes an fs_lock
  - f2fs_add_link()
   - __f2fs_add_link()
    - init_inode_metadata()
     - f2fs_init_security()
      - security_inode_init_security()
       - f2fs_initxattrs()
        - f2fs_setxattr() <-- also takes an fs_lock

If the caller happens to grab the same fs_lock from the pool in both
places, they will deadlock.  There are also deadlocks involving
multiple threads and mutexes:

- f2fs_write_begin()
 - f2fs_balance_fs() <-- takes gc_mutex
  - f2fs_gc()
   - write_checkpoint()
    - block_operations()
     - mutex_lock_all() <-- blocks trying to grab all fs_locks

- f2fs_mkdir() <-- takes an fs_lock
 - __f2fs_add_link()
  - f2fs_init_security()
   - security_inode_init_security()
    - f2fs_initxattrs()
     - f2fs_setxattr()
      - f2fs_balance_fs() <-- blocks trying to take gc_mutex

Signed-off-by: default avatarRuss Knize <Russ.Knize@motorola.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk.kim@samsung.com>
parent 885166c0

fs/f2fs/xattr.c

+25 −10
Original line number Diff line number Diff line
@@ -154,6 +154,9 @@ static int f2fs_xattr_advise_set(struct dentry *dentry, const char *name, 
}



#ifdef CONFIG_F2FS_FS_SECURITY

static int __f2fs_setxattr(struct inode *inode, int name_index,

			const char *name, const void *value, size_t value_len,

			struct page *ipage);

static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_array,

		void *page)

{
@@ -161,7 +164,7 @@ static int f2fs_initxattrs(struct inode *inode, const struct xattr *xattr_array, 
	int err = 0;



	for (xattr = xattr_array; xattr->name != NULL; xattr++) {

		err = f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,

		err = __f2fs_setxattr(inode, F2FS_XATTR_INDEX_SECURITY,

				xattr->name, xattr->value,

				xattr->value_len, (struct page *)page);

		if (err < 0)
@@ -469,16 +472,15 @@ cleanup: 
	return error;

}



int f2fs_setxattr(struct inode *inode, int name_index, const char *name,

			const void *value, size_t value_len, struct page *ipage)

static int __f2fs_setxattr(struct inode *inode, int name_index,

			const char *name, const void *value, size_t value_len,

			struct page *ipage)

{

	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);

	struct f2fs_inode_info *fi = F2FS_I(inode);

	struct f2fs_xattr_entry *here, *last;

	void *base_addr;

	int found, newsize;

	size_t name_len;

	int ilock;

	__u32 new_hsize;

	int error = -ENOMEM;
@@ -493,10 +495,6 @@ int f2fs_setxattr(struct inode *inode, int name_index, const char *name, 
	if (name_len > F2FS_NAME_LEN || value_len > MAX_VALUE_LEN(inode))

		return -ERANGE;



	f2fs_balance_fs(sbi);



	ilock = mutex_lock_op(sbi);



	base_addr = read_all_xattrs(inode, ipage);

	if (!base_addr)

		goto exit;
@@ -578,7 +576,24 @@ int f2fs_setxattr(struct inode *inode, int name_index, const char *name, 
	else

		update_inode_page(inode);

exit:

	mutex_unlock_op(sbi, ilock);

	kzfree(base_addr);

	return error;

}



int f2fs_setxattr(struct inode *inode, int name_index, const char *name,

			const void *value, size_t value_len, struct page *ipage)

{

	struct f2fs_sb_info *sbi = F2FS_SB(inode->i_sb);

	int ilock;

	int err;



	f2fs_balance_fs(sbi);



	ilock = mutex_lock_op(sbi);



	err = __f2fs_setxattr(inode, name_index, name, value, value_len, ipage);



	mutex_unlock_op(sbi, ilock);



	return err;

}