Commit 27161f13 authored by Yunlei He's avatar Yunlei He Committed by Jaegeuk Kim
Browse files

f2fs: avoid race in between read xattr & write xattr 



Thread A:					Thread B:
-f2fs_getxattr
   -lookup_all_xattrs
      -xnid = F2FS_I(inode)->i_xattr_nid;
						-f2fs_setxattr
						    -__f2fs_setxattr
						        -write_all_xattrs
						            -truncate_xattr_node
							          ...  ...
						-write_checkpoint
								  ...  ...
						-alloc_nid   <- nid reuse
          -get_node_page
              -f2fs_bug_on  <- nid != node_footer->nid

It's need a rw_sem to avoid the race

Signed-off-by: default avatarYunlei He <heyunlei@huawei.com>
Reviewed-by: default avatarChao Yu <yuchao0@huawei.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 13ba41e3

fs/f2fs/f2fs.h

+1 −0
Original line number Diff line number Diff line
@@ -589,6 +589,7 @@ struct f2fs_inode_info { 
	struct extent_tree *extent_tree;	/* cached extent_tree entry */

	struct rw_semaphore dio_rwsem[2];/* avoid racing between dio and gc */

	struct rw_semaphore i_mmap_sem;

	struct rw_semaphore i_xattr_sem; /* avoid racing between reading and changing EAs */



	int i_extra_isize;		/* size of extra space located in i_addr */

	kprojid_t i_projid;		/* id for project quota */

fs/f2fs/super.c

+1 −0
Original line number Diff line number Diff line
@@ -630,6 +630,7 @@ static struct inode *f2fs_alloc_inode(struct super_block *sb) 
	init_rwsem(&fi->dio_rwsem[READ]);

	init_rwsem(&fi->dio_rwsem[WRITE]);

	init_rwsem(&fi->i_mmap_sem);

	init_rwsem(&fi->i_xattr_sem);



#ifdef CONFIG_QUOTA

	memset(&fi->i_dquot, 0, sizeof(fi->i_dquot));

fs/f2fs/xattr.c

+6 −0
Original line number Diff line number Diff line
@@ -473,8 +473,10 @@ int f2fs_getxattr(struct inode *inode, int index, const char *name, 
	if (len > F2FS_NAME_LEN)

		return -ERANGE;



	down_read(&F2FS_I(inode)->i_xattr_sem);

	error = lookup_all_xattrs(inode, ipage, index, len, name,

				&entry, &base_addr);

	up_read(&F2FS_I(inode)->i_xattr_sem);

	if (error)

		return error;
@@ -503,7 +505,9 @@ ssize_t f2fs_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) 
	int error = 0;

	size_t rest = buffer_size;



	down_read(&F2FS_I(inode)->i_xattr_sem);

	error = read_all_xattrs(inode, NULL, &base_addr);

	up_read(&F2FS_I(inode)->i_xattr_sem);

	if (error)

		return error;
@@ -686,7 +690,9 @@ int f2fs_setxattr(struct inode *inode, int index, const char *name, 
	f2fs_lock_op(sbi);

	/* protect xattr_ver */

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

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

	err = __f2fs_setxattr(inode, index, name, value, size, ipage, flags);

	up_write(&F2FS_I(inode)->i_xattr_sem);

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

	f2fs_unlock_op(sbi);

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