From 27161f13e3c3241944846ac24942a85cceda0a2c Mon Sep 17 00:00:00 2001
From: Yunlei He <heyunlei@huawei.com>
Date: Thu, 7 Sep 2017 10:40:54 +0800
Subject: [PATCH] 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: Yunlei He <heyunlei@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
fs/f2fs/f2fs.h | 1 +
fs/f2fs/super.c | 1 +
fs/f2fs/xattr.c | 6 ++++++
3 files changed, 8 insertions(+)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 91fb749686f24..c0803b1873b36 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -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 */
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 7730316c19c64..89f61eb3d1671 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -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));
diff --git a/fs/f2fs/xattr.c b/fs/f2fs/xattr.c
index ef3a3721ea6b7..7c65540148f8b 100644
--- a/fs/f2fs/xattr.c
+++ b/fs/f2fs/xattr.c
@@ -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);
--
GitLab