Messages in this thread Patch in this message |  | | From | Chao Yu <> | Subject | [PATCH 1/2] f2fs: introduce sb_lock to make encrypt pwsalt update exclusive | Date | Sun, 11 Feb 2018 22:53:20 +0800 |
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From: Chao Yu <yuchao0@huawei.com>
f2fs_super_block.encrypt_pw_salt can be udpated and persisted concurrently, result in getting different pwsalt in separated threads, so let's introduce sb_lock to exclude concurrent accessers.
Signed-off-by: Chao Yu <yuchao0@huawei.com> --- fs/f2fs/f2fs.h | 1 + fs/f2fs/file.c | 19 +++++++++++-------- fs/f2fs/super.c | 2 ++ 3 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 7ed17cd657b5..0332c44a1d93 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -1048,6 +1048,7 @@ struct f2fs_sb_info { struct super_block *sb; /* pointer to VFS super block */ struct proc_dir_entry *s_proc; /* proc entry */ struct f2fs_super_block *raw_super; /* raw super block pointer */ + struct mutex sb_lock; /* lock for raw super block */ int valid_super_block; /* valid super block no */ unsigned long s_flag; /* flags for sbi */ diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index ef362899df4e..f26a0bd17469 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1965,13 +1965,15 @@ static int f2fs_ioc_get_encryption_pwsalt(struct file *filp, unsigned long arg) if (!f2fs_sb_has_encrypt(inode->i_sb)) return -EOPNOTSUPP; - if (uuid_is_nonzero(sbi->raw_super->encrypt_pw_salt)) - goto got_it; - err = mnt_want_write_file(filp); if (err) return err; + mutex_lock(&sbi->sb_lock); + + if (uuid_is_nonzero(sbi->raw_super->encrypt_pw_salt)) + goto got_it; + /* update superblock with uuid */ generate_random_uuid(sbi->raw_super->encrypt_pw_salt); @@ -1979,15 +1981,16 @@ static int f2fs_ioc_get_encryption_pwsalt(struct file *filp, unsigned long arg) if (err) { /* undo new data */ memset(sbi->raw_super->encrypt_pw_salt, 0, 16); - mnt_drop_write_file(filp); - return err; + goto out_err; } - mnt_drop_write_file(filp); got_it: if (copy_to_user((__u8 __user *)arg, sbi->raw_super->encrypt_pw_salt, 16)) - return -EFAULT; - return 0; + err = -EFAULT; +out_err: + mutex_unlock(&sbi->sb_lock); + mnt_drop_write_file(filp); + return err; } static int f2fs_ioc_gc(struct file *filp, unsigned long arg) diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 52986c9cc677..1b49ad477dd9 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -2232,6 +2232,8 @@ static void init_sb_info(struct f2fs_sb_info *sbi) sbi->dirty_device = 0; spin_lock_init(&sbi->dev_lock); + + mutex_init(&sbi->sb_lock); } static int init_percpu_info(struct f2fs_sb_info *sbi) -- 2.14.1.145.gb3622a4ee
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