From d0d3f1b329b01a9e16609eeadcc6d4fae0afc7c8 Mon Sep 17 00:00:00 2001 From: Chao Yu Date: Sun, 11 Feb 2018 22:53:20 +0800 Subject: [PATCH] f2fs: introduce sb_lock to make encrypt pwsalt update exclusive 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 Signed-off-by: Jaegeuk Kim --- 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 9f3841b..6d0e7b1 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -1047,6 +1047,7 @@ 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 29956e1..c355e44 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1962,13 +1962,15 @@ 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); @@ -1976,15 +1978,16 @@ 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 ff6da6e..d2833a2 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -2221,6 +2221,8 @@ 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) -- 2.7.4