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-rw-r--r--fs/Kconfig10
-rw-r--r--fs/locks.c2
-rw-r--r--fs/namespace.c10
-rw-r--r--include/linux/fs.h74
4 files changed, 62 insertions, 34 deletions
diff --git a/fs/Kconfig b/fs/Kconfig
index da3f32f1a4e4..59322e6e76f4 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -67,6 +67,16 @@ config FILE_LOCKING
for filesystems like NFS and for the flock() system
call. Disabling this option saves about 11k.
+config MANDATORY_FILE_LOCKING
+ bool "Enable Mandatory file locking"
+ depends on FILE_LOCKING
+ default y
+ help
+ This option enables files appropriately marked files on appropriely
+ mounted filesystems to support mandatory locking.
+
+ To the best of my knowledge this is dead code that no one cares about.
+
source "fs/notify/Kconfig"
source "fs/quota/Kconfig"
diff --git a/fs/locks.c b/fs/locks.c
index 0d2b3267e2a3..86c94674ab22 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1191,6 +1191,7 @@ static int posix_lock_inode_wait(struct inode *inode, struct file_lock *fl)
return error;
}
+#ifdef CONFIG_MANDATORY_FILE_LOCKING
/**
* locks_mandatory_locked - Check for an active lock
* @file: the file to check
@@ -1289,6 +1290,7 @@ int locks_mandatory_area(int read_write, struct inode *inode,
}
EXPORT_SYMBOL(locks_mandatory_area);
+#endif /* CONFIG_MANDATORY_FILE_LOCKING */
static void lease_clear_pending(struct file_lock *fl, int arg)
{
diff --git a/fs/namespace.c b/fs/namespace.c
index 0570729c87fd..4219885e9681 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1584,6 +1584,14 @@ static inline bool may_mount(void)
return ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN);
}
+static inline bool may_mandlock(void)
+{
+#ifndef CONFIG_MANDATORY_FILE_LOCKING
+ return false;
+#endif
+ return true;
+}
+
/*
* Now umount can handle mount points as well as block devices.
* This is important for filesystems which use unnamed block devices.
@@ -2677,6 +2685,8 @@ long do_mount(const char *dev_name, const char __user *dir_name,
type_page, flags, data_page);
if (!retval && !may_mount())
retval = -EPERM;
+ if (!retval && (flags & MS_MANDLOCK) && !may_mandlock())
+ retval = -EPERM;
if (retval)
goto dput_out;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3aa514254161..cbf08d5c246e 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2030,7 +2030,7 @@ extern struct kobject *fs_kobj;
#define FLOCK_VERIFY_READ 1
#define FLOCK_VERIFY_WRITE 2
-#ifdef CONFIG_FILE_LOCKING
+#ifdef CONFIG_MANDATORY_FILE_LOCKING
extern int locks_mandatory_locked(struct file *);
extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t, size_t);
@@ -2075,6 +2075,45 @@ static inline int locks_verify_truncate(struct inode *inode,
return 0;
}
+#else /* !CONFIG_MANDATORY_FILE_LOCKING */
+
+static inline int locks_mandatory_locked(struct file *file)
+{
+ return 0;
+}
+
+static inline int locks_mandatory_area(int rw, struct inode *inode,
+ struct file *filp, loff_t offset,
+ size_t count)
+{
+ return 0;
+}
+
+static inline int __mandatory_lock(struct inode *inode)
+{
+ return 0;
+}
+
+static inline int mandatory_lock(struct inode *inode)
+{
+ return 0;
+}
+
+static inline int locks_verify_locked(struct file *file)
+{
+ return 0;
+}
+
+static inline int locks_verify_truncate(struct inode *inode, struct file *filp,
+ size_t size)
+{
+ return 0;
+}
+
+#endif /* CONFIG_MANDATORY_FILE_LOCKING */
+
+
+#ifdef CONFIG_FILE_LOCKING
static inline int break_lease(struct inode *inode, unsigned int mode)
{
/*
@@ -2136,39 +2175,6 @@ static inline int break_layout(struct inode *inode, bool wait)
}
#else /* !CONFIG_FILE_LOCKING */
-static inline int locks_mandatory_locked(struct file *file)
-{
- return 0;
-}
-
-static inline int locks_mandatory_area(int rw, struct inode *inode,
- struct file *filp, loff_t offset,
- size_t count)
-{
- return 0;
-}
-
-static inline int __mandatory_lock(struct inode *inode)
-{
- return 0;
-}
-
-static inline int mandatory_lock(struct inode *inode)
-{
- return 0;
-}
-
-static inline int locks_verify_locked(struct file *file)
-{
- return 0;
-}
-
-static inline int locks_verify_truncate(struct inode *inode, struct file *filp,
- size_t size)
-{
- return 0;
-}
-
static inline int break_lease(struct inode *inode, unsigned int mode)
{
return 0;