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authorJeff Layton <jlayton@kernel.org>2021-09-10 15:36:29 -0400
committerJeff Layton <jlayton@kernel.org>2021-09-10 16:21:44 -0400
commit90f7d7a0d0d68623b5f7df5621a8d54d9518fcc4 (patch)
tree45d9848be89c64360b82aa49fbb19af46eb46164 /fs/locks.c
parentMerge tag '5.15-rc-ksmbd-part2' of git://git.samba.org/ksmbd (diff)
downloadlinux-dev-90f7d7a0d0d68623b5f7df5621a8d54d9518fcc4.tar.xz
linux-dev-90f7d7a0d0d68623b5f7df5621a8d54d9518fcc4.zip
locks: remove LOCK_MAND flock lock support
As best I can tell, the logic for these has been broken for a long time (at least before the move to git), such that they never conflict with anything. Also, nothing checks for these flags and prevented opens or read/write behavior on the files. They don't seem to do anything. Given that, we can rip these symbols out of the kernel, and just make flock(2) return 0 when LOCK_MAND is set in order to preserve existing behavior. Cc: Matthew Wilcox <willy@infradead.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Jeff Layton <jlayton@kernel.org>
Diffstat (limited to 'fs/locks.c')
-rw-r--r--fs/locks.c47
1 files changed, 22 insertions, 25 deletions
diff --git a/fs/locks.c b/fs/locks.c
index 3d6fb4ae847b..d397394633be 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -461,8 +461,6 @@ static void locks_move_blocks(struct file_lock *new, struct file_lock *fl)
}
static inline int flock_translate_cmd(int cmd) {
- if (cmd & LOCK_MAND)
- return cmd & (LOCK_MAND | LOCK_RW);
switch (cmd) {
case LOCK_SH:
return F_RDLCK;
@@ -942,8 +940,6 @@ static bool flock_locks_conflict(struct file_lock *caller_fl,
*/
if (caller_fl->fl_file == sys_fl->fl_file)
return false;
- if ((caller_fl->fl_type & LOCK_MAND) || (sys_fl->fl_type & LOCK_MAND))
- return false;
return locks_conflict(caller_fl, sys_fl);
}
@@ -2116,11 +2112,9 @@ EXPORT_SYMBOL(locks_lock_inode_wait);
* - %LOCK_SH -- a shared lock.
* - %LOCK_EX -- an exclusive lock.
* - %LOCK_UN -- remove an existing lock.
- * - %LOCK_MAND -- a 'mandatory' flock.
- * This exists to emulate Windows Share Modes.
+ * - %LOCK_MAND -- a 'mandatory' flock. (DEPRECATED)
*
- * %LOCK_MAND can be combined with %LOCK_READ or %LOCK_WRITE to allow other
- * processes read and write access respectively.
+ * %LOCK_MAND support has been removed from the kernel.
*/
SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
{
@@ -2137,9 +2131,22 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
cmd &= ~LOCK_NB;
unlock = (cmd == LOCK_UN);
- if (!unlock && !(cmd & LOCK_MAND) &&
- !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
+ if (!unlock && !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
+ goto out_putf;
+
+ /*
+ * LOCK_MAND locks were broken for a long time in that they never
+ * conflicted with one another and didn't prevent any sort of open,
+ * read or write activity.
+ *
+ * Just ignore these requests now, to preserve legacy behavior, but
+ * throw a warning to let people know that they don't actually work.
+ */
+ if (cmd & LOCK_MAND) {
+ pr_warn_once("Attempt to set a LOCK_MAND lock via flock(2). This support has been removed and the request ignored.\n");
+ error = 0;
goto out_putf;
+ }
lock = flock_make_lock(f.file, cmd, NULL);
if (IS_ERR(lock)) {
@@ -2718,6 +2725,7 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
struct inode *inode = NULL;
unsigned int fl_pid;
struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file)->i_sb);
+ int type;
fl_pid = locks_translate_pid(fl, proc_pidns);
/*
@@ -2745,11 +2753,7 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
seq_printf(f, " %s ",
(inode == NULL) ? "*NOINODE*" : "ADVISORY ");
} else if (IS_FLOCK(fl)) {
- if (fl->fl_type & LOCK_MAND) {
- seq_puts(f, "FLOCK MSNFS ");
- } else {
- seq_puts(f, "FLOCK ADVISORY ");
- }
+ seq_puts(f, "FLOCK ADVISORY ");
} else if (IS_LEASE(fl)) {
if (fl->fl_flags & FL_DELEG)
seq_puts(f, "DELEG ");
@@ -2765,17 +2769,10 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
} else {
seq_puts(f, "UNKNOWN UNKNOWN ");
}
- if (fl->fl_type & LOCK_MAND) {
- seq_printf(f, "%s ",
- (fl->fl_type & LOCK_READ)
- ? (fl->fl_type & LOCK_WRITE) ? "RW " : "READ "
- : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
- } else {
- int type = IS_LEASE(fl) ? target_leasetype(fl) : fl->fl_type;
+ type = IS_LEASE(fl) ? target_leasetype(fl) : fl->fl_type;
- seq_printf(f, "%s ", (type == F_WRLCK) ? "WRITE" :
- (type == F_RDLCK) ? "READ" : "UNLCK");
- }
+ seq_printf(f, "%s ", (type == F_WRLCK) ? "WRITE" :
+ (type == F_RDLCK) ? "READ" : "UNLCK");
if (inode) {
/* userspace relies on this representation of dev_t */
seq_printf(f, "%d %02x:%02x:%lu ", fl_pid,