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Merge tag 'locks-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/…
…git/jlayton/linux Pull file locking updates from Jeff Layton: "Most of this is just follow-on cleanup work of documentation and comments from the mandatory locking removal in v5.15. The only real functional change is that LOCK_MAND flock() support is also being removed, as it has basically been non-functional since the v2.5 days" * tag 'locks-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux: fs: remove leftover comments from mandatory locking removal locks: remove changelog comments docs: fs: locks.rst: update comment about mandatory file locking Documentation: remove reference to now removed mandatory-locking doc locks: remove LOCK_MAND flock lock support
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@@ -29,7 +29,6 @@ algorithms work. | |
fiemap | ||
files | ||
locks | ||
mandatory-locking | ||
mount_api | ||
quota | ||
seq_file | ||
|
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Original file line number | Diff line number | Diff line change |
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@@ -2,117 +2,11 @@ | |
/* | ||
* linux/fs/locks.c | ||
* | ||
* Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls. | ||
* Doug Evans ([email protected]), August 07, 1992 | ||
* We implement four types of file locks: BSD locks, posix locks, open | ||
* file description locks, and leases. For details about BSD locks, | ||
* see the flock(2) man page; for details about the other three, see | ||
* fcntl(2). | ||
* | ||
* Deadlock detection added. | ||
* FIXME: one thing isn't handled yet: | ||
* - mandatory locks (requires lots of changes elsewhere) | ||
* Kelly Carmichael (kelly@[142.24.8.65]), September 17, 1994. | ||
* | ||
* Miscellaneous edits, and a total rewrite of posix_lock_file() code. | ||
* Kai Petzke ([email protected]), 1994 | ||
* | ||
* Converted file_lock_table to a linked list from an array, which eliminates | ||
* the limits on how many active file locks are open. | ||
* Chad Page ([email protected]), November 27, 1994 | ||
* | ||
* Removed dependency on file descriptors. dup()'ed file descriptors now | ||
* get the same locks as the original file descriptors, and a close() on | ||
* any file descriptor removes ALL the locks on the file for the current | ||
* process. Since locks still depend on the process id, locks are inherited | ||
* after an exec() but not after a fork(). This agrees with POSIX, and both | ||
* BSD and SVR4 practice. | ||
* Andy Walker ([email protected]), February 14, 1995 | ||
* | ||
* Scrapped free list which is redundant now that we allocate locks | ||
* dynamically with kmalloc()/kfree(). | ||
* Andy Walker ([email protected]), February 21, 1995 | ||
* | ||
* Implemented two lock personalities - FL_FLOCK and FL_POSIX. | ||
* | ||
* FL_POSIX locks are created with calls to fcntl() and lockf() through the | ||
* fcntl() system call. They have the semantics described above. | ||
* | ||
* FL_FLOCK locks are created with calls to flock(), through the flock() | ||
* system call, which is new. Old C libraries implement flock() via fcntl() | ||
* and will continue to use the old, broken implementation. | ||
* | ||
* FL_FLOCK locks follow the 4.4 BSD flock() semantics. They are associated | ||
* with a file pointer (filp). As a result they can be shared by a parent | ||
* process and its children after a fork(). They are removed when the last | ||
* file descriptor referring to the file pointer is closed (unless explicitly | ||
* unlocked). | ||
* | ||
* FL_FLOCK locks never deadlock, an existing lock is always removed before | ||
* upgrading from shared to exclusive (or vice versa). When this happens | ||
* any processes blocked by the current lock are woken up and allowed to | ||
* run before the new lock is applied. | ||
* Andy Walker ([email protected]), June 09, 1995 | ||
* | ||
* Removed some race conditions in flock_lock_file(), marked other possible | ||
* races. Just grep for FIXME to see them. | ||
* Dmitry Gorodchanin ([email protected]), February 09, 1996. | ||
* | ||
* Addressed Dmitry's concerns. Deadlock checking no longer recursive. | ||
* Lock allocation changed to GFP_ATOMIC as we can't afford to sleep | ||
* once we've checked for blocking and deadlocking. | ||
* Andy Walker ([email protected]), April 03, 1996. | ||
* | ||
* Initial implementation of mandatory locks. SunOS turned out to be | ||
* a rotten model, so I implemented the "obvious" semantics. | ||
* See 'Documentation/filesystems/mandatory-locking.rst' for details. | ||
* Andy Walker ([email protected]), April 06, 1996. | ||
* | ||
* Don't allow mandatory locks on mmap()'ed files. Added simple functions to | ||
* check if a file has mandatory locks, used by mmap(), open() and creat() to | ||
* see if system call should be rejected. Ref. HP-UX/SunOS/Solaris Reference | ||
* Manual, Section 2. | ||
* Andy Walker ([email protected]), April 09, 1996. | ||
* | ||
* Tidied up block list handling. Added '/proc/locks' interface. | ||
* Andy Walker ([email protected]), April 24, 1996. | ||
* | ||
* Fixed deadlock condition for pathological code that mixes calls to | ||
* flock() and fcntl(). | ||
* Andy Walker ([email protected]), April 29, 1996. | ||
* | ||
* Allow only one type of locking scheme (FL_POSIX or FL_FLOCK) to be in use | ||
* for a given file at a time. Changed the CONFIG_LOCK_MANDATORY scheme to | ||
* guarantee sensible behaviour in the case where file system modules might | ||
* be compiled with different options than the kernel itself. | ||
* Andy Walker ([email protected]), May 15, 1996. | ||
* | ||
* Added a couple of missing wake_up() calls. Thanks to Thomas Meckel | ||
* ([email protected]) for spotting this. | ||
* Andy Walker ([email protected]), May 15, 1996. | ||
* | ||
* Changed FL_POSIX locks to use the block list in the same way as FL_FLOCK | ||
* locks. Changed process synchronisation to avoid dereferencing locks that | ||
* have already been freed. | ||
* Andy Walker ([email protected]), Sep 21, 1996. | ||
* | ||
* Made the block list a circular list to minimise searching in the list. | ||
* Andy Walker ([email protected]), Sep 25, 1996. | ||
* | ||
* Made mandatory locking a mount option. Default is not to allow mandatory | ||
* locking. | ||
* Andy Walker ([email protected]), Oct 04, 1996. | ||
* | ||
* Some adaptations for NFS support. | ||
* Olaf Kirch ([email protected]), Dec 1996, | ||
* | ||
* Fixed /proc/locks interface so that we can't overrun the buffer we are handed. | ||
* Andy Walker ([email protected]), May 12, 1997. | ||
* | ||
* Use slab allocator instead of kmalloc/kfree. | ||
* Use generic list implementation from <linux/list.h>. | ||
* Sped up posix_locks_deadlock by only considering blocked locks. | ||
* Matthew Wilcox <[email protected]>, March, 2000. | ||
* | ||
* Leases and LOCK_MAND | ||
* Matthew Wilcox <[email protected]>, June, 2000. | ||
* Stephen Rothwell <[email protected]>, June, 2000. | ||
* | ||
* Locking conflicts and dependencies: | ||
* If multiple threads attempt to lock the same byte (or flock the same file) | ||
|
@@ -461,8 +355,6 @@ 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 +834,6 @@ 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 +2006,9 @@ 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 +2025,22 @@ 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 +2619,7 @@ 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 +2647,7 @@ 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 +2663,10 @@ 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, | ||
|
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