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-rw-r--r--fs/locks.c538
1 files changed, 217 insertions, 321 deletions
diff --git a/fs/locks.c b/fs/locks.c
index b8a31c1c4fff..607f94a0e789 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -2,117 +2,11 @@
/*
* linux/fs/locks.c
*
- * Provide support for fcntl()'s F_GETLK, F_SETLK, and F_SETLKW calls.
- * Doug Evans (dje@spiff.uucp), 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 (wpp@marie.physik.tu-berlin.de), 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 (pageone@netcom.com), 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 (andy@lysaker.kvaerner.no), February 14, 1995
- *
- * Scrapped free list which is redundant now that we allocate locks
- * dynamically with kmalloc()/kfree().
- * Andy Walker (andy@lysaker.kvaerner.no), 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 (andy@lysaker.kvaerner.no), June 09, 1995
- *
- * Removed some race conditions in flock_lock_file(), marked other possible
- * races. Just grep for FIXME to see them.
- * Dmitry Gorodchanin (pgmdsg@ibi.com), 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 (andy@lysaker.kvaerner.no), 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.txt' for details.
- * Andy Walker (andy@lysaker.kvaerner.no), 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 (andy@lysaker.kvaerner.no), April 09, 1996.
- *
- * Tidied up block list handling. Added '/proc/locks' interface.
- * Andy Walker (andy@lysaker.kvaerner.no), April 24, 1996.
- *
- * Fixed deadlock condition for pathological code that mixes calls to
- * flock() and fcntl().
- * Andy Walker (andy@lysaker.kvaerner.no), 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 (andy@lysaker.kvaerner.no), May 15, 1996.
- *
- * Added a couple of missing wake_up() calls. Thanks to Thomas Meckel
- * (Thomas.Meckel@mni.fh-giessen.de) for spotting this.
- * Andy Walker (andy@lysaker.kvaerner.no), 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 (andy@lysaker.kvaerner.no), Sep 21, 1996.
- *
- * Made the block list a circular list to minimise searching in the list.
- * Andy Walker (andy@lysaker.kvaerner.no), Sep 25, 1996.
- *
- * Made mandatory locking a mount option. Default is not to allow mandatory
- * locking.
- * Andy Walker (andy@lysaker.kvaerner.no), Oct 04, 1996.
- *
- * Some adaptations for NFS support.
- * Olaf Kirch (okir@monad.swb.de), Dec 1996,
- *
- * Fixed /proc/locks interface so that we can't overrun the buffer we are handed.
- * Andy Walker (andy@lysaker.kvaerner.no), 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 <willy@debian.org>, March, 2000.
- *
- * Leases and LOCK_MAND
- * Matthew Wilcox <willy@debian.org>, June, 2000.
- * Stephen Rothwell <sfr@canb.auug.org.au>, June, 2000.
*
* Locking conflicts and dependencies:
* If multiple threads attempt to lock the same byte (or flock the same file)
@@ -168,6 +62,7 @@
#include <linux/pid_namespace.h>
#include <linux/hashtable.h>
#include <linux/percpu.h>
+#include <linux/sysctl.h>
#define CREATE_TRACE_POINTS
#include <trace/events/filelock.h>
@@ -194,8 +89,37 @@ static int target_leasetype(struct file_lock *fl)
return fl->fl_type;
}
-int leases_enable = 1;
-int lease_break_time = 45;
+static int leases_enable = 1;
+static int lease_break_time = 45;
+
+#ifdef CONFIG_SYSCTL
+static struct ctl_table locks_sysctls[] = {
+ {
+ .procname = "leases-enable",
+ .data = &leases_enable,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
+#ifdef CONFIG_MMU
+ {
+ .procname = "lease-break-time",
+ .data = &lease_break_time,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+ },
+#endif /* CONFIG_MMU */
+ {}
+};
+
+static int __init init_fs_locks_sysctls(void)
+{
+ register_sysctl_init("fs", locks_sysctls);
+ return 0;
+}
+early_initcall(init_fs_locks_sysctls);
+#endif /* CONFIG_SYSCTL */
/*
* The global file_lock_list is only used for displaying /proc/locks, so we
@@ -376,6 +300,34 @@ void locks_release_private(struct file_lock *fl)
}
EXPORT_SYMBOL_GPL(locks_release_private);
+/**
+ * locks_owner_has_blockers - Check for blocking lock requests
+ * @flctx: file lock context
+ * @owner: lock owner
+ *
+ * Return values:
+ * %true: @owner has at least one blocker
+ * %false: @owner has no blockers
+ */
+bool locks_owner_has_blockers(struct file_lock_context *flctx,
+ fl_owner_t owner)
+{
+ struct file_lock *fl;
+
+ spin_lock(&flctx->flc_lock);
+ list_for_each_entry(fl, &flctx->flc_posix, fl_list) {
+ if (fl->fl_owner != owner)
+ continue;
+ if (!list_empty(&fl->fl_blocked_requests)) {
+ spin_unlock(&flctx->flc_lock);
+ return true;
+ }
+ }
+ spin_unlock(&flctx->flc_lock);
+ return false;
+}
+EXPORT_SYMBOL_GPL(locks_owner_has_blockers);
+
/* Free a lock which is not in use. */
void locks_free_lock(struct file_lock *fl)
{
@@ -461,8 +413,6 @@ 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;
@@ -475,21 +425,9 @@ static inline int flock_translate_cmd(int cmd) {
}
/* Fill in a file_lock structure with an appropriate FLOCK lock. */
-static struct file_lock *
-flock_make_lock(struct file *filp, unsigned int cmd, struct file_lock *fl)
+static void flock_make_lock(struct file *filp, struct file_lock *fl, int type)
{
- int type = flock_translate_cmd(cmd);
-
- if (type < 0)
- return ERR_PTR(type);
-
- if (fl == NULL) {
- fl = locks_alloc_lock();
- if (fl == NULL)
- return ERR_PTR(-ENOMEM);
- } else {
- locks_init_lock(fl);
- }
+ locks_init_lock(fl);
fl->fl_file = filp;
fl->fl_owner = filp;
@@ -497,8 +435,6 @@ flock_make_lock(struct file *filp, unsigned int cmd, struct file_lock *fl)
fl->fl_flags = FL_FLOCK;
fl->fl_type = type;
fl->fl_end = OFFSET_MAX;
-
- return fl;
}
static int assign_type(struct file_lock *fl, long type)
@@ -542,7 +478,7 @@ static int flock64_to_posix_lock(struct file *filp, struct file_lock *fl,
if (l->l_len > 0) {
if (l->l_len - 1 > OFFSET_MAX - fl->fl_start)
return -EOVERFLOW;
- fl->fl_end = fl->fl_start + l->l_len - 1;
+ fl->fl_end = fl->fl_start + (l->l_len - 1);
} else if (l->l_len < 0) {
if (fl->fl_start + l->l_len < 0)
@@ -750,7 +686,7 @@ static void __locks_wake_up_blocks(struct file_lock *blocker)
}
/**
- * locks_delete_lock - stop waiting for a file lock
+ * locks_delete_block - stop waiting for a file lock
* @waiter: the lock which was waiting
*
* lockd/nfsd need to disconnect the lock while working on it.
@@ -942,8 +878,6 @@ 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);
}
@@ -954,6 +888,8 @@ posix_test_lock(struct file *filp, struct file_lock *fl)
struct file_lock *cfl;
struct file_lock_context *ctx;
struct inode *inode = locks_inode(filp);
+ void *owner;
+ void (*func)(void);
ctx = smp_load_acquire(&inode->i_flctx);
if (!ctx || list_empty_careful(&ctx->flc_posix)) {
@@ -961,12 +897,23 @@ posix_test_lock(struct file *filp, struct file_lock *fl)
return;
}
+retry:
spin_lock(&ctx->flc_lock);
list_for_each_entry(cfl, &ctx->flc_posix, fl_list) {
- if (posix_locks_conflict(fl, cfl)) {
- locks_copy_conflock(fl, cfl);
- goto out;
+ if (!posix_locks_conflict(fl, cfl))
+ continue;
+ if (cfl->fl_lmops && cfl->fl_lmops->lm_lock_expirable
+ && (*cfl->fl_lmops->lm_lock_expirable)(cfl)) {
+ owner = cfl->fl_lmops->lm_mod_owner;
+ func = cfl->fl_lmops->lm_expire_lock;
+ __module_get(owner);
+ spin_unlock(&ctx->flc_lock);
+ (*func)();
+ module_put(owner);
+ goto retry;
}
+ locks_copy_conflock(fl, cfl);
+ goto out;
}
fl->fl_type = F_UNLCK;
out:
@@ -1140,6 +1087,8 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request,
int error;
bool added = false;
LIST_HEAD(dispose);
+ void *owner;
+ void (*func)(void);
ctx = locks_get_lock_context(inode, request->fl_type);
if (!ctx)
@@ -1158,6 +1107,7 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request,
new_fl2 = locks_alloc_lock();
}
+retry:
percpu_down_read(&file_rwsem);
spin_lock(&ctx->flc_lock);
/*
@@ -1169,6 +1119,17 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request,
list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
if (!posix_locks_conflict(request, fl))
continue;
+ if (fl->fl_lmops && fl->fl_lmops->lm_lock_expirable
+ && (*fl->fl_lmops->lm_lock_expirable)(fl)) {
+ owner = fl->fl_lmops->lm_mod_owner;
+ func = fl->fl_lmops->lm_expire_lock;
+ __module_get(owner);
+ spin_unlock(&ctx->flc_lock);
+ percpu_up_read(&file_rwsem);
+ (*func)();
+ module_put(owner);
+ goto retry;
+ }
if (conflock)
locks_copy_conflock(conflock, fl);
error = -EAGAIN;
@@ -1282,6 +1243,7 @@ static int posix_lock_inode(struct inode *inode, struct file_lock *request,
if (!new_fl)
goto out;
locks_copy_lock(new_fl, request);
+ locks_move_blocks(new_fl, request);
request = new_fl;
new_fl = NULL;
locks_insert_lock_ctx(request, &fl->fl_list);
@@ -1396,109 +1358,12 @@ 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
- *
- * Searches the inode's list of locks to find any POSIX locks which conflict.
- * This function is called from locks_verify_locked() only.
- */
-int locks_mandatory_locked(struct file *file)
-{
- int ret;
- struct inode *inode = locks_inode(file);
- struct file_lock_context *ctx;
- struct file_lock *fl;
-
- ctx = smp_load_acquire(&inode->i_flctx);
- if (!ctx || list_empty_careful(&ctx->flc_posix))
- return 0;
-
- /*
- * Search the lock list for this inode for any POSIX locks.
- */
- spin_lock(&ctx->flc_lock);
- ret = 0;
- list_for_each_entry(fl, &ctx->flc_posix, fl_list) {
- if (fl->fl_owner != current->files &&
- fl->fl_owner != file) {
- ret = -EAGAIN;
- break;
- }
- }
- spin_unlock(&ctx->flc_lock);
- return ret;
-}
-
-/**
- * locks_mandatory_area - Check for a conflicting lock
- * @inode: the file to check
- * @filp: how the file was opened (if it was)
- * @start: first byte in the file to check
- * @end: lastbyte in the file to check
- * @type: %F_WRLCK for a write lock, else %F_RDLCK
- *
- * Searches the inode's list of locks to find any POSIX locks which conflict.
- */
-int locks_mandatory_area(struct inode *inode, struct file *filp, loff_t start,
- loff_t end, unsigned char type)
-{
- struct file_lock fl;
- int error;
- bool sleep = false;
-
- locks_init_lock(&fl);
- fl.fl_pid = current->tgid;
- fl.fl_file = filp;
- fl.fl_flags = FL_POSIX | FL_ACCESS;
- if (filp && !(filp->f_flags & O_NONBLOCK))
- sleep = true;
- fl.fl_type = type;
- fl.fl_start = start;
- fl.fl_end = end;
-
- for (;;) {
- if (filp) {
- fl.fl_owner = filp;
- fl.fl_flags &= ~FL_SLEEP;
- error = posix_lock_inode(inode, &fl, NULL);
- if (!error)
- break;
- }
-
- if (sleep)
- fl.fl_flags |= FL_SLEEP;
- fl.fl_owner = current->files;
- error = posix_lock_inode(inode, &fl, NULL);
- if (error != FILE_LOCK_DEFERRED)
- break;
- error = wait_event_interruptible(fl.fl_wait,
- list_empty(&fl.fl_blocked_member));
- if (!error) {
- /*
- * If we've been sleeping someone might have
- * changed the permissions behind our back.
- */
- if (__mandatory_lock(inode))
- continue;
- }
-
- break;
- }
- locks_delete_block(&fl);
-
- return error;
-}
-EXPORT_SYMBOL(locks_mandatory_area);
-#endif /* CONFIG_MANDATORY_FILE_LOCKING */
-
static void lease_clear_pending(struct file_lock *fl, int arg)
{
switch (arg) {
case F_UNLCK:
fl->fl_flags &= ~FL_UNLOCK_PENDING;
- /* fall through */
+ fallthrough;
case F_RDLCK:
fl->fl_flags &= ~FL_DOWNGRADE_PENDING;
}
@@ -1557,6 +1422,9 @@ static bool leases_conflict(struct file_lock *lease, struct file_lock *breaker)
{
bool rc;
+ if (lease->fl_lmops->lm_breaker_owns_lease
+ && lease->fl_lmops->lm_breaker_owns_lease(lease))
+ return false;
if ((breaker->fl_flags & FL_LAYOUT) != (lease->fl_flags & FL_LAYOUT)) {
rc = false;
goto trace;
@@ -1804,6 +1672,9 @@ check_conflicting_open(struct file *filp, const long arg, int flags)
if (flags & FL_LAYOUT)
return 0;
+ if (flags & FL_DELEG)
+ /* We leave these checks to the caller */
+ return 0;
if (arg == F_RDLCK)
return inode_is_open_for_write(inode) ? -EAGAIN : 0;
@@ -2206,57 +2077,62 @@ 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)
{
- struct fd f = fdget(fd);
- struct file_lock *lock;
- int can_sleep, unlock;
- int error;
+ int can_sleep, error, type;
+ struct file_lock fl;
+ struct fd f;
+
+ /*
+ * 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");
+ return 0;
+ }
+
+ type = flock_translate_cmd(cmd & ~LOCK_NB);
+ if (type < 0)
+ return type;
error = -EBADF;
+ f = fdget(fd);
if (!f.file)
- goto out;
-
- can_sleep = !(cmd & LOCK_NB);
- cmd &= ~LOCK_NB;
- unlock = (cmd == LOCK_UN);
+ return error;
- if (!unlock && !(cmd & LOCK_MAND) &&
- !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
+ if (type != F_UNLCK && !(f.file->f_mode & (FMODE_READ | FMODE_WRITE)))
goto out_putf;
- lock = flock_make_lock(f.file, cmd, NULL);
- if (IS_ERR(lock)) {
- error = PTR_ERR(lock);
+ flock_make_lock(f.file, &fl, type);
+
+ error = security_file_lock(f.file, fl.fl_type);
+ if (error)
goto out_putf;
- }
+ can_sleep = !(cmd & LOCK_NB);
if (can_sleep)
- lock->fl_flags |= FL_SLEEP;
-
- error = security_file_lock(f.file, lock->fl_type);
- if (error)
- goto out_free;
+ fl.fl_flags |= FL_SLEEP;
if (f.file->f_op->flock)
error = f.file->f_op->flock(f.file,
- (can_sleep) ? F_SETLKW : F_SETLK,
- lock);
+ (can_sleep) ? F_SETLKW : F_SETLK,
+ &fl);
else
- error = locks_lock_file_wait(f.file, lock);
-
- out_free:
- locks_free_lock(lock);
+ error = locks_lock_file_wait(f.file, &fl);
+ locks_release_private(&fl);
out_putf:
fdput(f);
- out:
+
return error;
}
@@ -2365,7 +2241,6 @@ int fcntl_getlk(struct file *filp, unsigned int cmd, struct flock *flock)
if (flock->l_pid != 0)
goto out;
- cmd = F_GETLK;
fl->fl_flags |= FL_OFDLCK;
fl->fl_owner = filp;
}
@@ -2480,14 +2355,6 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
if (file_lock == NULL)
return -ENOLCK;
- /* Don't allow mandatory locks on files that may be memory mapped
- * and shared.
- */
- if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
- error = -EAGAIN;
- goto out;
- }
-
error = flock_to_posix_lock(filp, file_lock, flock);
if (error)
goto out;
@@ -2518,7 +2385,7 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
cmd = F_SETLKW;
file_lock->fl_flags |= FL_OFDLCK;
file_lock->fl_owner = filp;
- /* Fallthrough */
+ fallthrough;
case F_SETLKW:
file_lock->fl_flags |= FL_SLEEP;
}
@@ -2532,14 +2399,15 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
*/
if (!error && file_lock->fl_type != F_UNLCK &&
!(file_lock->fl_flags & FL_OFDLCK)) {
+ struct files_struct *files = current->files;
/*
* We need that spin_lock here - it prevents reordering between
* update of i_flctx->flc_posix and check for it done in
* close(). rcu_read_lock() wouldn't do.
*/
- spin_lock(&current->files->file_lock);
- f = fcheck(fd);
- spin_unlock(&current->files->file_lock);
+ spin_lock(&files->file_lock);
+ f = files_lookup_fd_locked(files, fd);
+ spin_unlock(&files->file_lock);
if (f != filp) {
file_lock->fl_type = F_UNLCK;
error = do_lock_file_wait(filp, cmd, file_lock);
@@ -2604,21 +2472,12 @@ int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
struct flock64 *flock)
{
struct file_lock *file_lock = locks_alloc_lock();
- struct inode *inode = locks_inode(filp);
struct file *f;
int error;
if (file_lock == NULL)
return -ENOLCK;
- /* Don't allow mandatory locks on files that may be memory mapped
- * and shared.
- */
- if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
- error = -EAGAIN;
- goto out;
- }
-
error = flock64_to_posix_lock(filp, file_lock, flock);
if (error)
goto out;
@@ -2649,7 +2508,7 @@ int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
cmd = F_SETLKW64;
file_lock->fl_flags |= FL_OFDLCK;
file_lock->fl_owner = filp;
- /* Fallthrough */
+ fallthrough;
case F_SETLKW64:
file_lock->fl_flags |= FL_SLEEP;
}
@@ -2663,14 +2522,15 @@ int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
*/
if (!error && file_lock->fl_type != F_UNLCK &&
!(file_lock->fl_flags & FL_OFDLCK)) {
+ struct files_struct *files = current->files;
/*
* We need that spin_lock here - it prevents reordering between
* update of i_flctx->flc_posix and check for it done in
* close(). rcu_read_lock() wouldn't do.
*/
- spin_lock(&current->files->file_lock);
- f = fcheck(fd);
- spin_unlock(&current->files->file_lock);
+ spin_lock(&files->file_lock);
+ f = files_lookup_fd_locked(files, fd);
+ spin_unlock(&files->file_lock);
if (f != filp) {
file_lock->fl_type = F_UNLCK;
error = do_lock_file_wait(filp, cmd, file_lock);
@@ -2734,7 +2594,7 @@ locks_remove_flock(struct file *filp, struct file_lock_context *flctx)
if (list_empty(&flctx->flc_flock))
return;
- flock_make_lock(filp, LOCK_UN, &fl);
+ flock_make_lock(filp, &fl, F_UNLCK);
fl.fl_flags |= FL_CLOSE;
if (filp->f_op->flock)
@@ -2819,11 +2679,12 @@ struct locks_iterator {
};
static void lock_get_status(struct seq_file *f, struct file_lock *fl,
- loff_t id, char *pfx)
+ loff_t id, char *pfx, int repeat)
{
struct inode *inode = NULL;
unsigned int fl_pid;
- struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
+ struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file)->i_sb);
+ int type;
fl_pid = locks_translate_pid(fl, proc_pidns);
/*
@@ -2835,7 +2696,11 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
if (fl->fl_file != NULL)
inode = locks_inode(fl->fl_file);
- seq_printf(f, "%lld:%s ", id, pfx);
+ seq_printf(f, "%lld: ", id);
+
+ if (repeat)
+ seq_printf(f, "%*s", repeat - 1 + (int)strlen(pfx), pfx);
+
if (IS_POSIX(fl)) {
if (fl->fl_flags & FL_ACCESS)
seq_puts(f, "ACCESS");
@@ -2845,14 +2710,9 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
seq_puts(f, "POSIX ");
seq_printf(f, " %s ",
- (inode == NULL) ? "*NOINODE*" :
- mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
+ (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 ");
@@ -2868,17 +2728,10 @@ 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,
@@ -2897,21 +2750,64 @@ static void lock_get_status(struct seq_file *f, struct file_lock *fl,
}
}
+static struct file_lock *get_next_blocked_member(struct file_lock *node)
+{
+ struct file_lock *tmp;
+
+ /* NULL node or root node */
+ if (node == NULL || node->fl_blocker == NULL)
+ return NULL;
+
+ /* Next member in the linked list could be itself */
+ tmp = list_next_entry(node, fl_blocked_member);
+ if (list_entry_is_head(tmp, &node->fl_blocker->fl_blocked_requests, fl_blocked_member)
+ || tmp == node) {
+ return NULL;
+ }
+
+ return tmp;
+}
+
static int locks_show(struct seq_file *f, void *v)
{
struct locks_iterator *iter = f->private;
- struct file_lock *fl, *bfl;
- struct pid_namespace *proc_pidns = file_inode(f->file)->i_sb->s_fs_info;
+ struct file_lock *cur, *tmp;
+ struct pid_namespace *proc_pidns = proc_pid_ns(file_inode(f->file)->i_sb);
+ int level = 0;
- fl = hlist_entry(v, struct file_lock, fl_link);
+ cur = hlist_entry(v, struct file_lock, fl_link);
- if (locks_translate_pid(fl, proc_pidns) == 0)
+ if (locks_translate_pid(cur, proc_pidns) == 0)
return 0;
- lock_get_status(f, fl, iter->li_pos, "");
+ /* View this crossed linked list as a binary tree, the first member of fl_blocked_requests
+ * is the left child of current node, the next silibing in fl_blocked_member is the
+ * right child, we can alse get the parent of current node from fl_blocker, so this
+ * question becomes traversal of a binary tree
+ */
+ while (cur != NULL) {
+ if (level)
+ lock_get_status(f, cur, iter->li_pos, "-> ", level);
+ else
+ lock_get_status(f, cur, iter->li_pos, "", level);
- list_for_each_entry(bfl, &fl->fl_blocked_requests, fl_blocked_member)
- lock_get_status(f, bfl, iter->li_pos, " ->");
+ if (!list_empty(&cur->fl_blocked_requests)) {
+ /* Turn left */
+ cur = list_first_entry_or_null(&cur->fl_blocked_requests,
+ struct file_lock, fl_blocked_member);
+ level++;
+ } else {
+ /* Turn right */
+ tmp = get_next_blocked_member(cur);
+ /* Fall back to parent node */
+ while (tmp == NULL && cur->fl_blocker != NULL) {
+ cur = cur->fl_blocker;
+ level--;
+ tmp = get_next_blocked_member(cur);
+ }
+ cur = tmp;
+ }
+ }
return 0;
}
@@ -2932,7 +2828,7 @@ static void __show_fd_locks(struct seq_file *f,
(*id)++;
seq_puts(f, "lock:\t");
- lock_get_status(f, fl, *id, "");
+ lock_get_status(f, fl, *id, "", 0);
}
}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.