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-rw-r--r--fs/locks.c173
1 files changed, 119 insertions, 54 deletions
diff --git a/fs/locks.c b/fs/locks.c
index 0fca9d680978..607f94a0e789 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -62,6 +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>
@@ -88,8 +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
@@ -270,6 +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)
{
@@ -367,21 +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;
@@ -389,8 +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)
@@ -844,6 +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)) {
@@ -851,12 +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:
@@ -1030,6 +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)
@@ -1048,6 +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);
/*
@@ -1059,6 +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;
@@ -2012,21 +2083,9 @@ EXPORT_SYMBOL(locks_lock_inode_wait);
*/
SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
{
- struct fd f = fdget(fd);
- struct file_lock *lock;
- int can_sleep, unlock;
- int error;
-
- error = -EBADF;
- if (!f.file)
- goto out;
-
- can_sleep = !(cmd & LOCK_NB);
- cmd &= ~LOCK_NB;
- unlock = (cmd == LOCK_UN);
-
- if (!unlock && !(f.file->f_mode & (FMODE_READ|FMODE_WRITE)))
- goto out_putf;
+ 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
@@ -2038,36 +2097,42 @@ SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
*/
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;
+ return 0;
}
- lock = flock_make_lock(f.file, cmd, NULL);
- if (IS_ERR(lock)) {
- error = PTR_ERR(lock);
+ type = flock_translate_cmd(cmd & ~LOCK_NB);
+ if (type < 0)
+ return type;
+
+ error = -EBADF;
+ f = fdget(fd);
+ if (!f.file)
+ return error;
+
+ if (type != F_UNLCK && !(f.file->f_mode & (FMODE_READ | FMODE_WRITE)))
goto out_putf;
- }
- if (can_sleep)
- lock->fl_flags |= FL_SLEEP;
+ flock_make_lock(f.file, &fl, type);
- error = security_file_lock(f.file, lock->fl_type);
+ error = security_file_lock(f.file, fl.fl_type);
if (error)
- goto out_free;
+ goto out_putf;
+
+ can_sleep = !(cmd & LOCK_NB);
+ if (can_sleep)
+ 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;
}
@@ -2529,7 +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)
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