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-rw-r--r--fs/fcntl.c5
-rw-r--r--fs/locks.c81
-rw-r--r--include/linux/fs.h6
3 files changed, 55 insertions, 37 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 286a9f8..6fbc9d8 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -288,7 +288,7 @@ static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
break;
case F_SETLK:
case F_SETLKW:
- err = fcntl_setlk(filp, cmd, (struct flock __user *) arg);
+ err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
break;
case F_GETOWN:
/*
@@ -376,7 +376,8 @@ asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg
break;
case F_SETLK64:
case F_SETLKW64:
- err = fcntl_setlk64(filp, cmd, (struct flock64 __user *) arg);
+ err = fcntl_setlk64(fd, filp, cmd,
+ (struct flock64 __user *) arg);
break;
default:
err = do_fcntl(fd, cmd, arg, filp);
diff --git a/fs/locks.c b/fs/locks.c
index 29fa5da..11956b6 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -1591,7 +1591,8 @@ out:
/* Apply the lock described by l to an open file descriptor.
* This implements both the F_SETLK and F_SETLKW commands of fcntl().
*/
-int fcntl_setlk(struct file *filp, unsigned int cmd, struct flock __user *l)
+int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
+ struct flock __user *l)
{
struct file_lock *file_lock = locks_alloc_lock();
struct flock flock;
@@ -1620,6 +1621,7 @@ int fcntl_setlk(struct file *filp, unsigned int cmd, struct flock __user *l)
goto out;
}
+again:
error = flock_to_posix_lock(filp, file_lock, &flock);
if (error)
goto out;
@@ -1648,25 +1650,33 @@ int fcntl_setlk(struct file *filp, unsigned int cmd, struct flock __user *l)
if (error)
goto out;
- if (filp->f_op && filp->f_op->lock != NULL) {
+ if (filp->f_op && filp->f_op->lock != NULL)
error = filp->f_op->lock(filp, cmd, file_lock);
- goto out;
- }
+ else {
+ for (;;) {
+ error = __posix_lock_file(inode, file_lock);
+ if ((error != -EAGAIN) || (cmd == F_SETLK))
+ break;
+ error = wait_event_interruptible(file_lock->fl_wait,
+ !file_lock->fl_next);
+ if (!error)
+ continue;
- for (;;) {
- error = __posix_lock_file(inode, file_lock);
- if ((error != -EAGAIN) || (cmd == F_SETLK))
+ locks_delete_block(file_lock);
break;
- error = wait_event_interruptible(file_lock->fl_wait,
- !file_lock->fl_next);
- if (!error)
- continue;
+ }
+ }
- locks_delete_block(file_lock);
- break;
+ /*
+ * Attempt to detect a close/fcntl race and recover by
+ * releasing the lock that was just acquired.
+ */
+ if (!error && fcheck(fd) != filp && flock.l_type != F_UNLCK) {
+ flock.l_type = F_UNLCK;
+ goto again;
}
- out:
+out:
locks_free_lock(file_lock);
return error;
}
@@ -1724,7 +1734,8 @@ out:
/* Apply the lock described by l to an open file descriptor.
* This implements both the F_SETLK and F_SETLKW commands of fcntl().
*/
-int fcntl_setlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
+int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
+ struct flock64 __user *l)
{
struct file_lock *file_lock = locks_alloc_lock();
struct flock64 flock;
@@ -1753,6 +1764,7 @@ int fcntl_setlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
goto out;
}
+again:
error = flock64_to_posix_lock(filp, file_lock, &flock);
if (error)
goto out;
@@ -1781,22 +1793,30 @@ int fcntl_setlk64(struct file *filp, unsigned int cmd, struct flock64 __user *l)
if (error)
goto out;
- if (filp->f_op && filp->f_op->lock != NULL) {
+ if (filp->f_op && filp->f_op->lock != NULL)
error = filp->f_op->lock(filp, cmd, file_lock);
- goto out;
- }
+ else {
+ for (;;) {
+ error = __posix_lock_file(inode, file_lock);
+ if ((error != -EAGAIN) || (cmd == F_SETLK64))
+ break;
+ error = wait_event_interruptible(file_lock->fl_wait,
+ !file_lock->fl_next);
+ if (!error)
+ continue;
- for (;;) {
- error = __posix_lock_file(inode, file_lock);
- if ((error != -EAGAIN) || (cmd == F_SETLK64))
+ locks_delete_block(file_lock);
break;
- error = wait_event_interruptible(file_lock->fl_wait,
- !file_lock->fl_next);
- if (!error)
- continue;
+ }
+ }
- locks_delete_block(file_lock);
- break;
+ /*
+ * Attempt to detect a close/fcntl race and recover by
+ * releasing the lock that was just acquired.
+ */
+ if (!error && fcheck(fd) != filp && flock.l_type != F_UNLCK) {
+ flock.l_type = F_UNLCK;
+ goto again;
}
out:
@@ -1888,12 +1908,7 @@ void locks_remove_flock(struct file *filp)
while ((fl = *before) != NULL) {
if (fl->fl_file == filp) {
- /*
- * We might have a POSIX lock that was created at the same time
- * the filp was closed for the last time. Just remove that too,
- * regardless of ownership, since nobody can own it.
- */
- if (IS_FLOCK(fl) || IS_POSIX(fl)) {
+ if (IS_FLOCK(fl)) {
locks_delete_lock(before);
continue;
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0f53e01..f9adf75 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -697,11 +697,13 @@ extern struct list_head file_lock_list;
#include <linux/fcntl.h>
extern int fcntl_getlk(struct file *, struct flock __user *);
-extern int fcntl_setlk(struct file *, unsigned int, struct flock __user *);
+extern int fcntl_setlk(unsigned int, struct file *, unsigned int,
+ struct flock __user *);
#if BITS_PER_LONG == 32
extern int fcntl_getlk64(struct file *, struct flock64 __user *);
-extern int fcntl_setlk64(struct file *, unsigned int, struct flock64 __user *);
+extern int fcntl_setlk64(unsigned int, struct file *, unsigned int,
+ struct flock64 __user *);
#endif
extern void send_sigio(struct fown_struct *fown, int fd, int band);
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