1 files changed, 32 insertions, 91 deletions

diff --git a/fs/locks.c b/fs/locks.c
index ab61a8b54829..1ad29c9b6252 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -703,7 +703,7 @@ EXPORT_SYMBOL(posix_test_lock);
  * from a broken NFS client. But broken NFS clients have a lot more to
  * worry about than proper deadlock detection anyway... --okir
  */
-int posix_locks_deadlock(struct file_lock *caller_fl,
+static int posix_locks_deadlock(struct file_lock *caller_fl,
                                 struct file_lock *block_fl)
 {
         struct list_head *tmp;
@@ -722,8 +722,6 @@ next_task:
         return 0;
 }
 
-EXPORT_SYMBOL(posix_locks_deadlock);
-
 /* Try to create a FLOCK lock on filp. We always insert new FLOCK locks
  * at the head of the list, but that's secret knowledge known only to
  * flock_lock_file and posix_lock_file.
@@ -794,7 +792,8 @@ out:
 static int __posix_lock_file_conf(struct inode *inode, struct file_lock *request, struct file_lock *conflock)
 {
         struct file_lock *fl;
-        struct file_lock *new_fl, *new_fl2;
+        struct file_lock *new_fl = NULL;
+        struct file_lock *new_fl2 = NULL;
         struct file_lock *left = NULL;
         struct file_lock *right = NULL;
         struct file_lock **before;
@@ -803,9 +802,15 @@ static int __posix_lock_file_conf(struct inode *inode, struct file_lock *request
         /*
          * We may need two file_lock structures for this operation,
          * so we get them in advance to avoid races.
+         *
+         * In some cases we can be sure, that no new locks will be needed
          */
-        new_fl = locks_alloc_lock();
-        new_fl2 = locks_alloc_lock();
+        if (!(request->fl_flags & FL_ACCESS) &&
+            (request->fl_type != F_UNLCK ||
+             request->fl_start != 0 || request->fl_end != OFFSET_MAX)) {
+                new_fl = locks_alloc_lock();
+                new_fl2 = locks_alloc_lock();
+        }
 
         lock_kernel();
         if (request->fl_type != F_UNLCK) {
@@ -834,14 +839,7 @@ static int __posix_lock_file_conf(struct inode *inode, struct file_lock *request
         if (request->fl_flags & FL_ACCESS)
                 goto out;
 
-        error = -ENOLCK; /* "no luck" */
-        if (!(new_fl && new_fl2))
-                goto out;
-
         /*
-         * We've allocated the new locks in advance, so there are no
-         * errors possible (and no blocking operations) from here on.
-         * 
          * Find the first old lock with the same owner as the new lock.
          */
         
@@ -938,10 +936,25 @@ static int __posix_lock_file_conf(struct inode *inode, struct file_lock *request
                 before = &fl->fl_next;
         }
 
+        /*
+         * The above code only modifies existing locks in case of
+         * merging or replacing.  If new lock(s) need to be inserted
+         * all modifications are done bellow this, so it's safe yet to
+         * bail out.
+         */
+        error = -ENOLCK; /* "no luck" */
+        if (right && left == right && !new_fl2)
+                goto out;
+
         error = 0;
         if (!added) {
                 if (request->fl_type == F_UNLCK)
                         goto out;
+
+                if (!new_fl) {
+                        error = -ENOLCK;
+                        goto out;
+                }
                 locks_copy_lock(new_fl, request);
                 locks_insert_lock(before, new_fl);
                 new_fl = NULL;
@@ -1881,19 +1894,18 @@ out:
  */
 void locks_remove_posix(struct file *filp, fl_owner_t owner)
 {
-        struct file_lock lock, **before;
+        struct file_lock lock;
 
         /*
          * If there are no locks held on this file, we don't need to call
          * posix_lock_file().  Another process could be setting a lock on this
          * file at the same time, but we wouldn't remove that lock anyway.
          */
-        before = &filp->f_dentry->d_inode->i_flock;
-        if (*before == NULL)
+        if (!filp->f_dentry->d_inode->i_flock)
                 return;
 
         lock.fl_type = F_UNLCK;
-        lock.fl_flags = FL_POSIX;
+        lock.fl_flags = FL_POSIX | FL_CLOSE;
         lock.fl_start = 0;
         lock.fl_end = OFFSET_MAX;
         lock.fl_owner = owner;
@@ -1902,25 +1914,11 @@ void locks_remove_posix(struct file *filp, fl_owner_t owner)
         lock.fl_ops = NULL;
         lock.fl_lmops = NULL;
 
-        if (filp->f_op && filp->f_op->lock != NULL) {
+        if (filp->f_op && filp->f_op->lock != NULL)
                 filp->f_op->lock(filp, F_SETLK, &lock);
-                goto out;
-        }
+        else
+                posix_lock_file(filp, &lock);
 
-        /* Can't use posix_lock_file here; we need to remove it no matter
-         * which pid we have.
-         */
-        lock_kernel();
-        while (*before != NULL) {
-                struct file_lock *fl = *before;
-                if (IS_POSIX(fl) && posix_same_owner(fl, &lock)) {
-                        locks_delete_lock(before);
-                        continue;
-                }
-                before = &fl->fl_next;
-        }
-        unlock_kernel();
-out:
         if (lock.fl_ops && lock.fl_ops->fl_release_private)
                 lock.fl_ops->fl_release_private(&lock);
 }
@@ -2206,63 +2204,6 @@ int lock_may_write(struct inode *inode, loff_t start, unsigned long len)
 
 EXPORT_SYMBOL(lock_may_write);
 
-static inline void __steal_locks(struct file *file, fl_owner_t from)
-{
-        struct inode *inode = file->f_dentry->d_inode;
-        struct file_lock *fl = inode->i_flock;
-
-        while (fl) {
-                if (fl->fl_file == file && fl->fl_owner == from)
-                        fl->fl_owner = current->files;
-                fl = fl->fl_next;
-        }
-}
-
-/* When getting ready for executing a binary, we make sure that current
- * has a files_struct on its own. Before dropping the old files_struct,
- * we take over ownership of all locks for all file descriptors we own.
- * Note that we may accidentally steal a lock for a file that a sibling
- * has created since the unshare_files() call.
- */
-void steal_locks(fl_owner_t from)
-{
-        struct files_struct *files = current->files;
-        int i, j;
-        struct fdtable *fdt;
-
-        if (from == files)
-                return;
-
-        lock_kernel();
-        j = 0;
-
-        /*
-         * We are not taking a ref to the file structures, so
-         * we need to acquire ->file_lock.
-         */
-        spin_lock(&files->file_lock);
-        fdt = files_fdtable(files);
-        for (;;) {
-                unsigned long set;
-                i = j * __NFDBITS;
-                if (i >= fdt->max_fdset || i >= fdt->max_fds)
-                        break;
-                set = fdt->open_fds->fds_bits[j++];
-                while (set) {
-                        if (set & 1) {
-                                struct file *file = fdt->fd[i];
-                                if (file)
-                                        __steal_locks(file, from);
-                        }
-                        i++;
-                        set >>= 1;
-                }
-        }
-        spin_unlock(&files->file_lock);
-        unlock_kernel();
-}
-EXPORT_SYMBOL(steal_locks);
-
 static int __init filelock_init(void)
 {
         filelock_cache = kmem_cache_create("file_lock_cache",