2.6.24

 fs

diff --git a/fs/locks.c b/fs/locks.c
index c795eaa..8b8388e 100644
--- a/fs/locks.c
+++ b/fs/locks.c
@@ -199,7 +199,7 @@ EXPORT_SYMBOL(locks_init_lock);
  * Initialises the fields of the file lock which are invariant for
  * free file_locks.
  */
-static void init_once(void *foo, struct kmem_cache *cache, unsigned long flags)
+static void init_once(struct kmem_cache *cache, void *foo)
 {
    struct file_lock *lock = (struct file_lock *) foo;
 
@@ -534,7 +534,9 @@ static void locks_insert_block(struct file_lock *blocker,
 static void locks_wake_up_blocks(struct file_lock *blocker)
 {
    while (!list_empty(&blocker->fl_block)) {
-      struct file_lock *waiter = list_entry(blocker->fl_block.next,
+      struct file_lock *waiter;
+
+      waiter = list_first_entry(&blocker->fl_block,
             struct file_lock, fl_block);
       __locks_delete_block(waiter);
       if (waiter->fl_lmops && waiter->fl_lmops->fl_notify)
@@ -668,7 +670,7 @@ posix_test_lock(struct file *filp, struct file_lock *fl)
    for (cfl = filp->f_path.dentry->d_inode->i_flock; cfl; cfl = cfl->fl_next) {
       if (!IS_POSIX(cfl))
          continue;
-      if (posix_locks_conflict(cfl, fl))
+      if (posix_locks_conflict(fl, cfl))
          break;
    }
    if (cfl)
@@ -694,18 +696,28 @@ EXPORT_SYMBOL(posix_test_lock);
  * Note: the above assumption may not be true when handling lock requests
  * from a broken NFS client. But broken NFS clients have a lot more to
  * worry about than proper deadlock detection anyway... --okir
+ *
+ * However, the failure of this assumption (also possible in the case of
+ * multiple tasks sharing the same open file table) also means there's no
+ * guarantee that the loop below will terminate.  As a hack, we give up
+ * after a few iterations.
  */
+
+#define MAX_DEADLK_ITERATIONS 10
+
 static int posix_locks_deadlock(struct file_lock *caller_fl,
             struct file_lock *block_fl)
 {
-   struct list_head *tmp;
+   struct file_lock *fl;
+   int i = 0;
 
 next_task:
    if (posix_same_owner(caller_fl, block_fl))
       return 1;
-   list_for_each(tmp, &blocked_list) {
-      struct file_lock *fl = list_entry(tmp, struct file_lock, fl_link);
+   list_for_each_entry(fl, &blocked_list, fl_link) {
       if (posix_same_owner(fl, block_fl)) {
+         if (i++ > MAX_DEADLK_ITERATIONS)
+            return 0;
          fl = fl->fl_next;
          block_fl = fl;
          goto next_task;
@@ -715,8 +727,7 @@ next_task:
 }
 
 /* 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.
+ * after any leases, but before any posix locks.
  *
  * Note that if called with an FL_EXISTS argument, the caller may determine
  * whether or not a lock was successfully freed by testing the return
@@ -733,6 +744,15 @@ static int flock_lock_file(struct file *filp, struct file_lock *request)
    lock_kernel();
    if (request->fl_flags & FL_ACCESS)
       goto find_conflict;
+
+   if (request->fl_type != F_UNLCK) {
+      error = -ENOMEM;
+      new_fl = locks_alloc_lock();
+      if (new_fl == NULL)
+         goto out;
+      error = 0;
+   }
+
    for_each_lock(inode, before) {
       struct file_lock *fl = *before;
       if (IS_POSIX(fl))
@@ -754,10 +774,6 @@ static int flock_lock_file(struct file *filp, struct file_lock *request)
       goto out;
    }
 
-   error = -ENOMEM;
-   new_fl = locks_alloc_lock();
-   if (new_fl == NULL)
-      goto out;
    /*
     * If a higher-priority process was blocked on the old file lock,
     * give it the opportunity to lock the file.
@@ -819,7 +835,7 @@ static int __posix_lock_file(struct inode *inode, struct file_lock *request, str
    lock_kernel();
    if (request->fl_type != F_UNLCK) {
       for_each_lock(inode, before) {
-         struct file_lock *fl = *before;
+         fl = *before;
          if (!IS_POSIX(fl))
             continue;
          if (!posix_locks_conflict(request, fl))
@@ -1113,7 +1129,7 @@ int locks_mandatory_area(int read_write, struct inode *inode,
           * If we've been sleeping someone might have
           * changed the permissions behind our back.
           */
-         if ((inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID)
+         if (__mandatory_lock(inode))
             continue;
       }
 
@@ -1337,6 +1353,7 @@ int fcntl_getlease(struct file *filp)
 int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
 {
    struct file_lock *fl, **before, **my_before = NULL, *lease;
+   struct file_lock *new_fl = NULL;
    struct dentry *dentry = filp->f_path.dentry;
    struct inode *inode = dentry->d_inode;
    int error, rdlease_count = 0, wrlease_count = 0;
@@ -1363,6 +1380,11 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
       || (atomic_read(&inode->i_count) > 1)))
       goto out;
 
+   error = -ENOMEM;
+   new_fl = locks_alloc_lock();
+   if (new_fl == NULL)
+      goto out;
+
    /*
     * At this point, we know that if there is an exclusive
     * lease on this file, then we hold it on this filp
@@ -1405,18 +1427,15 @@ int generic_setlease(struct file *filp, long arg, struct file_lock **flp)
    if (!leases_enable)
       goto out;
 
-   error = -ENOMEM;
-   fl = locks_alloc_lock();
-   if (fl == NULL)
-      goto out;
-
-   locks_copy_lock(fl, lease);
+   locks_copy_lock(new_fl, lease);
+   locks_insert_lock(before, new_fl);
 
-   locks_insert_lock(before, fl);
+   *flp = new_fl;
+   return 0;
 
-   *flp = fl;
-   error = 0;
 out:
+   if (new_fl != NULL)
+      locks_free_lock(new_fl);
    return error;
 }
 EXPORT_SYMBOL(generic_setlease);
@@ -1752,9 +1771,7 @@ int fcntl_setlk(unsigned int fd, struct file *filp, unsigned int cmd,
    /* Don't allow mandatory locks on files that may be memory mapped
     * and shared.
     */
-   if (IS_MANDLOCK(inode) &&
-       (inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
-       mapping_writably_mapped(filp->f_mapping)) {
+   if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
       error = -EAGAIN;
       goto out;
    }
@@ -1878,9 +1895,7 @@ int fcntl_setlk64(unsigned int fd, struct file *filp, unsigned int cmd,
    /* Don't allow mandatory locks on files that may be memory mapped
     * and shared.
     */
-   if (IS_MANDLOCK(inode) &&
-       (inode->i_mode & (S_ISGID | S_IXGRP)) == S_ISGID &&
-       mapping_writably_mapped(filp->f_mapping)) {
+   if (mandatory_lock(inode) && mapping_writably_mapped(filp->f_mapping)) {
       error = -EAGAIN;
       goto out;
    }
@@ -2062,138 +2077,114 @@ int vfs_cancel_lock(struct file *filp, struct file_lock *fl)
 
 EXPORT_SYMBOL_GPL(vfs_cancel_lock);
 
-static void lock_get_status(char* out, struct file_lock *fl, int id, char *pfx)
+#ifdef CONFIG_PROC_FS
+#include <linux/seq_file.h>
+
+static void lock_get_status(struct seq_file *f, struct file_lock *fl,
+                     int id, char *pfx)
 {
    struct inode *inode = NULL;
 
    if (fl->fl_file != NULL)
       inode = fl->fl_file->f_path.dentry->d_inode;
 
-   out += sprintf(out, "%d:%s ", id, pfx);
+   seq_printf(f, "%d:%s ", id, pfx);
    if (IS_POSIX(fl)) {
-      out += sprintf(out, "%6s %s ",
+      seq_printf(f, "%6s %s ",
               (fl->fl_flags & FL_ACCESS) ? "ACCESS" : "POSIX ",
               (inode == NULL) ? "*NOINODE*" :
-              (IS_MANDLOCK(inode) &&
-               (inode->i_mode & (S_IXGRP | S_ISGID)) == S_ISGID) ?
-              "MANDATORY" : "ADVISORY ");
+              mandatory_lock(inode) ? "MANDATORY" : "ADVISORY ");
    } else if (IS_FLOCK(fl)) {
       if (fl->fl_type & LOCK_MAND) {
-         out += sprintf(out, "FLOCK  MSNFS     ");
+         seq_printf(f, "FLOCK  MSNFS     ");
       } else {
-         out += sprintf(out, "FLOCK  ADVISORY  ");
+         seq_printf(f, "FLOCK  ADVISORY  ");
       }
    } else if (IS_LEASE(fl)) {
-      out += sprintf(out, "LEASE  ");
+      seq_printf(f, "LEASE  ");
       if (fl->fl_type & F_INPROGRESS)
-         out += sprintf(out, "BREAKING  ");
+         seq_printf(f, "BREAKING  ");
       else if (fl->fl_file)
-         out += sprintf(out, "ACTIVE    ");
+         seq_printf(f, "ACTIVE    ");
       else
-         out += sprintf(out, "BREAKER   ");
+         seq_printf(f, "BREAKER   ");
    } else {
-      out += sprintf(out, "UNKNOWN UNKNOWN  ");
+      seq_printf(f, "UNKNOWN UNKNOWN  ");
    }
    if (fl->fl_type & LOCK_MAND) {
-      out += sprintf(out, "%s ",
+      seq_printf(f, "%s ",
                 (fl->fl_type & LOCK_READ)
                 ? (fl->fl_type & LOCK_WRITE) ? "RW   " : "READ "
                 : (fl->fl_type & LOCK_WRITE) ? "WRITE" : "NONE ");
    } else {
-      out += sprintf(out, "%s ",
+      seq_printf(f, "%s ",
                 (fl->fl_type & F_INPROGRESS)
                 ? (fl->fl_type & F_UNLCK) ? "UNLCK" : "READ "
                 : (fl->fl_type & F_WRLCK) ? "WRITE" : "READ ");
    }
    if (inode) {
 #ifdef WE_CAN_BREAK_LSLK_NOW
-      out += sprintf(out, "%d %s:%ld ", fl->fl_pid,
+      seq_printf(f, "%d %s:%ld ", fl->fl_pid,
             inode->i_sb->s_id, inode->i_ino);
 #else
       /* userspace relies on this representation of dev_t ;-( */
-      out += sprintf(out, "%d %02x:%02x:%ld ", fl->fl_pid,
+      seq_printf(f, "%d %02x:%02x:%ld ", fl->fl_pid,
             MAJOR(inode->i_sb->s_dev),
             MINOR(inode->i_sb->s_dev), inode->i_ino);
 #endif
    } else {
-      out += sprintf(out, "%d <none>:0 ", fl->fl_pid);
+      seq_printf(f, "%d <none>:0 ", fl->fl_pid);
    }
    if (IS_POSIX(fl)) {
       if (fl->fl_end == OFFSET_MAX)
-         out += sprintf(out, "%Ld EOF\n", fl->fl_start);
+         seq_printf(f, "%Ld EOF\n", fl->fl_start);
       else
-         out += sprintf(out, "%Ld %Ld\n", fl->fl_start,
-               fl->fl_end);
+         seq_printf(f, "%Ld %Ld\n", fl->fl_start, fl->fl_end);
    } else {
-      out += sprintf(out, "0 EOF\n");
+      seq_printf(f, "0 EOF\n");
    }
 }
 
-static void move_lock_status(char **p, off_t* pos, off_t offset)
+static int locks_show(struct seq_file *f, void *v)
 {
-   int len;
-   len = strlen(*p);
-   if(*pos >= offset) {
-      /* the complete line is valid */
-      *p += len;
-      *pos += len;
-      return;
-   }
-   if(*pos+len > offset) {
-      /* use the second part of the line */
-      int i = offset-*pos;
-      memmove(*p,*p+i,len-i);
-      *p += len-i;
-      *pos += len;
-      return;
-   }
-   /* discard the complete line */
-   *pos += len;
+   struct file_lock *fl, *bfl;
+
+   fl = list_entry(v, struct file_lock, fl_link);
+
+   lock_get_status(f, fl, (long)f->private, "");
+
+   list_for_each_entry(bfl, &fl->fl_block, fl_block)
+      lock_get_status(f, bfl, (long)f->private, " ->");
+
+   f->private++;
+   return 0;
 }
 
-/**
- *   get_locks_status   -   reports lock usage in /proc/locks
- *   @buffer: address in userspace to write into
- *   @start: ?
- *   @offset: how far we are through the buffer
- *   @length: how much to read
- */
+static void *locks_start(struct seq_file *f, loff_t *pos)
+{
+   lock_kernel();
+   f->private = (void *)1;
+   return seq_list_start(&file_lock_list, *pos);
+}
 
-int get_locks_status(char *buffer, char **start, off_t offset, int length)
+static void *locks_next(struct seq_file *f, void *v, loff_t *pos)
 {
-   struct list_head *tmp;
-   char *q = buffer;
-   off_t pos = 0;
-   int i = 0;
+   return seq_list_next(v, &file_lock_list, pos);
+}
 
-   lock_kernel();
-   list_for_each(tmp, &file_lock_list) {
-      struct list_head *btmp;
-      struct file_lock *fl = list_entry(tmp, struct file_lock, fl_link);
-      lock_get_status(q, fl, ++i, "");
-      move_lock_status(&q, &pos, offset);
-
-      if(pos >= offset+length)
-         goto done;
-
-      list_for_each(btmp, &fl->fl_block) {
-         struct file_lock *bfl = list_entry(btmp,
-               struct file_lock, fl_block);
-         lock_get_status(q, bfl, i, " ->");
-         move_lock_status(&q, &pos, offset);
-
-         if(pos >= offset+length)
-            goto done;
-      }
-   }
-done:
+static void locks_stop(struct seq_file *f, void *v)
+{
    unlock_kernel();
-   *start = buffer;
-   if(q-buffer < length)
-      return (q-buffer);
-   return length;
 }
 
+struct seq_operations locks_seq_operations = {
+   .start   = locks_start,
+   .next   = locks_next,
+   .stop   = locks_stop,
+   .show   = locks_show,
+};
+#endif
+
 /**
  *   lock_may_read - checks that the region is free of locks
  *   @inode: the inode that is being read