Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull second round of VFS updates from Al Viro:
 "Assorted fixes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  xtensa simdisk: fix braino in "xtensa simdisk: switch to proc_create_data()"
  hostfs: use kmalloc instead of kzalloc
  hostfs: move HOSTFS_SUPER_MAGIC to <linux/magic.h>
  hostfs: remove "will unlock" comment
  vfs: use list_move instead of list_del/list_add
  proc_devtree: Replace include linux/module.h with linux/export.h
  create_mnt_ns: unidiomatic use of list_add()
  fs: remove dentry_lru_prune()
  Removed unused typedef to avoid "unused local typedef" warnings.
  kill fs/read_write.h
  fs: Fix hang with BSD accounting on frozen filesystem
  sun3_scsi: add ->show_info()
  nubus: Kill nubus_proc_detach_device()
  more mode_t whack-a-mole...
  do_coredump(): don't wait for thaw if coredump has already been interrupted
  do_mount(): fix a leak introduced in 3.9 ("mount: consolidate permission checks")

kernel/acct.c

@@ -539,11 +539,16 @@ static void do_acct_process(struct bsd_acct_struct *acct,
 	ac.ac_rw = encode_comp_t(ac.ac_io / 1024);
 	ac.ac_swaps = encode_comp_t(0);
 
+	/*
+	 * Get freeze protection. If the fs is frozen, just skip the write
+	 * as we could deadlock the system otherwise.
+	 */
+	if (!file_start_write_trylock(file))
+		goto out;
 	/*
 	 * Kernel segment override to datasegment and write it
 	 * to the accounting file.
 	 */
-	file_start_write(file);
 	fs = get_fs();
 	set_fs(KERNEL_DS);
 	/*