update Documentation/filesystems/Locking

The rules for locking in many superblock operations has changed
significantly, so update the documentation for it.  Also correct some
older updates and ommissions.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 22 insertions, 21 deletions

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 229d7b7c50a3..18b9d0ca0630 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -109,27 +109,28 @@ prototypes:
 
 locking rules:
         All may block.
-                        BKL     s_lock  s_umount
-alloc_inode:            no      no      no
-destroy_inode:          no
-dirty_inode:            no                              (must not sleep)
-write_inode:            no
-drop_inode:             no                              !!!inode_lock!!!
-delete_inode:           no
-put_super:              yes     yes     no
-write_super:            no      yes     read
-sync_fs:                no      no      read
-freeze_fs:              ?
-unfreeze_fs:            ?
-statfs:                 no      no      no
-remount_fs:             yes     yes     maybe           (see below)
-clear_inode:            no
-umount_begin:           yes     no      no
-show_options:           no                              (vfsmount->sem)
-quota_read:             no      no      no              (see below)
-quota_write:            no      no      no              (see below)
-
-->remount_fs() will have the s_umount lock if it's already mounted.
+        None have BKL
+                        s_umount
+alloc_inode:
+destroy_inode:
+dirty_inode:                            (must not sleep)
+write_inode:
+drop_inode:                             !!!inode_lock!!!
+delete_inode:
+put_super:              write
+write_super:            read
+sync_fs:                read
+freeze_fs:              read
+unfreeze_fs:            read
+statfs:                 no
+remount_fs:             maybe           (see below)
+clear_inode:
+umount_begin:           no
+show_options:           no              (namespace_sem)
+quota_read:             no              (see below)
+quota_write:            no              (see below)
+
+->remount_fs() will have the s_umount exclusive lock if it's already mounted.
 When called from get_sb_single, it does NOT have the s_umount lock.
 ->quota_read() and ->quota_write() functions are both guaranteed to
 be the only ones operating on the quota file by the quota code (via