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>
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 229d7b7..18b9d0c 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -109,27 +109,28 @@
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)
+ 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 lock if it's already mounted.
+->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