Merge branch 'fixes-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

[pandora-kernel.git] / Documentation / filesystems / porting

diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index 07a32b4..dfbcd1b 100644 (file)
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -365,8 +365,8 @@ must be done in the RCU callback.
 [recommended]
        vfs now tries to do path walking in "rcu-walk mode", which avoids
 atomic operations and scalability hazards on dentries and inodes (see
-Documentation/filesystems/path-walk.txt). d_hash and d_compare changes (above)
-are examples of the changes required to support this. For more complex
+Documentation/filesystems/path-lookup.txt). d_hash and d_compare changes
+(above) are examples of the changes required to support this. For more complex
 filesystem callbacks, the vfs drops out of rcu-walk mode before the fs call, so
 no changes are required to the filesystem. However, this is costly and loses
 the benefits of rcu-walk mode. We will begin to add filesystem callbacks that
@@ -383,5 +383,14 @@ Documentation/filesystems/vfs.txt for more details.
 
        permission and check_acl are inode permission checks that are called
 on many or all directory inodes on the way down a path walk (to check for
-exec permission). These must now be rcu-walk aware (flags & IPERM_RCU). See
-Documentation/filesystems/vfs.txt for more details.
+exec permission). These must now be rcu-walk aware (flags & IPERM_FLAG_RCU).
+See Documentation/filesystems/vfs.txt for more details.
+ 
+--
+[mandatory]
+       In ->fallocate() you must check the mode option passed in.  If your
+filesystem does not support hole punching (deallocating space in the middle of a
+file) you must return -EOPNOTSUPP if FALLOC_FL_PUNCH_HOLE is set in mode.
+Currently you can only have FALLOC_FL_PUNCH_HOLE with FALLOC_FL_KEEP_SIZE set,
+so the i_size should not change when hole punching, even when puching the end of
+a file off.