X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;f=Documentation%2Ffilesystems%2FLocking;h=28bfea75bcf26151ac5594d131cbbc71d0dc93d0;hb=4aa9ab67fb9c0dfdb1692f4ec413120832a22ddc;hp=eb1a6cad21e6a8cadc993111b1f4c7099d794ad2;hpb=63c422afe3739b68bec0b5c42807d1450c951caf;p=powerpc.git

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index eb1a6cad21..28bfea75bc 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -124,7 +124,7 @@ sync_fs:		no	no	read
 write_super_lockfs:	?
 unlockfs:		?
 statfs:			no	no	no
-remount_fs:		no	yes	maybe		(see below)
+remount_fs:		yes	yes	maybe		(see below)
 clear_inode:		no
 umount_begin:		yes	no	no
 show_options:		no				(vfsmount->sem)
@@ -171,6 +171,7 @@ prototypes:
 	int (*releasepage) (struct page *, int);
 	int (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
 			loff_t offset, unsigned long nr_segs);
+	int (*launder_page) (struct page *);
 
 locking rules:
 	All except set_page_dirty may block
@@ -188,6 +189,7 @@ bmap:			yes
 invalidatepage:		no	yes
 releasepage:		no	yes
 direct_IO:		no
+launder_page:		no	yes
 
 	->prepare_write(), ->commit_write(), ->sync_page() and ->readpage()
 may be called from the request handler (/dev/loop).
@@ -281,6 +283,12 @@ buffers from the page in preparation for freeing it.  It returns zero to
 indicate that the buffers are (or may be) freeable.  If ->releasepage is zero,
 the kernel assumes that the fs has no private interest in the buffers.
 
+	->launder_page() may be called prior to releasing a page if
+it is still found to be dirty. It returns zero if the page was successfully
+cleaned, or an error value if not. Note that in order to prevent the page
+getting mapped back in and redirtied, it needs to be kept locked
+across the entire operation.
+
 	Note: currently almost all instances of address_space methods are
 using BKL for internal serialization and that's one of the worst sources
 of contention. Normally they are calling library functions (in fs/buffer.c)