Commit fea9f718 authored Jul 11, 2012 by Bob Liu Committed by Linus Torvalds Jul 11, 2012

fs: ramfs: file-nommu: add SetPageUptodate()



There is a bug in the below scenario for !CONFIG_MMU:

 1. create a new file
 2. mmap the file and write to it
 3. read the file can't get the correct value

Because

  sys_read() -> generic_file_aio_read() -> simple_readpage() -> clear_page()

which causes the page to be zeroed.

Add SetPageUptodate() to ramfs_nommu_expand_for_mapping() so that
generic_file_aio_read() do not call simple_readpage().

Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent b59f6d1f

fs/ramfs/file-nommu.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -110,6 +110,7 @@ int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)

		/* prevent the page from being discarded on memory pressure */
		SetPageDirty(page);
		SetPageUptodate(page);

		unlock_page(page);
		put_page(page);

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