From: Bob Liu <lliubbo@gmail.com>
To: akpm@linux-foundation.org
Cc: hughd@google.com, dhowells@redhat.com, linux-mm@kvack.org,
Bob Liu <lliubbo@gmail.com>
Subject: [PATCH] fs: ramfs: file-nommu: add SetPageUptodate()
Date: Wed, 27 Jun 2012 22:55:12 +0800 [thread overview]
Message-ID: <1340808912-4722-1-git-send-email-lliubbo@gmail.com> (raw)
There is a bug in below scene for platform !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 make the page 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>
---
fs/ramfs/file-nommu.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c
index fbb0b47..d5378d0 100644
--- a/fs/ramfs/file-nommu.c
+++ b/fs/ramfs/file-nommu.c
@@ -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);
--
1.7.9.5
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reply other threads:[~2012-06-27 6:53 UTC|newest]
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