lkml.org 
[lkml]   [2013]   [Aug]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 15/23] mm, fs: avoid page allocation beyond i_size on read
Date
From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>

I've noticed that we allocated unneeded page for cache on read beyond
i_size. Simple test case (I checked it on ramfs):

$ touch testfile
$ cat testfile

It triggers 'no_cached_page' code path in do_generic_file_read().

Looks like it's regression since commit a32ea1e. Let's fix it.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: NeilBrown <neilb@suse.de>
---
mm/filemap.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/mm/filemap.c b/mm/filemap.c
index 066bbff..c31d296 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1163,6 +1163,10 @@ static void do_generic_file_read(struct file *filp, loff_t *ppos,
loff_t isize;
unsigned long nr, ret;

+ isize = i_size_read(inode);
+ if (!isize || index > (isize - 1) >> PAGE_CACHE_SHIFT)
+ goto out;
+
cond_resched();
find_page:
page = find_get_page(mapping, index);
--
1.8.3.2


\
 
 \ /
  Last update: 2013-08-04 04:41    [W:0.164 / U:0.256 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site