| From | "Kirill A. Shutemov" <> | Subject | [PATCH 15/23] mm, fs: avoid page allocation beyond i_size on read | Date | Sun, 4 Aug 2013 05:17:17 +0300 |
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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
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