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-rw-r--r--mm/fadvise.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/mm/fadvise.c b/mm/fadvise.c
index ec70d6e4b86d..767887f5f3bf 100644
--- a/mm/fadvise.c
+++ b/mm/fadvise.c
@@ -127,7 +127,15 @@ SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice)
*/
start_index = (offset+(PAGE_SIZE-1)) >> PAGE_SHIFT;
end_index = (endbyte >> PAGE_SHIFT);
- if ((endbyte & ~PAGE_MASK) != ~PAGE_MASK) {
+ /*
+ * The page at end_index will be inclusively discarded according
+ * by invalidate_mapping_pages(), so subtracting 1 from
+ * end_index means we will skip the last page. But if endbyte
+ * is page aligned or is at the end of file, we should not skip
+ * that page - discarding the last page is safe enough.
+ */
+ if ((endbyte & ~PAGE_MASK) != ~PAGE_MASK &&
+ endbyte != inode->i_size - 1) {
/* First page is tricky as 0 - 1 = -1, but pgoff_t
* is unsigned, so the end_index >= start_index
* check below would be true and we'll discard the whole