diff options
| -rw-r--r-- | mm/fadvise.c | 10 |
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 |