diff options
| -rw-r--r-- | fs/xfs/xfs_aops.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 596ec71da00e..79670869d436 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -1516,13 +1516,26 @@ xfs_vm_write_failed( loff_t pos, unsigned len) { - loff_t block_offset = pos & PAGE_MASK; + loff_t block_offset; loff_t block_start; loff_t block_end; loff_t from = pos & (PAGE_CACHE_SIZE - 1); loff_t to = from + len; struct buffer_head *bh, *head; + /* + * The request pos offset might be 32 or 64 bit, this is all fine + * on 64-bit platform. However, for 64-bit pos request on 32-bit + * platform, the high 32-bit will be masked off if we evaluate the + * block_offset via (pos & PAGE_MASK) because the PAGE_MASK is + * 0xfffff000 as an unsigned long, hence the result is incorrect + * which could cause the following ASSERT failed in most cases. + * In order to avoid this, we can evaluate the block_offset of the + * start of the page by using shifts rather than masks the mismatch + * problem. + */ + block_offset = (pos >> PAGE_CACHE_SHIFT) << PAGE_CACHE_SHIFT; + ASSERT(block_offset + from == pos); head = page_buffers(page); |