ceph: fix page alignment corrections

 dd if=/dev/urandom of=/mnt/fs_depot/dd10 bs=500 seek=8388 count=1
 dd if=/mnt/fs_depot/dd10 of=/root/dd10out bs=500 skip=8388 count=1

Reported-by: Henry C Chang <henry.cy.chang@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 3 insertions, 5 deletions

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 9542f07d0b93..2be0f35afdfb 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -290,7 +290,6 @@ static int striped_read(struct inode *inode,
         struct ceph_inode_info *ci = ceph_inode(inode);
         u64 pos, this_len;
         int io_align, page_align;
-        int page_off = off & ~PAGE_CACHE_MASK; /* first byte's offset in page */
         int left, pages_left;
         int read;
         struct page **page_pos;
@@ -326,12 +325,11 @@ more:
              ret, hit_stripe ? " HITSTRIPE" : "", was_short ? " SHORT" : "");
 
         if (ret > 0) {
-                int didpages =
-                        ((pos & ~PAGE_CACHE_MASK) + ret) >> PAGE_CACHE_SHIFT;
+                int didpages = (page_align + ret) >> PAGE_CACHE_SHIFT;
 
                 if (read < pos - off) {
                         dout(" zero gap %llu to %llu\n", off + read, pos);
-                        ceph_zero_page_vector_range(page_off + read,
+                        ceph_zero_page_vector_range(page_align + read,
                                                     pos - off - read, pages);
                 }
                 pos += ret;
@@ -356,7 +354,7 @@ more:
                                 left = inode->i_size - pos;
 
                         dout("zero tail %d\n", left);
-                        ceph_zero_page_vector_range(page_off + read, left,
+                        ceph_zero_page_vector_range(page_align + read, left,
                                                     pages);
                         read += left;
                 }