ceph: fix direct-io on non-page-aligned buffers

The user buffer may be 512-byte aligned, not page-aligned.  We were
assuming the buffer was page-aligned and only accounting for
non-page-aligned io offsets.

Signed-off-by: Henry C Chang <henry_c_chang@tcloudcomputing.com>
Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 19 insertions, 12 deletions

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 8d79b8912e31..e860d8f1bb45 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -282,7 +282,8 @@ int ceph_release(struct inode *inode, struct file *file)
 static int striped_read(struct inode *inode,
                         u64 off, u64 len,
                         struct page **pages, int num_pages,
-                        int *checkeof, bool align_to_pages)
+                        int *checkeof, bool align_to_pages,
+                        unsigned long buf_align)
 {
         struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
         struct ceph_inode_info *ci = ceph_inode(inode);
@@ -307,7 +308,7 @@ static int striped_read(struct inode *inode,
 
 more:
         if (align_to_pages)
-                page_align = (pos - io_align) & ~PAGE_MASK;
+                page_align = (pos - io_align + buf_align) & ~PAGE_MASK;
         else
                 page_align = pos & ~PAGE_MASK;
         this_len = left;
@@ -376,16 +377,18 @@ static ssize_t ceph_sync_read(struct file *file, char __user *data,
         struct inode *inode = file->f_dentry->d_inode;
         struct page **pages;
         u64 off = *poff;
-        int num_pages = calc_pages_for(off, len);
-        int ret;
+        int num_pages, ret;
 
         dout("sync_read on file %p %llu~%u %s\n", file, off, len,
              (file->f_flags & O_DIRECT) ? "O_DIRECT" : "");
 
-        if (file->f_flags & O_DIRECT)
+        if (file->f_flags & O_DIRECT) {
+                num_pages = calc_pages_for((unsigned long)data, len);
                 pages = ceph_get_direct_page_vector(data, num_pages);
-        else
+        } else {
+                num_pages = calc_pages_for(off, len);
                 pages = ceph_alloc_page_vector(num_pages, GFP_NOFS);
+        }
         if (IS_ERR(pages))
                 return PTR_ERR(pages);
 
@@ -400,7 +403,8 @@ static ssize_t ceph_sync_read(struct file *file, char __user *data,
                 goto done;
 
         ret = striped_read(inode, off, len, pages, num_pages, checkeof,
-                           file->f_flags & O_DIRECT);
+                           file->f_flags & O_DIRECT,
+                           (unsigned long)data & ~PAGE_MASK);
 
         if (ret >= 0 && (file->f_flags & O_DIRECT) == 0)
                 ret = ceph_copy_page_vector_to_user(pages, data, off, ret);
@@ -456,6 +460,7 @@ static ssize_t ceph_sync_write(struct file *file, const char __user *data,
         int do_sync = 0;
         int check_caps = 0;
         int page_align, io_align;
+        unsigned long buf_align;
         int ret;
         struct timespec mtime = CURRENT_TIME;
 
@@ -471,6 +476,7 @@ static ssize_t ceph_sync_write(struct file *file, const char __user *data,
                 pos = *offset;
 
         io_align = pos & ~PAGE_MASK;
+        buf_align = (unsigned long)data & ~PAGE_MASK;
 
         ret = filemap_write_and_wait_range(inode->i_mapping, pos, pos + left);
         if (ret < 0)
@@ -496,12 +502,15 @@ static ssize_t ceph_sync_write(struct file *file, const char __user *data,
          */
 more:
         len = left;
-        if (file->f_flags & O_DIRECT)
+        if (file->f_flags & O_DIRECT) {
                 /* write from beginning of first page, regardless of
                    io alignment */
-                page_align = (pos - io_align) & ~PAGE_MASK;
-        else
+                page_align = (pos - io_align + buf_align) & ~PAGE_MASK;
+                num_pages = calc_pages_for((unsigned long)data, len);
+        } else {
                 page_align = pos & ~PAGE_MASK;
+                num_pages = calc_pages_for(pos, len);
+        }
         req = ceph_osdc_new_request(&fsc->client->osdc, &ci->i_layout,
                                     ceph_vino(inode), pos, &len,
                                     CEPH_OSD_OP_WRITE, flags,
@@ -512,8 +521,6 @@ more:
         if (!req)
                 return -ENOMEM;
 
-        num_pages = calc_pages_for(pos, len);
-
         if (file->f_flags & O_DIRECT) {
                 pages = ceph_get_direct_page_vector(data, num_pages);
                 if (IS_ERR(pages)) {