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>

diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 8d79b8912e31e4cb8fcb4961ec1f81d63c3d5070..e860d8f1bb452f3b6fd1ba85de18de9833394982 100644 (file)
--- 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)) {