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ceph: avoid 32-bit page index overflow 

A pgoff_t is defined (by default) to have type (unsigned long).  On
architectures such as i686 that's a 32-bit type.  The ceph address
space code was attempting to produce 64 bit offsets by shifting a
page's index by PAGE_CACHE_SHIFT, but the result was not what was
desired because the shift occurred before the result got promoted
to 64 bits.

Fix this by converting all uses of page->index used in this way to
use the page_offset() macro, which ensures the 64-bit result has the
intended value.

This fixes http://tracker.newdream.net/issues/3112

Reported-by:  Mohamed Pakkeer <pakkeer.mohideen@realimage.com>
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
This commit is contained in:
Alex Elder 2012-10-02 10:25:51 -05:00
parent 457712a0bc
commit 6285bc2312
1 changed files with 5 additions and 6 deletions
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11
fs/ceph/addr.c
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@ -205,7 +205,7 @@ static int readpage_nounlock(struct file *filp, struct page *page)
dout("readpage inode %p file %p page %p index %lu\n",
inode, filp, page, page->index);
err = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
page->index << PAGE_CACHE_SHIFT, &len,
(u64) page_offset(page), &len,
ci->i_truncate_seq, ci->i_truncate_size,
&page, 1, 0);
if (err == -ENOENT)
@ -286,7 +286,7 @@ static int start_read(struct inode *inode, struct list_head *page_list, int max)
int nr_pages = 0;
int ret;
off = page->index << PAGE_CACHE_SHIFT;
off = (u64) page_offset(page);
/* count pages */
next_index = page->index;
@ -426,7 +426,7 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
struct ceph_inode_info *ci;
struct ceph_fs_client *fsc;
struct ceph_osd_client *osdc;
loff_t page_off = page->index << PAGE_CACHE_SHIFT;
loff_t page_off = page_offset(page);
int len = PAGE_CACHE_SIZE;
loff_t i_size;
int err = 0;
@ -817,8 +817,7 @@ get_more_pages:
/* ok */
if (locked_pages == 0) {
/* prepare async write request */
offset = (unsigned long long)page->index
<< PAGE_CACHE_SHIFT;
offset = (u64) page_offset(page);
len = wsize;
req = ceph_osdc_new_request(&fsc->client->osdc,
&ci->i_layout,
@ -1180,7 +1179,7 @@ static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
struct inode *inode = vma->vm_file->f_dentry->d_inode;
struct page *page = vmf->page;
struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
loff_t off = page->index << PAGE_CACHE_SHIFT;
loff_t off = page_offset(page);
loff_t size, len;
int ret;