This is a note to let you know that I've just added the patch titled
GFS2: Fix writing to non-page aligned gfs2_quota structures
to the 2.6.32-longterm tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/longterm/longterm-queue-2.6.32.git;a=summary
The filename of the patch is:
gfs2-fix-writing-to-non-page-aligned-gfs2_quota-stru.patch
and it can be found in the queue-2.6.32 subdirectory.
If you, or anyone else, feels it should not be added to the 2.6.32 longterm
tree,
please let <[email protected]> know about it.
>From ba91013ba6defd37d5f681827b7293fd0a801deb Mon Sep 17 00:00:00 2001
From: Abhijith Das <[email protected]>
Date: Fri, 7 May 2010 17:50:18 -0400
Subject: GFS2: Fix writing to non-page aligned gfs2_quota structures
From: Abhijith Das <[email protected]>
commit 7e619bc3e6252dc746f64ac3b486e784822e9533 upstream.
This is the upstream fix for this bug. This patch differs
from the RHEL5 fix (Red Hat bz #555754) which simply writes to the 8-byte
value field of the quota. In upstream quota code, we're
required to write the entire quota (88 bytes) which can be split
across a page boundary. We check for such quotas, and read/write
the two parts from/to the corresponding pages holding these parts.
With this patch, I don't see the bug anymore using the reproducer
in Red Hat bz 555754. I successfully ran a couple of simple tests/mounts/
umounts and it doesn't seem like this patch breaks anything else.
Signed-off-by: Abhi Das <[email protected]>
Signed-off-by: Steven Whitehouse <[email protected]>
[Backported to 2.6.32 by dann frazier <[email protected]>]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/gfs2/quota.c | 62 +++++++++++++++++++++++++++++++++++++++++++-------------
1 file changed, 48 insertions(+), 14 deletions(-)
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -633,14 +633,29 @@ static int gfs2_adjust_quota(struct gfs2
unsigned blocksize, iblock, pos;
struct buffer_head *bh;
struct page *page;
- void *kaddr;
- struct gfs2_quota *qp;
- s64 value;
- int err = -EIO;
+ void *kaddr, *ptr;
+ struct gfs2_quota q, *qp;
+ int err, nbytes;
if (gfs2_is_stuffed(ip))
gfs2_unstuff_dinode(ip, NULL);
-
+
+ memset(&q, 0, sizeof(struct gfs2_quota));
+ err = gfs2_internal_read(ip, NULL, (char *)&q, &loc, sizeof(q));
+ if (err < 0)
+ return err;
+
+ err = -EIO;
+ qp = &q;
+ qp->qu_value = be64_to_cpu(qp->qu_value);
+ qp->qu_value += change;
+ qp->qu_value = cpu_to_be64(qp->qu_value);
+ qd->qd_qb.qb_value = qp->qu_value;
+
+ /* Write the quota into the quota file on disk */
+ ptr = qp;
+ nbytes = sizeof(struct gfs2_quota);
+get_a_page:
page = grab_cache_page(mapping, index);
if (!page)
return -ENOMEM;
@@ -662,7 +677,12 @@ static int gfs2_adjust_quota(struct gfs2
if (!buffer_mapped(bh)) {
gfs2_block_map(inode, iblock, bh, 1);
if (!buffer_mapped(bh))
- goto unlock;
+ goto unlock_out;
+ /* If it's a newly allocated disk block for quota, zero it */
+ if (buffer_new(bh)) {
+ memset(bh->b_data, 0, bh->b_size);
+ set_buffer_uptodate(bh);
+ }
}
if (PageUptodate(page))
@@ -672,20 +692,32 @@ static int gfs2_adjust_quota(struct gfs2
ll_rw_block(READ_META, 1, &bh);
wait_on_buffer(bh);
if (!buffer_uptodate(bh))
- goto unlock;
+ goto unlock_out;
}
gfs2_trans_add_bh(ip->i_gl, bh, 0);
kaddr = kmap_atomic(page, KM_USER0);
- qp = kaddr + offset;
- value = (s64)be64_to_cpu(qp->qu_value) + change;
- qp->qu_value = cpu_to_be64(value);
- qd->qd_qb.qb_value = qp->qu_value;
+ if (offset + sizeof(struct gfs2_quota) > PAGE_CACHE_SIZE)
+ nbytes = PAGE_CACHE_SIZE - offset;
+ memcpy(kaddr + offset, ptr, nbytes);
flush_dcache_page(page);
kunmap_atomic(kaddr, KM_USER0);
+ unlock_page(page);
+ page_cache_release(page);
+
+ /* If quota straddles page boundary, we need to update the rest of the
+ * quota at the beginning of the next page */
+ if (offset != 0) { /* first page, offset is closer to PAGE_CACHE_SIZE */
+ ptr = ptr + nbytes;
+ nbytes = sizeof(struct gfs2_quota) - nbytes;
+ offset = 0;
+ index++;
+ goto get_a_page;
+ }
err = 0;
-unlock:
+ return err;
+unlock_out:
unlock_page(page);
page_cache_release(page);
return err;
@@ -748,8 +780,10 @@ static int do_sync(unsigned int num_qd,
* rgrp since it won't be allocated during the transaction
*/
al->al_requested = 1;
- /* +1 in the end for block requested above for unstuffing */
- blocks = num_qd * data_blocks + RES_DINODE + num_qd + 1;
+ /* +3 in the end for unstuffing block, inode size update block
+ * and another block in case quota straddles page boundary and
+ * two blocks need to be updated instead of 1 */
+ blocks = num_qd * data_blocks + RES_DINODE + num_qd + 3;
if (nalloc)
al->al_requested += nalloc * (data_blocks + ind_blocks);
Patches currently in longterm-queue-2.6.32 which might be from [email protected]
are
/home/gregkh/linux/longterm/longterm-queue-2.6.32/queue-2.6.32/gfs2-fix-writing-to-non-page-aligned-gfs2_quota-stru.patch
/home/gregkh/linux/longterm/longterm-queue-2.6.32/queue-2.6.32/gfs2-bug-in-gfs2_adjust_quota.patch
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