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GFS2: Fix writing to non-page aligned gfs2_quota structures

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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 <adas@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This commit is contained in:
Abhijith Das 2010-05-07 17:50:18 -04:00 committed by Steven Whitehouse
parent 913a71d250
commit 7e619bc3e6
1 changed files with 61 additions and 25 deletions
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86
fs/gfs2/quota.c
View file

@ -637,15 +637,40 @@ static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,
unsigned blocksize, iblock, pos;
struct buffer_head *bh, *dibh;
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;
u64 size;
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;
if (fdq) {
if (fdq->d_fieldmask & FS_DQ_BSOFT) {
qp->qu_warn = cpu_to_be64(fdq->d_blk_softlimit);
qd->qd_qb.qb_warn = qp->qu_warn;
}
if (fdq->d_fieldmask & FS_DQ_BHARD) {
qp->qu_limit = cpu_to_be64(fdq->d_blk_hardlimit);
qd->qd_qb.qb_limit = qp->qu_limit;
}
}
/* 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;
@ -667,7 +692,12 @@ static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,
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))
@ -677,32 +707,34 @@ static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,
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 (fdq) {
if (fdq->d_fieldmask & FS_DQ_BSOFT) {
qp->qu_warn = cpu_to_be64(fdq->d_blk_softlimit);
qd->qd_qb.qb_warn = qp->qu_warn;
}
if (fdq->d_fieldmask & FS_DQ_BHARD) {
qp->qu_limit = cpu_to_be64(fdq->d_blk_hardlimit);
qd->qd_qb.qb_limit = qp->qu_limit;
}
}
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;
}
/* Update the disk inode timestamp and size (if extended) */
err = gfs2_meta_inode_buffer(ip, &dibh);
if (err)
goto unlock;
goto out;
size = loc + sizeof(struct gfs2_quota);
if (size > inode->i_size) {
@ -715,7 +747,9 @@ static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,
brelse(dibh);
mark_inode_dirty(inode);
unlock:
out:
return err;
unlock_out:
unlock_page(page);
page_cache_release(page);
return err;
@ -779,8 +813,10 @@ static int do_sync(unsigned int num_qd, struct gfs2_quota_data **qda)
* 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);