GFS2: Fix writing to non-page aligned gfs2_quota structures
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>
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@ -637,15 +637,40 @@ static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,
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unsigned blocksize, iblock, pos;
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struct buffer_head *bh, *dibh;
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struct page *page;
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void *kaddr;
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struct gfs2_quota *qp;
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s64 value;
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int err = -EIO;
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void *kaddr, *ptr;
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struct gfs2_quota q, *qp;
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int err, nbytes;
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u64 size;
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if (gfs2_is_stuffed(ip))
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gfs2_unstuff_dinode(ip, NULL);
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memset(&q, 0, sizeof(struct gfs2_quota));
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err = gfs2_internal_read(ip, NULL, (char *)&q, &loc, sizeof(q));
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if (err < 0)
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return err;
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err = -EIO;
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qp = &q;
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qp->qu_value = be64_to_cpu(qp->qu_value);
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qp->qu_value += change;
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qp->qu_value = cpu_to_be64(qp->qu_value);
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qd->qd_qb.qb_value = qp->qu_value;
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if (fdq) {
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if (fdq->d_fieldmask & FS_DQ_BSOFT) {
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qp->qu_warn = cpu_to_be64(fdq->d_blk_softlimit);
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qd->qd_qb.qb_warn = qp->qu_warn;
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}
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if (fdq->d_fieldmask & FS_DQ_BHARD) {
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qp->qu_limit = cpu_to_be64(fdq->d_blk_hardlimit);
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qd->qd_qb.qb_limit = qp->qu_limit;
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}
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}
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/* Write the quota into the quota file on disk */
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ptr = qp;
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nbytes = sizeof(struct gfs2_quota);
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get_a_page:
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page = grab_cache_page(mapping, index);
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if (!page)
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return -ENOMEM;
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@ -667,7 +692,12 @@ static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,
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if (!buffer_mapped(bh)) {
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gfs2_block_map(inode, iblock, bh, 1);
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if (!buffer_mapped(bh))
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goto unlock;
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goto unlock_out;
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/* If it's a newly allocated disk block for quota, zero it */
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if (buffer_new(bh)) {
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memset(bh->b_data, 0, bh->b_size);
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set_buffer_uptodate(bh);
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}
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}
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if (PageUptodate(page))
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@ -677,32 +707,34 @@ static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,
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ll_rw_block(READ_META, 1, &bh);
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wait_on_buffer(bh);
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if (!buffer_uptodate(bh))
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goto unlock;
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goto unlock_out;
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}
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gfs2_trans_add_bh(ip->i_gl, bh, 0);
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kaddr = kmap_atomic(page, KM_USER0);
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qp = kaddr + offset;
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value = (s64)be64_to_cpu(qp->qu_value) + change;
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qp->qu_value = cpu_to_be64(value);
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qd->qd_qb.qb_value = qp->qu_value;
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if (fdq) {
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if (fdq->d_fieldmask & FS_DQ_BSOFT) {
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qp->qu_warn = cpu_to_be64(fdq->d_blk_softlimit);
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qd->qd_qb.qb_warn = qp->qu_warn;
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}
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if (fdq->d_fieldmask & FS_DQ_BHARD) {
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qp->qu_limit = cpu_to_be64(fdq->d_blk_hardlimit);
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qd->qd_qb.qb_limit = qp->qu_limit;
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}
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}
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if (offset + sizeof(struct gfs2_quota) > PAGE_CACHE_SIZE)
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nbytes = PAGE_CACHE_SIZE - offset;
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memcpy(kaddr + offset, ptr, nbytes);
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flush_dcache_page(page);
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kunmap_atomic(kaddr, KM_USER0);
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unlock_page(page);
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page_cache_release(page);
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/* If quota straddles page boundary, we need to update the rest of the
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* quota at the beginning of the next page */
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if (offset != 0) { /* first page, offset is closer to PAGE_CACHE_SIZE */
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ptr = ptr + nbytes;
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nbytes = sizeof(struct gfs2_quota) - nbytes;
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offset = 0;
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index++;
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goto get_a_page;
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}
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/* Update the disk inode timestamp and size (if extended) */
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err = gfs2_meta_inode_buffer(ip, &dibh);
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if (err)
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goto unlock;
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goto out;
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size = loc + sizeof(struct gfs2_quota);
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if (size > inode->i_size) {
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@ -715,7 +747,9 @@ static int gfs2_adjust_quota(struct gfs2_inode *ip, loff_t loc,
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brelse(dibh);
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mark_inode_dirty(inode);
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unlock:
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out:
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return err;
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unlock_out:
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unlock_page(page);
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page_cache_release(page);
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return err;
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@ -779,8 +813,10 @@ static int do_sync(unsigned int num_qd, struct gfs2_quota_data **qda)
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* rgrp since it won't be allocated during the transaction
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*/
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al->al_requested = 1;
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/* +1 in the end for block requested above for unstuffing */
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blocks = num_qd * data_blocks + RES_DINODE + num_qd + 1;
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/* +3 in the end for unstuffing block, inode size update block
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* and another block in case quota straddles page boundary and
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* two blocks need to be updated instead of 1 */
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blocks = num_qd * data_blocks + RES_DINODE + num_qd + 3;
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if (nalloc)
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al->al_requested += nalloc * (data_blocks + ind_blocks);
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