ocfs2: Fix possible deadlock when extending quota file
In OCFS2, allocator locks rank above transaction start. Thus we cannot extend quota file from inside a transaction less we could deadlock. We solve the problem by starting transaction not already in ocfs2_acquire_dquot() but only in ocfs2_local_read_dquot() and ocfs2_global_read_dquot() and we allocate blocks to quota files before starting the transaction. In case we crash, quota files will just have a few blocks more but that's no problem since we just use them next time we extend the quota file. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Joel Becker <joel.becker@oracle.com>
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8a57a9dda7
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@ -363,11 +363,6 @@ static inline int ocfs2_quota_trans_credits(struct super_block *sb)
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return credits;
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}
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/* Number of credits needed for removing quota structure from file */
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int ocfs2_calc_qdel_credits(struct super_block *sb, int type);
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/* Number of credits needed for initialization of new quota structure */
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int ocfs2_calc_qinit_credits(struct super_block *sb, int type);
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/* group extend. inode update and last group update. */
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#define OCFS2_GROUP_EXTEND_CREDITS (OCFS2_INODE_UPDATE_CREDITS + 1)
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@ -215,11 +215,7 @@ ssize_t ocfs2_quota_write(struct super_block *sb, int type,
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loff_t rounded_end =
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ocfs2_align_bytes_to_blocks(sb, off + len);
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down_write(&OCFS2_I(gqinode)->ip_alloc_sem);
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err = ocfs2_extend_no_holes(gqinode, rounded_end, off);
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up_write(&OCFS2_I(gqinode)->ip_alloc_sem);
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if (err < 0)
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goto out;
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/* Space is already allocated in ocfs2_global_read_dquot() */
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err = ocfs2_simple_size_update(gqinode,
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oinfo->dqi_gqi_bh,
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rounded_end);
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@ -405,13 +401,36 @@ int ocfs2_global_write_info(struct super_block *sb, int type)
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return err;
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}
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static int ocfs2_global_qinit_alloc(struct super_block *sb, int type)
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{
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struct ocfs2_mem_dqinfo *oinfo = sb_dqinfo(sb, type)->dqi_priv;
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/*
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* We may need to allocate tree blocks and a leaf block but not the
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* root block
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*/
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return oinfo->dqi_gi.dqi_qtree_depth;
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}
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static int ocfs2_calc_global_qinit_credits(struct super_block *sb, int type)
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{
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/* We modify all the allocated blocks, tree root, and info block */
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return (ocfs2_global_qinit_alloc(sb, type) + 2) *
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OCFS2_QUOTA_BLOCK_UPDATE_CREDITS;
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}
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/* Read in information from global quota file and acquire a reference to it.
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* dquot_acquire() has already started the transaction and locked quota file */
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int ocfs2_global_read_dquot(struct dquot *dquot)
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{
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int err, err2, ex = 0;
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struct ocfs2_mem_dqinfo *info =
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sb_dqinfo(dquot->dq_sb, dquot->dq_type)->dqi_priv;
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struct super_block *sb = dquot->dq_sb;
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int type = dquot->dq_type;
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struct ocfs2_mem_dqinfo *info = sb_dqinfo(sb, type)->dqi_priv;
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struct ocfs2_super *osb = OCFS2_SB(sb);
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struct inode *gqinode = info->dqi_gqinode;
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int need_alloc = ocfs2_global_qinit_alloc(sb, type);
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handle_t *handle = NULL;
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err = ocfs2_qinfo_lock(info, 0);
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if (err < 0)
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@ -422,14 +441,33 @@ int ocfs2_global_read_dquot(struct dquot *dquot)
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OCFS2_DQUOT(dquot)->dq_use_count++;
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OCFS2_DQUOT(dquot)->dq_origspace = dquot->dq_dqb.dqb_curspace;
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OCFS2_DQUOT(dquot)->dq_originodes = dquot->dq_dqb.dqb_curinodes;
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ocfs2_qinfo_unlock(info, 0);
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if (!dquot->dq_off) { /* No real quota entry? */
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/* Upgrade to exclusive lock for allocation */
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ocfs2_qinfo_unlock(info, 0);
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err = ocfs2_qinfo_lock(info, 1);
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if (err < 0)
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goto out_qlock;
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ex = 1;
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/*
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* Add blocks to quota file before we start a transaction since
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* locking allocators ranks above a transaction start
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*/
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WARN_ON(journal_current_handle());
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down_write(&OCFS2_I(gqinode)->ip_alloc_sem);
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err = ocfs2_extend_no_holes(gqinode,
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gqinode->i_size + (need_alloc << sb->s_blocksize_bits),
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gqinode->i_size);
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up_write(&OCFS2_I(gqinode)->ip_alloc_sem);
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if (err < 0)
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goto out;
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}
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handle = ocfs2_start_trans(osb,
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ocfs2_calc_global_qinit_credits(sb, type));
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if (IS_ERR(handle)) {
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err = PTR_ERR(handle);
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goto out;
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}
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err = ocfs2_qinfo_lock(info, ex);
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if (err < 0)
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goto out_trans;
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err = qtree_write_dquot(&info->dqi_gi, dquot);
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if (ex && info_dirty(sb_dqinfo(dquot->dq_sb, dquot->dq_type))) {
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err2 = __ocfs2_global_write_info(dquot->dq_sb, dquot->dq_type);
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@ -441,6 +479,9 @@ out_qlock:
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ocfs2_qinfo_unlock(info, 1);
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else
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ocfs2_qinfo_unlock(info, 0);
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out_trans:
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if (handle)
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ocfs2_commit_trans(osb, handle);
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out:
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if (err < 0)
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mlog_errno(err);
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@ -638,24 +679,17 @@ out:
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return status;
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}
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int ocfs2_calc_qdel_credits(struct super_block *sb, int type)
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static int ocfs2_calc_qdel_credits(struct super_block *sb, int type)
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{
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struct ocfs2_mem_dqinfo *oinfo;
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int features[MAXQUOTAS] = { OCFS2_FEATURE_RO_COMPAT_USRQUOTA,
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OCFS2_FEATURE_RO_COMPAT_GRPQUOTA };
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if (!OCFS2_HAS_RO_COMPAT_FEATURE(sb, features[type]))
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return 0;
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oinfo = sb_dqinfo(sb, type)->dqi_priv;
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struct ocfs2_mem_dqinfo *oinfo = sb_dqinfo(sb, type)->dqi_priv;
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/*
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* We modify tree, leaf block, global info, local chunk header,
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* global and local inode; OCFS2_QINFO_WRITE_CREDITS already
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* accounts for inode update
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*/
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return oinfo->dqi_gi.dqi_qtree_depth +
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return (oinfo->dqi_gi.dqi_qtree_depth + 2) *
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OCFS2_QUOTA_BLOCK_UPDATE_CREDITS +
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OCFS2_QINFO_WRITE_CREDITS +
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2 * OCFS2_QUOTA_BLOCK_UPDATE_CREDITS +
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OCFS2_INODE_UPDATE_CREDITS;
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}
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@ -688,36 +722,10 @@ out:
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return status;
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}
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int ocfs2_calc_qinit_credits(struct super_block *sb, int type)
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{
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struct ocfs2_mem_dqinfo *oinfo;
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int features[MAXQUOTAS] = { OCFS2_FEATURE_RO_COMPAT_USRQUOTA,
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OCFS2_FEATURE_RO_COMPAT_GRPQUOTA };
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struct ocfs2_dinode *lfe, *gfe;
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if (!OCFS2_HAS_RO_COMPAT_FEATURE(sb, features[type]))
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return 0;
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oinfo = sb_dqinfo(sb, type)->dqi_priv;
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gfe = (struct ocfs2_dinode *)oinfo->dqi_gqi_bh->b_data;
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lfe = (struct ocfs2_dinode *)oinfo->dqi_lqi_bh->b_data;
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/* We can extend local file + global file. In local file we
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* can modify info, chunk header block and dquot block. In
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* global file we can modify info, tree and leaf block */
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return ocfs2_calc_extend_credits(sb, &lfe->id2.i_list, 0) +
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ocfs2_calc_extend_credits(sb, &gfe->id2.i_list, 0) +
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OCFS2_LOCAL_QINFO_WRITE_CREDITS +
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2 * OCFS2_QUOTA_BLOCK_UPDATE_CREDITS +
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oinfo->dqi_gi.dqi_qtree_depth +
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2 * OCFS2_QUOTA_BLOCK_UPDATE_CREDITS;
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}
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static int ocfs2_acquire_dquot(struct dquot *dquot)
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{
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handle_t *handle;
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struct ocfs2_mem_dqinfo *oinfo =
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sb_dqinfo(dquot->dq_sb, dquot->dq_type)->dqi_priv;
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struct ocfs2_super *osb = OCFS2_SB(dquot->dq_sb);
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int status = 0;
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mlog_entry("id=%u, type=%d", dquot->dq_id, dquot->dq_type);
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@ -726,16 +734,7 @@ static int ocfs2_acquire_dquot(struct dquot *dquot)
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status = ocfs2_lock_global_qf(oinfo, 1);
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if (status < 0)
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goto out;
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handle = ocfs2_start_trans(osb,
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ocfs2_calc_qinit_credits(dquot->dq_sb, dquot->dq_type));
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if (IS_ERR(handle)) {
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status = PTR_ERR(handle);
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mlog_errno(status);
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goto out_ilock;
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}
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status = dquot_acquire(dquot);
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ocfs2_commit_trans(osb, handle);
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out_ilock:
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ocfs2_unlock_global_qf(oinfo, 1);
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out:
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mlog_exit(status);
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