ocfs2: Fix ocfs2_read_quota_block() error handling.

ocfs2_bread() has become ocfs2_read_virt_blocks(), with a prototype to
match ocfs2_read_blocks().  The quota code, converting from
ocfs2_bread(), wraps the call to ocfs2_read_virt_blocks() in
ocfs2_read_quota_block().  Unfortunately, the prototype of
ocfs2_read_quota_block() matches the old prototype of ocfs2_bread().

The problem is that ocfs2_bread() returned the buffer head, and callers
assumed that a NULL pointer was indicative of error.  It wasn't.  This
is why ocfs2_bread() took an int*err argument as well.

The new prototype of ocfs2_read_virt_blocks() avoids this error handling
confusion.  Let's change ocfs2_read_quota_block() to match.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

4 files changed, 60 insertions, 48 deletions

diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index 058aa86490a..b1c75911d8a 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -3519,7 +3519,7 @@ static int ocfs2_refresh_qinfo(struct ocfs2_mem_dqinfo *oinfo)
                                             oinfo->dqi_gi.dqi_type);
         struct ocfs2_lock_res *lockres = &oinfo->dqi_gqlock;
         struct ocfs2_qinfo_lvb *lvb = ocfs2_dlm_lvb(&lockres->l_lksb);
-        struct buffer_head *bh;
+        struct buffer_head *bh = NULL;
         struct ocfs2_global_disk_dqinfo *gdinfo;
         int status = 0;
 
@@ -3532,8 +3532,8 @@ static int ocfs2_refresh_qinfo(struct ocfs2_mem_dqinfo *oinfo)
                 oinfo->dqi_gi.dqi_free_entry =
                                         be32_to_cpu(lvb->lvb_free_entry);
         } else {
-                bh = ocfs2_read_quota_block(oinfo->dqi_gqinode, 0, &status);
-                if (!bh) {
+                status = ocfs2_read_quota_block(oinfo->dqi_gqinode, 0, &bh);
+                if (status) {
                         mlog_errno(status);
                         goto bail;
                 }
diff --git a/fs/ocfs2/quota.h b/fs/ocfs2/quota.h
index 04872b45b99..7365e2e0870 100644
--- a/fs/ocfs2/quota.h
+++ b/fs/ocfs2/quota.h
@@ -107,8 +107,8 @@ static inline int ocfs2_global_release_dquot(struct dquot *dquot)
 
 int ocfs2_lock_global_qf(struct ocfs2_mem_dqinfo *oinfo, int ex);
 void ocfs2_unlock_global_qf(struct ocfs2_mem_dqinfo *oinfo, int ex);
-struct buffer_head *ocfs2_read_quota_block(struct inode *inode,
-                                           int block, int *err);
+int ocfs2_read_quota_block(struct inode *inode, u64 v_block,
+                           struct buffer_head **bh);
 
 extern struct dquot_operations ocfs2_quota_operations;
 extern struct quota_format_type ocfs2_quota_format;
diff --git a/fs/ocfs2/quota_global.c b/fs/ocfs2/quota_global.c
index 10ecb33298d..2bdcddd3f1c 100644
--- a/fs/ocfs2/quota_global.c
+++ b/fs/ocfs2/quota_global.c
@@ -87,16 +87,21 @@ struct qtree_fmt_operations ocfs2_global_ops = {
         .is_id = ocfs2_global_is_id,
 };
 
-struct buffer_head *ocfs2_read_quota_block(struct inode *inode,
-                                           int block, int *err)
+int ocfs2_read_quota_block(struct inode *inode, u64 v_block,
+                           struct buffer_head **bh)
 {
-        struct buffer_head *tmp = NULL;
+        int rc = 0;
+        struct buffer_head *tmp = *bh;
 
-        *err = ocfs2_read_virt_blocks(inode, block, 1, &tmp, 0, NULL);
-        if (*err)
-                mlog_errno(*err);
+        rc = ocfs2_read_virt_blocks(inode, v_block, 1, &tmp, 0, NULL);
+        if (rc)
+                mlog_errno(rc);
+
+        /* If ocfs2_read_virt_blocks() got us a new bh, pass it up. */
+        if (!rc && !*bh)
+                *bh = tmp;
 
-        return tmp;
+        return rc;
 }
 
 static struct buffer_head *ocfs2_get_quota_block(struct inode *inode,
@@ -143,8 +148,9 @@ ssize_t ocfs2_quota_read(struct super_block *sb, int type, char *data,
         toread = len;
         while (toread > 0) {
                 tocopy = min((size_t)(sb->s_blocksize - offset), toread);
-                bh = ocfs2_read_quota_block(gqinode, blk, &err);
-                if (!bh) {
+                bh = NULL;
+                err = ocfs2_read_quota_block(gqinode, blk, &bh);
+                if (err) {
                         mlog_errno(err);
                         return err;
                 }
@@ -169,7 +175,7 @@ ssize_t ocfs2_quota_write(struct super_block *sb, int type,
         int offset = off & (sb->s_blocksize - 1);
         sector_t blk = off >> sb->s_blocksize_bits;
         int err = 0, new = 0;
-        struct buffer_head *bh;
+        struct buffer_head *bh = NULL;
         handle_t *handle = journal_current_handle();
 
         if (!handle) {
@@ -200,13 +206,13 @@ ssize_t ocfs2_quota_write(struct super_block *sb, int type,
         /* Not rewriting whole block? */
         if ((offset || len < sb->s_blocksize - OCFS2_QBLK_RESERVED_SPACE) &&
             !new) {
-                bh = ocfs2_read_quota_block(gqinode, blk, &err);
-                if (!bh) {
+                err = ocfs2_read_quota_block(gqinode, blk, &bh);
+                if (err) {
                         mlog_errno(err);
                         return err;
                 }
                 err = ocfs2_journal_access(handle, gqinode, bh,
-                                                OCFS2_JOURNAL_ACCESS_WRITE);
+                                           OCFS2_JOURNAL_ACCESS_WRITE);
         } else {
                 bh = ocfs2_get_quota_block(gqinode, blk, &err);
                 if (!bh) {
@@ -214,7 +220,7 @@ ssize_t ocfs2_quota_write(struct super_block *sb, int type,
                         return err;
                 }
                 err = ocfs2_journal_access(handle, gqinode, bh,
-                                                OCFS2_JOURNAL_ACCESS_CREATE);
+                                           OCFS2_JOURNAL_ACCESS_CREATE);
         }
         if (err < 0) {
                 brelse(bh);
diff --git a/fs/ocfs2/quota_local.c b/fs/ocfs2/quota_local.c
index b98562174cd..7053664f66a 100644
--- a/fs/ocfs2/quota_local.c
+++ b/fs/ocfs2/quota_local.c
@@ -139,15 +139,15 @@ static int ocfs2_local_check_quota_file(struct super_block *sb, int type)
         unsigned int gversions[MAXQUOTAS] = OCFS2_GLOBAL_QVERSIONS;
         unsigned int ino[MAXQUOTAS] = { USER_QUOTA_SYSTEM_INODE,
                                         GROUP_QUOTA_SYSTEM_INODE };
-        struct buffer_head *bh;
+        struct buffer_head *bh = NULL;
         struct inode *linode = sb_dqopt(sb)->files[type];
         struct inode *ginode = NULL;
         struct ocfs2_disk_dqheader *dqhead;
         int status, ret = 0;
 
         /* First check whether we understand local quota file */
-        bh = ocfs2_read_quota_block(linode, 0, &status);
-        if (!bh) {
+        status = ocfs2_read_quota_block(linode, 0, &bh);
+        if (status) {
                 mlog_errno(status);
                 mlog(ML_ERROR, "failed to read quota file header (type=%d)\n",
                         type);
@@ -178,8 +178,8 @@ static int ocfs2_local_check_quota_file(struct super_block *sb, int type)
                 goto out_err;
         }
         /* Since the header is read only, we don't care about locking */
-        bh = ocfs2_read_quota_block(ginode, 0, &status);
-        if (!bh) {
+        status = ocfs2_read_quota_block(ginode, 0, &bh);
+        if (status) {
                 mlog_errno(status);
                 mlog(ML_ERROR, "failed to read global quota file header "
                                 "(type=%d)\n", type);
@@ -235,10 +235,11 @@ static int ocfs2_load_local_quota_bitmaps(struct inode *inode,
                         return -ENOMEM;
                 }
                 newchunk->qc_num = i;
-                newchunk->qc_headerbh = ocfs2_read_quota_block(inode,
+                newchunk->qc_headerbh = NULL;
+                status = ocfs2_read_quota_block(inode,
                                 ol_quota_chunk_block(inode->i_sb, i),
-                                &status);
-                if (!newchunk->qc_headerbh) {
+                                &newchunk->qc_headerbh);
+                if (status) {
                         mlog_errno(status);
                         kmem_cache_free(ocfs2_qf_chunk_cachep, newchunk);
                         ocfs2_release_local_quota_bitmaps(head);
@@ -320,10 +321,11 @@ static int ocfs2_recovery_load_quota(struct inode *lqinode,
         int status = 0;
 
         for (i = 0; i < chunks; i++) {
-                hbh = ocfs2_read_quota_block(lqinode,
-                                             ol_quota_chunk_block(sb, i),
-                                             &status);
-                if (!hbh) {
+                hbh = NULL;
+                status = ocfs2_read_quota_block(lqinode,
+                                                ol_quota_chunk_block(sb, i),
+                                                &hbh);
+                if (status) {
                         mlog_errno(status);
                         break;
                 }
@@ -392,8 +394,9 @@ struct ocfs2_quota_recovery *ocfs2_begin_quota_recovery(
                         goto out_put;
                 }
                 /* Now read local header */
-                bh = ocfs2_read_quota_block(lqinode, 0, &status);
-                if (!bh) {
+                bh = NULL;
+                status = ocfs2_read_quota_block(lqinode, 0, &bh);
+                if (status) {
                         mlog_errno(status);
                         mlog(ML_ERROR, "failed to read quota file info header "
                                 "(slot=%d type=%d)\n", slot_num, type);
@@ -447,19 +450,21 @@ static int ocfs2_recover_local_quota_file(struct inode *lqinode,
 
         list_for_each_entry_safe(rchunk, next, &(rec->r_list[type]), rc_list) {
                 chunk = rchunk->rc_chunk;
-                hbh = ocfs2_read_quota_block(lqinode,
-                                             ol_quota_chunk_block(sb, chunk),
-                                             &status);
-                if (!hbh) {
+                hbh = NULL;
+                status = ocfs2_read_quota_block(lqinode,
+                                                ol_quota_chunk_block(sb, chunk),
+                                                &hbh);
+                if (status) {
                         mlog_errno(status);
                         break;
                 }
                 dchunk = (struct ocfs2_local_disk_chunk *)hbh->b_data;
                 for_each_bit(bit, rchunk->rc_bitmap, ol_chunk_entries(sb)) {
-                        qbh = ocfs2_read_quota_block(lqinode,
+                        qbh = NULL;
+                        status = ocfs2_read_quota_block(lqinode,
                                                 ol_dqblk_block(sb, chunk, bit),
-                                                &status);
-                        if (!qbh) {
+                                                &qbh);
+                        if (status) {
                                 mlog_errno(status);
                                 break;
                         }
@@ -581,8 +586,9 @@ int ocfs2_finish_quota_recovery(struct ocfs2_super *osb,
                         goto out_put;
                 }
                 /* Now read local header */
-                bh = ocfs2_read_quota_block(lqinode, 0, &status);
-                if (!bh) {
+                bh = NULL;
+                status = ocfs2_read_quota_block(lqinode, 0, &bh);
+                if (status) {
                         mlog_errno(status);
                         mlog(ML_ERROR, "failed to read quota file info header "
                                 "(slot=%d type=%d)\n", slot_num, type);
@@ -676,8 +682,8 @@ static int ocfs2_local_read_info(struct super_block *sb, int type)
         locked = 1;
 
         /* Now read local header */
-        bh = ocfs2_read_quota_block(lqinode, 0, &status);
-        if (!bh) {
+        status = ocfs2_read_quota_block(lqinode, 0, &bh);
+        if (status) {
                 mlog_errno(status);
                 mlog(ML_ERROR, "failed to read quota file info header "
                         "(type=%d)\n", type);
@@ -850,13 +856,13 @@ static int ocfs2_local_write_dquot(struct dquot *dquot)
 {
         struct super_block *sb = dquot->dq_sb;
         struct ocfs2_dquot *od = OCFS2_DQUOT(dquot);
-        struct buffer_head *bh;
+        struct buffer_head *bh = NULL;
         int status;
 
-        bh = ocfs2_read_quota_block(sb_dqopt(sb)->files[dquot->dq_type],
+        status = ocfs2_read_quota_block(sb_dqopt(sb)->files[dquot->dq_type],
                                     ol_dqblk_file_block(sb, od->dq_local_off),
-                                    &status);
-        if (!bh) {
+                                    &bh);
+        if (status) {
                 mlog_errno(status);
                 goto out;
         }