[Ocfs2-devel] [PATCH] ocfs2: fix BUG due to uncleaned localalloc during mount

[Joseph Qi]

Tariq has reported a BUG before and posted a fix at:
https://oss.oracle.com/pipermail/ocfs2-devel/2015-April/010696.html

This is because during umount, localalloc shutdown relies on journal
shutdown. But during journal shutdown, it just stops commit thread
without checking its result. So it may happen that localalloc shutdown
uncleaned during I/O error and after that, journal then has been marked
clean if I/O restores.
Then during mount, localalloc won't be recovered because of clean
journal and then trigger BUG when claiming clusters from localalloc.

In Tariq's fix, we have to run fsck offline and a separate fix to fsck
is needed because it currently does not support clearing out localalloc
inode. And my way to fix this issue is checking localalloc before
actually loading it during mount. And this is somewhat online.

Signed-off-by: Joseph Qi <joseph.qi at huawei.com>
---
 fs/ocfs2/localalloc.c | 19 ++++++++++++-------
 fs/ocfs2/localalloc.h |  2 +-
 fs/ocfs2/super.c      | 17 ++++++++++++++---
 3 files changed, 27 insertions(+), 11 deletions(-)

diff --git a/fs/ocfs2/localalloc.c b/fs/ocfs2/localalloc.c
index 0a4457f..ceebaef 100644
--- a/fs/ocfs2/localalloc.c
+++ b/fs/ocfs2/localalloc.c
@@ -281,7 +281,7 @@ bail:
 	return ret;
 }

-int ocfs2_load_local_alloc(struct ocfs2_super *osb)
+int ocfs2_load_local_alloc(struct ocfs2_super *osb, int check, int *recovery)
 {
 	int status = 0;
 	struct ocfs2_dinode *alloc = NULL;
@@ -345,21 +345,26 @@ int ocfs2_load_local_alloc(struct ocfs2_super *osb)
 	if (num_used
 	    || alloc->id1.bitmap1.i_used
 	    || alloc->id1.bitmap1.i_total
-	    || la->la_bm_off)
+	    || la->la_bm_off) {
 		mlog(ML_ERROR, "Local alloc hasn't been recovered!\n"
 		     "found = %u, set = %u, taken = %u, off = %u\n",
 		     num_used, le32_to_cpu(alloc->id1.bitmap1.i_used),
 		     le32_to_cpu(alloc->id1.bitmap1.i_total),
 		     OCFS2_LOCAL_ALLOC(alloc)->la_bm_off);
+		status = -EINVAL;
+		*recovery = 1;
+		goto bail;
+	}

-	osb->local_alloc_bh = alloc_bh;
-	osb->local_alloc_state = OCFS2_LA_ENABLED;
+	if (!check) {
+		osb->local_alloc_bh = alloc_bh;
+		osb->local_alloc_state = OCFS2_LA_ENABLED;
+	}

 bail:
-	if (status < 0)
+	if (status < 0 || check)
 		brelse(alloc_bh);
-	if (inode)
-		iput(inode);
+	iput(inode);

 	trace_ocfs2_load_local_alloc(osb->local_alloc_bits);

diff --git a/fs/ocfs2/localalloc.h b/fs/ocfs2/localalloc.h
index 44a7d1f..a913841 100644
--- a/fs/ocfs2/localalloc.h
+++ b/fs/ocfs2/localalloc.h
@@ -26,7 +26,7 @@
 #ifndef OCFS2_LOCALALLOC_H
 #define OCFS2_LOCALALLOC_H

-int ocfs2_load_local_alloc(struct ocfs2_super *osb);
+int ocfs2_load_local_alloc(struct ocfs2_super *osb, int check, int *recovery);

 void ocfs2_shutdown_local_alloc(struct ocfs2_super *osb);

diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 2de4c8a..4004b29 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -2428,6 +2428,7 @@ static int ocfs2_check_volume(struct ocfs2_super *osb)
 	int status;
 	int dirty;
 	int local;
+	int la_dirty = 0, recovery = 0;
 	struct ocfs2_dinode *local_alloc = NULL; /* only used if we
 						  * recover
 						  * ourselves. */
@@ -2449,6 +2450,16 @@ static int ocfs2_check_volume(struct ocfs2_super *osb)
 	 * recover anything. Otherwise, journal_load will do that
 	 * dirty work for us :) */
 	if (!dirty) {
+		/* It may happen that local alloc is unclean shutdown, but
+		 * journal has been marked clean, so check it here and do
+		 * recovery if needed */
+		status = ocfs2_load_local_alloc(osb, 1, &recovery);
+		if (recovery) {
+			printk(KERN_NOTICE "ocfs2: local alloc needs recovery "
+					"on device (%s).\n", osb->dev_str);
+			la_dirty = 1;
+		}
+
 		status = ocfs2_journal_wipe(osb->journal, 0);
 		if (status < 0) {
 			mlog_errno(status);
@@ -2477,7 +2488,7 @@ static int ocfs2_check_volume(struct ocfs2_super *osb)
 				JBD2_FEATURE_COMPAT_CHECKSUM, 0,
 				JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT);

-	if (dirty) {
+	if (dirty || la_dirty) {
 		/* recover my local alloc if we didn't unmount cleanly. */
 		status = ocfs2_begin_local_alloc_recovery(osb,
 							  osb->slot_num,
@@ -2490,13 +2501,13 @@ static int ocfs2_check_volume(struct ocfs2_super *osb)
 		 * ourselves as mounted. */
 	}

-	status = ocfs2_load_local_alloc(osb);
+	status = ocfs2_load_local_alloc(osb, 0, &recovery);
 	if (status < 0) {
 		mlog_errno(status);
 		goto finally;
 	}

-	if (dirty) {
+	if (dirty || la_dirty) {
 		/* Recovery will be completed after we've mounted the
 		 * rest of the volume. */
 		osb->dirty = 1;
-- 
1.8.4.3