From 3b50d5018ed06a647bb26c44bb5ae74e59c903c7 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Thu, 27 Apr 2023 22:49:34 -0400
Subject: [PATCH] ext4: reflect error codes from ext4_multi_mount_protect() to
 its callers
Git-commit: 3b50d5018ed06a647bb26c44bb5ae74e59c903c7
Patch-mainline: v6.4-rc1
References: bsc#1214941

This will allow more fine-grained errno codes to be returned by the
mount system call.

Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Acked-by: Jan Kara <jack@suse.cz>

---
 fs/ext4/mmp.c   |    9 ++++++++-
 fs/ext4/super.c |   16 +++++++++-------
 2 files changed, 17 insertions(+), 8 deletions(-)

--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -290,6 +290,7 @@ int ext4_multi_mount_protect(struct supe
 	if (mmp_block < le32_to_cpu(es->s_first_data_block) ||
 	    mmp_block >= ext4_blocks_count(es)) {
 		ext4_warning(sb, "Invalid MMP block in superblock");
+		retval = -EINVAL;
 		goto failed;
 	}
 
@@ -315,6 +316,7 @@ int ext4_multi_mount_protect(struct supe
 
 	if (seq == EXT4_MMP_SEQ_FSCK) {
 		dump_mmp_msg(sb, mmp, "fsck is running on the filesystem");
+		retval = -EBUSY;
 		goto failed;
 	}
 
@@ -328,6 +330,7 @@ int ext4_multi_mount_protect(struct supe
 
 	if (schedule_timeout_interruptible(HZ * wait_time) != 0) {
 		ext4_warning(sb, "MMP startup interrupted, failing mount\n");
+		retval = -ETIMEDOUT;
 		goto failed;
 	}
 
@@ -338,6 +341,7 @@ int ext4_multi_mount_protect(struct supe
 	if (seq != le32_to_cpu(mmp->mmp_seq)) {
 		dump_mmp_msg(sb, mmp,
 			     "Device is already active on another node.");
+		retval = -EBUSY;
 		goto failed;
 	}
 
@@ -357,6 +361,7 @@ skip:
 	 */
 	if (schedule_timeout_interruptible(HZ * wait_time) != 0) {
 		ext4_warning(sb, "MMP startup interrupted, failing mount");
+		retval = -ETIMEDOUT;
 		goto failed;
 	}
 
@@ -367,6 +372,7 @@ skip:
 	if (seq != le32_to_cpu(mmp->mmp_seq)) {
 		dump_mmp_msg(sb, mmp,
 			     "Device is already active on another node.");
+		retval = -EBUSY;
 		goto failed;
 	}
 
@@ -383,6 +389,7 @@ skip:
 		EXT4_SB(sb)->s_mmp_tsk = NULL;
 		ext4_warning(sb, "Unable to create kmmpd thread for %s.",
 			     sb->s_id);
+		retval = -ENOMEM;
 		goto failed;
 	}
 
@@ -390,5 +397,5 @@ skip:
 
 failed:
 	brelse(bh);
-	return 1;
+	return retval;
 }
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4806,9 +4806,11 @@ static int ext4_fill_super(struct super_
 	needs_recovery = (es->s_last_orphan != 0 ||
 			  ext4_has_feature_journal_needs_recovery(sb));
 
-	if (ext4_has_feature_mmp(sb) && !sb_rdonly(sb))
-		if (ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block)))
+	if (ext4_has_feature_mmp(sb) && !sb_rdonly(sb)) {
+		err = ext4_multi_mount_protect(sb, le64_to_cpu(es->s_mmp_block));
+		if (err)
 			goto failed_mount3a;
+	}
 
 	/*
 	 * The first inode we look at is the journal inode.  Don't try
@@ -6094,12 +6096,12 @@ static int ext4_remount(struct super_blo
 				goto restore_opts;
 
 			sb->s_flags &= ~SB_RDONLY;
-			if (ext4_has_feature_mmp(sb))
-				if (ext4_multi_mount_protect(sb,
-						le64_to_cpu(es->s_mmp_block))) {
-					err = -EROFS;
+			if (ext4_has_feature_mmp(sb)) {
+				err = ext4_multi_mount_protect(sb,
+						le64_to_cpu(es->s_mmp_block));
+				if (err)
 					goto restore_opts;
-				}
+			}
 			enable_quota = 1;
 		}
 	}