1 files changed, 33 insertions, 18 deletions

diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index 4681fff6665f..6f57c181ff77 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -14,14 +14,14 @@ static __le32 ext4_mmp_csum(struct super_block *sb, struct mmp_struct *mmp)
 	int offset = offsetof(struct mmp_struct, mmp_checksum);
 	__u32 csum;
 
-	csum = ext4_chksum(sbi, sbi->s_csum_seed, (char *)mmp, offset);
+	csum = ext4_chksum(sbi->s_csum_seed, (char *)mmp, offset);
 
 	return cpu_to_le32(csum);
 }
 
 static int ext4_mmp_csum_verify(struct super_block *sb, struct mmp_struct *mmp)
 {
-	if (!ext4_has_metadata_csum(sb))
+	if (!ext4_has_feature_metadata_csum(sb))
 		return 1;
 
 	return mmp->mmp_checksum == ext4_mmp_csum(sb, mmp);
@@ -29,7 +29,7 @@ static int ext4_mmp_csum_verify(struct super_block *sb, struct mmp_struct *mmp)
 
 static void ext4_mmp_csum_set(struct super_block *sb, struct mmp_struct *mmp)
 {
-	if (!ext4_has_metadata_csum(sb))
+	if (!ext4_has_feature_metadata_csum(sb))
 		return;
 
 	mmp->mmp_checksum = ext4_mmp_csum(sb, mmp);
@@ -39,28 +39,32 @@ static void ext4_mmp_csum_set(struct super_block *sb, struct mmp_struct *mmp)
  * Write the MMP block using REQ_SYNC to try to get the block on-disk
  * faster.
  */
-static int write_mmp_block(struct super_block *sb, struct buffer_head *bh)
+static int write_mmp_block_thawed(struct super_block *sb,
+				  struct buffer_head *bh)
 {
 	struct mmp_struct *mmp = (struct mmp_struct *)(bh->b_data);
 
-	/*
-	 * We protect against freezing so that we don't create dirty buffers
-	 * on frozen filesystem.
-	 */
-	sb_start_write(sb);
 	ext4_mmp_csum_set(sb, mmp);
 	lock_buffer(bh);
 	bh->b_end_io = end_buffer_write_sync;
 	get_bh(bh);
 	submit_bh(REQ_OP_WRITE | REQ_SYNC | REQ_META | REQ_PRIO, bh);
 	wait_on_buffer(bh);
-	sb_end_write(sb);
 	if (unlikely(!buffer_uptodate(bh)))
 		return -EIO;
-
 	return 0;
 }
 
+static int write_mmp_block(struct super_block *sb, struct buffer_head *bh)
+{
+	/*
+	 * We protect against freezing so that we don't create dirty buffers
+	 * on frozen filesystem.
+	 */
+	scoped_guard(super_write, sb)
+		return write_mmp_block_thawed(sb, bh);
+}
+
 /*
  * Read the MMP block. It _must_ be read from disk and hence we clear the
  * uptodate flag on the buffer.
@@ -86,7 +90,7 @@ static int read_mmp_block(struct super_block *sb, struct buffer_head **bh,
 	}
 
 	lock_buffer(*bh);
-	ret = ext4_read_bh(*bh, REQ_META | REQ_PRIO, NULL);
+	ret = ext4_read_bh(*bh, REQ_META | REQ_PRIO, NULL, false);
 	if (ret)
 		goto warn_exit;
 
@@ -154,7 +158,7 @@ static int kmmpd(void *data)
 	memcpy(mmp->mmp_nodename, init_utsname()->nodename,
 	       sizeof(mmp->mmp_nodename));
 
-	while (!kthread_should_stop() && !sb_rdonly(sb)) {
+	while (!kthread_should_stop() && !ext4_emergency_state(sb)) {
 		if (!ext4_has_feature_mmp(sb)) {
 			ext4_warning(sb, "kmmpd being stopped since MMP feature"
 				     " has been disabled.");
@@ -223,9 +227,9 @@ static int kmmpd(void *data)
 		 * Adjust the mmp_check_interval depending on how much time
 		 * it took for the MMP block to be written.
 		 */
-		mmp_check_interval = max(min(EXT4_MMP_CHECK_MULT * diff / HZ,
-					     EXT4_MMP_MAX_CHECK_INTERVAL),
-					 EXT4_MMP_MIN_CHECK_INTERVAL);
+		mmp_check_interval = clamp(EXT4_MMP_CHECK_MULT * diff / HZ,
+					   EXT4_MMP_MIN_CHECK_INTERVAL,
+					   EXT4_MMP_MAX_CHECK_INTERVAL);
 		mmp->mmp_check_interval = cpu_to_le16(mmp_check_interval);
 	}
 
@@ -282,6 +286,7 @@ int ext4_multi_mount_protect(struct super_block *sb,
 	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;
 	}
 
@@ -307,6 +312,7 @@ int ext4_multi_mount_protect(struct super_block *sb,
 
 	if (seq == EXT4_MMP_SEQ_FSCK) {
 		dump_mmp_msg(sb, mmp, "fsck is running on the filesystem");
+		retval = -EBUSY;
 		goto failed;
 	}
 
@@ -320,6 +326,7 @@ int ext4_multi_mount_protect(struct super_block *sb,
 
 	if (schedule_timeout_interruptible(HZ * wait_time) != 0) {
 		ext4_warning(sb, "MMP startup interrupted, failing mount\n");
+		retval = -ETIMEDOUT;
 		goto failed;
 	}
 
@@ -330,6 +337,7 @@ int ext4_multi_mount_protect(struct super_block *sb,
 	if (seq != le32_to_cpu(mmp->mmp_seq)) {
 		dump_mmp_msg(sb, mmp,
 			     "Device is already active on another node.");
+		retval = -EBUSY;
 		goto failed;
 	}
 
@@ -340,7 +348,11 @@ skip:
 	seq = mmp_new_seq();
 	mmp->mmp_seq = cpu_to_le32(seq);
 
-	retval = write_mmp_block(sb, bh);
+	/*
+	 * On mount / remount we are protected against fs freezing (by s_umount
+	 * semaphore) and grabbing freeze protection upsets lockdep
+	 */
+	retval = write_mmp_block_thawed(sb, bh);
 	if (retval)
 		goto failed;
 
@@ -349,6 +361,7 @@ skip:
 	 */
 	if (schedule_timeout_interruptible(HZ * wait_time) != 0) {
 		ext4_warning(sb, "MMP startup interrupted, failing mount");
+		retval = -ETIMEDOUT;
 		goto failed;
 	}
 
@@ -359,6 +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;
 	}
 
@@ -378,6 +392,7 @@ 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;
 	}
 
@@ -385,5 +400,5 @@ skip:
 
 failed:
 	brelse(bh);
-	return 1;
+	return retval;
 }