Thread (2 messages) 2 messages, 2 authors, 2020-03-29

Re: [PATCH v2] ext4: Fix incorrect group count in ext4_fill_super error message

From: Andreas Dilger <hidden>
Date: 2020-03-29 00:11:11
Also in: lkml

On Mar 28, 2020, at 5:43 PM, Josh Triplett [off-list ref] wrote:

ext4_fill_super doublechecks the number of groups before mounting; if
that check fails, the resulting error message prints the group count
from the ext4_sb_info sbi, which hasn't been set yet. Move the
assignment to sbi->s_groups_count above its use in the error message.

Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Fixes: 4ec1102813798 ("ext4: Add sanity checks for the superblock before mounting the filesystem")
Much better, thanks.

Reviewed-by: Andreas Dilger <redacted>
quoted hunk ↗ jump to hunk
---
v2: Rather than using the computed group count value in blocks_count,
move the assignment to sbi->s_groups_count up and keep using that. That
makes the code, and the patch, simpler to read and understand.

fs/ext4/super.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 0c7c4adb664e..6692bc48520a 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -4285,6 +4285,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
			le32_to_cpu(es->s_first_data_block) +
			EXT4_BLOCKS_PER_GROUP(sb) - 1);
	do_div(blocks_count, EXT4_BLOCKS_PER_GROUP(sb));
+	sbi->s_groups_count = blocks_count;
	if (blocks_count > ((uint64_t)1<<32) - EXT4_DESC_PER_BLOCK(sb)) {
		ext4_msg(sb, KERN_WARNING, "groups count too large: %u "
		       "(block count %llu, first data block %u, "
@@ -4294,7 +4295,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
		       EXT4_BLOCKS_PER_GROUP(sb));
		goto failed_mount;
	}
-	sbi->s_groups_count = blocks_count;
	sbi->s_blockfile_groups = min_t(ext4_group_t, sbi->s_groups_count,
			(EXT4_MAX_BLOCK_FILE_PHYS / EXT4_BLOCKS_PER_GROUP(sb)));
	if (((u64)sbi->s_groups_count * sbi->s_inodes_per_group) !=
--
2.26.0

Cheers, Andreas




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