linux-ext4 - [PATCH] ext2: do not sleep in ext2

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Message-ID: <20210903090538.GA7283@kili>
Date:   Fri, 3 Sep 2021 12:05:38 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Jan Kara <jack@...e.com>
Cc:     linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: [PATCH] ext2: do not sleep in ext2_error()

No one expects error logging functions to sleep so sometimes they are
called with spinlocks held.  In this case the problematic call tree is:

ext2_statfs() <- disables preempt
-> ext2_count_free_inodes()
   -> ext2_get_group_desc()
      -> ext2_error()

Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
---
This is just from static analysis.  NOT TESTED!

Probably a safer fix would be to just call pr_err() instead of
ext2_error() in ext2_get_group_desc().  I can send that fix instead if
people want.

 fs/ext2/super.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index d8d580b609ba..ba345ab860f0 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -59,7 +59,7 @@ void ext2_error(struct super_block *sb, const char *function,
 		sbi->s_mount_state |= EXT2_ERROR_FS;
 		es->s_state |= cpu_to_le16(EXT2_ERROR_FS);
 		spin_unlock(&sbi->s_lock);
-		ext2_sync_super(sb, es, 1);
+		ext2_sync_super(sb, es, 0);
 	}
 
 	va_start(args, fmt);
-- 
2.20.1