ext4: don't set dioread_nolock by default for blocksize < pagesize (626b035b) · Commits · 戴 / test

Currently on calling echo 3 > drop_caches on host machine, we see FS corruption in the guest. This happens on Power machine where blocksize < pagesize. So as a temporary workaound don't enable dioread_nolock by default for blocksize < pagesize until we identify the root cause. Also emit a warning msg in case if this mount option is manually enabled for blocksize < pagesize. Reported-by:

Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Signed-off-by:

Ritesh Harjani <riteshh@linux.ibm.com> Link: https://lore.kernel.org/r/20200327200744.12473-1-riteshh@linux.ibm.com Signed-off-by:

Theodore Ts'o <tytso@mit.edu>

fs/ext4/super.c

+12 −1

Original line number	Diff line number	Diff line
		@@ -2187,6 +2187,14 @@ static int parse_options(char options, struct super_block sb,
		}
		}
		#endif
		if (test_opt(sb, DIOREAD_NOLOCK)) {
		int blocksize =
		BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
		if (blocksize < PAGE_SIZE)
		ext4_msg(sb, KERN_WARNING, "Warning: mounting with an "
		"experimental mount option 'dioread_nolock' "
		"for blocksize < PAGE_SIZE");
		}
		return 1;
		}

		@@ -3793,7 +3801,6 @@ static int ext4_fill_super(struct super_block sb, void data, int silent)
		set_opt(sb, NO_UID32);
		/* xattr user namespace & acls are now defaulted on */
		set_opt(sb, XATTR_USER);
		set_opt(sb, DIOREAD_NOLOCK);
		#ifdef CONFIG_EXT4_FS_POSIX_ACL
		set_opt(sb, POSIX_ACL);
		#endif
		@@ -3843,6 +3850,10 @@ static int ext4_fill_super(struct super_block sb, void data, int silent)
		sbi->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT;

		blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);

		if (blocksize == PAGE_SIZE)
		set_opt(sb, DIOREAD_NOLOCK);

		if (blocksize < EXT4_MIN_BLOCK_SIZE \|\|
		blocksize > EXT4_MAX_BLOCK_SIZE) {
		ext4_msg(sb, KERN_ERR,

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