[PATCH 5.19 367/717] ext4: dont run ext4lazyinit for read-only filesystems

Greg Kroah-Hartman
2022-10-22T08:26:30Z

From: Josh Triplett <josh@joshtriplett.org>

[ Upstream commit 426d15ad11419066f7042ffa8fbf1b5c21a1ecbe ]

On a read-only filesystem, we won't invoke the block allocator, so we
don't need to prefetch the block bitmaps.

This avoids starting and running the ext4lazyinit thread at all on a
system with no read-write ext4 filesystems (for instance, a container VM
with read-only filesystems underneath an overlayfs).

Fixes: 21175ca434c5 ("ext4: make prefetch_block_bitmaps default")
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>
Link: https://lore.kernel.org/r/48b41da1498fcac3287e2e06b660680646c1c050.1659323972.git.josh@joshtriplett.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/ext4/super.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index fd358e5f88ff..5cacd513d0df 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3953,9 +3953,9 @@ int ext4_register_li_request(struct super_block *sb,
goto out;
}

- if (test_opt(sb, NO_PREFETCH_BLOCK_BITMAPS) &&
- (first_not_zeroed == ngroups || sb_rdonly(sb) ||
- !test_opt(sb, INIT_INODE_TABLE)))
+ if (sb_rdonly(sb) ||
+ (test_opt(sb, NO_PREFETCH_BLOCK_BITMAPS) &&
+ (first_not_zeroed == ngroups || !test_opt(sb, INIT_INODE_TABLE))))
goto out;

elr = ext4_li_request_new(sb, first_not_zeroed);
--
2.35.1