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@xxxxxxxxxxxxxxxx>
---
Tested in a VM, with a read-only ext4 root filesystem. Confirmed that
ext4lazyinit starts without this patch, and does not start with this
patch.
(For a future merge window, not the current one. Please let me know if I
need to re-send this at a later, more convenient time.)
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 845f2f8aee5f..20437acc8865 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3973,9 +3973,9 @@ 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);
--
2.36.1
