ext4: enable the lazy init thread when remounting read/write

stable inclusion
from stable-v5.10.183
commit 2c0ea7a06db5268085a5bd5044cedce6c950ad87
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8IRR2

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=2c0ea7a06db5268085a5bd5044cedce6c950ad87



--------------------------------

commit eb1f822c upstream.

In commit a44be64b ("ext4: don't clear SB_RDONLY when remounting
r/w until quota is re-enabled") we defer clearing tyhe SB_RDONLY flag
in struct super.  However, we didn't defer when we checked sb_rdonly()
to determine the lazy itable init thread should be enabled, with the
next result that the lazy inode table initialization would not be
properly started.  This can cause generic/231 to fail in ext4's
nojournal mode.

Fix this by moving when we decide to start or stop the lazy itable
init thread to after we clear the SB_RDONLY flag when we are
remounting the file system read/write.

Fixes a44be64b ("ext4: don't clear SB_RDONLY when remounting r/w until...")

Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Link: https://lore.kernel.org/r/20230527035729.1001605-1-tytso@mit.edu


Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>
(cherry picked from commit d7076bad)