ext4_journal_start_sb() should not prevent an active handle from being
started due to s_frozen. Otherwise, deadlock is easy to happen, below
is a situation.
================================================
freeze | truncate
================================================
| ext4_ext_truncate()
freeze_super() | starts a handle
sets s_frozen |
| ext4_ext_truncate()
| holds i_data_sem
ext4_freeze() |
waits for updates |
| ext4_free_blocks()
| calls dquot_free_block()
|
| dquot_free_blocks()
| calls ext4_dirty_inode()
|
| ext4_dirty_inode()
| trys to start an active
| handle
|
| block due to s_frozen
================================================
Signed-off-by: Yongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: Amir Goldstein <amir73il@users.sf.net>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
be4f27d324