nilfs2: fix potential hang in nilfs_error on errors=remount-ro
nilfs_error() calls nilfs_detach_segment_constructor() if
errors=remount-ro option is specified, and this may lead to a hang due
to recursive locking of, for instance, nilfs->ns_segctor_sem and
others.
In this case, detaching segment constructor is not necessary because
read-only flag is set to the filesystem and further writes are
blocked.
This fixes the potential hang issue by removing the
nilfs_detach_segment_constructor() call from nilfs_error.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 9280b0f..ab439a7 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -2875,8 +2875,15 @@
struct the_nilfs *nilfs = sbi->s_nilfs;
int err;
- /* Each field of nilfs_segctor is cleared through the initialization
- of super-block info */
+ if (NILFS_SC(sbi)) {
+ /*
+ * This happens if the filesystem was remounted
+ * read/write after nilfs_error degenerated it into a
+ * read-only mount.
+ */
+ nilfs_detach_segment_constructor(sbi);
+ }
+
sbi->s_sc_info = nilfs_segctor_new(sbi);
if (!sbi->s_sc_info)
return -ENOMEM;