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@xxxxxxxxxxxxx>
---
fs/nilfs2/segment.c | 11 +++++++++--
fs/nilfs2/super.c | 3 ---
2 files changed, 9 insertions(+), 5 deletions(-)
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 @@ int nilfs_attach_segment_constructor(struct nilfs_sb_info *sbi)
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;
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 3f88401..f068270 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -96,9 +96,6 @@ void nilfs_error(struct super_block *sb, const char *function,
if (!(sb->s_flags & MS_RDONLY)) {
struct the_nilfs *nilfs = sbi->s_nilfs;
- if (!nilfs_test_opt(sbi, ERRORS_CONT))
- nilfs_detach_segment_constructor(sbi);
-
down_write(&nilfs->ns_sem);
if (!(nilfs->ns_mount_state & NILFS_ERROR_FS)) {
nilfs->ns_mount_state |= NILFS_ERROR_FS;
--
1.6.3.4
--
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