[PATCH 2/3] vfs: Add a super block operation to check for writeback errors

From: Vivek Goyal
Date: Mon Dec 21 2020 - 14:53:01 EST


Right now we check for errors on super block in syncfs().

ret2 = errseq_check_and_advance(&sb->s_wb_err, &f.file->f_sb_err);

overlayfs does not update sb->s_wb_err and it is tracked on upper filesystem.
So provide a superblock operation to check errors so that filesystem
can provide override generic method and provide its own method to
check for writeback errors.

Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
---
fs/sync.c | 5 ++++-
include/linux/fs.h | 1 +
2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/sync.c b/fs/sync.c
index b5fb83a734cd..57e43a16dfca 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -176,7 +176,10 @@ SYSCALL_DEFINE1(syncfs, int, fd)
ret = sync_filesystem(sb);
up_read(&sb->s_umount);

- ret2 = errseq_check_and_advance(&sb->s_wb_err, &f.file->f_sb_err);
+ if (sb->s_op->errseq_check_advance)
+ ret2 = sb->s_op->errseq_check_advance(sb, f.file);
+ else
+ ret2 = errseq_check_and_advance(&sb->s_wb_err, &f.file->f_sb_err);

fdput(f);
return ret ? ret : ret2;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 8667d0cdc71e..4297b6127adf 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1965,6 +1965,7 @@ struct super_operations {
struct shrink_control *);
long (*free_cached_objects)(struct super_block *,
struct shrink_control *);
+ int (*errseq_check_advance)(struct super_block *, struct file *);
};

/*
--
2.25.4