[PATCH v2 4/8] ext2: mark s_mount_state as guarded by s_lock

s_mount_state tracks the filesystem's mount/error state and is protected
by s_lock everywhere it is accessed. Annotate it with __guarded_by() for
Clang's context analysis.

ext2_setup_super() reads s_mount_state and is called with s_lock held
from the remount path, so annotate it with __must_hold().

There are two accesses (the initial read in ext2_fill_super() and the
setup_super() call) in the mount flow. This is before the superblock
is live, so no concurrent access should be possible. Convert the
spinlock initialization to use guard(spinlock_init) to prevent
warnings on the writes later in initialization.

Signed-off-by: Timothy Day <[email protected]>
---
 fs/ext2/ext2.h  | 2 +-
 fs/ext2/super.c | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index ecca898653eb..4c30d6f5c972 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -86,7 +86,7 @@ struct ext2_sb_info {
 	unsigned long s_sb_block;
 	kuid_t s_resuid;
 	kgid_t s_resgid;
-	unsigned short s_mount_state;
+	unsigned short s_mount_state __guarded_by(&s_lock);
 	unsigned short s_pad;
 	int s_addr_per_block_bits;
 	int s_desc_per_block_bits;
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index 5bf63943828b..0fa7914e5f04 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -633,6 +633,7 @@ static int ext2_parse_param(struct fs_context *fc, struct fs_parameter *param)
 static int ext2_setup_super (struct super_block * sb,
 			      struct ext2_super_block * es,
 			      int read_only)
+	__must_hold(&EXT2_SB(sb)->s_lock)
 {
 	int res = 0;
 	struct ext2_sb_info *sbi = EXT2_SB(sb);
@@ -894,7 +895,7 @@ static int ext2_fill_super(struct super_block *sb, struct fs_context *fc)
 	sb->s_fs_info = sbi;
 	sbi->s_sb_block = sb_block;
 
-	spin_lock_init(&sbi->s_lock);
+	guard(spinlock_init)(&EXT2_SB(sb)->s_lock);
 	ret = -EINVAL;
 
 	/*
-- 
2.43.0