[PATCH 2/2] Add a new function to get root directory with ATTR_VOLUME

[chenchacha <chen.chenchacha@foxmail.com>]

Signed-off-by: chenchacha <chen.chenchacha@foxmail.com>
---
 fs/fat/dir.c | 13 +++++++++++++
 fs/fat/fat.h |  2 ++
 2 files changed, 15 insertions(+)

diff --git a/fs/fat/dir.c b/fs/fat/dir.c
index 7f5f3699fc6c..4fdcc1200f2b 100644
--- a/fs/fat/dir.c
+++ b/fs/fat/dir.c
@@ -881,6 +881,19 @@ static int fat_get_short_entry(struct inode *dir, loff_t *pos,
 	return -ENOENT;
 }
 
+int fat_get_root_entry(struct inode *dir, struct buffer_head **bh,
+		       struct msdos_dir_entry **de)
+{
+	loff_t offset = 0;
+
+	*de = NULL;
+	while (fat_get_entry(dir, &offset, bh, de) >= 0) {
+		if (!IS_FREE((*de)->name) && (*de)->attr & ATTR_VOLUME)
+			return 0;
+	}
+	return -ENOENT;
+}
+
 /*
  * The ".." entry can not provide the "struct fat_slot_info" information
  * for inode, nor a usable i_pos. So, this function provides some information
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index be012de96f65..4195cb1e891a 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -302,6 +302,8 @@ extern int fat_scan(struct inode *dir, const unsigned char *name,
 		    struct fat_slot_info *sinfo);
 extern int fat_scan_logstart(struct inode *dir, int i_logstart,
 			     struct fat_slot_info *sinfo);
+extern int fat_get_root_entry(struct inode *dir, struct buffer_head **bh,
+			      struct msdos_dir_entry **de);
 extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
 				struct msdos_dir_entry **de);
 extern int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts);
-- 
2.19.0