fs: remove sb->s_mode

There is no real need to store the open mode in the super_block now.
It is only used by f2fs, which can easily recalculate it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Christian Brauner <brauner@kernel.org>
Link: https://lore.kernel.org/r/20230608110258.189493-18-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

fs/f2fs/super.c

@@ -3993,6 +3993,7 @@ static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
 	struct f2fs_super_block *raw_super = F2FS_RAW_SUPER(sbi);
 	unsigned int max_devices = MAX_DEVICES;
 	unsigned int logical_blksize;
+	fmode_t mode = sb_open_mode(sbi->sb->s_flags);
 	int i;
 
 	/* Initialize single device information */
@@ -4024,8 +4025,8 @@ static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
 		if (max_devices == 1) {
 			/* Single zoned block device mount */
 			FDEV(0).bdev =
-				blkdev_get_by_dev(sbi->sb->s_bdev->bd_dev,
-					sbi->sb->s_mode, sbi->sb->s_type, NULL);
+				blkdev_get_by_dev(sbi->sb->s_bdev->bd_dev, mode,
+						  sbi->sb->s_type, NULL);
 		} else {
 			/* Multi-device mount */
 			memcpy(FDEV(i).path, RDEV(i).path, MAX_PATH_LEN);
@@ -4043,8 +4044,9 @@ static int f2fs_scan_devices(struct f2fs_sb_info *sbi)
 					(FDEV(i).total_segments <<
 					sbi->log_blocks_per_seg) - 1;
 			}
-			FDEV(i).bdev = blkdev_get_by_path(FDEV(i).path,
-					sbi->sb->s_mode, sbi->sb->s_type, NULL);
+			FDEV(i).bdev = blkdev_get_by_path(FDEV(i).path, mode,
+							  sbi->sb->s_type,
+							  NULL);
 		}
 		if (IS_ERR(FDEV(i).bdev))
 			return PTR_ERR(FDEV(i).bdev);

fs/nilfs2/super.c

@@ -1316,7 +1316,6 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
 		s_new = true;
 
 		/* New superblock instance created */
-		s->s_mode = mode;
 		snprintf(s->s_id, sizeof(s->s_id), "%pg", sd.bdev);
 		sb_set_blocksize(s, block_size(sd.bdev));
 

fs/super.c

@@ -1308,7 +1308,6 @@ int get_tree_bdev(struct fs_context *fc,
 		blkdev_put(bdev, fc->fs_type);
 		down_write(&s->s_umount);
 	} else {
-		s->s_mode = mode;
 		snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
 		shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s",
 					fc->fs_type->name, s->s_id);
@@ -1382,7 +1381,6 @@ struct dentry *mount_bdev(struct file_system_type *fs_type,
 		blkdev_put(bdev, fs_type);
 		down_write(&s->s_umount);
 	} else {
-		s->s_mode = mode;
 		snprintf(s->s_id, sizeof(s->s_id), "%pg", bdev);
 		shrinker_debugfs_rename(&s->s_shrink, "sb-%s:%s",
 					fs_type->name, s->s_id);

include/linux/fs.h

@@ -1215,7 +1215,6 @@ struct super_block {
 	uuid_t			s_uuid;		/* UUID */
 
 	unsigned int		s_max_links;
-	fmode_t			s_mode;
 
 	/*
 	 * The next field is for VFS *only*. No filesystems have any business