diff --git a/drivers/mtd/mtdsuper.c b/drivers/mtd/mtdsuper.c index 5ff001140ef4..b7e3763c47f0 100644 --- a/drivers/mtd/mtdsuper.c +++ b/drivers/mtd/mtdsuper.c @@ -19,38 +19,6 @@ #include #include "mtdcore.h" -/* - * compare superblocks to see if they're equivalent - * - they are if the underlying MTD device is the same - */ -static int mtd_test_super(struct super_block *sb, struct fs_context *fc) -{ - struct mtd_info *mtd = fc->sget_key; - - if (sb->s_mtd == fc->sget_key) { - pr_debug("MTDSB: Match on device %d (\"%s\")\n", - mtd->index, mtd->name); - return 1; - } - - pr_debug("MTDSB: No match, device %d (\"%s\"), device %d (\"%s\")\n", - sb->s_mtd->index, sb->s_mtd->name, mtd->index, mtd->name); - return 0; -} - -/* - * mark the superblock by the MTD device it is using - * - set the device number to be the correct MTD block device for pesuperstence - * of NFS exports - */ -static int mtd_set_super(struct super_block *sb, struct fs_context *fc) -{ - sb->s_mtd = fc->sget_key; - sb->s_dev = MKDEV(MTD_BLOCK_MAJOR, sb->s_mtd->index); - sb->s_bdi = bdi_get(mtd_bdi); - return 0; -} - /* * get a superblock on an MTD-backed filesystem */ @@ -62,8 +30,7 @@ static int mtd_get_sb(struct fs_context *fc, struct super_block *sb; int ret; - fc->sget_key = mtd; - sb = sget_fc(fc, mtd_test_super, mtd_set_super); + sb = sget_dev(fc, MKDEV(MTD_BLOCK_MAJOR, mtd->index)); if (IS_ERR(sb)) return PTR_ERR(sb); @@ -77,6 +44,16 @@ static int mtd_get_sb(struct fs_context *fc, pr_debug("MTDSB: New superblock for device %d (\"%s\")\n", mtd->index, mtd->name); + /* + * Would usually have been set with @sb_lock held but in + * contrast to sb->s_bdev that's checked with only + * @sb_lock held, nothing checks sb->s_mtd without also + * holding sb->s_umount and we're holding sb->s_umount + * here. + */ + sb->s_mtd = mtd; + sb->s_bdi = bdi_get(mtd_bdi); + ret = fill_super(sb, fc); if (ret < 0) goto error_sb;