From: Daniel Golle <daniel@makrotopia.org>
To: linux-mtd@lists.infradead.org
Cc: Vignesh Raghavendra <vigneshr@ti.com>,
Richard Weinberger <richard@nod.at>,
Miquel Raynal <miquel.raynal@bootlin.com>,
David Woodhouse <dwmw2@infradead.org>
Subject: [PATCH v3] mtd: super: don't rely on mtdblock device minor
Date: Mon, 12 Apr 2021 16:14:44 +0100 [thread overview]
Message-ID: <YHRj5MUb5MGdPQqw@makrotopia.org> (raw)
In-Reply-To: <YG9qzC/SaD7SNWVm@makrotopia.org>
For blktrans devices with partitions (ie. part_bits != 0) the
assumption that the minor number of the mtdblock device matches
the mtdnum doesn't hold true.
Properly resolve mtd device from blktrans layer instead.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
v3: fix typo in patch description
v2: remove BUG() calls as requested by Miquel Raynal
drivers/mtd/mtdsuper.c | 31 ++++++++++++++++++++++++-------
1 file changed, 24 insertions(+), 7 deletions(-)
diff --git a/drivers/mtd/mtdsuper.c b/drivers/mtd/mtdsuper.c
index c3e2098372f2e..d3af80a7ce86e 100644
--- a/drivers/mtd/mtdsuper.c
+++ b/drivers/mtd/mtdsuper.c
@@ -9,6 +9,7 @@
*/
#include <linux/mtd/super.h>
+#include <linux/mtd/blktrans.h>
#include <linux/namei.h>
#include <linux/export.h>
#include <linux/ctype.h>
@@ -121,7 +122,8 @@ int get_tree_mtd(struct fs_context *fc,
{
#ifdef CONFIG_BLOCK
struct block_device *bdev;
- int ret, major;
+ struct mtd_blktrans_dev *blktrans_dev;
+ int ret, major, part_bits;
#endif
int mtdnr;
@@ -169,21 +171,36 @@ int get_tree_mtd(struct fs_context *fc,
/* try the old way - the hack where we allowed users to mount
* /dev/mtdblock$(n) but didn't actually _use_ the blockdev
*/
- bdev = lookup_bdev(fc->source);
+ bdev = blkdev_get_by_path(fc->source, FMODE_READ, NULL);
if (IS_ERR(bdev)) {
ret = PTR_ERR(bdev);
errorf(fc, "MTD: Couldn't look up '%s': %d", fc->source, ret);
return ret;
}
- pr_debug("MTDSB: lookup_bdev() returned 0\n");
+ pr_debug("MTDSB: blkdev_get_by_path() returned 0\n");
major = MAJOR(bdev->bd_dev);
- mtdnr = MINOR(bdev->bd_dev);
- bdput(bdev);
- if (major == MTD_BLOCK_MAJOR)
- return mtd_get_sb_by_nr(fc, mtdnr, fill_super);
+ if (major == MTD_BLOCK_MAJOR) {
+ if (!bdev->bd_disk) {
+ blkdev_put(bdev, FMODE_READ);
+ return -EINVAL;
+ }
+
+ blktrans_dev = (struct mtd_blktrans_dev *)(bdev->bd_disk->private_data);
+ if (!blktrans_dev || !blktrans_dev->tr) {
+ blkdev_put(bdev, FMODE_READ);
+ return -EINVAL;
+ }
+ mtdnr = blktrans_dev->devnum;
+ part_bits = blktrans_dev->tr->part_bits;
+ blkdev_put(bdev, FMODE_READ);
+ if (MINOR(bdev->bd_dev) != (mtdnr << part_bits))
+ return -EINVAL;
+ return mtd_get_sb_by_nr(fc, mtdnr, fill_super);
+ }
+ blkdev_put(bdev, FMODE_READ);
#endif /* CONFIG_BLOCK */
if (!(fc->sb_flags & SB_SILENT))
--
2.31.0
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next prev parent reply other threads:[~2021-04-12 15:16 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-07 21:55 [PATCH] mtd: super: don't reply on mtdblock device minor Daniel Golle
2021-04-08 6:15 ` Miquel Raynal
2021-04-08 20:42 ` [PATCH v2] " Daniel Golle
2021-04-12 15:14 ` Daniel Golle [this message]
2021-05-10 10:18 ` [PATCH v3] mtd: super: don't rely " Miquel Raynal
2021-05-10 22:20 ` Daniel Golle
2021-05-10 22:21 ` [PATCH v4] " Daniel Golle
2021-05-11 5:49 ` Christoph Hellwig
2021-05-11 7:57 ` Daniel Golle
2021-05-11 16:42 ` Christoph Hellwig
2021-05-11 20:17 ` Daniel Golle
2021-05-12 6:42 ` Christoph Hellwig
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