From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Daniel Golle <daniel@makrotopia.org>
Cc: linux-mtd@lists.infradead.org,
Vignesh Raghavendra <vigneshr@ti.com>,
Richard Weinberger <richard@nod.at>,
David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH] mtd: super: don't reply on mtdblock device minor
Date: Thu, 8 Apr 2021 08:15:08 +0200 [thread overview]
Message-ID: <20210408081508.1d04eb31@xps13> (raw)
In-Reply-To: <YG4qVPz68WAwPtB+@makrotopia.org>
Hi Daniel,
Daniel Golle <daniel@makrotopia.org> wrote on Wed, 7 Apr 2021 22:55:32
+0100:
> For mtdblock 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>
> ---
> drivers/mtd/mtdsuper.c | 33 ++++++++++++++++++++++++++-------
> 1 file changed, 26 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/mtd/mtdsuper.c b/drivers/mtd/mtdsuper.c
> index c3e2098372f2e..dc52f9929c8fb 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 +171,38 @@ 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);
> + BUG();
> + return -EINVAL;
> + }
> +
> + blktrans_dev = (struct mtd_blktrans_dev *)(bdev->bd_disk->private_data);
> + if (!blktrans_dev || !blktrans_dev->tr) {
> + blkdev_put(bdev, FMODE_READ);
> + BUG();
Could you avoid these calls? I doubt they bring anything useful and
returning -EINVAL should be enough anyway.
> + 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))
Otherwise lgtm.
Thanks,
Miquèl
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
next prev parent reply other threads:[~2021-04-08 6:16 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 [this message]
2021-04-08 20:42 ` [PATCH v2] " Daniel Golle
2021-04-12 15:14 ` [PATCH v3] mtd: super: don't rely " Daniel Golle
2021-05-10 10:18 ` 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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210408081508.1d04eb31@xps13 \
--to=miquel.raynal@bootlin.com \
--cc=daniel@makrotopia.org \
--cc=dwmw2@infradead.org \
--cc=linux-mtd@lists.infradead.org \
--cc=richard@nod.at \
--cc=vigneshr@ti.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.