86 lines
2.5 KiB
Diff
86 lines
2.5 KiB
Diff
From f9760b158f610b1792a222cc924073724c061bfb Mon Sep 17 00:00:00 2001
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From: Daniel Golle <daniel@makrotopia.org>
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Date: Wed, 7 Apr 2021 22:37:57 +0100
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Subject: [PATCH 1/2] mtd: super: don't reply on mtdblock device minor
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To: linux-mtd@lists.infradead.org
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Cc: Vignesh Raghavendra <vigneshr@ti.com>,
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Richard Weinberger <richard@nod.at>,
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Miquel Raynal <miquel.raynal@bootlin.com>,
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David Woodhouse <dwmw2@infradead.org>
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For blktrans devices with partitions (ie. part_bits != 0) the
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assumption that the minor number of the mtdblock device matches
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the mtdnum doesn't hold true.
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Properly resolve mtd device from blktrans layer instead.
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Signed-off-by: Daniel Golle <daniel@makrotopia.org>
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---
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drivers/mtd/mtdsuper.c | 33 ++++++++++++++++++++++++++-------
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1 file changed, 26 insertions(+), 7 deletions(-)
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--- a/drivers/mtd/mtdsuper.c
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+++ b/drivers/mtd/mtdsuper.c
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@@ -9,6 +9,7 @@
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*/
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#include <linux/mtd/super.h>
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+#include <linux/mtd/blktrans.h>
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#include <linux/namei.h>
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#include <linux/export.h>
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#include <linux/ctype.h>
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@@ -121,7 +122,8 @@ int get_tree_mtd(struct fs_context *fc,
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{
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#ifdef CONFIG_BLOCK
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struct block_device *bdev;
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- int ret, major;
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+ struct mtd_blktrans_dev *blktrans_dev;
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+ int ret, major, part_bits;
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#endif
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int mtdnr;
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@@ -169,21 +171,38 @@ int get_tree_mtd(struct fs_context *fc,
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/* try the old way - the hack where we allowed users to mount
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* /dev/mtdblock$(n) but didn't actually _use_ the blockdev
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*/
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- bdev = lookup_bdev(fc->source);
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+ bdev = blkdev_get_by_path(fc->source, FMODE_READ, NULL);
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if (IS_ERR(bdev)) {
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ret = PTR_ERR(bdev);
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errorf(fc, "MTD: Couldn't look up '%s': %d", fc->source, ret);
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return ret;
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}
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- pr_debug("MTDSB: lookup_bdev() returned 0\n");
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+ pr_debug("MTDSB: blkdev_get_by_path() returned 0\n");
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major = MAJOR(bdev->bd_dev);
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- mtdnr = MINOR(bdev->bd_dev);
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- bdput(bdev);
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- if (major == MTD_BLOCK_MAJOR)
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- return mtd_get_sb_by_nr(fc, mtdnr, fill_super);
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+ if (major == MTD_BLOCK_MAJOR) {
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+ if (!bdev->bd_disk) {
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+ blkdev_put(bdev, FMODE_READ);
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+ BUG();
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+ return -EINVAL;
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+ }
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+
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+ blktrans_dev = (struct mtd_blktrans_dev *)(bdev->bd_disk->private_data);
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+ if (!blktrans_dev || !blktrans_dev->tr) {
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+ blkdev_put(bdev, FMODE_READ);
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+ BUG();
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+ return -EINVAL;
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+ }
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+ mtdnr = blktrans_dev->devnum;
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+ part_bits = blktrans_dev->tr->part_bits;
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+ blkdev_put(bdev, FMODE_READ);
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+ if (MINOR(bdev->bd_dev) != (mtdnr << part_bits))
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+ return -EINVAL;
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+ return mtd_get_sb_by_nr(fc, mtdnr, fill_super);
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+ }
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+ blkdev_put(bdev, FMODE_READ);
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#endif /* CONFIG_BLOCK */
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if (!(fc->sb_flags & SB_SILENT))
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