From: Dan Williams <dan.j.williams@intel.com>
To: linux-nvdimm@lists.01.org
Cc: Jan Kara <jack@suse.cz>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: [PATCH v2] dax: Check the end of the block-device capacity with dax_direct_access()
Date: Wed, 20 Feb 2019 21:15:51 -0800 [thread overview]
Message-ID: <155072611007.2172474.11471824752162528833.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <CAPcyv4jwMx2ohs9QobTohL8jxc5G74XhmY5QFpmiVF9siWLuwA@mail.gmail.com>
The checks in __bdev_dax_supported() helped mitigate a potential data
corruption bug in the pmem driver's handling of section alignment
padding. Strengthen the checks, including checking the end of the range,
to validate the dev_pagemap, Xarray entries, and sector-to-pfn
translation established for pmem namespaces.
Acked-by: Jan Kara <jack@suse.cz>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
Changes in v2, simplify the calculation of the sector representing the
last page / pfn of the device.
drivers/dax/super.c | 38 ++++++++++++++++++++++++++++----------
1 file changed, 28 insertions(+), 10 deletions(-)
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 6e928f37d084..0cb8c30ea278 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -86,12 +86,14 @@ bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
{
struct dax_device *dax_dev;
bool dax_enabled = false;
+ pgoff_t pgoff, pgoff_end;
struct request_queue *q;
- pgoff_t pgoff;
- int err, id;
- pfn_t pfn;
- long len;
char buf[BDEVNAME_SIZE];
+ void *kaddr, *end_kaddr;
+ pfn_t pfn, end_pfn;
+ sector_t last_page;
+ long len, len2;
+ int err, id;
if (blocksize != PAGE_SIZE) {
pr_debug("%s: error: unsupported blocksize for dax\n",
@@ -113,6 +115,14 @@ bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
return false;
}
+ last_page = PFN_DOWN(i_size_read(bdev->bd_inode) - 1) * 8;
+ err = bdev_dax_pgoff(bdev, last_page, PAGE_SIZE, &pgoff_end);
+ if (err) {
+ pr_debug("%s: error: unaligned partition for dax\n",
+ bdevname(bdev, buf));
+ return false;
+ }
+
dax_dev = dax_get_by_host(bdev->bd_disk->disk_name);
if (!dax_dev) {
pr_debug("%s: error: device does not support dax\n",
@@ -121,14 +131,15 @@ bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
}
id = dax_read_lock();
- len = dax_direct_access(dax_dev, pgoff, 1, NULL, &pfn);
+ len = dax_direct_access(dax_dev, pgoff, 1, &kaddr, &pfn);
+ len2 = dax_direct_access(dax_dev, pgoff_end, 1, &end_kaddr, &end_pfn);
dax_read_unlock(id);
put_dax(dax_dev);
- if (len < 1) {
+ if (len < 1 || len2 < 1) {
pr_debug("%s: error: dax access failed (%ld)\n",
- bdevname(bdev, buf), len);
+ bdevname(bdev, buf), len < 1 ? len : len2);
return false;
}
@@ -143,13 +154,20 @@ bool __bdev_dax_supported(struct block_device *bdev, int blocksize)
*/
WARN_ON(IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API));
dax_enabled = true;
- } else if (pfn_t_devmap(pfn)) {
- struct dev_pagemap *pgmap;
+ } else if (pfn_t_devmap(pfn) && pfn_t_devmap(end_pfn)) {
+ struct dev_pagemap *pgmap, *end_pgmap;
pgmap = get_dev_pagemap(pfn_t_to_pfn(pfn), NULL);
- if (pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX)
+ end_pgmap = get_dev_pagemap(pfn_t_to_pfn(end_pfn), NULL);
+ if (pgmap && pgmap == end_pgmap && pgmap->type == MEMORY_DEVICE_FS_DAX
+ && pfn_t_to_page(pfn)->pgmap == pgmap
+ && pfn_t_to_page(end_pfn)->pgmap == pgmap
+ && pfn_t_to_pfn(pfn) == PHYS_PFN(__pa(kaddr))
+ && pfn_t_to_pfn(end_pfn) == PHYS_PFN(__pa(end_kaddr)))
dax_enabled = true;
put_dev_pagemap(pgmap);
+ put_dev_pagemap(end_pgmap);
+
}
if (!dax_enabled) {
next prev parent reply other threads:[~2019-02-21 5:28 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-12 21:24 [PATCH 0/7] libnvdimm/pfn: Fix section-alignment padding Dan Williams
2019-02-12 21:24 ` [PATCH 1/7] libnvdimm/pfn: Account for PAGE_SIZE > info-block-size in nd_pfn_init() Dan Williams
2019-02-12 21:24 ` [PATCH 2/7] libnvdimm/pmem: Honor force_raw for legacy pmem regions Dan Williams
2019-02-12 21:24 ` [PATCH 3/7] dax: Check the end of the block-device capacity with dax_direct_access() Dan Williams
2019-02-13 10:22 ` Jan Kara
2019-02-13 16:49 ` Dan Williams
2019-02-21 5:15 ` Dan Williams [this message]
2019-02-12 21:25 ` [PATCH 4/7] libnvdimm/pfn: Introduce super-block minimum version requirements Dan Williams
2019-02-12 21:25 ` [PATCH 5/7] libnvdimm/pfn: Remove dax_label_reserve Dan Williams
2019-02-12 21:25 ` [PATCH 6/7] libnvdimm/pfn: Introduce 'struct pfn_map_info' Dan Williams
2019-02-12 21:25 ` [PATCH 7/7] libnvdimm/pfn: Fix 'start_pad' implementation Dan Williams
2019-02-21 23:47 ` Jeff Moyer
2019-02-22 3:58 ` Dan Williams
2019-02-22 15:42 ` Jeff Moyer
2019-02-22 17:12 ` Dan Williams
2019-02-22 17:21 ` Jeff Moyer
2019-02-20 17:11 ` [PATCH 0/7] libnvdimm/pfn: Fix section-alignment padding Dan Williams
2019-02-20 17:19 ` Johannes Thumshirn
2019-02-20 17:45 ` Jeff Moyer
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