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| author | Dan Williams <dan.j.williams@intel.com> | 2019-02-20 21:12:50 -0800 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2019-02-20 21:12:50 -0800 |
| commit | ad428cdb525a97d15c0349fdc80f3d58befb50df (patch) | |
| tree | 31bebae17f60a5e5a214e135e216fab74e840966 /drivers | |
| parent | fa7d2e639cd90442d868dfc6ca1d4cc9d8bf206e (diff) | |
| download | linux-ad428cdb525a97d15c0349fdc80f3d58befb50df.tar.gz linux-ad428cdb525a97d15c0349fdc80f3d58befb50df.tar.bz2 linux-ad428cdb525a97d15c0349fdc80f3d58befb50df.zip | |
dax: Check the end of the block-device capacity with dax_direct_access()
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>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/dax/super.c | 38 |
1 files 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) { |