Commit graph

373 commits

Author SHA1 Message Date
Jeff Layton
5660e13d2f fs: new infrastructure for writeback error handling and reporting
Most filesystems currently use mapping_set_error and
filemap_check_errors for setting and reporting/clearing writeback errors
at the mapping level. filemap_check_errors is indirectly called from
most of the filemap_fdatawait_* functions and from
filemap_write_and_wait*. These functions are called from all sorts of
contexts to wait on writeback to finish -- e.g. mostly in fsync, but
also in truncate calls, getattr, etc.

The non-fsync callers are problematic. We should be reporting writeback
errors during fsync, but many places spread over the tree clear out
errors before they can be properly reported, or report errors at
nonsensical times.

If I get -EIO on a stat() call, there is no reason for me to assume that
it is because some previous writeback failed. The fact that it also
clears out the error such that a subsequent fsync returns 0 is a bug,
and a nasty one since that's potentially silent data corruption.

This patch adds a small bit of new infrastructure for setting and
reporting errors during address_space writeback. While the above was my
original impetus for adding this, I think it's also the case that
current fsync semantics are just problematic for userland. Most
applications that call fsync do so to ensure that the data they wrote
has hit the backing store.

In the case where there are multiple writers to the file at the same
time, this is really hard to determine. The first one to call fsync will
see any stored error, and the rest get back 0. The processes with open
fds may not be associated with one another in any way. They could even
be in different containers, so ensuring coordination between all fsync
callers is not really an option.

One way to remedy this would be to track what file descriptor was used
to dirty the file, but that's rather cumbersome and would likely be
slow. However, there is a simpler way to improve the semantics here
without incurring too much overhead.

This set adds an errseq_t to struct address_space, and a corresponding
one is added to struct file. Writeback errors are recorded in the
mapping's errseq_t, and the one in struct file is used as the "since"
value.

This changes the semantics of the Linux fsync implementation such that
applications can now use it to determine whether there were any
writeback errors since fsync(fd) was last called (or since the file was
opened in the case of fsync having never been called).

Note that those writeback errors may have occurred when writing data
that was dirtied via an entirely different fd, but that's the case now
with the current mapping_set_error/filemap_check_error infrastructure.
This will at least prevent you from getting a false report of success.

The new behavior is still consistent with the POSIX spec, and is more
reliable for application developers. This patch just adds some basic
infrastructure for doing this, and ensures that the f_wb_err "cursor"
is properly set when a file is opened. Later patches will change the
existing code to use this new infrastructure for reporting errors at
fsync time.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
2017-07-06 07:02:25 -04:00
Linus Torvalds
0fcc3ab23d Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm
Pull libnvdimm fixes from Dan Williams:
 "Incremental fixes and a small feature addition on top of the main
  libnvdimm 4.12 pull request:

   - Geert noticed that tinyconfig was bloated by BLOCK selecting DAX.
     The size regression is fixed by moving all dax helpers into the
     dax-core and only specifying "select DAX" for FS_DAX and
     dax-capable drivers. He also asked for clarification of the
     NR_DEV_DAX config option which, on closer look, does not need to be
     a config option at all. Mike also throws in a DEV_DAX_PMEM fixup
     for good measure.

   - Ben's attention to detail on -stable patch submissions caught a
     case where the recent fixes to arch_copy_from_iter_pmem() missed a
     condition where we strand dirty data in the cache. This is tagged
     for -stable and will also be included in the rework of the pmem api
     to a proposed {memcpy,copy_user}_flushcache() interface for 4.13.

   - Vishal adds a feature that missed the initial pull due to pending
     review feedback. It allows the kernel to clear media errors when
     initializing a BTT (atomic sector update driver) instance on a pmem
     namespace.

   - Ross noticed that the dax_device + dax_operations conversion broke
     __dax_zero_page_range(). The nvdimm unit tests fail to check this
     path, but xfstests immediately trips over it. No excuse for missing
     this before submitting the 4.12 pull request.

  These all pass the nvdimm unit tests and an xfstests spot check. The
  set has received a build success notification from the kbuild robot"

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  filesystem-dax: fix broken __dax_zero_page_range() conversion
  libnvdimm, btt: ensure that initializing metadata clears poison
  libnvdimm: add an atomic vs process context flag to rw_bytes
  x86, pmem: Fix cache flushing for iovec write < 8 bytes
  device-dax: kill NR_DEV_DAX
  block, dax: move "select DAX" from BLOCK to FS_DAX
  device-dax: Tell kbuild DEV_DAX_PMEM depends on DEV_DAX
2017-05-12 15:43:10 -07:00
Dan Williams
ef51042472 block, dax: move "select DAX" from BLOCK to FS_DAX
For configurations that do not enable DAX filesystems or drivers, do not
require the DAX core to be built.

Given that the 'direct_access' method has been removed from
'block_device_operations', we can also go ahead and remove the
block-related dax helper functions from fs/block_dev.c to
drivers/dax/super.c. This keeps dax details out of the block layer and
lets the DAX core be built as a module in the FS_DAX=n case.

Filesystems need to include dax.h to call bdev_dax_supported().

Cc: linux-xfs@vger.kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-05-08 10:55:27 -07:00
Linus Torvalds
53ef7d0e20 libnvdimm for 4.12
* Region media error reporting: A libnvdimm region device is the parent
 to one or more namespaces. To date, media errors have been reported via
 the "badblocks" attribute attached to pmem block devices for namespaces
 in "raw" or "memory" mode. Given that namespaces can be in "device-dax"
 or "btt-sector" mode this new interface reports media errors
 generically, i.e. independent of namespace modes or state. This
 subsequently allows userspace tooling to craft "ACPI 6.1 Section
 9.20.7.6 Function Index 4 - Clear Uncorrectable Error" requests and
 submit them via the ioctl path for NVDIMM root bus devices.
 
 * Introduce 'struct dax_device' and 'struct dax_operations': Prompted by
 a request from Linus and feedback from Christoph this allows for dax
 capable drivers to publish their own custom dax operations. This fixes
 the broken assumption that all dax operations are related to a
 persistent memory device, and makes it easier for other architectures
 and platforms to add customized persistent memory support.
 
 * 'libnvdimm' core updates: A new "deep_flush" sysfs attribute is
 available for storage appliance applications to manually trigger memory
 controllers to drain write-pending buffers that would otherwise be
 flushed automatically by the platform ADR (asynchronous-DRAM-refresh)
 mechanism at a power loss event. Support for "locked" DIMMs is included
 to prevent namespaces from surfacing when the namespace label data area
 is locked. Finally, fixes for various reported deadlocks and crashes,
 also tagged for -stable.
 
 * ACPI / nfit driver updates: General updates of the nfit driver to add
 DSM command overrides, ACPI 6.1 health state flags support, DSM payload
 debug available by default, and various fixes.
 
 Acknowledgements that came after the branch was pushed:
 
 commmit 565851c972 "device-dax: fix sysfs attribute deadlock"
 Tested-by: Yi Zhang <yizhan@redhat.com>
 
 commit 23f4984483 "libnvdimm: rework region badblocks clearing"
 Tested-by: Toshi Kani <toshi.kani@hpe.com>
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Merge tag 'libnvdimm-for-4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm updates from Dan Williams:
 "The bulk of this has been in multiple -next releases. There were a few
  late breaking fixes and small features that got added in the last
  couple days, but the whole set has received a build success
  notification from the kbuild robot.

  Change summary:

   - Region media error reporting: A libnvdimm region device is the
     parent to one or more namespaces. To date, media errors have been
     reported via the "badblocks" attribute attached to pmem block
     devices for namespaces in "raw" or "memory" mode. Given that
     namespaces can be in "device-dax" or "btt-sector" mode this new
     interface reports media errors generically, i.e. independent of
     namespace modes or state.

     This subsequently allows userspace tooling to craft "ACPI 6.1
     Section 9.20.7.6 Function Index 4 - Clear Uncorrectable Error"
     requests and submit them via the ioctl path for NVDIMM root bus
     devices.

   - Introduce 'struct dax_device' and 'struct dax_operations': Prompted
     by a request from Linus and feedback from Christoph this allows for
     dax capable drivers to publish their own custom dax operations.
     This fixes the broken assumption that all dax operations are
     related to a persistent memory device, and makes it easier for
     other architectures and platforms to add customized persistent
     memory support.

   - 'libnvdimm' core updates: A new "deep_flush" sysfs attribute is
     available for storage appliance applications to manually trigger
     memory controllers to drain write-pending buffers that would
     otherwise be flushed automatically by the platform ADR
     (asynchronous-DRAM-refresh) mechanism at a power loss event.
     Support for "locked" DIMMs is included to prevent namespaces from
     surfacing when the namespace label data area is locked. Finally,
     fixes for various reported deadlocks and crashes, also tagged for
     -stable.

   - ACPI / nfit driver updates: General updates of the nfit driver to
     add DSM command overrides, ACPI 6.1 health state flags support, DSM
     payload debug available by default, and various fixes.

  Acknowledgements that came after the branch was pushed:

   - commmit 565851c972 "device-dax: fix sysfs attribute deadlock":
     Tested-by: Yi Zhang <yizhan@redhat.com>

   - commit 23f4984483 "libnvdimm: rework region badblocks clearing"
     Tested-by: Toshi Kani <toshi.kani@hpe.com>"

* tag 'libnvdimm-for-4.12' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (52 commits)
  libnvdimm, pfn: fix 'npfns' vs section alignment
  libnvdimm: handle locked label storage areas
  libnvdimm: convert NDD_ flags to use bitops, introduce NDD_LOCKED
  brd: fix uninitialized use of brd->dax_dev
  block, dax: use correct format string in bdev_dax_supported
  device-dax: fix sysfs attribute deadlock
  libnvdimm: restore "libnvdimm: band aid btt vs clear poison locking"
  libnvdimm: fix nvdimm_bus_lock() vs device_lock() ordering
  libnvdimm: rework region badblocks clearing
  acpi, nfit: kill ACPI_NFIT_DEBUG
  libnvdimm: fix clear length of nvdimm_forget_poison()
  libnvdimm, pmem: fix a NULL pointer BUG in nd_pmem_notify
  libnvdimm, region: sysfs trigger for nvdimm_flush()
  libnvdimm: fix phys_addr for nvdimm_clear_poison
  x86, dax, pmem: remove indirection around memcpy_from_pmem()
  block: remove block_device_operations ->direct_access()
  block, dax: convert bdev_dax_supported() to dax_direct_access()
  filesystem-dax: convert to dax_direct_access()
  Revert "block: use DAX for partition table reads"
  ext2, ext4, xfs: retrieve dax_device for iomap operations
  ...
2017-05-05 18:49:20 -07:00
Andrey Ryabinin
a5f6a6a9c7 fs/block_dev: always invalidate cleancache in invalidate_bdev()
invalidate_bdev() calls cleancache_invalidate_inode() iff ->nrpages != 0
which doen't make any sense.

Make sure that invalidate_bdev() always calls cleancache_invalidate_inode()
regardless of mapping->nrpages value.

Fixes: c515e1fd36 ("mm/fs: add hooks to support cleancache")
Link: http://lkml.kernel.org/r/20170424164135.22350-3-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Alexey Kuznetsov <kuznet@virtuozzo.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Nikolay Borisov <n.borisov.lkml@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-05-03 15:52:12 -07:00
Arnd Bergmann
67fd389735 block, dax: use correct format string in bdev_dax_supported
The new message has an incorrect format string, causing a warning in some
configurations:

fs/block_dev.c: In function 'bdev_dax_supported':
fs/block_dev.c:779:5: error: format '%d' expects argument of type 'int', but argument 2 has type 'long int' [-Werror=format=]
     "error: dax access failed (%d)", len);

This changes it to use the correct %ld instead of %d.

Fixes: 2093f2e9df ("block, dax: convert bdev_dax_supported() to dax_direct_access()")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-05-01 13:16:29 -07:00
Dan Williams
d4b29fd78e block: remove block_device_operations ->direct_access()
Now that all the producers and consumers of dax interfaces have been
converted to using dax_operations on a dax_device, remove the block
device direct_access enabling.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-04-25 13:20:46 -07:00
Dan Williams
2093f2e9df block, dax: convert bdev_dax_supported() to dax_direct_access()
Kill of the final user of bdev_direct_access() and struct blk_dax_ctl.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-04-25 13:20:46 -07:00
Ilya Dryomov
19b7ccf865 block: get rid of blk_integrity_revalidate()
Commit 25520d55cd ("block: Inline blk_integrity in struct gendisk")
introduced blk_integrity_revalidate(), which seems to assume ownership
of the stable pages flag and unilaterally clears it if no blk_integrity
profile is registered:

    if (bi->profile)
            disk->queue->backing_dev_info->capabilities |=
                    BDI_CAP_STABLE_WRITES;
    else
            disk->queue->backing_dev_info->capabilities &=
                    ~BDI_CAP_STABLE_WRITES;

It's called from revalidate_disk() and rescan_partitions(), making it
impossible to enable stable pages for drivers that support partitions
and don't use blk_integrity: while the call in revalidate_disk() can be
trivially worked around (see zram, which doesn't support partitions and
hence gets away with zram_revalidate_disk()), rescan_partitions() can
be triggered from userspace at any time.  This breaks rbd, where the
ceph messenger is responsible for generating/verifying CRCs.

Since blk_integrity_{un,}register() "must" be used for (un)registering
the integrity profile with the block layer, move BDI_CAP_STABLE_WRITES
setting there.  This way drivers that call blk_integrity_register() and
use integrity infrastructure won't interfere with drivers that don't
but still want stable pages.

Fixes: 25520d55cd ("block: Inline blk_integrity in struct gendisk")
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 4.4+, needs backporting
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-21 14:17:27 -06:00
Dan Williams
b0686260fe dax: introduce dax_direct_access()
Replace bdev_direct_access() with dax_direct_access() that uses
dax_device and dax_operations instead of a block_device and
block_device_operations for dax. Once all consumers of the old api have
been converted bdev_direct_access() will be deleted.

Given that block device partitioning decisions can cause dax page
alignment constraints to be violated this also introduces the
bdev_dax_pgoff() helper. It handles calculating a logical pgoff relative
to the dax_device and also checks for page alignment.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-04-20 11:57:52 -07:00
Dan Williams
d8f07aee3f block: kill bdev_dax_capable()
This is leftover dead code that has since been replaced by
bdev_dax_supported().

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2017-04-20 11:57:52 -07:00
Christoph Hellwig
34045129b1 block_dev: use blkdev_issue_zerout for hole punches
This gets us support for non-discard efficient write of zeroes (e.g. NVMe)
and prepares for removing the discard_zeroes_data flag.

Also remove a pointless discard support check, which is done in
blkdev_issue_discard already.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>

Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-08 11:25:38 -06:00
Christoph Hellwig
ee472d835c block: add a flags argument to (__)blkdev_issue_zeroout
Turn the existing discard flag into a new BLKDEV_ZERO_UNMAP flag with
similar semantics, but without referring to diѕcard.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-08 11:25:38 -06:00
Jan Kara
f759741d9d block: Fix oops in locked_inode_to_wb_and_lock_list()
When block device is closed, we call inode_detach_wb() in __blkdev_put()
which sets inode->i_wb to NULL. That is contrary to expectations that
inode->i_wb stays valid once set during the whole inode's lifetime and
leads to oops in wb_get() in locked_inode_to_wb_and_lock_list() because
inode_to_wb() returned NULL.

The reason why we called inode_detach_wb() is not valid anymore though.
BDI is guaranteed to stay along until we call bdi_put() from
bdev_evict_inode() so we can postpone calling inode_detach_wb() to that
moment.

Also add a warning to catch if someone uses inode_detach_wb() in a
dangerous way.

Reported-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-22 20:11:33 -06:00
Jan Kara
03e2627988 block: Fix bdi assignment to bdev inode when racing with disk delete
When disk->fops->open() in __blkdev_get() returns -ERESTARTSYS, we
restart the process of opening the block device. However we forget to
switch bdev->bd_bdi back to noop_backing_dev_info and as a result bdev
inode will be pointing to a stale bdi. Fix the problem by setting
bdev->bd_bdi later when __blkdev_get() is already guaranteed to succeed.

Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-22 20:11:22 -06:00
Jan Kara
a5a79d0001 block: Initialize bd_bdi on inode initialization
So far we initialized bd_bdi only in bdget(). That is fine for normal
bdev inodes however for the special case of the root inode of
blockdev_superblock that function is never called and thus bd_bdi is
left uninitialized. As a result bdev_evict_inode() may oops doing
bdi_put(root->bd_bdi) on that inode as can be seen when doing:

mount -t bdev none /mnt

Fix the problem by initializing bd_bdi when first allocating the inode
and then reinitializing bd_bdi in bdev_evict_inode().

Thanks to syzkaller team for finding the problem.

Reported-by: Dmitry Vyukov <dvyukov@google.com>
Fixes: b1d2dc5659 ("block: Make blk_get_backing_dev_info() safe without open bdev")
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-03-02 08:56:59 -07:00
Fabian Frederick
93407472a2 fs: add i_blocksize()
Replace all 1 << inode->i_blkbits and (1 << inode->i_blkbits) in fs
branch.

This patch also fixes multiple checkpatch warnings: WARNING: Prefer
'unsigned int' to bare use of 'unsigned'

Thanks to Andrew Morton for suggesting more appropriate function instead
of macro.

[geliangtang@gmail.com: truncate: use i_blocksize()]
  Link: http://lkml.kernel.org/r/9c8b2cd83c8f5653805d43debde9fa8817e02fc4.1484895804.git.geliangtang@gmail.com
Link: http://lkml.kernel.org/r/1481319905-10126-1-git-send-email-fabf@skynet.be
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-02-27 18:43:46 -08:00
Jan Kara
cccd9fb9ec block: Revalidate i_bdev reference in bd_aquire()
When a device gets removed, block device inode unhashed so that it is not
used anymore (bdget() will not find it anymore). Later when a new device
gets created with the same device number, we create new block device
inode. However there may be file system device inodes whose i_bdev still
points to the original block device inode and thus we get two active
block device inodes for the same device. They will share the same
gendisk so the only visible differences will be that page caches will
not be coherent and BDIs will be different (the old block device inode
still points to unregistered BDI).

Fix the problem by checking in bd_acquire() whether i_bdev still points
to active block device inode and re-lookup the block device if not. That
way any open of a block device happening after the old device has been
removed will get correct block device inode.

Tested-by: Lekshmi Pillai <lekshmicpillai@in.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-21 12:51:54 -07:00
Jens Axboe
818551e2b2 Merge branch 'for-4.11/next' into for-4.11/linus-merge
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-17 14:08:19 -07:00
Jan Kara
b1d2dc5659 block: Make blk_get_backing_dev_info() safe without open bdev
Currenly blk_get_backing_dev_info() is not safe to be called when the
block device is not open as bdev->bd_disk is NULL in that case. However
inode_to_bdi() uses this function and may be call called from flusher
worker or other writeback related functions without bdev being open
which leads to crashes such as:

[113031.075540] Unable to handle kernel paging request for data at address 0x00000000
[113031.075614] Faulting instruction address: 0xc0000000003692e0
0:mon> t
[c0000000fb65f900] c00000000036cb6c writeback_sb_inodes+0x30c/0x590
[c0000000fb65fa10] c00000000036ced4 __writeback_inodes_wb+0xe4/0x150
[c0000000fb65fa70] c00000000036d33c wb_writeback+0x30c/0x450
[c0000000fb65fb40] c00000000036e198 wb_workfn+0x268/0x580
[c0000000fb65fc50] c0000000000f3470 process_one_work+0x1e0/0x590
[c0000000fb65fce0] c0000000000f38c8 worker_thread+0xa8/0x660
[c0000000fb65fd80] c0000000000fc4b0 kthread+0x110/0x130
[c0000000fb65fe30] c0000000000098f0 ret_from_kernel_thread+0x5c/0x6c

Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-02 08:20:53 -07:00
Jan Kara
f44f1ab5a2 block: Unhash block device inodes on gendisk destruction
Currently, block device inodes stay around after corresponding gendisk
hash died until memory reclaim finds them and frees them. Since we will
make block device inode pin the bdi, we want to free the block device
inode as soon as the device goes away so that bdi does not stay around
unnecessarily. Furthermore we need to avoid issues when new device with
the same major,minor pair gets created since reusing the bdi structure
would be rather difficult in this case.

Unhashing block device inode on gendisk destruction nicely deals with
these problems. Once last block device inode reference is dropped (which
may be directly in del_gendisk()), the inode gets evicted. Furthermore if
the major,minor pair gets reallocated, we are guaranteed to get new
block device inode even if old block device inode is not yet evicted and
thus we avoid issues with possible reuse of bdi.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-02-02 08:18:41 -07:00
Christoph Hellwig
690e5325b8 block: fix use after free in __blkdev_direct_IO
We can't dereference the dio structure after submitting the last bio for
this request, as I/O completion might have happened before the code is
run. Introduce a local is_sync variable instead.

Fixes: 542ff7bf ("block: new direct I/O implementation")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Matias Bjørling <m@bjorling.me>
Tested-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-24 07:55:53 -07:00
Linus Torvalds
62f8c40592 Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block layer fixes from Jens Axboe:
 "A set of fixes for the current series, one fixing a regression with
  block size < page cache size in the alias series from Jan. Outside of
  that, two small cleanups for wbt from Bart, a nvme pull request from
  Christoph, and a few small fixes of documentation updates"

* 'for-linus' of git://git.kernel.dk/linux-block:
  block: fix up io_poll documentation
  block: Avoid that sparse complains about context imbalance in __wbt_wait()
  block: Make wbt_wait() definition consistent with declaration
  clean_bdev_aliases: Prevent cleaning blocks that are not in block range
  genhd: remove dead and duplicated scsi code
  block: add back plugging in __blkdev_direct_IO
  nvmet/fcloop: remove some logically dead code performing redundant ret checks
  nvmet: fix KATO offset in Set Features
  nvme/fc: simplify error handling of nvme_fc_create_hw_io_queues
  nvme/fc: correct some printk information
  nvme/scsi: Remove START STOP emulation
  nvme/pci: Delete misleading queue-wrap comment
  nvme/pci: Fix whitespace problem
  nvme: simplify stripe quirk
  nvme: update maintainers information
2017-01-04 09:03:37 -08:00
Linus Torvalds
7c0f6ba682 Replace <asm/uaccess.h> with <linux/uaccess.h> globally
This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.

Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-12-24 11:46:01 -08:00
Christoph Hellwig
64d656a162 block: add back plugging in __blkdev_direct_IO
This allows sending larger than 1 MB requests to devices that support
large I/O sizes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Laurence Oberman <loberman@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-12-22 11:48:20 -07:00
Shaohua Li
7a62a52333 block_dev: don't update file access position for sync direct IO
For sync direct IO, generic_file_direct_write/generic_file_read_iter
will update file access position. Don't duplicate the update in
.direct_IO. This cause my raid array can't assemble.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-12-13 21:07:08 -07:00
NeilBrown
bcc7f5b4be block_dev: don't test bdev->bd_contains when it is not stable
bdev->bd_contains is not stable before calling __blkdev_get().
When __blkdev_get() is called on a parition with ->bd_openers == 0
it sets
  bdev->bd_contains = bdev;
which is not correct for a partition.
After a call to __blkdev_get() succeeds, ->bd_openers will be > 0
and then ->bd_contains is stable.

When FMODE_EXCL is used, blkdev_get() calls
   bd_start_claiming() ->  bd_prepare_to_claim() -> bd_may_claim()

This call happens before __blkdev_get() is called, so ->bd_contains
is not stable.  So bd_may_claim() cannot safely use ->bd_contains.
It currently tries to use it, and this can lead to a BUG_ON().

This happens when a whole device is already open with a bd_holder (in
use by dm in my particular example) and two threads race to open a
partition of that device for the first time, one opening with O_EXCL and
one without.

The thread that doesn't use O_EXCL gets through blkdev_get() to
__blkdev_get(), gains the ->bd_mutex, and sets bdev->bd_contains = bdev;

Immediately thereafter the other thread, using FMODE_EXCL, calls
bd_start_claiming() from blkdev_get().  This should fail because the
whole device has a holder, but because bdev->bd_contains == bdev
bd_may_claim() incorrectly reports success.
This thread continues and blocks on bd_mutex.

The first thread then sets bdev->bd_contains correctly and drops the mutex.
The thread using FMODE_EXCL then continues and when it calls bd_may_claim()
again in:
			BUG_ON(!bd_may_claim(bdev, whole, holder));
The BUG_ON fires.

Fix this by removing the dependency on ->bd_contains in
bd_may_claim().  As bd_may_claim() has direct access to the whole
device, it can simply test if the target bdev is the whole device.

Fixes: 6b4517a791 ("block: implement bd_claiming and claiming block")
Cc: stable@vger.kernel.org (v2.6.35+)
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-12-13 21:07:08 -07:00
Rabin Vincent
af309226db block: protect iterate_bdevs() against concurrent close
If a block device is closed while iterate_bdevs() is handling it, the
following NULL pointer dereference occurs because bdev->b_disk is NULL
in bdev_get_queue(), which is called from blk_get_backing_dev_info() (in
turn called by the mapping_cap_writeback_dirty() call in
__filemap_fdatawrite_range()):

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000508
 IP: [<ffffffff81314790>] blk_get_backing_dev_info+0x10/0x20
 PGD 9e62067 PUD 9ee8067 PMD 0
 Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
 Modules linked in:
 CPU: 1 PID: 2422 Comm: sync Not tainted 4.5.0-rc7+ #400
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
 task: ffff880009f4d700 ti: ffff880009f5c000 task.ti: ffff880009f5c000
 RIP: 0010:[<ffffffff81314790>]  [<ffffffff81314790>] blk_get_backing_dev_info+0x10/0x20
 RSP: 0018:ffff880009f5fe68  EFLAGS: 00010246
 RAX: 0000000000000000 RBX: ffff88000ec17a38 RCX: ffffffff81a4e940
 RDX: 7fffffffffffffff RSI: 0000000000000000 RDI: ffff88000ec176c0
 RBP: ffff880009f5fe68 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88000ec17860
 R13: ffffffff811b25c0 R14: ffff88000ec178e0 R15: ffff88000ec17a38
 FS:  00007faee505d700(0000) GS:ffff88000fb00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
 CR2: 0000000000000508 CR3: 0000000009e8a000 CR4: 00000000000006e0
 Stack:
  ffff880009f5feb8 ffffffff8112e7f5 0000000000000000 7fffffffffffffff
  0000000000000000 0000000000000000 7fffffffffffffff 0000000000000001
  ffff88000ec178e0 ffff88000ec17860 ffff880009f5fec8 ffffffff8112e81f
 Call Trace:
  [<ffffffff8112e7f5>] __filemap_fdatawrite_range+0x85/0x90
  [<ffffffff8112e81f>] filemap_fdatawrite+0x1f/0x30
  [<ffffffff811b25d6>] fdatawrite_one_bdev+0x16/0x20
  [<ffffffff811bc402>] iterate_bdevs+0xf2/0x130
  [<ffffffff811b2763>] sys_sync+0x63/0x90
  [<ffffffff815d4272>] entry_SYSCALL_64_fastpath+0x12/0x76
 Code: 0f 1f 44 00 00 48 8b 87 f0 00 00 00 55 48 89 e5 <48> 8b 80 08 05 00 00 5d
 RIP  [<ffffffff81314790>] blk_get_backing_dev_info+0x10/0x20
  RSP <ffff880009f5fe68>
 CR2: 0000000000000508
 ---[ end trace 2487336ceb3de62d ]---

The crash is easily reproducible by running the following command, if an
msleep(100) is inserted before the call to func() in iterate_devs():

 while :; do head -c1 /dev/nullb0; done > /dev/null & while :; do sync; done

Fix it by holding the bd_mutex across the func() call and only calling
func() if the bdev is opened.

Cc: stable@vger.kernel.org
Fixes: 5c0d6b60a0 ("vfs: Create function for iterating over block devices")
Reported-and-tested-by: Wei Fang <fangwei1@huawei.com>
Signed-off-by: Rabin Vincent <rabinv@axis.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-12-01 08:26:39 -07:00
Ming Lei
3a83f46775 block: bio: pass bvec table to bio_init()
Some drivers often use external bvec table, so introduce
this helper for this case. It is always safe to access the
bio->bi_io_vec in this way for this case.

After converting to this usage, it will becomes a bit easier
to evaluate the remaining direct access to bio->bi_io_vec,
so it can help to prepare for the following multipage bvec
support.

Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

Fixed up the new O_DIRECT cases.

Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-22 08:57:21 -07:00
Jens Axboe
9a794fb9bd block_dev: get rid of blksize bits calculation
We store the bits in the bdev sector size locally, but we don't use
the calculation anymore. All we do with it is shift it back up to
the bdev sector size. So let's just use that directly and kill the
variable and bits calculation.

Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-22 08:56:25 -07:00
Damien Le Moal
4d1a476542 block_dev: Fixed direct I/O bio sector calculation
A direct I/O alignment must be always checked against the device blocks size,
but the I/O offset (bio->bi_iter.bi_sector must always use 512B sector unit, and
not the actual logical block size.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-22 08:09:09 -07:00
Christoph Hellwig
542ff7bf18 block: new direct I/O implementation
Similar to the simple fast path, but we now need a dio structure to
track multiple-bio completions.  It's basically a cut-down version
of the new iomap-based direct I/O code for filesystems, but without
all the logic to call into the filesystem for extent lookup or
allocation, and without the complex I/O completion workqueue handler
for AIO - instead we just use the FUA bit on the bios to ensure
data is flushed to stable storage.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-17 13:35:11 -07:00
Jens Axboe
78250c02d9 block: make __blkdev_direct_IO_sync() support O_SYNC/DSYNC
Split the op setting code into a helper, use it in both places.

Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-17 13:35:05 -07:00
Jens Axboe
72ecad22d9 block: support a full bio worth of IO for simplified bdev direct-io
Just alloc the bio_vec array if we exceed the inline limit.

Signed-off-by: Jens Axboe <axboe@fb.com>
2016-11-17 13:35:02 -07:00
Christoph Hellwig
189ce2b9dc block: fast-path for small and simple direct I/O requests
This patch adds a small and simple fast patch for small direct I/O
requests on block devices that don't use AIO.  Between the neat
bio_iov_iter_get_pages helper that avoids allocating a page array
for get_user_pages and the on-stack bio and biovec this avoid memory
allocations and atomic operations entirely in the direct I/O code
(lower levels might still do memory allocations and will usually
have at least some atomic operations, though).

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
Tested-By: Stephen Bates <sbates@raithlin.com>
Reviewed-By: Stephen Bates <sbates@raithlin.com>
2016-11-17 13:34:45 -07:00
Darrick J. Wong
25f4c41415 block: implement (some of) fallocate for block devices
After much discussion, it seems that the fallocate feature flag
FALLOC_FL_ZERO_RANGE maps nicely to SCSI WRITE SAME; and the feature
FALLOC_FL_PUNCH_HOLE maps nicely to the devices that have been whitelisted
for zeroing SCSI UNMAP.  Punch still requires that FALLOC_FL_KEEP_SIZE is
set.  A length that goes past the end of the device will be clamped to the
device size if KEEP_SIZE is set; or will return -EINVAL if not.  Both
start and length must be aligned to the device's logical block size.

Since the semantics of fallocate are fairly well established already, wire
up the two pieces.  The other fallocate variants (collapse range, insert
range, and allocate blocks) are not supported.

Link: http://lkml.kernel.org/r/147518379992.22791.8849838163218235007.stgit@birch.djwong.org
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Mike Snitzer <snitzer@redhat.com> # tweaked header
Cc: Brian Foster <bfoster@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-11 15:06:30 -07:00
Pierre Morel
997198ba1e fs/block_dev.c: return the right error in thaw_bdev()
When triggering thaw-filesystems via magic sysrq, the system enters a
loop in do_thaw_one(), as thaw_bdev() still returns success if
bd_fsfreeze_count == 0. To fix this, let thaw_bdev() always return
error (and simplify the code a bit at the same time).

Reviewed-by: Eric Farman <farman@linux.vnet.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Pierre Morel <pmorel@linux.vnet.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-05 14:35:13 -06:00
Christoph Hellwig
2237570168 block_dev: remove DAX leftovers
DAX support for block devices was removed in commits 03cdad
("block: disable block device DAX by default") and 99a01cd
("block: remove BLK_DEV_DAX config option"), but we still kept a call to
dax_do_io and some uneeded i_flags manipulations introduced in commit
bbab37 ("block: Add support for DAX reads/writes to block devices").

Remove those leftovers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-14 08:41:59 -06:00
Andrey Ryabinin
5bb53c0fb8 fs/block_dev: fix potential NULL ptr deref in freeze_bdev()
Calling freeze_bdev() twice on the same block device without mounted
filesystem get_super() will return NULL, which will lead to NULL-ptr
dereference later in drop_super().

Check get_super() result to fix that.

Note, that this is a purely theoretical issue. We have only 3
freeze_bdev() callers. 2 of them are in filesystem code and used on a
device with mounted fs. The third one in lock_fs() has protection in
upper-layer code against freezing block device the second time without
thawing it first.

Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-08-25 08:38:26 -06:00
Vegard Nossum
e9e5e3fae8 bdev: fix NULL pointer dereference
I got this:

    kasan: GPF could be caused by NULL-ptr deref or user memory access
    general protection fault: 0000 [#1] PREEMPT SMP KASAN
    Dumping ftrace buffer:
       (ftrace buffer empty)
    CPU: 0 PID: 5505 Comm: syz-executor Not tainted 4.8.0-rc2+ #161
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.9.3-0-ge2fc41e-prebuilt.qemu-project.org 04/01/2014
    task: ffff880113415940 task.stack: ffff880118350000
    RIP: 0010:[<ffffffff8172cb32>]  [<ffffffff8172cb32>] bd_mount+0x52/0xa0
    RSP: 0018:ffff880118357ca0  EFLAGS: 00010207
    RAX: dffffc0000000000 RBX: ffffffffffffffff RCX: ffffc90000bb6000
    RDX: 0000000000000018 RSI: ffffffff846d6b20 RDI: 00000000000000c7
    RBP: ffff880118357cb0 R08: ffff880115967c68 R09: 0000000000000000
    R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801188211e8
    R13: ffffffff847baa20 R14: ffff8801139cb000 R15: 0000000000000080
    FS:  00007fa3ff6c0700(0000) GS:ffff88011aa00000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    CR2: 00007fc1d8cc7e78 CR3: 0000000109f20000 CR4: 00000000000006f0
    DR0: 000000000000001e DR1: 000000000000001e DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
    Stack:
     ffff880112cfd6c0 ffff8801188211e8 ffff880118357cf0 ffffffff8167f207
     ffffffff816d7a1e ffff880112a413c0 ffffffff847baa20 ffff8801188211e8
     0000000000000080 ffff880112cfd6c0 ffff880118357d38 ffffffff816dce0a
    Call Trace:
     [<ffffffff8167f207>] mount_fs+0x97/0x2e0
     [<ffffffff816d7a1e>] ? alloc_vfsmnt+0x55e/0x760
     [<ffffffff816dce0a>] vfs_kern_mount+0x7a/0x300
     [<ffffffff83c3247c>] ? _raw_read_unlock+0x2c/0x50
     [<ffffffff816dfc87>] do_mount+0x3d7/0x2730
     [<ffffffff81235fd4>] ? trace_do_page_fault+0x1f4/0x3a0
     [<ffffffff816df8b0>] ? copy_mount_string+0x40/0x40
     [<ffffffff8161ea81>] ? memset+0x31/0x40
     [<ffffffff816df73e>] ? copy_mount_options+0x1ee/0x320
     [<ffffffff816e2a02>] SyS_mount+0xb2/0x120
     [<ffffffff816e2950>] ? copy_mnt_ns+0x970/0x970
     [<ffffffff81005524>] do_syscall_64+0x1c4/0x4e0
     [<ffffffff83c3282a>] entry_SYSCALL64_slow_path+0x25/0x25
    Code: 83 e8 63 1b fc ff 48 85 c0 48 89 c3 74 4c e8 56 35 d1 ff 48 8d bb c8 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 36 4c 8b a3 c8 00 00 00 48 b8 00 00 00 00 00 fc
    RIP  [<ffffffff8172cb32>] bd_mount+0x52/0xa0
     RSP <ffff880118357ca0>
    ---[ end trace 13690ad962168b98 ]---

mount_pseudo() returns ERR_PTR(), not NULL, on error.

Fixes: 3684aa7099 ("block-dev: enable writeback cgroup support")
Cc: Shaohua Li <shli@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@fb.com>
Cc: stable@vger.kernel.org
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-08-22 08:06:15 -06:00
Jens Axboe
c11f0c0b5b block/mm: make bdev_ops->rw_page() take a bool for read/write
Commit abf545484d changed it from an 'rw' flags type to the
newer ops based interface, but now we're effectively leaking
some bdev internals to the rest of the kernel. Since we only
care about whether it's a read or a write at that level, just
pass in a bool 'is_write' parameter instead.

Then we can also move op_is_write() and friends back under
CONFIG_BLOCK protection.

Reviewed-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-08-07 14:41:02 -06:00
Mike Christie
abf545484d mm/block: convert rw_page users to bio op use
The rw_page users were not converted to use bio/req ops. As a result
bdev_write_page is not passing down REQ_OP_WRITE and the IOs will
be sent down as reads.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Fixes: 4e1b2d52a8 ("block, fs, drivers: remove REQ_OP compat defs and related code")

Modified by me to:

1) Drop op_flags passing into ->rw_page(), as we don't use it.
2) Make op_is_write() and friends safe to use for !CONFIG_BLOCK

Signed-off-by: Jens Axboe <axboe@fb.com>
2016-08-04 14:25:33 -06:00
Ross Zwisler
99a01cdf9d block: remove BLK_DEV_DAX config option
The functionality for block device DAX was already removed with commit
acc93d30d7 ("Revert "block: enable dax for raw block devices"")

However, we still had a config option hanging around that was always
disabled because it depended on CONFIG_BROKEN.  This config option was
introduced in commit 03cdadb040 ("block: disable block device DAX by
default")

This change reverts that commit, removing the dead config option.

Link: http://lkml.kernel.org/r/20160729182314.6368-1-ross.zwisler@linux.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-08-04 08:50:07 -04:00
Linus Torvalds
a867d7349e Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull userns vfs updates from Eric Biederman:
 "This tree contains some very long awaited work on generalizing the
  user namespace support for mounting filesystems to include filesystems
  with a backing store.  The real world target is fuse but the goal is
  to update the vfs to allow any filesystem to be supported.  This
  patchset is based on a lot of code review and testing to approach that
  goal.

  While looking at what is needed to support the fuse filesystem it
  became clear that there were things like xattrs for security modules
  that needed special treatment.  That the resolution of those concerns
  would not be fuse specific.  That sorting out these general issues
  made most sense at the generic level, where the right people could be
  drawn into the conversation, and the issues could be solved for
  everyone.

  At a high level what this patchset does a couple of simple things:

   - Add a user namespace owner (s_user_ns) to struct super_block.

   - Teach the vfs to handle filesystem uids and gids not mapping into
     to kuids and kgids and being reported as INVALID_UID and
     INVALID_GID in vfs data structures.

  By assigning a user namespace owner filesystems that are mounted with
  only user namespace privilege can be detected.  This allows security
  modules and the like to know which mounts may not be trusted.  This
  also allows the set of uids and gids that are communicated to the
  filesystem to be capped at the set of kuids and kgids that are in the
  owning user namespace of the filesystem.

  One of the crazier corner casees this handles is the case of inodes
  whose i_uid or i_gid are not mapped into the vfs.  Most of the code
  simply doesn't care but it is easy to confuse the inode writeback path
  so no operation that could cause an inode write-back is permitted for
  such inodes (aka only reads are allowed).

  This set of changes starts out by cleaning up the code paths involved
  in user namespace permirted mounts.  Then when things are clean enough
  adds code that cleanly sets s_user_ns.  Then additional restrictions
  are added that are possible now that the filesystem superblock
  contains owner information.

  These changes should not affect anyone in practice, but there are some
  parts of these restrictions that are changes in behavior.

   - Andy's restriction on suid executables that does not honor the
     suid bit when the path is from another mount namespace (think
     /proc/[pid]/fd/) or when the filesystem was mounted by a less
     privileged user.

   - The replacement of the user namespace implicit setting of MNT_NODEV
     with implicitly setting SB_I_NODEV on the filesystem superblock
     instead.

     Using SB_I_NODEV is a stronger form that happens to make this state
     user invisible.  The user visibility can be managed but it caused
     problems when it was introduced from applications reasonably
     expecting mount flags to be what they were set to.

  There is a little bit of work remaining before it is safe to support
  mounting filesystems with backing store in user namespaces, beyond
  what is in this set of changes.

   - Verifying the mounter has permission to read/write the block device
     during mount.

   - Teaching the integrity modules IMA and EVM to handle filesystems
     mounted with only user namespace root and to reduce trust in their
     security xattrs accordingly.

   - Capturing the mounters credentials and using that for permission
     checks in d_automount and the like.  (Given that overlayfs already
     does this, and we need the work in d_automount it make sense to
     generalize this case).

  Furthermore there are a few changes that are on the wishlist:

   - Get all filesystems supporting posix acls using the generic posix
     acls so that posix_acl_fix_xattr_from_user and
     posix_acl_fix_xattr_to_user may be removed.  [Maintainability]

   - Reducing the permission checks in places such as remount to allow
     the superblock owner to perform them.

   - Allowing the superblock owner to chown files with unmapped uids and
     gids to something that is mapped so the files may be treated
     normally.

  I am not considering even obvious relaxations of permission checks
  until it is clear there are no more corner cases that need to be
  locked down and handled generically.

  Many thanks to Seth Forshee who kept this code alive, and putting up
  with me rewriting substantial portions of what he did to handle more
  corner cases, and for his diligent testing and reviewing of my
  changes"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (30 commits)
  fs: Call d_automount with the filesystems creds
  fs: Update i_[ug]id_(read|write) to translate relative to s_user_ns
  evm: Translate user/group ids relative to s_user_ns when computing HMAC
  dquot: For now explicitly don't support filesystems outside of init_user_ns
  quota: Handle quota data stored in s_user_ns in quota_setxquota
  quota: Ensure qids map to the filesystem
  vfs: Don't create inodes with a uid or gid unknown to the vfs
  vfs: Don't modify inodes with a uid or gid unknown to the vfs
  cred: Reject inodes with invalid ids in set_create_file_as()
  fs: Check for invalid i_uid in may_follow_link()
  vfs: Verify acls are valid within superblock's s_user_ns.
  userns: Handle -1 in k[ug]id_has_mapping when !CONFIG_USER_NS
  fs: Refuse uid/gid changes which don't map into s_user_ns
  selinux: Add support for unprivileged mounts from user namespaces
  Smack: Handle labels consistently in untrusted mounts
  Smack: Add support for unprivileged mounts from user namespaces
  fs: Treat foreign mounts as nosuid
  fs: Limit file caps to the user namespace of the super block
  userns: Remove the now unnecessary FS_USERNS_DEV_MOUNT flag
  userns: Remove implicit MNT_NODEV fragility.
  ...
2016-07-29 15:54:19 -07:00
Linus Torvalds
6784725ab0 Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs updates from Al Viro:
 "Assorted cleanups and fixes.

  Probably the most interesting part long-term is ->d_init() - that will
  have a bunch of followups in (at least) ceph and lustre, but we'll
  need to sort the barrier-related rules before it can get used for
  really non-trivial stuff.

  Another fun thing is the merge of ->d_iput() callers (dentry_iput()
  and dentry_unlink_inode()) and a bunch of ->d_compare() ones (all
  except the one in __d_lookup_lru())"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (26 commits)
  fs/dcache.c: avoid soft-lockup in dput()
  vfs: new d_init method
  vfs: Update lookup_dcache() comment
  bdev: get rid of ->bd_inodes
  Remove last traces of ->sync_page
  new helper: d_same_name()
  dentry_cmp(): use lockless_dereference() instead of smp_read_barrier_depends()
  vfs: clean up documentation
  vfs: document ->d_real()
  vfs: merge .d_select_inode() into .d_real()
  unify dentry_iput() and dentry_unlink_inode()
  binfmt_misc: ->s_root is not going anywhere
  drop redundant ->owner initializations
  ufs: get rid of redundant checks
  orangefs: constify inode_operations
  missed comment updates from ->direct_IO() prototype change
  file_inode(f)->i_mapping is f->f_mapping
  trim fsnotify hooks a bit
  9p: new helper - v9fs_parent_fid()
  debugfs: ->d_parent is never NULL or negative
  ...
2016-07-28 12:59:05 -07:00
Toshi Kani
163d4baaeb block: add QUEUE_FLAG_DAX for devices to advertise their DAX support
Currently, presence of direct_access() in block_device_operations
indicates support of DAX on its block device.  Because
block_device_operations is instantiated with 'const', this DAX
capablity may not be enabled conditinally.

In preparation for supporting DAX to device-mapper devices, add
QUEUE_FLAG_DAX to request_queue flags to advertise their DAX
support.  This will allow to set the DAX capability based on how
mapped device is composed.

Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: <linux-s390@vger.kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-07-20 21:01:01 -06:00
Al Viro
a4a4f9439c bdev: get rid of ->bd_inodes
Since 2006 we have ->i_bdev pinning bdev in question, so there's no
way to get to bdev ->evict_inode() while there's an aliasing inode
anywhere.  In other words, the only place walking the list of aliases
is guaranteed to do it only when the list is empty...

Remove the detritus; it should've been done in "[PATCH] Fix a race
condition between ->i_mapping and iput()", but nobody had noticed it
back then.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-07-19 13:16:52 -04:00
Eric W. Biederman
a2982cc922 vfs: Generalize filesystem nodev handling.
Introduce a function may_open_dev that tests MNT_NODEV and a new
superblock flab SB_I_NODEV.  Use this new function in all of the
places where MNT_NODEV was previously tested.

Add the new SB_I_NODEV s_iflag to proc, sysfs, and mqueuefs as those
filesystems should never support device nodes, and a simple superblock
flags makes that very hard to get wrong.  With SB_I_NODEV set if any
device nodes somehow manage to show up on on a filesystem those
device nodes will be unopenable.

Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2016-06-23 15:41:57 -05:00
Linus Torvalds
315227f6da DAX error handling for 4.7
- Until now, dax has been disabled if media errors were found on
   any device. This enables the use of DAX in the presence of these
   errors by making all sector-aligned zeroing go through the driver.
 - The driver (already) has the ability to clear errors on writes that
   are sent through the block layer using 'DSMs' defined in ACPI 6.1.
 
 Other misc changes:
 
 - When mounting DAX filesystems, check to make sure the partition
   is page aligned. This is a requirement for DAX, and previously, we
   allowed such unaligned mounts to succeed, but subsequent reads/writes
   would fail.
 
 - Misc/cleanup fixes from Jan that remove unused code from DAX related to
   zeroing, writeback, and some size checks.
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Merge tag 'dax-misc-for-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull misc DAX updates from Vishal Verma:
 "DAX error handling for 4.7

   - Until now, dax has been disabled if media errors were found on any
     device.  This enables the use of DAX in the presence of these
     errors by making all sector-aligned zeroing go through the driver.

   - The driver (already) has the ability to clear errors on writes that
     are sent through the block layer using 'DSMs' defined in ACPI 6.1.

  Other misc changes:

   - When mounting DAX filesystems, check to make sure the partition is
     page aligned.  This is a requirement for DAX, and previously, we
     allowed such unaligned mounts to succeed, but subsequent
     reads/writes would fail.

   - Misc/cleanup fixes from Jan that remove unused code from DAX
     related to zeroing, writeback, and some size checks"

* tag 'dax-misc-for-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  dax: fix a comment in dax_zero_page_range and dax_truncate_page
  dax: for truncate/hole-punch, do zeroing through the driver if possible
  dax: export a low-level __dax_zero_page_range helper
  dax: use sb_issue_zerout instead of calling dax_clear_sectors
  dax: enable dax in the presence of known media errors (badblocks)
  dax: fallback from pmd to pte on error
  block: Update blkdev_dax_capable() for consistency
  xfs: Add alignment check for DAX mount
  ext2: Add alignment check for DAX mount
  ext4: Add alignment check for DAX mount
  block: Add bdev_dax_supported() for dax mount checks
  block: Add vfs_msg() interface
  dax: Remove redundant inode size checks
  dax: Remove pointless writeback from dax_do_io()
  dax: Remove zeroing from dax_io()
  dax: Remove dead zeroing code from fault handlers
  ext2: Avoid DAX zeroing to corrupt data
  ext2: Fix block zeroing in ext2_get_blocks() for DAX
  dax: Remove complete_unwritten argument
  DAX: move RADIX_DAX_ definitions to dax.c
2016-05-26 19:34:26 -07:00
Linus Torvalds
1f40c49570 libnvdimm for 4.7
1/ Device DAX for persistent memory:
    Device DAX is the device-centric analogue of Filesystem DAX
    (CONFIG_FS_DAX).  It allows memory ranges to be allocated and mapped
    without need of an intervening file system.  Device DAX is strict,
    precise and predictable.  Specifically this interface:
 
    a) Guarantees fault granularity with respect to a given page size
       (pte, pmd, or pud) set at configuration time.
 
    b) Enforces deterministic behavior by being strict about what fault
       scenarios are supported.
 
    Persistent memory is the first target, but the mechanism is also
    targeted for exclusive allocations of performance/feature differentiated
    memory ranges.
 
 2/ Support for the HPE DSM (device specific method) command formats.
    This enables management of these first generation devices until a
    unified DSM specification materializes.
 
 3/ Further ACPI 6.1 compliance with support for the common dimm
    identifier format.
 
 4/ Various fixes and cleanups across the subsystem.
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Merge tag 'libnvdimm-for-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm updates from Dan Williams:
 "The bulk of this update was stabilized before the merge window and
  appeared in -next.  The "device dax" implementation was revised this
  week in response to review feedback, and to address failures detected
  by the recently expanded ndctl unit test suite.

  Not included in this pull request are two dax topic branches (dax
  error handling, and dax radix-tree locking).  These topics were
  deferred to get a few more days of -next integration testing, and to
  coordinate a branch baseline with Ted and the ext4 tree.  Vishal and
  Ross will send the error handling and locking topics respectively in
  the next few days.

  This branch has received a positive build result from the kbuild robot
  across 226 configs.

  Summary:

   - Device DAX for persistent memory: Device DAX is the device-centric
     analogue of Filesystem DAX (CONFIG_FS_DAX).  It allows memory
     ranges to be allocated and mapped without need of an intervening
     file system.  Device DAX is strict, precise and predictable.
     Specifically this interface:

      a) Guarantees fault granularity with respect to a given page size
         (pte, pmd, or pud) set at configuration time.

      b) Enforces deterministic behavior by being strict about what
         fault scenarios are supported.

     Persistent memory is the first target, but the mechanism is also
     targeted for exclusive allocations of performance/feature
     differentiated memory ranges.

   - Support for the HPE DSM (device specific method) command formats.
     This enables management of these first generation devices until a
     unified DSM specification materializes.

   - Further ACPI 6.1 compliance with support for the common dimm
     identifier format.

   - Various fixes and cleanups across the subsystem"

* tag 'libnvdimm-for-4.7' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (40 commits)
  libnvdimm, dax: fix deletion
  libnvdimm, dax: fix alignment validation
  libnvdimm, dax: autodetect support
  libnvdimm: release ida resources
  Revert "block: enable dax for raw block devices"
  /dev/dax, core: file operations and dax-mmap
  /dev/dax, pmem: direct access to persistent memory
  libnvdimm: stop requiring a driver ->remove() method
  libnvdimm, dax: record the specified alignment of a dax-device instance
  libnvdimm, dax: reserve space to store labels for device-dax
  libnvdimm, dax: introduce device-dax infrastructure
  nfit: add sysfs dimm 'family' and 'dsm_mask' attributes
  tools/testing/nvdimm: ND_CMD_CALL support
  nfit: disable vendor specific commands
  nfit: export subsystem ids as attributes
  nfit: fix format interface code byte order per ACPI6.1
  nfit, libnvdimm: limited/whitelisted dimm command marshaling mechanism
  nfit, libnvdimm: clarify "commands" vs "_DSMs"
  libnvdimm: increase max envelope size for ioctl
  acpi/nfit: Add sysfs "id" for NVDIMM ID
  ...
2016-05-23 11:18:01 -07:00