do_blockdev_direct_IO() increments and decrements the inode
->i_dio_count for each IO operation. It does this to protect against
truncate of a file. Block devices don't need this sort of protection.
For a capable multiqueue setup, this atomic int is the only shared
state between applications accessing the device for O_DIRECT, and it
presents a scaling wall for that. In my testing, as much as 30% of
system time is spent incrementing and decrementing this value. A mixed
read/write workload improved from ~2.5M IOPS to ~9.6M IOPS, with
better latencies too. Before:
clat percentiles (usec):
| 1.00th=[ 33], 5.00th=[ 34], 10.00th=[ 34], 20.00th=[ 34],
| 30.00th=[ 34], 40.00th=[ 34], 50.00th=[ 35], 60.00th=[ 35],
| 70.00th=[ 35], 80.00th=[ 35], 90.00th=[ 37], 95.00th=[ 80],
| 99.00th=[ 98], 99.50th=[ 151], 99.90th=[ 155], 99.95th=[ 155],
| 99.99th=[ 165]
After:
clat percentiles (usec):
| 1.00th=[ 95], 5.00th=[ 108], 10.00th=[ 129], 20.00th=[ 149],
| 30.00th=[ 155], 40.00th=[ 161], 50.00th=[ 167], 60.00th=[ 171],
| 70.00th=[ 177], 80.00th=[ 185], 90.00th=[ 201], 95.00th=[ 270],
| 99.00th=[ 390], 99.50th=[ 398], 99.90th=[ 418], 99.95th=[ 422],
| 99.99th=[ 438]
In other setups, Robert Elliott reported seeing good performance
improvements:
https://lkml.org/lkml/2015/4/3/557
The more applications accessing the device, the worse it gets.
Add a new direct-io flags, DIO_SKIP_DIO_COUNT, which tells
do_blockdev_direct_IO() that it need not worry about incrementing
or decrementing the inode i_dio_count for this caller.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Elliott, Robert (Server Storage) <elliott@hp.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Most filesystems call through to these at some point, so we'll start
here.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
All places outside of core VFS that checked ->read and ->write for being NULL or
called the methods directly are gone now, so NULL {read,write} with non-NULL
{read,write}_iter will do the right thing in all cases.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
struct kiocb now is a generic I/O container, so move it to fs.h.
Also do a #include diet for aio.h while we're at it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull core block IO changes from Jens Axboe:
"This contains:
- A series from Christoph that cleans up and refactors various parts
of the REQ_BLOCK_PC handling. Contributions in that series from
Dongsu Park and Kent Overstreet as well.
- CFQ:
- A bug fix for cfq for realtime IO scheduling from Jeff Moyer.
- A stable patch fixing a potential crash in CFQ in OOM
situations. From Konstantin Khlebnikov.
- blk-mq:
- Add support for tag allocation policies, from Shaohua. This is
a prep patch enabling libata (and other SCSI parts) to use the
blk-mq tagging, instead of rolling their own.
- Various little tweaks from Keith and Mike, in preparation for
DM blk-mq support.
- Minor little fixes or tweaks from me.
- A double free error fix from Tony Battersby.
- The partition 4k issue fixes from Matthew and Boaz.
- Add support for zero+unprovision for blkdev_issue_zeroout() from
Martin"
* 'for-3.20/core' of git://git.kernel.dk/linux-block: (27 commits)
block: remove unused function blk_bio_map_sg
block: handle the null_mapped flag correctly in blk_rq_map_user_iov
blk-mq: fix double-free in error path
block: prevent request-to-request merging with gaps if not allowed
blk-mq: make blk_mq_run_queues() static
dm: fix multipath regression due to initializing wrong request
cfq-iosched: handle failure of cfq group allocation
block: Quiesce zeroout wrapper
block: rewrite and split __bio_copy_iov()
block: merge __bio_map_user_iov into bio_map_user_iov
block: merge __bio_map_kern into bio_map_kern
block: pass iov_iter to the BLOCK_PC mapping functions
block: add a helper to free bio bounce buffer pages
block: use blk_rq_map_user_iov to implement blk_rq_map_user
block: simplify bio_map_kern
block: mark blk-mq devices as stackable
block: keep established cmd_flags when cloning into a blk-mq request
block: add blk-mq support to blk_insert_cloned_request()
block: require blk_rq_prep_clone() be given an initialized clone request
blk-mq: add tag allocation policy
...
Now that we never use the backing_dev_info pointer in struct address_space
we can simply remove it and save 4 to 8 bytes in every inode.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Reviewed-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Since 018a17bdc8 ("bdi: reimplement bdev_inode_switch_bdi()") the
block device code writes out all dirty data whenever switching the
backing_dev_info for a block device inode. But a block device inode can
only be dirtied when it is in use, which means we only have to write it
out on the final blkdev_put, but not when doing a blkdev_get.
Factoring out the write out from the bdi list switch prepares from
removing the list switch later in the series.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
In order to support accesses to larger chunks of memory, pass in a
'size' parameter (counted in bytes), and return the amount available at
that address.
Add a new helper function, bdev_direct_access(), to handle common
functionality including partition handling, checking the length requested
is positive, checking for the sector being page-aligned, and checking
the length of the request does not pass the end of the partition.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Boaz Harrosh <boaz@plexistor.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Currently, freezing a filesystem involves calling freeze_super, which locks
sb->s_umount and then calls the fs-specific freeze_fs hook. This makes it
hard for gfs2 (and potentially other cluster filesystems) to use the vfs
freezing code to do freezes on all the cluster nodes.
In order to communicate that a freeze has been requested, and to make sure
that only one node is trying to freeze at a time, gfs2 uses a glock
(sd_freeze_gl). The problem is that there is no hook for gfs2 to acquire
this lock before calling freeze_super. This means that two nodes can
attempt to freeze the filesystem by both calling freeze_super, acquiring
the sb->s_umount lock, and then attempting to grab the cluster glock
sd_freeze_gl. Only one will succeed, and the other will be stuck in
freeze_super, making it impossible to finish freezing the node.
To solve this problem, this patch adds the freeze_super and thaw_super
hooks. If a filesystem implements these hooks, they are called instead of
the vfs freeze_super and thaw_super functions. This means that every
filesystem that implements these hooks must call the vfs freeze_super and
thaw_super functions itself within the hook function to make use of the vfs
freezing code.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Author: David Jeffery <djeffery@redhat.com>
Changes to the basic direct I/O code have broken the raw driver when reading
to the end of a raw device. Instead of returning a short read for a read that
extends partially beyond the device's end or 0 when at the end of the device,
these reads now return EIO.
The raw driver needs the same end of device handling as was added for normal
block devices. Using blkdev_read_iter, which has the needed size checks,
prevents the EIO conditions at the end of the device.
Signed-off-by: David Jeffery <djeffery@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull core block layer changes from Jens Axboe:
"This is the core block IO pull request for 3.18. Apart from the new
and improved flush machinery for blk-mq, this is all mostly bug fixes
and cleanups.
- blk-mq timeout updates and fixes from Christoph.
- Removal of REQ_END, also from Christoph. We pass it through the
->queue_rq() hook for blk-mq instead, freeing up one of the request
bits. The space was overly tight on 32-bit, so Martin also killed
REQ_KERNEL since it's no longer used.
- blk integrity updates and fixes from Martin and Gu Zheng.
- Update to the flush machinery for blk-mq from Ming Lei. Now we
have a per hardware context flush request, which both cleans up the
code should scale better for flush intensive workloads on blk-mq.
- Improve the error printing, from Rob Elliott.
- Backing device improvements and cleanups from Tejun.
- Fixup of a misplaced rq_complete() tracepoint from Hannes.
- Make blk_get_request() return error pointers, fixing up issues
where we NULL deref when a device goes bad or missing. From Joe
Lawrence.
- Prep work for drastically reducing the memory consumption of dm
devices from Junichi Nomura. This allows creating clone bio sets
without preallocating a lot of memory.
- Fix a blk-mq hang on certain combinations of queue depths and
hardware queues from me.
- Limit memory consumption for blk-mq devices for crash dump
scenarios and drivers that use crazy high depths (certain SCSI
shared tag setups). We now just use a single queue and limited
depth for that"
* 'for-3.18/core' of git://git.kernel.dk/linux-block: (58 commits)
block: Remove REQ_KERNEL
blk-mq: allocate cpumask on the home node
bio-integrity: remove the needless fail handle of bip_slab creating
block: include func name in __get_request prints
block: make blk_update_request print prefix match ratelimited prefix
blk-merge: don't compute bi_phys_segments from bi_vcnt for cloned bio
block: fix alignment_offset math that assumes io_min is a power-of-2
blk-mq: Make bt_clear_tag() easier to read
blk-mq: fix potential hang if rolling wakeup depth is too high
block: add bioset_create_nobvec()
block: use bio_clone_fast() in blk_rq_prep_clone()
block: misplaced rq_complete tracepoint
sd: Honor block layer integrity handling flags
block: Replace strnicmp with strncasecmp
block: Add T10 Protection Information functions
block: Don't merge requests if integrity flags differ
block: Integrity checksum flag
block: Relocate bio integrity flags
block: Add a disk flag to block integrity profile
block: Add prefix to block integrity profile flags
...
Sequential read from a block device is expected to be equal or faster than
from the file on a filesystem. But it is not correct due to the lack of
effective readpages() in the address space operations for block device.
This implements readpages() operation for block device by using
mpage_readpages() which can create multipage BIOs instead of BIOs for each
page and reduce system CPU time consumption.
Install 1GB of RAM disk storage:
# modprobe scsi_debug dev_size_mb=1024 delay=0
Sequential read from file on a filesystem:
# mkfs.ext4 /dev/$DEV
# mount /dev/$DEV /mnt
# fio --name=t --size=512m --rw=read --filename=/mnt/file
...
read : io=524288KB, bw=2133.4MB/s, iops=546133, runt= 240msec
Sequential read from a block device:
# fio --name=t --size=512m --rw=read --filename=/dev/$DEV
...
(Without this commit)
read : io=524288KB, bw=1700.2MB/s, iops=435455, runt= 301msec
(With this commit)
read : io=524288KB, bw=2160.4MB/s, iops=553046, runt= 237msec
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A block_device may be attached to different gendisks and thus
different bdis over time. bdev_inode_switch_bdi() is used to switch
the associated bdi. The function assumes that the inode could be
dirty and transfers it between bdis if so. This is a bit nasty in
that it reaches into bdi internals.
This patch reimplements the function so that it writes out the inode
if dirty. This is a lot simpler and can be implemented without
exposing bdi internals.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jens Axboe <axboe@fb.com>
bdev_get_queue() returns the request_queue associated with the
specified block_device. blk_get_backing_dev_info() makes use of
bdev_get_queue() to determine the associated bdi given a block_device.
All the callers of bdev_get_queue() including
blk_get_backing_dev_info() assume that bdev_get_queue() may return
NULL and implement NULL handling; however, bdev_get_queue() requires
the passed in block_device is opened and attached to its gendisk.
Because an active gendisk always has a valid request_queue associated
with it, bdev_get_queue() can never return NULL and neither can
blk_get_backing_dev_info().
Make it clear that neither of the two functions can return NULL and
remove NULL handling from all the callers.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Pull vfs updates from Al Viro:
"This the bunch that sat in -next + lock_parent() fix. This is the
minimal set; there's more pending stuff.
In particular, I really hope to get acct.c fixes merged this cycle -
we need that to deal sanely with delayed-mntput stuff. In the next
pile, hopefully - that series is fairly short and localized
(kernel/acct.c, fs/super.c and fs/namespace.c). In this pile: more
iov_iter work. Most of prereqs for ->splice_write with sane locking
order are there and Kent's dio rewrite would also fit nicely on top of
this pile"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (70 commits)
lock_parent: don't step on stale ->d_parent of all-but-freed one
kill generic_file_splice_write()
ceph: switch to iter_file_splice_write()
shmem: switch to iter_file_splice_write()
nfs: switch to iter_splice_write_file()
fs/splice.c: remove unneeded exports
ocfs2: switch to iter_file_splice_write()
->splice_write() via ->write_iter()
bio_vec-backed iov_iter
optimize copy_page_{to,from}_iter()
bury generic_file_aio_{read,write}
lustre: get rid of messing with iovecs
ceph: switch to ->write_iter()
ceph_sync_direct_write: stop poking into iov_iter guts
ceph_sync_read: stop poking into iov_iter guts
new helper: copy_page_from_iter()
fuse: switch to ->write_iter()
btrfs: switch to ->write_iter()
ocfs2: switch to ->write_iter()
xfs: switch to ->write_iter()
...
iter_file_splice_write() - a ->splice_write() instance that gathers the
pipe buffers, builds a bio_vec-based iov_iter covering those and feeds
it to ->write_iter(). A bunch of simple cases coverted to that...
[AV: fixed the braino spotted by Cyrill]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
A block device driver may choose to provide a rw_page operation. These
will be called when the filesystem is attempting to do page sized I/O to
page cache pages (ie not for direct I/O). This does preclude I/Os that
are larger than page size, so this may only be a performance gain for
some devices.
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
Tested-by: Dheeraj Reddy <dheeraj.reddy@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull vfs updates from Al Viro:
"The first vfs pile, with deep apologies for being very late in this
window.
Assorted cleanups and fixes, plus a large preparatory part of iov_iter
work. There's a lot more of that, but it'll probably go into the next
merge window - it *does* shape up nicely, removes a lot of
boilerplate, gets rid of locking inconsistencie between aio_write and
splice_write and I hope to get Kent's direct-io rewrite merged into
the same queue, but some of the stuff after this point is having
(mostly trivial) conflicts with the things already merged into
mainline and with some I want more testing.
This one passes LTP and xfstests without regressions, in addition to
usual beating. BTW, readahead02 in ltp syscalls testsuite has started
giving failures since "mm/readahead.c: fix readahead failure for
memoryless NUMA nodes and limit readahead pages" - might be a false
positive, might be a real regression..."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
missing bits of "splice: fix racy pipe->buffers uses"
cifs: fix the race in cifs_writev()
ceph_sync_{,direct_}write: fix an oops on ceph_osdc_new_request() failure
kill generic_file_buffered_write()
ocfs2_file_aio_write(): switch to generic_perform_write()
ceph_aio_write(): switch to generic_perform_write()
xfs_file_buffered_aio_write(): switch to generic_perform_write()
export generic_perform_write(), start getting rid of generic_file_buffer_write()
generic_file_direct_write(): get rid of ppos argument
btrfs_file_aio_write(): get rid of ppos
kill the 5th argument of generic_file_buffered_write()
kill the 4th argument of __generic_file_aio_write()
lustre: don't open-code kernel_recvmsg()
ocfs2: don't open-code kernel_recvmsg()
drbd: don't open-code kernel_recvmsg()
constify blk_rq_map_user_iov() and friends
lustre: switch to kernel_sendmsg()
ocfs2: don't open-code kernel_sendmsg()
take iov_iter stuff to mm/iov_iter.c
process_vm_access: tidy up a bit
...
Reclaim will be leaving shadow entries in the page cache radix tree upon
evicting the real page. As those pages are found from the LRU, an
iput() can lead to the inode being freed concurrently. At this point,
reclaim must no longer install shadow pages because the inode freeing
code needs to ensure the page tree is really empty.
Add an address_space flag, AS_EXITING, that the inode freeing code sets
under the tree lock before doing the final truncate. Reclaim will check
for this flag before installing shadow pages.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Metin Doslu <metin@citusdata.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Ozgun Erdogan <ozgun@citusdata.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <klamm@yandex-team.ru>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We know that "ret > 0" is true here. These tests were left over from
commit 02afc27fae ('direct-io: Handle O_(D)SYNC AIO') and aren't
needed any more.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Merge tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux
Pull writeback fix from Wu Fengguang:
"A trivial writeback fix"
* tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
writeback: Do not sort b_io list only because of block device inode
Pull aio changes from Ben LaHaise:
"First off, sorry for this pull request being late in the merge window.
Al had raised a couple of concerns about 2 items in the series below.
I addressed the first issue (the race introduced by Gu's use of
mm_populate()), but he has not provided any further details on how he
wants to rework the anon_inode.c changes (which were sent out months
ago but have yet to be commented on).
The bulk of the changes have been sitting in the -next tree for a few
months, with all the issues raised being addressed"
* git://git.kvack.org/~bcrl/aio-next: (22 commits)
aio: rcu_read_lock protection for new rcu_dereference calls
aio: fix race in ring buffer page lookup introduced by page migration support
aio: fix rcu sparse warnings introduced by ioctx table lookup patch
aio: remove unnecessary debugging from aio_free_ring()
aio: table lookup: verify ctx pointer
staging/lustre: kiocb->ki_left is removed
aio: fix error handling and rcu usage in "convert the ioctx list to table lookup v3"
aio: be defensive to ensure request batching is non-zero instead of BUG_ON()
aio: convert the ioctx list to table lookup v3
aio: double aio_max_nr in calculations
aio: Kill ki_dtor
aio: Kill ki_users
aio: Kill unneeded kiocb members
aio: Kill aio_rw_vect_retry()
aio: Don't use ctx->tail unnecessarily
aio: io_cancel() no longer returns the io_event
aio: percpu ioctx refcount
aio: percpu reqs_available
aio: reqs_active -> reqs_available
aio: fix build when migration is disabled
...
Call generic_write_sync() from the deferred I/O completion handler if
O_DSYNC is set for a write request. Also make sure various callers
don't call generic_write_sync if the direct I/O code returns
-EIOCBQUEUED.
Based on an earlier patch from Jan Kara <jack@suse.cz> with updates from
Jeff Moyer <jmoyer@redhat.com> and Darrick J. Wong <darrick.wong@oracle.com>.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This code doesn't serve any purpose anymore, since the aio retry
infrastructure has been removed.
This change should be safe because aio_read/write are also used for
synchronous IO, and called from do_sync_read()/do_sync_write() - and
there's no looping done in the sync case (the read and write syscalls).
Signed-off-by: Kent Overstreet <koverstreet@google.com>
Cc: Zach Brown <zab@redhat.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Asai Thambi S P <asamymuthupa@micron.com>
Cc: Selvan Mani <smani@micron.com>
Cc: Sam Bradshaw <sbradshaw@micron.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Pull core block IO updates from Jens Axboe:
"Here are the core IO block bits for 3.11. It contains:
- A tweak to the reserved tag logic from Jan, for weirdo devices with
just 3 free tags. But for those it improves things substantially
for random writes.
- Periodic writeback fix from Jan. Marked for stable as well.
- Fix for a race condition in IO scheduler switching from Jianpeng.
- The hierarchical blk-cgroup support from Tejun. This is the grunt
of the series.
- blk-throttle fix from Vivek.
Just a note that I'm in the middle of a relocation, whole family is
flying out tomorrow. Hence I will be awal the remainder of this week,
but back at work again on Monday the 15th. CC'ing Tejun, since any
potential "surprises" will most likely be from the blk-cgroup work.
But it's been brewing for a while and sitting in my tree and
linux-next for a long time, so should be solid."
* 'for-3.11/core' of git://git.kernel.dk/linux-block: (36 commits)
elevator: Fix a race in elevator switching
block: Reserve only one queue tag for sync IO if only 3 tags are available
writeback: Fix periodic writeback after fs mount
blk-throttle: implement proper hierarchy support
blk-throttle: implement throtl_grp->has_rules[]
blk-throttle: Account for child group's start time in parent while bio climbs up
blk-throttle: add throtl_qnode for dispatch fairness
blk-throttle: make throtl_pending_timer_fn() ready for hierarchy
blk-throttle: make tg_dispatch_one_bio() ready for hierarchy
blk-throttle: make blk_throtl_bio() ready for hierarchy
blk-throttle: make blk_throtl_drain() ready for hierarchy
blk-throttle: dispatch from throtl_pending_timer_fn()
blk-throttle: implement dispatch looping
blk-throttle: separate out throtl_service_queue->pending_timer from throtl_data->dispatch_work
blk-throttle: set REQ_THROTTLED from throtl_charge_bio() and gate stats update with it
blk-throttle: implement sq_to_tg(), sq_to_td() and throtl_log()
blk-throttle: add throtl_service_queue->parent_sq
blk-throttle: generalize update_disptime optimization in blk_throtl_bio()
blk-throttle: dispatch to throtl_data->service_queue.bio_lists[]
blk-throttle: move bio_lists[] and friends to throtl_service_queue
...
It is very likely that block device inode will be part of BDI dirty list
as well. However it doesn't make sence to sort inodes on the b_io list
just because of this inode (as it contains buffers all over the device
anyway). So save some CPU cycles which is valuable since we hold relatively
contented wb->list_lock.
Signed-off-by: Jan Kara <jack@suse.cz>
Page reclaim keeps track of dirty and under writeback pages and uses it
to determine if wait_iff_congested() should stall or if kswapd should
begin writing back pages. This fails to account for buffer pages that
can be under writeback but not PageWriteback which is the case for
filesystems like ext3 ordered mode. Furthermore, PageDirty buffer pages
can have all the buffers clean and writepage does no IO so it should not
be accounted as congested.
This patch adds an address_space operation that filesystems may
optionally use to check if a page is really dirty or really under
writeback. An implementation is provided for for buffer_heads is added
and used for block operations and ext3 in ordered mode. By default the
page flags are obeyed.
Credit goes to Jan Kara for identifying that the page flags alone are
not sufficient for ext3 and sanity checking a number of ideas on how the
problem could be addressed.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Cc: Zlatko Calusic <zcalusic@bitsync.net>
Cc: dormando <dormando@rydia.net>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Code in blkdev.c moves a device inode to default_backing_dev_info when
the last reference to the device is put and moves the device inode back
to its bdi when the first reference is acquired. This includes moving to
wb.b_dirty list if the device inode is dirty. The code however doesn't
setup timer to wake corresponding flusher thread and while wb.b_dirty
list is non-empty __mark_inode_dirty() will not set it up either. Thus
periodic writeback is effectively disabled until a sync(2) call which can
lead to unexpected data loss in case of crash or power failure.
Fix the problem by setting up a timer for periodic writeback in case we
add the first dirty inode to wb.b_dirty list in bdev_inode_switch_bdi().
Reported-by: Bert De Jonghe <Bert.DeJonghe@amplidata.com>
CC: stable@vger.kernel.org # >= 3.0
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull block core updates from Jens Axboe:
- Major bit is Kents prep work for immutable bio vecs.
- Stable candidate fix for a scheduling-while-atomic in the queue
bypass operation.
- Fix for the hang on exceeded rq->datalen 32-bit unsigned when merging
discard bios.
- Tejuns changes to convert the writeback thread pool to the generic
workqueue mechanism.
- Runtime PM framework, SCSI patches exists on top of these in James'
tree.
- A few random fixes.
* 'for-3.10/core' of git://git.kernel.dk/linux-block: (40 commits)
relay: move remove_buf_file inside relay_close_buf
partitions/efi.c: replace useless kzalloc's by kmalloc's
fs/block_dev.c: fix iov_shorten() criteria in blkdev_aio_read()
block: fix max discard sectors limit
blkcg: fix "scheduling while atomic" in blk_queue_bypass_start
Documentation: cfq-iosched: update documentation help for cfq tunables
writeback: expose the bdi_wq workqueue
writeback: replace custom worker pool implementation with unbound workqueue
writeback: remove unused bdi_pending_list
aoe: Fix unitialized var usage
bio-integrity: Add explicit field for owner of bip_buf
block: Add an explicit bio flag for bios that own their bvec
block: Add bio_alloc_pages()
block: Convert some code to bio_for_each_segment_all()
block: Add bio_for_each_segment_all()
bounce: Refactor __blk_queue_bounce to not use bi_io_vec
raid1: use bio_copy_data()
pktcdvd: Use bio_reset() in disabled code to kill bi_idx usage
pktcdvd: use bio_copy_data()
block: Add bio_copy_data()
...
Merge more incoming from Andrew Morton:
- Various fixes which were stalled or which I picked up recently
- A large rotorooting of the AIO code. Allegedly to improve
performance but I don't really have good performance numbers (I might
have lost the email) and I can't raise Kent today. I held this out
of 3.9 and we could give it another cycle if it's all too late/scary.
I ended up taking only the first two thirds of the AIO rotorooting. I
left the percpu parts and the batch completion for later. - Linus
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (33 commits)
aio: don't include aio.h in sched.h
aio: kill ki_retry
aio: kill ki_key
aio: give shared kioctx fields their own cachelines
aio: kill struct aio_ring_info
aio: kill batch allocation
aio: change reqs_active to include unreaped completions
aio: use cancellation list lazily
aio: use flush_dcache_page()
aio: make aio_read_evt() more efficient, convert to hrtimers
wait: add wait_event_hrtimeout()
aio: refcounting cleanup
aio: make aio_put_req() lockless
aio: do fget() after aio_get_req()
aio: dprintk() -> pr_debug()
aio: move private stuff out of aio.h
aio: add kiocb_cancel()
aio: kill return value of aio_complete()
char: add aio_{read,write} to /dev/{null,zero}
aio: remove retry-based AIO
...
same story as with the previous patches - note that return
value of blkdev_close() is lost, since there's nowhere the
caller (__fput()) could return it to.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The value passed is 0 in all but "it can never happen" cases (and those
only in a couple of drivers) *and* it would've been lost on the way
out anyway, even if something tried to pass something meaningful.
Just don't bother.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Its only caller evict() has promised a non-NULL inode->i_bdev.
Signed-off-by: Yan Hong <clouds.yan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
blkdev_aio_read() test 'size' to see if it is equal or greater than the
target count we request(iocb->ki_left). If so there is no need to call
iov_shorten() to reduce number of segments and the iovec's length. So the
judgement should be changed to 'if (size < iocb->ki_left)' instead.
Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
Signed-off-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
struct block_device lifecycle is defined by its inode (see fs/block_dev.c) -
block_device allocated first time we access /dev/loopXX and deallocated on
bdev_destroy_inode. When we create the device "losetup /dev/loopXX afile"
we want that block_device stay alive until we destroy the loop device
with "losetup -d".
But because we do not hold /dev/loopXX inode its counter goes 0, and
inode/bdev can be destroyed at any moment. Usually it happens at memory
pressure or when user drops inode cache (like in the test below). When later in
loop_clr_fd() we want to use bdev we have use-after-free error with following
stack:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000280
bd_set_size+0x10/0xa0
loop_clr_fd+0x1f8/0x420 [loop]
lo_ioctl+0x200/0x7e0 [loop]
lo_compat_ioctl+0x47/0xe0 [loop]
compat_blkdev_ioctl+0x341/0x1290
do_filp_open+0x42/0xa0
compat_sys_ioctl+0xc1/0xf20
do_sys_open+0x16e/0x1d0
sysenter_dispatch+0x7/0x1a
To prevent use-after-free we need to grab the device in loop_set_fd()
and put it later in loop_clr_fd().
The issue is reprodusible on current Linus head and v3.3. Here is the test:
dd if=/dev/zero of=loop.file bs=1M count=1
while [ true ]; do
losetup /dev/loop0 loop.file
echo 2 > /proc/sys/vm/drop_caches
losetup -d /dev/loop0
done
[ Doing bdgrab/bput in loop_set_fd/loop_clr_fd is safe, because every
time we call loop_set_fd() we check that loop_device->lo_state is
Lo_unbound and set it to Lo_bound If somebody will try to set_fd again
it will get EBUSY. And if we try to loop_clr_fd() on unbound loop
device we'll get ENXIO.
loop_set_fd/loop_clr_fd (and any other loop ioctl) is called under
loop_device->lo_ctl_mutex. ]
Signed-off-by: Anatol Pomozov <anatol.pomozov@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull block IO core bits from Jens Axboe:
"Below are the core block IO bits for 3.9. It was delayed a few days
since my workstation kept crashing every 2-8h after pulling it into
current -git, but turns out it is a bug in the new pstate code (divide
by zero, will report separately). In any case, it contains:
- The big cfq/blkcg update from Tejun and and Vivek.
- Additional block and writeback tracepoints from Tejun.
- Improvement of the should sort (based on queues) logic in the plug
flushing.
- _io() variants of the wait_for_completion() interface, using
io_schedule() instead of schedule() to contribute to io wait
properly.
- Various little fixes.
You'll get two trivial merge conflicts, which should be easy enough to
fix up"
Fix up the trivial conflicts due to hlist traversal cleanups (commit
b67bfe0d42: "hlist: drop the node parameter from iterators").
* 'for-3.9/core' of git://git.kernel.dk/linux-block: (39 commits)
block: remove redundant check to bd_openers()
block: use i_size_write() in bd_set_size()
cfq: fix lock imbalance with failed allocations
drivers/block/swim3.c: fix null pointer dereference
block: don't select PERCPU_RWSEM
block: account iowait time when waiting for completion of IO request
sched: add wait_for_completion_io[_timeout]
writeback: add more tracepoints
block: add block_{touch|dirty}_buffer tracepoint
buffer: make touch_buffer() an exported function
block: add @req to bio_{front|back}_merge tracepoints
block: add missing block_bio_complete() tracepoint
block: Remove should_sort judgement when flush blk_plug
block,elevator: use new hashtable implementation
cfq-iosched: add hierarchical cfq_group statistics
cfq-iosched: collect stats from dead cfqgs
cfq-iosched: separate out cfqg_stats_reset() from cfq_pd_reset_stats()
blkcg: make blkcg_print_blkgs() grab q locks instead of blkcg lock
block: RCU free request_queue
blkcg: implement blkg_[rw]stat_recursive_sum() and blkg_[rw]stat_merge()
...
Pull vfs pile (part one) from Al Viro:
"Assorted stuff - cleaning namei.c up a bit, fixing ->d_name/->d_parent
locking violations, etc.
The most visible changes here are death of FS_REVAL_DOT (replaced with
"has ->d_weak_revalidate()") and a new helper getting from struct file
to inode. Some bits of preparation to xattr method interface changes.
Misc patches by various people sent this cycle *and* ocfs2 fixes from
several cycles ago that should've been upstream right then.
PS: the next vfs pile will be xattr stuff."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (46 commits)
saner proc_get_inode() calling conventions
proc: avoid extra pde_put() in proc_fill_super()
fs: change return values from -EACCES to -EPERM
fs/exec.c: make bprm_mm_init() static
ocfs2/dlm: use GFP_ATOMIC inside a spin_lock
ocfs2: fix possible use-after-free with AIO
ocfs2: Fix oops in ocfs2_fast_symlink_readpage() code path
get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero
target: writev() on single-element vector is pointless
export kernel_write(), convert open-coded instances
fs: encode_fh: return FILEID_INVALID if invalid fid_type
kill f_vfsmnt
vfs: kill FS_REVAL_DOT by adding a d_weak_revalidate dentry op
nfsd: handle vfs_getattr errors in acl protocol
switch vfs_getattr() to struct path
default SET_PERSONALITY() in linux/elf.h
ceph: prepopulate inodes only when request is aborted
d_hash_and_lookup(): export, switch open-coded instances
9p: switch v9fs_set_create_acl() to inode+fid, do it before d_instantiate()
9p: split dropping the acls from v9fs_set_create_acl()
...
