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commit a5faeaf9109578e65e1a32e2a3e76c8b47e7dcb6 upstream.
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>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit c1681bf8a7b1b98edee8b862a42c19c4e53205fd upstream.
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit d646a02a9d44d1421f273ae3923d97b47b918176 upstream.
blkdev_ioctl(GETBLKSIZE) uses i_size_read() to read size of block device.
If we update block size directly, reader may see intermediate result in
some machines and configurations. Use i_size_write() instead.
Signed-off-by: Guo Chao <yan@linux.vnet.ibm.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Guo Chao <yan@linux.vnet.ibm.com>
Cc: M. Hindess <hindessm@uk.ibm.com>
Cc: Nikanth Karthikesan <knikanth@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 3a2d63f87989e01437ba994df5f297528c353d7d upstream.
There are two problems with shutdown in the NBD driver.
1: Receiving the NBD_DISCONNECT ioctl does not sync the filesystem.
This patch adds the sync operation into __nbd_ioctl()'s
NBD_DISCONNECT handler. This is useful because BLKFLSBUF is restricted
to processes that have CAP_SYS_ADMIN, and the NBD client may not
possess it (fsync of the block device does not sync the filesystem,
either).
2: Once we clear the socket we have no guarantee that later reads will
come from the same backing storage.
The patch adds calls to kill_bdev() in __nbd_ioctl()'s socket
clearing code so the page cache is cleaned, lest reads that hit on the
page cache will return stale data from the previously-accessible disk.
Example:
# qemu-nbd -r -c/dev/nbd0 /dev/sr0
# file -s /dev/nbd0
/dev/stdin: # UDF filesystem data (version 1.5) etc.
# qemu-nbd -d /dev/nbd0
# qemu-nbd -r -c/dev/nbd0 /dev/sda
# file -s /dev/nbd0
/dev/stdin: # UDF filesystem data (version 1.5) etc.
While /dev/sda has:
# file -s /dev/sda
/dev/sda: x86 boot sector; etc.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Paul Clements <Paul.Clements@steeleye.com>
Cc: Alex Bligh <alex@alex.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2:
- Adjusted context
- s/\bnbd\b/lo/
- Incorporate export of kill_bdev() from commit ff01bb483265
('fs: move code out of buffer.c')]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 7630b661da330b35dd57b6f5d6d62b386f2dd751 upstream.
We found that bdev->bd_invalidated was left set once revalidate_disk()
is called, which results in page cache flush every time that device is
open.
Specifically, we found this problem in MD block device. Once we resize
a MD device, mdadm --monitor periodically flush all page cache for that
device every 60 or 1000 seconds when it opens the device.
This bug lies since at least 3.2.0 till the latest kernel(3.6.2). Patch
is attached.
The following steps will reproduce the problem.
1. prepair a block device (eg /dev/sdb).
2. create two partitions:
sudo parted /dev/sdb
mklabel gpt
mkpart primary 0% 50%
mkpart primary 50% 100%
3. create a md device.
sudo mdadm -C /dev/md/hoge -l 1 -n 2 -e 1.2 --assume-clean --auto=md --symlink=no /dev/sdb1 /dev/sdb2
4. create file system and mount it
sudo mkfs.ext3 /dev/md/hoge
sudo mkdir /mnt/test
sudo mount /dev/md/hoge /mnt/test
5. try to resize the device
sudo mdadm -G /dev/md/hoge --size=max
6. create a file to fill file cache.
sudo dd if=/dev/urandom of=/mnt/test/data bs=1M count=10
and verify the current status of file by free command.
7. mdadm monitor will open the md device every 1000 seconds and you
will find all file cache on the device are cleared.
The timing can be reduced by the following steps.
a) kill mdadm and restart it with --delay option
/sbin/mdadm --monitor --delay=30 --pid-file /var/run/mdadm/monitor.pid --daemonise --scan --syslog
or open the md device directly.
sudo dd if=/dev/md/hoge of=/dev/null bs=4096 count=1
Signed-off-by: MITSUNARI Shigeo <herumi@nifty.com>
Cc: Al 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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit 080399aaaf3531f5b8761ec0ac30ff98891e8686 upstream.
Hi,
We have a bug report open where a squashfs image mounted on ppc64 would
exhibit errors due to trying to read beyond the end of the disk. It can
easily be reproduced by doing the following:
[root@ibm-p750e-02-lp3 ~]# ls -l install.img
-rw-r--r-- 1 root root 142032896 Apr 30 16:46 install.img
[root@ibm-p750e-02-lp3 ~]# mount -o loop ./install.img /mnt/test
[root@ibm-p750e-02-lp3 ~]# dd if=/dev/loop0 of=/dev/null
dd: reading `/dev/loop0': Input/output error
277376+0 records in
277376+0 records out
142016512 bytes (142 MB) copied, 0.9465 s, 150 MB/s
In dmesg, you'll find the following:
squashfs: version 4.0 (2009/01/31) Phillip Lougher
[ 43.106012] attempt to access beyond end of device
[ 43.106029] loop0: rw=0, want=277410, limit=277408
[ 43.106039] Buffer I/O error on device loop0, logical block 138704
[ 43.106053] attempt to access beyond end of device
[ 43.106057] loop0: rw=0, want=277412, limit=277408
[ 43.106061] Buffer I/O error on device loop0, logical block 138705
[ 43.106066] attempt to access beyond end of device
[ 43.106070] loop0: rw=0, want=277414, limit=277408
[ 43.106073] Buffer I/O error on device loop0, logical block 138706
[ 43.106078] attempt to access beyond end of device
[ 43.106081] loop0: rw=0, want=277416, limit=277408
[ 43.106085] Buffer I/O error on device loop0, logical block 138707
[ 43.106089] attempt to access beyond end of device
[ 43.106093] loop0: rw=0, want=277418, limit=277408
[ 43.106096] Buffer I/O error on device loop0, logical block 138708
[ 43.106101] attempt to access beyond end of device
[ 43.106104] loop0: rw=0, want=277420, limit=277408
[ 43.106108] Buffer I/O error on device loop0, logical block 138709
[ 43.106112] attempt to access beyond end of device
[ 43.106116] loop0: rw=0, want=277422, limit=277408
[ 43.106120] Buffer I/O error on device loop0, logical block 138710
[ 43.106124] attempt to access beyond end of device
[ 43.106128] loop0: rw=0, want=277424, limit=277408
[ 43.106131] Buffer I/O error on device loop0, logical block 138711
[ 43.106135] attempt to access beyond end of device
[ 43.106139] loop0: rw=0, want=277426, limit=277408
[ 43.106143] Buffer I/O error on device loop0, logical block 138712
[ 43.106147] attempt to access beyond end of device
[ 43.106151] loop0: rw=0, want=277428, limit=277408
[ 43.106154] Buffer I/O error on device loop0, logical block 138713
[ 43.106158] attempt to access beyond end of device
[ 43.106162] loop0: rw=0, want=277430, limit=277408
[ 43.106166] attempt to access beyond end of device
[ 43.106169] loop0: rw=0, want=277432, limit=277408
...
[ 43.106307] attempt to access beyond end of device
[ 43.106311] loop0: rw=0, want=277470, limit=2774
Squashfs manages to read in the end block(s) of the disk during the
mount operation. Then, when dd reads the block device, it leads to
block_read_full_page being called with buffers that are beyond end of
disk, but are marked as mapped. Thus, it would end up submitting read
I/O against them, resulting in the errors mentioned above. I fixed the
problem by modifying init_page_buffers to only set the buffer mapped if
it fell inside of i_size.
Cheers,
Jeff
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Acked-by: Nick Piggin <npiggin@kernel.dk>
--
Changes from v1->v2: re-used max_block, as suggested by Nick Piggin.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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commit fe316bf2d5847bc5dd975668671a7b1067603bc7 upstream.
Since 2.6.39 (1196f8b), when a driver returns -ENOMEDIUM for open(),
__blkdev_get() calls rescan_partitions() to remove
in-kernel partition structures and raise KOBJ_CHANGE uevent.
However it ends up calling driver's revalidate_disk without open
and could cause oops.
In the case of SCSI:
process A process B
----------------------------------------------
sys_open
__blkdev_get
sd_open
returns -ENOMEDIUM
scsi_remove_device
<scsi_device torn down>
rescan_partitions
sd_revalidate_disk
<oops>
Oopses are reported here:
http://marc.info/?l=linux-scsi&m=132388619710052
This patch separates the partition invalidation from rescan_partitions()
and use it for -ENOMEDIUM case.
Reported-by: Huajun Li <huajun.li.lee@gmail.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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* 'for-3.2/drivers' of git://git.kernel.dk/linux-block: (30 commits)
virtio-blk: use ida to allocate disk index
hpsa: add small delay when using PCI Power Management to reset for kump
cciss: add small delay when using PCI Power Management to reset for kump
xen/blkback: Fix two races in the handling of barrier requests.
xen/blkback: Check for proper operation.
xen/blkback: Fix the inhibition to map pages when discarding sector ranges.
xen/blkback: Report VBD_WSECT (wr_sect) properly.
xen/blkback: Support 'feature-barrier' aka old-style BARRIER requests.
xen-blkfront: plug device number leak in xlblk_init() error path
xen-blkfront: If no barrier or flush is supported, use invalid operation.
xen-blkback: use kzalloc() in favor of kmalloc()+memset()
xen-blkback: fixed indentation and comments
xen-blkfront: fix a deadlock while handling discard response
xen-blkfront: Handle discard requests.
xen-blkback: Implement discard requests ('feature-discard')
xen-blkfront: add BLKIF_OP_DISCARD and discard request struct
drivers/block/loop.c: remove unnecessary bdev argument from loop_clr_fd()
drivers/block/loop.c: emit uevent on auto release
drivers/block/cpqarray.c: use pci_dev->revision
loop: always allow userspace partitions and optionally support automatic scanning
...
Fic up trivial header file includsion conflict in drivers/block/loop.c
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The following command sequence triggers an oops.
# mount /dev/sdb1 /mnt
# echo 1 > /sys/class/scsi_device/0\:0\:1\:0/device/delete
# umount /mnt
general protection fault: 0000 [#1] PREEMPT SMP
CPU 2
Modules linked in:
Pid: 791, comm: umount Not tainted 3.1.0-rc3-work+ #8 Bochs Bochs
RIP: 0010:[<ffffffff810d0879>] [<ffffffff810d0879>] __lock_acquire+0x389/0x1d60
...
Call Trace:
[<ffffffff810d2845>] lock_acquire+0x95/0x140
[<ffffffff81aed87b>] _raw_spin_lock+0x3b/0x50
[<ffffffff811573bc>] bdi_lock_two+0x5c/0x70
[<ffffffff811c2f6c>] bdev_inode_switch_bdi+0x4c/0xf0
[<ffffffff811c3fcb>] __blkdev_put+0x11b/0x1d0
[<ffffffff811c4010>] __blkdev_put+0x160/0x1d0
[<ffffffff811c40df>] blkdev_put+0x5f/0x190
[<ffffffff8118f18d>] kill_block_super+0x4d/0x80
[<ffffffff8118f4a5>] deactivate_locked_super+0x45/0x70
[<ffffffff8119003a>] deactivate_super+0x4a/0x70
[<ffffffff811ac4ad>] mntput_no_expire+0xed/0x130
[<ffffffff811acf2e>] sys_umount+0x7e/0x3a0
[<ffffffff81aeeeab>] system_call_fastpath+0x16/0x1b
This is because bdev holds on to disk but disk doesn't pin the
associated queue. If a SCSI device is removed while the device is
still open, the sdev puts the base reference to the queue on release.
When the bdev is finally released, the associated queue is already
gone along with the bdi and bdev_inode_switch_bdi() ends up
dereferencing already freed bdi.
Even if it were not for this bug, disk not holding onto the associated
queue is very unusual and error-prone.
Fix it by making add_disk() take an extra reference to its queue and
put it on disk_release() and ensuring that disk and its fops owner are
put in that order after all accesses to the disk and queue are
complete.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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On the last close of an 'md' device which as been stopped, the device
is destroyed and in particular the request_queue is freed. The free
is done in a separate thread so it might happen a short time later.
__blkdev_put calls bdev_inode_switch_bdi *after* ->release has been
called.
Since commit f758eeabeb96f878c860e8f110f94ec8820822a9
bdev_inode_switch_bdi will dereference the 'old' bdi, which lives
inside a request_queue, to get a spin lock. This causes the last
close on an md device to sometime take a spin_lock which lives in
freed memory - which results in an oops.
So move the called to bdev_inode_switch_bdi before the call to
->release.
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
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There are cases where suppressing partition scan is useful - e.g. for
lo devices and pseudo SATA devices which advertise to be a disk but
get upset on partition scan (some port multiplier control devices show
such behavior).
This patch adds GENHD_FL_NO_PART_SCAN which suppresses partition scan
regardless of the number of possible partitions. disk_partitionable()
is renamed to disk_part_scan_enabled() as suppressing partition scan
doesn't imply the device can't be partitioned using
BLKPG_ADD/DEL_PARTITION calls from userland. show_partition() now
directly tests disk_max_parts() to maintain backward-compatibility.
-v2: Updated to make it clear that only partition scan is suppressed
not partitioning itself as suggested by Kay Sievers.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
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blkdev_fsync() needs to write pages in pagecache...
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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bd_super is currently reset to NULL in kill_block_super() so we rely on previous
users of the block_device object to initialise this value for the next user.
This quirk was exposed on RHEL5 when a third party filesystem did not always use
kill_block_super() and therefore bd_super wasn't being reset when a block_device
object was recycled within the cache. This may not be a problem upstream but
makes sense to be defensive.
Signed-off-by: Lachlan McIlroy <lmcilroy@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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git://git.kernel.org/pub/scm/linux/kernel/git/wfg/writeback
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/writeback: (27 commits)
mm: properly reflect task dirty limits in dirty_exceeded logic
writeback: don't busy retry writeback on new/freeing inodes
writeback: scale IO chunk size up to half device bandwidth
writeback: trace global_dirty_state
writeback: introduce max-pause and pass-good dirty limits
writeback: introduce smoothed global dirty limit
writeback: consolidate variable names in balance_dirty_pages()
writeback: show bdi write bandwidth in debugfs
writeback: bdi write bandwidth estimation
writeback: account per-bdi accumulated written pages
writeback: make writeback_control.nr_to_write straight
writeback: skip tmpfs early in balance_dirty_pages_ratelimited_nr()
writeback: trace event writeback_queue_io
writeback: trace event writeback_single_inode
writeback: remove .nonblocking and .encountered_congestion
writeback: remove writeback_control.more_io
writeback: skip balance_dirty_pages() for in-memory fs
writeback: add bdi_dirty_limit() kernel-doc
writeback: avoid extra sync work at enqueue time
writeback: elevate queue_io() into wb_writeback()
...
Fix up trivial conflicts in fs/fs-writeback.c and mm/filemap.c
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* 'for-3.1/core' of git://git.kernel.dk/linux-block: (24 commits)
block: strict rq_affinity
backing-dev: use synchronize_rcu_expedited instead of synchronize_rcu
block: fix patch import error in max_discard_sectors check
block: reorder request_queue to remove 64 bit alignment padding
CFQ: add think time check for group
CFQ: add think time check for service tree
CFQ: move think time check variables to a separate struct
fixlet: Remove fs_excl from struct task.
cfq: Remove special treatment for metadata rqs.
block: document blk_plug list access
block: avoid building too big plug list
compat_ioctl: fix make headers_check regression
block: eliminate potential for infinite loop in blkdev_issue_discard
compat_ioctl: fix warning caused by qemu
block: flush MEDIA_CHANGE from drivers on close(2)
blk-throttle: Make total_nr_queued unsigned
block: Add __attribute__((format(printf...) and fix fallout
fs/partitions/check.c: make local symbols static
block:remove some spare spaces in genhd.c
block:fix the comment error in blkdev.h
...
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Btrfs needs to be able to control how filemap_write_and_wait_range() is called
in fsync to make it less of a painful operation, so push down taking i_mutex and
the calling of filemap_write_and_wait() down into the ->fsync() handlers. Some
file systems can drop taking the i_mutex altogether it seems, like ext3 and
ocfs2. For correctness sake I just pushed everything down in all cases to make
sure that we keep the current behavior the same for everybody, and then each
individual fs maintainer can make up their mind about what to do from there.
Thanks,
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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This converts everybody to handle SEEK_HOLE/SEEK_DATA properly. In some cases
we just return -EINVAL, in others we do the normal generic thing, and in others
we're simply making sure that the properly due-dilligence is done. For example
in NFS/CIFS we need to make sure the file size is update properly for the
SEEK_HOLE and SEEK_DATA case, but since it calls the generic llseek stuff itself
that is all we have to do. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Currently, only open(2) is defined as the 'clearing' point. It has
two roles - first, it's an acknowledgement from userland indicating
that the event has been received and kernel can clear pending states
and proceed to generate more events. Secondly, it's passed on to
device drivers as a hint indicating that a synchronization point has
been reached and it might want to take a deeper look at the device.
The latter currently is only used by sr which uses two different
mechanisms - GET_EVENT_MEDIA_STATUS_NOTIFICATION and TEST_UNIT_READY
to discover events, where the former is lighter weight and safe to be
used repeatedly but may not provide full coverage. Among other
things, GET_EVENT can't detect media removal while TUR can.
This patch makes close(2) - blkdev_put() - indicate clearing hint for
MEDIA_CHANGE to drivers. disk_check_events() is renamed to
disk_flush_events() and updated to take @mask for events to flush
which is or'd to ev->clearing and will be passed to the driver on the
next ->check_events() invocation.
This change makes sr generate MEDIA_CHANGE when media is ejected from
userland - e.g. with eject(1).
Note: Given the current usage, it seems @clearing hint is needlessly
complex. disk_clear_events() can simply clear all events and the hint
can be boolean @flush.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
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6b4517a791 (block: implement bd_claiming and claiming block)
introduced claiming block to support O_EXCL blkdev opens properly.
bd_start_claiming() looks up the part 0 bdev and starts claiming
block. The function assumed that there is only one part 0 bdev and
always used bdget_disk(disk, 0) to look it up; unfortunately, this
isn't true for some drivers (floppy) which use multiple block devices
to denote different operating parameters for the same physical device.
There can be multiple part 0 bdev's for the same device number.
This incorrect assumption caused the wrong bdev to be used during
claiming leading to unbalanced bd_holders as reported in the following
bug.
https://bugzilla.kernel.org/show_bug.cgi?id=28522
This patch updates bd_start_claiming() such that it uses the bdev
specified as argument if its partno is zero.
Note that this means that different bdev's can be used for the same
device and O_EXCL check can be effectively bypassed. It has always
been broken that way and floppy is fortunately on its way out. Leave
that breakage alone.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Alex Villacis Lasso <avillaci@ceibo.fiec.espol.edu.ec>
Tested-by: Alex Villacis Lasso <avillaci@ceibo.fiec.espol.edu.ec>
Cc: stable@kernel.org # >= v2.6.36
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
|
Split the global inode_wb_list_lock into a per-bdi_writeback list_lock,
as it's currently the most contended lock in the system for metadata
heavy workloads. It won't help for single-filesystem workloads for
which we'll need the I/O-less balance_dirty_pages, but at least we
can dedicate a cpu to spinning on each bdi now for larger systems.
Based on earlier patches from Nick Piggin and Dave Chinner.
It reduces lock contentions to 1/4 in this test case:
10 HDD JBOD, 100 dd on each disk, XFS, 6GB ram
lock_stat version 0.3
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
vanilla 2.6.39-rc3:
inode_wb_list_lock: 42590 44433 0.12 147.74 144127.35 252274 886792 0.08 121.34 917211.23
------------------
inode_wb_list_lock 2 [<ffffffff81165da5>] bdev_inode_switch_bdi+0x29/0x85
inode_wb_list_lock 34 [<ffffffff8115bd0b>] inode_wb_list_del+0x22/0x49
inode_wb_list_lock 12893 [<ffffffff8115bb53>] __mark_inode_dirty+0x170/0x1d0
inode_wb_list_lock 10702 [<ffffffff8115afef>] writeback_single_inode+0x16d/0x20a
------------------
inode_wb_list_lock 2 [<ffffffff81165da5>] bdev_inode_switch_bdi+0x29/0x85
inode_wb_list_lock 19 [<ffffffff8115bd0b>] inode_wb_list_del+0x22/0x49
inode_wb_list_lock 5550 [<ffffffff8115bb53>] __mark_inode_dirty+0x170/0x1d0
inode_wb_list_lock 8511 [<ffffffff8115b4ad>] writeback_sb_inodes+0x10f/0x157
2.6.39-rc3 + patch:
&(&wb->list_lock)->rlock: 11383 11657 0.14 151.69 40429.51 90825 527918 0.11 145.90 556843.37
------------------------
&(&wb->list_lock)->rlock 10 [<ffffffff8115b189>] inode_wb_list_del+0x5f/0x86
&(&wb->list_lock)->rlock 1493 [<ffffffff8115b1ed>] writeback_inodes_wb+0x3d/0x150
&(&wb->list_lock)->rlock 3652 [<ffffffff8115a8e9>] writeback_sb_inodes+0x123/0x16f
&(&wb->list_lock)->rlock 1412 [<ffffffff8115a38e>] writeback_single_inode+0x17f/0x223
------------------------
&(&wb->list_lock)->rlock 3 [<ffffffff8110b5af>] bdi_lock_two+0x46/0x4b
&(&wb->list_lock)->rlock 6 [<ffffffff8115b189>] inode_wb_list_del+0x5f/0x86
&(&wb->list_lock)->rlock 2061 [<ffffffff8115af97>] __mark_inode_dirty+0x173/0x1cf
&(&wb->list_lock)->rlock 2629 [<ffffffff8115a8e9>] writeback_sb_inodes+0x123/0x16f
hughd@google.com: fix recursive lock when bdi_lock_two() is called with new the same as old
akpm@linux-foundation.org: cleanup bdev_inode_switch_bdi() comment
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
|
|
d4dc210f69 (block: don't block events on excl write for non-optical
devices) added dereferencing of bdev->bd_disk to test
GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE; however, bdev->bd_disk can be
%NULL if open failed which can lead to an oops.
Test the flag after testing open was successful, not before.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: David Miller <davem@davemloft.net>
Tested-by: David Miller <davem@davemloft.net>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
|
02e352287a4 (block: rescan partitions on invalidated devices on
-ENOMEDIA too) relocated partition rescan above explicit bd_set_size()
to simplify condition check. As rescan_partitions() does its own bdev
size setting, this doesn't break anything; however,
rescan_partitions() prints out the following messages when adjusting
bdev size, which can be confusing.
sda: detected capacity change from 0 to 146815737856
sdb: detected capacity change from 0 to 146815737856
This patch restores the original order and remove the warning
messages.
stable: Please apply together with 02e352287a4 (block: rescan
partitions on invalidated devices on -ENOMEDIA too).
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Tony Luck <tony.luck@gmail.com>
Tested-by: Tony Luck <tony.luck@gmail.com>
Cc: stable@kernel.org
Stable note: 2.6.39 only.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
|
Disk event code automatically blocks events on excl write. This is
primarily to avoid issuing polling commands while burning is in
progress. This behavior doesn't fit other types of devices with
removeable media where polling commands don't have adverse side
effects and door locking usually doesn't exist.
This patch introduces new genhd flag which controls the auto-blocking
behavior and uses it to enable auto-blocking only on optical devices.
Note for stable: 2.6.38 and later only
Cc: stable@kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
|
__blkdev_get() doesn't rescan partitions if disk->fops->open() fails,
which leads to ghost partition devices lingering after medimum removal
is known to both the kernel and userland. The behavior also creates a
subtle inconsistency where O_NONBLOCK open, which doesn't fail even if
there's no medium, clears the ghots partitions, which is exploited to
work around the problem from userland.
Fix it by updating __blkdev_get() to issue partition rescan after
-ENOMEDIA too.
This was reported in the following bz.
https://bugzilla.kernel.org/show_bug.cgi?id=13029
Note for stable: 2.6.38 and later only
Cc: stable@kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: David Zeuthen <zeuthen@gmail.com>
Reported-by: Martin Pitt <martin.pitt@ubuntu.com>
Reported-by: Kay Sievers <kay.sievers@vrfy.org>
Tested-by: Kay Sievers <kay.sievers@vrfy.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
|
Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
fs: simplify iget & friends
fs: pull inode->i_lock up out of writeback_single_inode
fs: rename inode_lock to inode_hash_lock
fs: move i_wb_list out from under inode_lock
fs: move i_sb_list out from under inode_lock
fs: remove inode_lock from iput_final and prune_icache
fs: Lock the inode LRU list separately
fs: factor inode disposal
fs: protect inode->i_state with inode->i_lock
autofs4: Do not potentially dereference NULL pointer returned by fget() in autofs_dev_ioctl_setpipefd()
autofs4 - remove autofs4_lock
autofs4 - fix d_manage() return on rcu-walk
autofs4 - fix autofs4_expire_indirect() traversal
autofs4 - fix dentry leak in autofs4_expire_direct()
autofs4 - reinstate last used update on access
vfs - check non-mountpoint dentry might block in __follow_mount_rcu()
|
|
Protect the inode writeback list with a new global lock
inode_wb_list_lock and use it to protect the list manipulations and
traversals. This lock replaces the inode_lock as the inodes on the
list can be validity checked while holding the inode->i_lock and
hence the inode_lock is no longer needed to protect the list.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
Protect inode state transitions and validity checks with the
inode->i_lock. This enables us to make inode state transitions
independently of the inode_lock and is the first step to peeling
away the inode_lock from the code.
This requires that __iget() is done atomically with i_state checks
during list traversals so that we don't race with another thread
marking the inode I_FREEING between the state check and grabbing the
reference.
Also remove the unlock_new_inode() memory barrier optimisation
required to avoid taking the inode_lock when clearing I_NEW.
Simplify the code by simply taking the inode->i_lock around the
state change and wakeup. Because the wakeup is no longer tricky,
remove the wake_up_inode() function and open code the wakeup where
necessary.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
"disk" is always NULL when we goto out. There was a check for this
before, but it was removed in 69e02c59a7d9 "block: Don't check events
while open is in progress".
Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@carl>
|
|
Conflicts:
block/blk-core.c
block/blk-flush.c
drivers/md/raid1.c
drivers/md/raid10.c
drivers/md/raid5.c
fs/nilfs2/btnode.c
fs/nilfs2/mdt.c
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
|
Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
|
Not all block drivers clear events immediately after reporting. Some
do so in ->revalidate_disk() or other steps during ->open(). There is
a slim chance event poll may happen between the clearing event check
from check_disk_change() and the actual clearing of the events which
would result in spurious events.
Block event checks while block device open is in progress. There is
no need to kick explicit event check afterwards as events are always
checked during open.
-v2: The original patch could have called disk_unblock_events() with
an already released or %NULL @disk causing oops. Fixed by making
sure references are put after disk_unblock_events() is called.
It also makes the error path of __blkdev_get() a bit simpler.
This problem was reported by Jens.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
|
|
The block event mechanism currently always checks events when the
device is being closed regardless of the open mode. The intention was
to allow detection of EJECT_REQUEST when a device is closed whether
disk event polling is enabled or not.
This is unnecessary as, for devices of interest, events are checked
from either userland or kernel and in the former case ->check_events()
is performed on open of each poll attempt anyway. Furthermore, this
unconditional event check on close makes the code susceptible to event
loop if the block driver doesn't clear reported events correctly - an
event triggers userland to open and close the device which in turn
causes another event, rinse and repeat.
Check events on close only if it was blocked by excl write open.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
|
|
Currently, disk_unblock_events() implicitly kick event check if the
block count reaches zero. This behavior is not described in the
comment and hinders with future changes. Make the unblocker
explicitly check events by calling disk_check_events() as necessary.
This patch doesn't cause any behavior difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
|
|
Fix new kernel-doc warning in fs/block_dev.c:
Warning(fs/block_dev.c:937): No description found for parameter 'kill_dirty'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
* 'for-linus' of git://neil.brown.name/md:
md: Fix - again - partition detection when array becomes active
Fix over-zealous flush_disk when changing device size.
md: avoid spinlock problem in blk_throtl_exit
md: correctly handle probe of an 'mdp' device.
md: don't set_capacity before array is active.
md: Fix raid1->raid0 takeover
|
|
The new implementation of bd_link_disk_holder() added by 49731baa41d
(block: restore multiple bd_link_disk_holder() support) didn't get an
extra reference for the holder_dir kobject of the slave bdev; however,
bdev kills holder_dir on removal, not release, so if the slave bdev is
removed while there are holder links, the holder_dir will be destroyed
while there still are holder links, which leads to oops later when
bd_unlink_disk_order() tries to remove those links.
Make bd_link_disk_holder() grab an extra reference for the slave's
holder_dir and put it in bd_unlink_disk_holder().
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: "Hawrylewicz Czarnowski, Przemyslaw" <przemyslaw.hawrylewicz.czarnowski@intel.com>
Tested-by: "Hawrylewicz Czarnowski, Przemyslaw" <przemyslaw.hawrylewicz.czarnowski@intel.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
There are two cases when we call flush_disk.
In one, the device has disappeared (check_disk_change) so any
data will hold becomes irrelevant.
In the oter, the device has changed size (check_disk_size_change)
so data we hold may be irrelevant.
In both cases it makes sense to discard any 'clean' buffers,
so they will be read back from the device if needed.
In the former case it makes sense to discard 'dirty' buffers
as there will never be anywhere safe to write the data. In the
second case it *does*not* make sense to discard dirty buffers
as that will lead to file system corruption when you simply enlarge
the containing devices.
flush_disk calls __invalidate_devices.
__invalidate_device calls both invalidate_inodes and invalidate_bdev.
invalidate_inodes *does* discard I_DIRTY inodes and this does lead
to fs corruption.
invalidate_bev *does*not* discard dirty pages, but I don't really care
about that at present.
So this patch adds a flag to __invalidate_device (calling it
__invalidate_device2) to indicate whether dirty buffers should be
killed, and this is passed to invalidate_inodes which can choose to
skip dirty inodes.
flusk_disk then passes true from check_disk_change and false from
check_disk_size_change.
dm avoids tripping over this problem by calling i_size_write directly
rathher than using check_disk_size_change.
md does use check_disk_size_change and so is affected.
This regression was introduced by commit 608aeef17a which causes
check_disk_size_change to call flush_disk, so it is suitable for any
kernel since 2.6.27.
Cc: stable@kernel.org
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Cc: Andrew Patterson <andrew.patterson@hp.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NeilBrown <neilb@suse.de>
|
|
This reverts commit 75f1dc0d076d ("block: check bdev_read_only() from
blkdev_get()"). That commit added stricter checking to make sure
devices that were being used read-only were actually opened in that
mode.
It turns out that the change breaks a bunch of kernel code that opens
block devices. Affected systems include dm, md, and the loop device.
Because strict checking for read-only opens of block devices was not
done before this, the code that opens the devices was opening them
read-write even if they were being used read-only. Auditing all that
code will take time, and new userspace packages for dm, mdadm, etc.
will also be required.
Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Commit e09b457b (block: simplify holder symlink handling) incorrectly
assumed that there is only one link at maximum. dm may use multiple
links and expects block layer to track reference count for each link,
which is different from and unrelated to the exclusive device holder
identified by @holder when the device is opened.
Remove the single holder assumption and automatic removal of the link
and revive the per-link reference count tracking. The code
essentially behaves the same as before commit e09b457b sans the
unnecessary kobject reference count dancing.
While at it, note that this facility should not be used by anyone else
than the current ones. Sysfs symlinks shouldn't be abused like this
and the whole thing doesn't belong in the block layer at all.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Milan Broz <mbroz@redhat.com>
Cc: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Neil Brown <neilb@suse.de>
Cc: linux-raid@vger.kernel.org
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
|
* 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block: (43 commits)
block: ensure that completion error gets properly traced
blktrace: add missing probe argument to block_bio_complete
block cfq: don't use atomic_t for cfq_group
block cfq: don't use atomic_t for cfq_queue
block: trace event block fix unassigned field
block: add internal hd part table references
block: fix accounting bug on cross partition merges
kref: add kref_test_and_get
bio-integrity: mark kintegrityd_wq highpri and CPU intensive
block: make kblockd_workqueue smarter
Revert "sd: implement sd_check_events()"
block: Clean up exit_io_context() source code.
Fix compile warnings due to missing removal of a 'ret' variable
fs/block: type signature of major_to_index(int) to major_to_index(unsigned)
block: convert !IS_ERR(p) && p to !IS_ERR_NOR_NULL(p)
cfq-iosched: don't check cfqg in choose_service_tree()
fs/splice: Pull buf->ops->confirm() from splice_from_pipe actors
cdrom: export cdrom_check_events()
sd: implement sd_check_events()
sr: implement sr_check_events()
...
|
|
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
|
RCU free the struct inode. This will allow:
- Subsequent store-free path walking patch. The inode must be consulted for
permissions when walking, so an RCU inode reference is a must.
- sb_inode_list_lock to be moved inside i_lock because sb list walkers who want
to take i_lock no longer need to take sb_inode_list_lock to walk the list in
the first place. This will simplify and optimize locking.
- Could remove some nested trylock loops in dcache code
- Could potentially simplify things a bit in VM land. Do not need to take the
page lock to follow page->mapping.
The downsides of this is the performance cost of using RCU. In a simple
creat/unlink microbenchmark, performance drops by about 10% due to inability to
reuse cache-hot slab objects. As iterations increase and RCU freeing starts
kicking over, this increases to about 20%.
In cases where inode lifetimes are longer (ie. many inodes may be allocated
during the average life span of a single inode), a lot of this cache reuse is
not applicable, so the regression caused by this patch is smaller.
The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU,
however this adds some complexity to list walking and store-free path walking,
so I prefer to implement this at a later date, if it is shown to be a win in
real situations. I haven't found a regression in any non-micro benchmark so I
doubt it will be a problem.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
|
|
Currently, media presence polling for removeable block devices is done
from userland. There are several issues with this.
* Polling is done by periodically opening the device. For SCSI
devices, the command sequence generated by such action involves a
few different commands including TEST_UNIT_READY. This behavior,
while perfectly legal, is different from Windows which only issues
single command, GET_EVENT_STATUS_NOTIFICATION. Unfortunately, some
ATAPI devices lock up after being periodically queried such command
sequences.
* There is no reliable and unintrusive way for a userland program to
tell whether the target device is safe for media presence polling.
For example, polling for media presence during an on-going burning
session can make it fail. The polling program can avoid this by
opening the device with O_EXCL but then it risks making a valid
exclusive user of the device fail w/ -EBUSY.
* Userland polling is unnecessarily heavy and in-kernel implementation
is lighter and better coordinated (workqueue, timer slack).
This patch implements framework for in-kernel disk event handling,
which includes media presence polling.
* bdops->check_events() is added, which supercedes ->media_changed().
It should check whether there's any pending event and return if so.
Currently, two events are defined - DISK_EVENT_MEDIA_CHANGE and
DISK_EVENT_EJECT_REQUEST. ->check_events() is guaranteed not to be
called parallelly.
* gendisk->events and ->async_events are added. These should be
initialized by block driver before passing the device to add_disk().
The former contains the mask of all supported events and the latter
the mask of all events which the device can report without polling.
/sys/block/*/events[_async] export these to userland.
* Kernel parameter block.events_dfl_poll_msecs controls the system
polling interval (default is 0 which means disable) and
/sys/block/*/events_poll_msecs control polling intervals for
individual devices (default is -1 meaning use system setting). Note
that if a device can report all supported events asynchronously and
its polling interval isn't explicitly set, the device won't be
polled regardless of the system polling interval.
* If a device is opened exclusively with write access, event checking
is automatically disabled until all write exclusive accesses are
released.
* There are event 'clearing' events. For example, both of currently
defined events are cleared after the device has been successfully
opened. This information is passed to ->check_events() callback
using @clearing argument as a hint.
* Event checking is always performed from system_nrt_wq and timer
slack is set to 25% for polling.
* Nothing changes for drivers which implement ->media_changed() but
not ->check_events(). Going forward, all drivers will be converted
to ->check_events() and ->media_change() will be dropped.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
|
The big kernel lock has been removed from all these files at some point,
leaving only the #include.
Remove this too as a cleanup.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
After recent blkdev_get() modifications, open_by_devnum() and
open_bdev_exclusive() are simple wrappers around blkdev_get().
Replace them with blkdev_get_by_dev() and blkdev_get_by_path().
blkdev_get_by_dev() is identical to open_by_devnum().
blkdev_get_by_path() is slightly different in that it doesn't
automatically add %FMODE_EXCL to @mode.
All users are converted. Most conversions are mechanical and don't
introduce any behavior difference. There are several exceptions.
* btrfs now sets FMODE_EXCL in btrfs_device->mode, so there's no
reason to OR it explicitly on blkdev_put().
* gfs2, nilfs2 and the generic mount_bdev() now set FMODE_EXCL in
sb->s_mode.
* With the above changes, sb->s_mode now always should contain
FMODE_EXCL. WARN_ON_ONCE() added to kill_block_super() to detect
errors.
The new blkdev_get_*() functions are with proper docbook comments.
While at it, add function description to blkdev_get() too.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Joern Engel <joern@lazybastard.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jan Kara <jack@suse.cz>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: reiserfs-devel@vger.kernel.org
Cc: xfs-masters@oss.sgi.com
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
|
|
bdev read-only status can be queried using bdev_read_only() and may
change while the device is being opened. Enforce it by checking it
from blkdev_get() after open succeeds.
This makes bdev_read_only() check in open_bdev_exclusive() and
fsg_lun_open() unnecessary. Drop them.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: linux-usb@vger.kernel.org
|
|
With claim/release rolled into blkdev_get/put(), there's no reason to
keep bd_abort/finish_claim(), __bd_claim() and bd_release() as
separate functions. It only makes the code difficult to follow.
Collapse them into blkdev_get/put(). This will ease future changes
around claim/release.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
|
Over time, block layer has accumulated a set of APIs dealing with bdev
open, close, claim and release.
* blkdev_get/put() are the primary open and close functions.
* bd_claim/release() deal with exclusive open.
* open/close_bdev_exclusive() are combination of open and claim and
the other way around, respectively.
* bd_link/unlink_disk_holder() to create and remove holder/slave
symlinks.
* open_by_devnum() wraps bdget() + blkdev_get().
The interface is a bit confusing and the decoupling of open and claim
makes it impossible to properly guarantee exclusive access as
in-kernel open + claim sequence can disturb the existing exclusive
open even before the block layer knows the current open if for another
exclusive access. Reorganize the interface such that,
* blkdev_get() is extended to include exclusive access management.
@holder argument is added and, if is @FMODE_EXCL specified, it will
gain exclusive access atomically w.r.t. other exclusive accesses.
* blkdev_put() is similarly extended. It now takes @mode argument and
if @FMODE_EXCL is set, it releases an exclusive access. Also, when
the last exclusive claim is released, the holder/slave symlinks are
removed automatically.
* bd_claim/release() and close_bdev_exclusive() are no longer
necessary and either made static or removed.
* bd_link_disk_holder() remains the same but bd_unlink_disk_holder()
is no longer necessary and removed.
* open_bdev_exclusive() becomes a simple wrapper around lookup_bdev()
and blkdev_get(). It also has an unexpected extra bdev_read_only()
test which probably should be moved into blkdev_get().
* open_by_devnum() is modified to take @holder argument and pass it to
blkdev_get().
Most of bdev open/close operations are unified into blkdev_get/put()
and most exclusive accesses are tested atomically at the open time (as
it should). This cleans up code and removes some, both valid and
invalid, but unnecessary all the same, corner cases.
open_bdev_exclusive() and open_by_devnum() can use further cleanup -
rename to blkdev_get_by_path() and blkdev_get_by_devt() and drop
special features. Well, let's leave them for another day.
Most conversions are straight-forward. drbd conversion is a bit more
involved as there was some reordering, but the logic should stay the
same.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Brown <neilb@suse.de>
Acked-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Peter Osterlund <petero2@telia.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Alex Elder <aelder@sgi.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: dm-devel@redhat.com
Cc: drbd-dev@lists.linbit.com
Cc: Leo Chen <leochen@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
Cc: Joern Engel <joern@logfs.org>
Cc: reiserfs-devel@vger.kernel.org
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
|
|
Code to manage symlinks in /sys/block/*/{holders|slaves} are overly
complex with multiple holder considerations, redundant extra
references to all involved kobjects, unused generic kobject holder
support and unnecessary mixup with bd_claim/release functionalities.
Strip it down to what's necessary (single gendisk holder) and make it
use a separate interface. This is a step for cleaning up
bd_claim/release. This patch makes dm-table slightly more complex but
it will be simplified again with further changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Neil Brown <neilb@suse.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
|
