We should return NULL on failure instead of returning a freed pointer.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This version number is printed to the console on module initialization
and is available in sysfs, which is where the userland aoe-version tool
looks for it.
Signed-off-by: Ed Cashin <ecashin@coraid.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>
This change only affects experimental AoE storage networks.
It modifies the console message about runt packets detected so that the
AoE major and minor addresses of the AoE target that generated the runt
are mentioned.
Signed-off-by: Ed Cashin <ecashin@coraid.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>
By default, the aoe driver uses any ethernet interface for AoE, but the
aoe_iflist module parameter provides a convenient way to limit AoE
traffic to a specific list of local network interfaces.
This change allows a list to be specified using the comma character as a
separator. For example,
modprobe aoe aoe_iflist=eth2,eth3
Before, it was inconvenient to get the quoting right in shell scripts
when setting aoe_iflist to have more than one network interface.
Signed-off-by: Ed Cashin <ecashin@coraid.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>
With this change, the aoe driver treats the value zero as special for
the aoe_deadsecs module parameter. Normally, this value specifies the
number of seconds during which the driver will continue to attempt
retransmits to an unresponsive AoE target. After aoe_deadsecs has
elapsed, the aoe driver marks the aoe device as "down" and fails all
I/O.
The new meaning of an aoe_deadsecs of zero is for the driver to
retransmit commands indefinitely.
Signed-off-by: Ed Cashin <ecashin@coraid.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>
Many AoE targets have four or fewer network ports, but some existing
storage devices have many, and the AoE protocol sets no limit.
This patch allows the use of more than eight remote MAC addresses per AoE
target, while reducing the amount of memory used by the aoe driver in
cases where there are many AoE targets with fewer than eight MAC addresses
each.
Signed-off-by: Ed Cashin <ecashin@coraid.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>
This change avoids a race that could result in a NULL pointer derference
following a WARNing from kobject_add_internal, "don't try to register
things with the same name in the same directory."
The problem was found with a test that forgets and discovers an
aoe device in a loop:
while test ! -r /tmp/stop; do
aoe-flush -a
aoe-discover
done
The race was between aoedev_flush taking aoedevs out of the devlist,
allowing a new discovery of the same AoE target to take place before the
driver gets around to calling sysfs_remove_group. Fixing that one
revealed another race between do_open and add_disk, and this patch avoids
that, too.
The fix required some care, because for flushing (forgetting) an aoedev,
some of the steps must be performed under lock and some must be able to
sleep. Also, for discovering a new aoedev, some steps might sleep.
The check for a bad aoedev pointer remains from a time when about half of
this patch was done, and it was possible for the
bdev->bd_disk->private_data to become corrupted. The check should be
removed eventually, but it is not expected to add significant overhead,
occurring in the aoeblk_open routine.
Signed-off-by: Ed Cashin <ecashin@coraid.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>
An AoE target can have multiple network ports used for AoE, and in the
aoe driver, those are tracked by the aoetgt struct. These changes allow
the aoe driver to handle network paths, or aoetgts, that are not working
well, compared to the others.
Paths that do not get responses despite the retransmission of AoE
commands are marked as "tainted", and non-tainted paths are preferred.
Meanwhile, the aoe driver attempts to "probe" the tainted path in the
background by issuing reads of LBA 0 that are padded out to full
(possibly jumbo-frame) size. If the probes get responses, then the path
is "redeemed", and its taint is removed.
This mechanism has been shown to be helpful in transparently handling
and recovering from real-world network "brown outs" in ways that the
earlier "shoot the help-needing target in the head" mechanism could not.
Signed-off-by: Ed Cashin <ecashin@coraid.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>
The value returned by the static minor device number number allocator is
the real minor number, so it must be multiplied by the supported number
of partitions per aoedev.
Without this fix the support for systems without udev is incomplete, and
the few users of aoe on such systems will have surprising results when
device nodes names do not match the AoE target.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Because the minor_get and related functions use the return values for
errors, the compiler doesn't know that sysminor will always either 1) be
initialized in aoedev_by_aoeaddr by the call to minor_get, or 2) be
unused as the "goto out" is executed.
This patch avoids the compiler warning.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For some special-purpose systems where udev isn't present, static
allocation of minor numbers is desirable. This update distinguishes
different failure scenarios, to help the user understand what went
wrong.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is no need to call the request handler function in the I/O
completion routine. The user impact of not doing it is a more "nice" aoe
driver that is less susceptible to causing soft lockups.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A misplaced comment was attached to the nout member of the aoetgt. This
change corrects the comment.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The aoe driver will never be waiting for more than aoe_maxout AoE
commands from a given remote network port on an AoE target. Increasing
the cap increases performance. Users can tighten the setting to reduce
the amount of memory used for handling AoE traffic or the network
bandwidth used for AoE.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Before the aoe driver was an I/O request handler, it was a
make_request-style block driver. Even so, there was a problem where
sysfs expected a request queue to exist, so one was provided in commit
7135a71b19 ("aoe: allocate unused request_queue for sysfs").
During the transition to the request-handler style, a patch was merged
that was based on a driver without the noop queue, and the noop queue
remained in place after the patch was merged, even though a new
functional queue was introduced by the patch, allocated through
blk_init_queue.
The user impact is a memory leak proportional to the number of AoE
targets discovered. This patch removes the memory leak and cleans up
vestiges of the old do-nothing queue from the aoeblk_gdalloc function.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit f3b8e07af774 ("aoe: commands in retransmit queue use new
destination on failure") omits the copying of the coarse-grained time
when an AoE command was sent during the failover from one destination
MAC address on the AoE target to another.
The coarse-grained timing is only used when the system time changes or
an unlikely length of time has passed since the sending of the AoE
command. Users will not be impacted unless their system clock is very
inaccurate or something unusual (e.g., 10 GbE link reset) happens during
the period when the aoe driver is handling the failure of a port on the
AoE target. Being effected will mean that an AoE target could be
considered "down" too eagerly.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When one remote MAC address isn't working as a destination for AoE
commands, the frames used to track information associated with the AoE
commands are moved to a new aoetgt (defined by the tuple of {AoE major,
AoE minor, target MAC address}).
This patch makes sure that the frames on the queue for retransmits that
need to be done are updated to use the new destination, so that
retransmits will be sent through a working network path.
Without this change, packets on the retransmit queue will be needlessly
retransmitted to the unresponsive destination MAC, possibly causing
premature target failure before there's time for the retransmit timer to
run again, decide to retransmit again, and finally update the destination
to a working MAC address on the AoE target.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
These changes improve the accuracy of the decision about whether it's time
to retransmit an AoE command by using the microsecond-resolution
gettimeofday instead of jiffies.
Because the system time can jump suddenly, the decision reverts to using
jiffies if the high-resolution time difference is relatively large.
Otherwise the AoE targets could be considered failed inappropriately.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With this bugfix in place the calculation of the criterion for "lateness"
is performed under lock. Without the lock, there is a chance that one of
the non-atomic operations performed on the round trip time statistics
could be incomplete, such that an incorrect lateness criterion would be
calculated.
Without this change, the effect of the bug would be rare unecessary but
benign retransmissions.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The /dev/etherd/err character device provides low-level information about
normal but sometimes interesting AoE command retransmits and "unexpected
responses", i.e., responses for packets that have already been
retransmitted.
This change adds MAC addresses to the messages about unexpected responses,
so that when they occur, it's more easy to determine the network paths to
which they belong.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The aoe driver already had some congestion handling, but it was limited in
its ability to cope with the kind of congestion that can arise on more
complex networks such as those involving paths through multiple ethernet
switches.
Some of the lessons from TCP's history of development can be applied to
improving the congestion control and avoidance on AoE storage networks.
These changes use familar concepts from Van Jacobson's "Congestion
Avoidance and Control" paper from '88, without adding significant
overhead.
This patch depends on an upcoming patch that covers the failover case when
AoE commands being retransmitted are transferred from one retransmit queue
to another. Another upcoming patch increases the timing accuracy.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make the aoe driver follow expected behavior when the user uses ioctl to
get the ATA device identify information, allowing access to model, serial
number, etc.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The userland aoetools package includes an "aoe-stat" command that can
display a "payload size" column when the aoe driver exports this
information. Users can quickly see what amount of user data is
transferred inside each AoE command on the network, network headers
excluded.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The GPFS filesystem is an example of an aoe user that requires the aoe
driver to support I/O request sizes larger than the default. Most users
will not need large I/O request sizes, because they would need to be split
up into multiple AoE commands anyway.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Users sometimes want to cause the aoe driver to forget a particular
previously discovered device when it is no longer online. The aoetools
provide an "aoe-flush" command that users run to perform this
administrative task. The changes below provide the support needed in the
driver.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The ATA over Ethernet config query response contains a "buffer count"
field reflecting the AoE target's capacity to buffer incoming AoE
commands.
By taking the current value of this field into accound, we increase
performance throughput or avoid network congestion, when the value
has increased or decreased, respectively.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dropped transmits are not common, but when they do occur, increasing
the transmit queue length often helps.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Calling the request handler directly on a plugged queue defeats
the performance improvements provided by the plugging mechanism.
Use the __blk_run_queue function instead of calling the request
handler directly, so that we don't interfere with the block
layer's ability to plug the queue.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Because udev use is so widespread, making the old static mapping the
default is too conservative, given the severe limitations it places on
usable AoE addresses. Storage virtualization and larger shelves have made
the old limitations too confining.
These changes make the dynamic block device minor numbers the default,
removing the limitations on usable AoE addresses.
The static arrangement is still available with aoe_dyndevs=0, and the
aoe-stat tool from the userland aoetools package, the user space
counterpart to the aoe driver, recognizes the case where there is a
mismatch between the minor number in sysfs and the minor number in a
special device file.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In general, specific is better when it comes to messages about AoE usage
problems. Also, explicit checks for the AoE broadcast addresses are
added.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The old mapping between AoE target shelf and slot addresses and the block
device minor number is retained as a backwards-compatible feature, with a
new "aoe_dyndevs" module parameter available for enabling dynamic block
device minor numbers.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The ATA over Ethernet protocol uses a major (shelf) and minor (slot)
address to identify a particular storage target. These changes remove an
artificial limitation the aoe driver imposes on the use of AoE addresses.
For example, without these changes, the slot address has a maximum of 15,
but users commonly use slot numbers much greater than that.
The AoE shelf and slot address space is often used sparsely. Instead of
using a static mapping between AoE addresses and the block device minor
number, the block device minor numbers are now allocated on demand.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The internal version number of the aoe driver appears in a console message
when the driver loads and is usually obtained by the user with the
userland aoe-version tool, part of the aoetools.[1]
Although this patchset includes bugfixes backported from higher-numbered
versions published on the coraid.com website, it is a form of version 49.
1. http://aoetools.sourceforge.net/
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This change removes some unused code and attempts to increase code
consistency.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This change eliminates the danger that the user could rmmod the driver for
a network interface that is being used for AoE by the aoe driver.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In the driver code, "target" and aoetgt refer to a particular remote
interface on the AoE storage target. The latter is identified by its AoE
major and minor addresses. Commands that are being sent to an AoE storage
target {major, minor} can be sent or retransmitted to any of the remote
MAC addresses associated with the AoE storage target.
That is, frames are naturally associated with not an aoetgt (AoE major,
AoE minor, remote MAC address) but an aoedev (AoE major, AoE minor).
Making the code reflect that reality simplifies the driver, especially
when the path to a remote MAC address becomes unusable.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A guard is inserted to prevent AoE minor addresses (slot addresses) higher
than 15 to be used, as they are not yet supported by the driver.
There is a change coming that will allow the aoe driver to overcome this
limit by using system device minor numbers dynamically, but until then,
this guard prevents unexpected targets from being used by the driver when
AoE targets with high minor numbers are on the AoE network.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The discovery process begins with an optional AoE config query command and
an AoE config query response. Normally when an aoe device is already
open, the config query response does not trigger an ATA identify device
command to be sent out, since the response contains storage capacity
information that, if changed, could surprise the user of the device.
The userland "aoe-revalidate" tool uses a character device to trigger an
AoE config query for a particular AoE storage target and an ATA device
identify command, even when the device is open.
This change causes the config query to go out first, reflecting the normal
discovery sequence. The responses could come back in any order, so this
change is fairly cosmetic.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The aoe_deadsecs module parameter allows the user to specify a hard limit
on the number of seconds an AoE command can be retransmitted before the
AoE block device is considered to have failed.
Using aoe_deadsecs to determine the time we try using a different remote
interface helps to ensure that the hard limit is not reached before we've
tried to recover by sending to a different remote port.
As a data storage target, the AoE target is unambiguously identified by
its {major, minor} AoE address tuple, and an AoE target can have multiple
MAC addresses. However, note that "target" in the driver code and
comments means a {major, minor, MAC address} tuple, as in "somewhere to
send packets".
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Users with several network interfaces dedicated to AoE generally do not
configure them to support different-sized AoE data payloads on purpose.
For a given AoE target, there will be a set of local network interfaces
that can reach it. Using only the payload that will fit in the
smallest-sized MTU of all those local interfaces greatly simplifies the
driver, especially in failure scenarios.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The dev_queue_xmit function needs to have interrupts enabled, so the most
simple way to get the locking right but still fulfill that requirement is
to use a process that can call dev_queue_xmit serially over queued
transmissions.
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To allow users to choose an elevator algorithm for their particular
workloads, change from a make_request-style driver to an
I/O-request-queue-handler-style driver.
We have to do a couple of things that might be surprising. We manipulate
the page _count directly on the assumption that we still have no guarantee
that users of the block layer are prohibited from submitting bios
containing pages with zero reference counts.[1] If such a prohibition now
exists, I can get rid of the _count manipulation.
Just as before this patch, we still keep track of the sk_buffs that the
network layer still hasn't finished yet and cap the resources we use with
a "pool" of skbs.[2]
Now that the block layer maintains the disk stats, the aoe driver's
diskstats function can go away.
1. https://lkml.org/lkml/2007/3/1/374
2. https://lkml.org/lkml/2007/7/6/241
Signed-off-by: Ed Cashin <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
