xen-blkback: print stats about persistent grants

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: xen-devel@lists.xen.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkback: use balloon pages for all mappings

Using balloon pages for all granted pages allows us to simplify the
logic in blkback, especially in the xen_blkbk_map function, since now
we can decide if we want to map a grant persistently or not after we
have actually mapped it. This could not be done before because
persistent grants used ballooned pages, whereas non-persistent grants
used pages from the kernel.

This patch also introduces several changes, the first one is that the
list of free pages is no longer global, now each blkback instance has
it's own list of free pages that can be used to map grants. Also, a
run time parameter (max_buffer_pages) has been added in order to tune
the maximum number of free pages each blkback instance will keep in
it's buffer.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: xen-devel@lists.xen.org
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkback: implement LRU mechanism for persistent grants

This mechanism allows blkback to change the number of grants
persistently mapped at run time.

The algorithm uses a simple LRU mechanism that removes (if needed) the
persistent grants that have not been used since the last LRU run, or
if all grants have been used it removes the first grants in the list
(that are not in use).

The algorithm allows the user to change the maximum number of
persistent grants, by changing max_persistent_grants in sysfs.

Since we are storing the persistent grants used inside the request
struct (to be able to mark them as "unused" when unmapping), we no
longer need the bitmap (unmap_seg).

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen-devel@lists.xen.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkback: move pending handles list from blkbk to pending_req

Moving grant ref handles from blkbk to pending_req will allow us to
get rid of the shared blkbk structure.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen-devel@lists.xen.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkback: make the queue of free requests per backend

Remove the last dependency from blkbk by moving the list of free
requests to blkif. This change reduces the contention on the list of
available requests.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen-devel@lists.xen.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkback: expand map/unmap functions

Preparatory change for implementing indirect descriptors. Change
xen_blkbk_{map/unmap} in order to be able to map/unmap a random amount
of grants (previously it was limited to
BLKIF_MAX_SEGMENTS_PER_REQUEST). Also, remove the usage of pending_req
in the map/unmap functions, so we can map/unmap grants without needing
to pass a pending_req.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: xen-devel@lists.xen.org
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-block: implement indirect descriptors

Indirect descriptors introduce a new block operation
(BLKIF_OP_INDIRECT) that passes grant references instead of segments
in the request. This grant references are filled with arrays of
blkif_request_segment_aligned, this way we can send more segments in a
request.

The proposed implementation sets the maximum number of indirect grefs
(frames filled with blkif_request_segment_aligned) to 256 in the
backend and 32 in the frontend. The value in the frontend has been
chosen experimentally, and the backend value has been set to a sane
value that allows expanding the maximum number of indirect descriptors
in the frontend if needed.

The migration code has changed from the previous implementation, in
which we simply remapped the segments on the shared ring. Now the
maximum number of segments allowed in a request can change depending
on the backend, so we have to requeue all the requests in the ring and
in the queue and split the bios in them if they are bigger than the
new maximum number of segments.

[v2: Fixed minor comments by Konrad.
[v1: Added padding to make the indirect request 64bit aligned.
 Added some BUGs, comments; fixed number of indirect pages in
 blkif_get_x86_{32/64}_req. Added description about the indirect operation
 in blkif.h]
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
[v3: Fixed spaces and tabs mix ups]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkback: allocate list of pending reqs in small chunks

Allocate pending requests in smaller chunks instead of allocating them
all at the same time.

This change also removes the global array of pending_reqs, it is no
longer necessay.

Variables related to the grant mapping have been grouped into a struct
called "grant_page", this allows to allocate them in smaller chunks,
and also improves memory locality.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
xen-blkfront: use a different scatterlist for each request

In blkif_queue_request blkfront iterates over the scatterlist in order
to set the segments of the request, and in blkif_completion blkfront
iterates over the raw request, which makes it hard to know the exact
position of the source and destination memory positions.

This can be solved by allocating a scatterlist for each request, that
will be keep until the request is finished, allowing us to copy the
data back to the original memory without having to iterate over the
raw request.

Oracle-Bug: 16660413 - LARGE ASYNCHRONOUS READS APPEAR BROKEN ON 2.6.39-400
CC: stable@vger.kernel.org
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reported-and-Tested-by: Anne Milicia <anne.milicia@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
libfcoe: Fix Conflicting FCFs issue in the fabric

When multiple FCFs in use, and first FIP Advertisement received is
with "Available for Login" i.e A bit set to 0, FCF selection will fail.
The fix is to remove the assumption in the code that first FCF is only
allowed selectable FCF.
Consider the scenario fip->fcfs contains FCF1(fabricname X, marked A=0)
FCF2(fabricname Y, marked A=1). list_first_entry(first) points to FCF1
and 1st iteration we ignore the FCF and on 2nd iteration we compare
FCF1 & FCF2 fabric name and we fails to perform FCF selection.

Signed-off-by: Krishna Mohan <krmohan@cisco.com>
Reviewed-by: Bhanu Prakash Gollapudi <bprakash@broadcom.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
libfc: Correct check for initiator role

The service_params field is being checked against the symbol
FC_RPORT_ROLE_FCP_INITIATOR where it really should be checked
against FCP_SPPF_INIT_FCN.

Signed-off-by: Mark Rustad <mark.d.rustad@intel.com>
Tested-by: Jack Morgan <jack.morgan@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
libfc: extend ex_lock to protect all of fc_seq_send

This warning was reported recently:

WARNING: at drivers/scsi/libfc/fc_exch.c:478 fc_seq_send+0x14f/0x160 [libfc]()
(Not tainted)
Hardware name: ProLiant DL120 G7
Modules linked in: tcm_fc target_core_iblock target_core_file target_core_pscsi
target_core_mod configfs dm_round_robin dm_multipath 8021q garp stp llc bnx2fc
cnic uio fcoe libfcoe libfc scsi_transport_fc scsi_tgt autofs4 sunrpc
pcc_cpufreq ipv6 hpilo hpwdt e1000e microcode iTCO_wdt iTCO_vendor_support
serio_raw shpchp ixgbe dca mdio sg ext4 mbcache jbd2 sd_mod crc_t10dif pata_acpi
ata_generic ata_piix hpsa dm_mirror dm_region_hash dm_log dm_mod [last unloaded:
scsi_wait_scan]
Pid: 5464, comm: target_completi Not tainted 2.6.32-272.el6.x86_64 #1
Call Trace:
 [<ffffffff8106b747>] ? warn_slowpath_common+0x87/0xc0
 [<ffffffff8106b79a>] ? warn_slowpath_null+0x1a/0x20
 [<ffffffffa025f7df>] ? fc_seq_send+0x14f/0x160 [libfc]
 [<ffffffffa035cbce>] ? ft_queue_status+0x16e/0x210 [tcm_fc]
 [<ffffffffa030a660>] ? target_complete_ok_work+0x0/0x4b0 [target_core_mod]
 [<ffffffffa030a766>] ? target_complete_ok_work+0x106/0x4b0 [target_core_mod]
 [<ffffffffa030a660>] ? target_complete_ok_work+0x0/0x4b0 [target_core_mod]
 [<ffffffff8108c760>] ? worker_thread+0x170/0x2a0
 [<ffffffff810920d0>] ? autoremove_wake_function+0x0/0x40
 [<ffffffff8108c5f0>] ? worker_thread+0x0/0x2a0
 [<ffffffff81091d66>] ? kthread+0x96/0xa0
 [<ffffffff8100c14a>] ? child_rip+0xa/0x20
 [<ffffffff81091cd0>] ? kthread+0x0/0xa0
 [<ffffffff8100c140>] ? child_rip+0x0/0x20

It occurs because fc_seq_send can have multiple contexts executing within it at
the same time, and fc_seq_send doesn't consistently use the ep->ex_lock that
protects this structure.  Because of that, its possible for one context to clear
the INIT bit in the ep->esb_state field while another checks it, leading to the
above stack trace generated by the WARN_ON in the function.

We should probably undertake the effort to convert access to the fc_exch
structures to use rcu, but that a larger work item.  To just fix this specific
issue, we can just extend the ex_lock protection through the entire fc_seq_send
path

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reported-by: Gris Ge <fge@redhat.com>
CC: Robert Love <robert.w.love@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
MAINTAINERS: Fix fcoe mailing list

The FCoE mailing list has moved, updte it in the MAINTAINERS file
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
CC: Robert Love <robert.w.love@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
ext3: Fix fsync error handling after filesystem abort.

If filesystem was aborted we will return success
due to (sb->s_flags & MS_RDONLY) which is incorrect and
results in data loss.
In order to handle fs abort correctly we have to check
fs state once we discover that it is in MS_RDONLY state

Test case: http://patchwork.ozlabs.org/patch/244297/
Changes from V1:
 - fix spelling
 - fix smp_rmb()/debug order

Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Jan Kara <jack@suse.cz>
reiserfs: fix spurious multiple-fill in reiserfs_readdir_dentry

After sleeping for filldir(), we check to see if the file system has
changed and research. The next_pos pointer is updated but its value
isn't pushed into the key used for the search itself. As a result,
the search returns the same item that the last cycle of the loop did
and filldir() is called multiple times with the same data.

The end result is that the buffer can contain the same name multiple
times. This can be returned to userspace or used internally in the
xattr code where it can manifest with the following warning:

jdm-20004 reiserfs_delete_xattrs: Couldn't delete all xattrs (-2)

reiserfs_for_each_xattr uses reiserfs_readdir_dentry to iterate over
the xattr names and ends up trying to unlink the same name twice. The
second attempt fails with -ENOENT and the error is returned. At some
point I'll need to add support into reiserfsck to remove the orphaned
directories left behind when this occurs.

The fix is to push the value into the key before researching.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
reiserfs: fix problems with chowning setuid file w/ xattrs

reiserfs_chown_xattrs() takes the iattr struct passed into ->setattr
and uses it to iterate over all the attrs associated with a file to change
ownership of xattrs (and transfer quota associated with the xattr files).

When the setuid bit is cleared during chown, ATTR_MODE and iattr->ia_mode
are passed to all the xattrs as well. This means that the xattr directory
will have S_IFREG added to its mode bits.

This has been prevented in practice by a missing IS_PRIVATE check
in reiserfs_acl_chmod, which caused a double-lock to occur while holding
the write lock. Since the file system was completely locked up, the
writeout of the corrupted mode never happened.

This patch temporarily clears everything but ATTR_UID|ATTR_GID for the
calls to reiserfs_setattr and adds the missing IS_PRIVATE check.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
reiserfs: fix deadlock with nfs racing on create/lookup

Reiserfs is currently able to be deadlocked by having two NFS clients
where one has removed and recreated a file and another is accessing the
file with an open file handle.

If one client deletes and recreates a file with timing such that the
recreated file obtains the same [dirid, objectid] pair as the original
file while another client accesses the file via file handle, the create
and lookup can race and deadlock if the lookup manages to create the
in-memory inode first.

The create thread, in insert_inode_locked4, will hold the write lock
while waiting on the other inode to be unlocked. The lookup thread,
anywhere in the iget path, will release and reacquire the write lock while
it schedules. If it needs to reacquire the lock while the create thread
has it, it will never be able to make forward progress because it needs
to reacquire the lock before ultimately unlocking the inode.

This patch drops the write lock across the insert_inode_locked4 call so
that the ordering of inode_wait -> write lock is retained. Since this
would have been the case before the BKL push-down, this is safe.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
x86/MSI: Conserve interrupt resources when using multiple-MSIs

Current multiple-MSI implementation does not take into account actual
number of requested MSIs and always rounds that number to a larger
power-of-two value.  Yet, the number of MSIs a PCI device could send (and
therefore the number of messages a device driver could request) may be
smaller.  As result, resources allocated for extra MSIs are just wasted.

This update takes advantage of 'msi_desc::nvec_used' field introduced with
generic MSI code to track the number of requested and used MSIs.  As
result, resources associated with interrupts are conserved.  Of those
resources most noticeable are x86 interrupt vectors.

The initial version of this fix also conserved IRTEs, but Jan noticed that
a malfunctioning PCI device might send a message number it did not claim
and thus refer to an IRTE it does not own.  To avoid this security hole,
as many IRTEs are reserved as the device could possibly send.

[bhelgaas: changelog, rename to "nvec_used"]
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Joerg Roedel <joro@8bytes.org>
dmaengine: ste_dma40: fix error return code in d40_probe()

In many of the error handling case, the return value 'ret' not set
and 0 will be return from d40_probe() even if error, but we should
return a negative error code instead in those error handling case.
This patch fixed them, and also removed useless variable 'err'.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
[SCSI] libsas: implement > 16 byte CDB support

Remove the arbitrary expectation in libsas that all SCSI commands are 16 bytes
or less.  Instead do all copies via cmd->cmd_len (and use a pointer to this in
the libsas task instead of a copy).  Note that this still doesn't enable > 16
byte CDB support in the underlying drivers because their internal format has
to be fixed and the wire format of > 16 byte CDBs according to the SAS spec is
different.  the libsas drivers (isci, aic94xx, mvsas and pm8xxx are all
updated for this change.

Cc: Lukasz Dorau <lukasz.dorau@intel.com>
Cc: Maciej Patelczyk <maciej.patelczyk@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Jack Wang <xjtuwjp@gmail.com>
Cc: Lindar Liu <lindar_liu@usish.com>
Cc: Xiangliang Yu <yuxiangl@marvell.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>