Wendy Cheng [Wed, 27 Jun 2007 21:07:53 +0000 (17:07 -0400)]
[GFS2] Remove i_mode passing from NFS File Handle
GFS2 has been passing i_mode within NFS File Handle. Other than the
wrong assumption that there is always room for this extra 16 bit value,
the current gfs2_get_dentry doesn't really need the i_mode to work
correctly. Note that GFS2 NFS code does go thru the same lookup code
path as direct file access route (where the mode is obtained from name
lookup) but gfs2_get_dentry() is coded for different purpose. It is not
used during lookup time. It is part of the file access procedure call.
When the call is invoked, if on-disk inode is not in-memory, it has to
be read-in. This makes i_mode passing a useless overhead.
Signed-off-by: S. Wendy Cheng <wcheng@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Wendy Cheng [Wed, 27 Jun 2007 21:07:08 +0000 (17:07 -0400)]
[GFS2] Obtaining no_formal_ino from directory entry
GFS2 lookup code doesn't ask for inode shared glock. This implies during
in-memory inode creation for existing file, GFS2 will not disk-read in
the inode contents. This leaves no_formal_ino un-initialized during
lookup time. The un-initialized no_formal_ino is subsequently encoded
into file handle. Clients will get ESTALE error whenever it tries to
access these files.
Signed-off-by: S. Wendy Cheng <wcheng@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Abhijith Das [Wed, 27 Jun 2007 16:06:19 +0000 (11:06 -0500)]
[GFS2] System won't suspend with GFS2 file system mounted
The kernel threads in gfs2, namely gfs2_scand, gfs2_logd, gfs2_quotad,
gfs2_glockd, gfs2_recoverd weren't doing anything when the suspend
mechanism was trying to freeze them.
I put in calls to refrigerator() in the loops for all the daemons and
suspend works as expected.
Signed-off-by: Abhijith Das <adas@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch is for bugzilla bug #245663. This crosswrites a fix from
gfs1 (bz #210369) so that the mount options are reset properly upon
remount. This was tested on system trin-10.
Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Wendy Cheng [Wed, 27 Jun 2007 15:00:03 +0000 (11:00 -0400)]
[GFS2] inode size inconsistency
This should have been part of the NFS patch #1 but somehow I missed it
when packaging the patches. It is not a critical issue as the others (I
hope). RHEL 5.1 31.el5 kernel runs fine without this change.
Our truncate code is chopped into two parts, one for vfs inode changes
(in vmtruncate()) and one of gfs inode (in gfs2_truncatei()). These two
operatons are, unfortunately, not atomic. So it could happens that
vmtruncate() succeeds (inode->i_size is changed) but gfs2_truncatei
fails (say kernel temporarily out of memory). This would leave gfs inode
i_di.di_size out of sync with vfs inode i_size. It will later confuse
gfs2_commit_write() if a write is issued. Last time I checked, it will
cause file corruption.
Signed-off-by: S. Wendy Cheng <wcheng@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
[DLM] Telnet to port 21064 can stop all lockspaces
This patch fixes Red Hat bz#245892
Opening a tcp connection from a cluster member to another cluster member
targeting the dlm port it is enough to stop every dlm operation in the cluster.
This means that GFS and rgmanager will hang.
Signed-Off-By: Patrick Caulfield <pcaulfie@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
S. Wendy Cheng [Tue, 26 Jun 2007 01:14:31 +0000 (21:14 -0400)]
[GFS2] Fix gfs2_block_truncate_page err return
Code segment inside gfs2_block_truncate_page() doesn't set the return
code correctly. This causes NFSD erroneously returns EIO back to client
with setattr procedure call (truncate error).
Signed-off-by: S. Wendy Cheng <wcheng@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
There is a bug in the code which acquires multiple glocks where if the
initial out-of-order attempt fails part way though we can land up trying
to acquire the wrong number of glocks. This is part of the fix for red
hat bz #239737. The other part of the bz doesn't apply to upstream
kernels since it was fixed by:
Since the out-of-order code doesn't appear to add anything to the
performance of GFS2, this patch just removed it rather than trying to
fix it. It should be much easier to see whats going on here now. In
addition, we don't allocate any memory unless we are using a lot of
glocks (which is a relatively uncommon case).
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Robert Peterson [Mon, 18 Jun 2007 19:50:20 +0000 (14:50 -0500)]
[GFS2] assertion failure after writing to journaled file, umount
This patch passes all my nasty tests that were causing the code to
fail under one circumstance or another. Here is a complete summary
of all changes from today's git tree, in order of appearance:
1. There are now separate variables for metadata buffer accounting.
2. Variable sd_log_num_hdrs is no longer needed, since the header
accounting is taken care of by the reserve/refund sequence.
3. Fixed a tiny grammatical problem in a comment.
4. Added a new function "calc_reserved" to calculate the reserved
log space. This isn't entirely necessary, but it has two benefits:
First, it simplifies the gfs2_log_refund function greatly.
Second, it allows for easier debugging because I could sprinkle the
code with calls to this function to make sure the accounting is
proper (by adding asserts and printks) at strategic point of the code.
5. In log_pull_tail there apparently was a kludge to fix up the
accounting based on a "pull" parameter. The buffer accounting is
now done properly, so the kludge was removed.
6. File sync operations were making a call to gfs2_log_flush that
writes another journal header. Since that header was unplanned
for (reserved) by the reserve/refund sequence, the free space had
to be decremented so that when log_pull_tail gets called, the free
space is be adjusted properly. (Did I hear you call that a kludge?
well, maybe, but a lot more justifiable than the one I removed).
7. In the gfs2_log_shutdown code, it optionally syncs the log by
specifying the PULL parameter to log_write_header. I'm not sure
this is necessary anymore. It just seems to me there could be
cases where shutdown is called while there are outstanding log
buffers.
8. In the (data)buf_lo_before_commit functions, I changed some offset
values from being calculated on the fly to being constants. That
simplified some code and we might as well let the compiler do the
calculation once rather than redoing those cycles at run time.
9. This version has my rewritten databuf_lo_add function.
This version is much more like its predecessor, buf_lo_add, which
makes it easier to understand. Again, this might not be necessary,
but it seems as if this one works as well as the previous one,
maybe even better, so I decided to leave it in.
10. In databuf_lo_before_commit, a previous data corruption problem
was caused by going off the end of the buffer. The proper solution
is to have the proper limit in place, rather than stopping earlier.
(Thus my previous attempt to fix it is wrong).
If you don't wrap the buffer, you're stopping too early and that
causes more log buffer accounting problems.
11. In lops.h there are two new (previously mentioned) constants for
figuring out the data offset for the journal buffers.
12. There are also two new functions, buf_limit and databuf_limit to
calculate how many entries will fit in the buffer.
13. In function gfs2_meta_wipe, it needs to distinguish between pinned
metadata buffers and journaled data buffers for proper journal buffer
accounting. It can't use the JDATA gfs2_inode flag because it's
sometimes passed the "real" inode and sometimes the "metadata
inode" and the inode flags will be random bits in a metadata
gfs2_inode. It needs to base its decision on which was passed in.
Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Robert Peterson [Tue, 12 Jun 2007 16:24:36 +0000 (11:24 -0500)]
[GFS2] Journaled file write/unstuff bug
This patch is for bugzilla bug 283162, which uncovered a number of
bugs pertaining to writing to files that have the journaled bit on.
These bugs happen most often when writing to the meta_fs because
the files are always journaled. So operations like gfs2_grow were
particularly vulnerable, although many of the problems could be
recreated with normal files after setting the journaled bit on.
The problems fixed are:
-GFS2 wasn't ever writing unstuffed journaled data blocks to their
in-place location on disk. Now it does.
-If you unmounted too quickly after doing IO to a journaled file,
GFS2 was crashing because you would discard a buffer whose bufdata
was still on the active items list. GFS2 now deals with this
gracefully.
-GFS2 was losing track of the bufdata for journaled data blocks,
and it wasn't getting freed, causing an error when you tried to
unmount the module. GFS2 now frees all the bufdata structures.
-There was a memory corruption occurring because GFS2 wrote
twice as many log entries for journaled buffers.
-It was occasionally trying to write journal headers in buffers
that weren't currently mapped.
Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
David Teigland [Mon, 11 Jun 2007 15:47:18 +0000 (10:47 -0500)]
[DLM] don't require FS flag on all nodes
Mask off the recently added DLM_LSFL_FS flag when setting the exflags.
This way all the nodes in the lockspace aren't required to have the FS
flag set, since we later check that exflags matches among all nodes.
Signed-off-by: Patrick Caulfield <pcaulfie@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Abhijith Das [Mon, 11 Jun 2007 07:22:32 +0000 (08:22 +0100)]
[GFS2] Fix deallocation issues
There were two issues during deallocation of unlinked inodes. The
first was relating to the use of a "try" lock which in the case of
the inode lock wasn't trying hard enough to deallocate in all
circumstances (now changed to a normal glock) and in the case of
the iopen lock didn't wait for the demotion of the shared lock before
attempting to get the exclusive lock, and thereby sometimes (timing dependent)
not completing the deallocation when it should have done.
The second issue related to the lack of a way to invalidate dcache entries
on remote nodes (now fixed by this patch) which meant that unlinks were
taking a long time to return disk space to the fs. By adding some code to
invalidate the dcache entries across the cluster for unlinked inodes, that
is now fixed.
This patch was written jointly by Abhijith Das and Steven Whitehouse.
Signed-off-by: Abhijith Das <adas@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
David Teigland [Fri, 8 Jun 2007 21:00:22 +0000 (16:00 -0500)]
[GFS2] set plock owner in GETLK info
Set the owner field in the plock info sent to userspace for GETLK.
Without this, gfs_controld won't correctly see when the GETLK from a
process matches one of the process's existing locks.
Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
fs/gfs2/inode.c: In function 'gfs2_lookupi':
fs/gfs2/inode.c:392: warning: 'error' may be used uninitialized in this function
Looks like a real bug to me.
Cc: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Under certain circumstances its possible (though rather unlikely) that
inodes which were unlinked by one node while still open on another might
get "lost" in the sense that they don't get deallocated if the node
which held the inode open crashed before it was unlinked.
This patch adds the recovery code which allows automatic deallocation of
the inode if its found during block allocation (the sensible time to
look for such inodes since we are scanning the rgrp's bitmaps anyway at
this time, so it adds no overhead to do this).
Since the inode will have had its i_nlink set to zero, all we need to
trigger recovery is a lookup and an iput(), and the normal deallocation
code takes care of the rest.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Robert Peterson [Thu, 7 Jun 2007 14:10:01 +0000 (09:10 -0500)]
[GFS2] Can't mount GFS2 file system on AoE device
This patch fixes bug 243131: Can't mount GFS2 file system on AoE device.
When using AoE devices with lock_nolock, there is no locking table, so
gfs2 (and gfs1) uses the superblock s_id. This turns out to be the device
name in some cases. In the case of AoE, the device contains a slash,
(e.g. "etherd/e1.1p2") which is an invalid character when we try to
register the table in sysfs. This patch replaces the "/" with underscore.
Rather than add a new variable to the stack, I'm just reusing a (char *)
variable that's no longer used: table.
This code has been tested on the failing system using a RHEL5 patch.
The upstream code was tested by using gfs2_tool sb to interject a "/"
into the table name of a clustered gfs2 file system.
Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This fixes a bug in the ordering of operations in the error path of
createi. Its not valid to do an iput() when holding the inode's glock
since the iput() will (in this case) result in delete_inode() being
called which needs to grab the lock itself. This was causing the
recursive lock checking code to trigger.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Add a new flag, DLM_LSFL_FS, to be used when a file system creates a lockspace.
This flag causes the dlm to use GFP_NOFS for allocations instead of GFP_KERNEL.
(This updated version of the patch uses gfp_t for ls_allocation.)
Signed-Off-By: Patrick Caulfield <pcaulfie@redhat.com> Signed-Off-By: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This adds a nanosecond timestamp feature to the GFS2 filesystem. Due
to the way that the on-disk format works, older filesystems will just
appear to have this field set to zero. When mounted by an older version
of GFS2, the filesystem will simply ignore the extra fields so that
it will again appear to have whole second resolution, so that its
trivially backward compatible.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
[GFS2] Fix sign problem in quota/statfs and cleanup _host structures
This patch fixes some sign issues which were accidentally introduced
into the quota & statfs code during the endianess annotation process.
Also included is a general clean up which moves all of the _host
structures out of gfs2_ondisk.h (where they should not have been to
start with) and into the places where they are actually used (often only
one place). Also those _host structures which are not required any more
are removed entirely (which is the eventual plan for all of them).
The conversion routines from ondisk.c are also moved into the places
where they are actually used, which for almost every one, was just one
single place, so all those are now static functions. This also cleans up
the end of gfs2_ondisk.h which no longer needs the #ifdef __KERNEL__.
The net result is a reduction of about 100 lines of code, many functions
now marked static plus the bug fixes as mentioned above. For good
measure I ran the code through sparse after making these changes to
check that there are no warnings generated.
This fixes Red Hat bz #239686
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This is a patch for the first three issues of RHBZ #238162
The first issue is that when you allocate a new page for a file, it will not
start off uptodate. This makes sense, since you haven't written anything to that
part of the file yet. Unfortunately, gfs2_pin() checks to make sure that the
buffers are uptodate. The solution to this is to mark the buffers uptodate in
gfs2_commit_write(), after they have been zeroed out and have the data written
into them. I'm pretty confident with this fix, although it's not completely
obvious that there is no problem with marking the buffers uptodate here.
The second issue is simply that you can try to pin a data buffer that is already
on the incore log, and thus, already pinned. This patch checks to see if this
buffer is already on the log, and exits databuf_lo_add() if it is, just like
buf_lo_add() does.
The third issue is that gfs2_log_flush() doesn't do it's block accounting
correctly. Both metadata and journaled data are logged, but gfs2_log_flush()
only compares the number of metadata blocks with the number of blocks to commit
to the ondisk journal. This patch also counts the journaled data blocks.
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch clears the user_data of active sockets as part of cleanup.
This prevents any late-arriving data from trying to add jobs to the work
queue while we are tidying up.
Signed-Off-By: Patrick Caulfield <pcaulfie@redhat.com> Signed-Off-By: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
[GFS2] Make the log reserved blocks depend on block size
The number of blocks which we reserve in the log at the start of each
transaction needs to depends upon the block size since the overhead is
related to the number of "pointers" which can be fitted into a single
block.
This relates to Red Hat bz #240435
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
David Teigland [Tue, 29 May 2007 13:47:51 +0000 (08:47 -0500)]
[DLM] show default protocol
Display the initial value of the "protocol" config value in configfs.
The default value has always been 0 in the past anyway, so it's always
appeared to be correct.
Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
David Teigland [Tue, 29 May 2007 13:47:04 +0000 (08:47 -0500)]
[DLM] dumping master locks
Add a new debugfs file that dumps a compact list of mastered locks.
This will be used by a userland daemon to collect state for deadlock
detection.
Also, for the existing function that prints all lock state, lock the rsb
before going through the lock lists since they can be changing in the
course of normal dlm activity.
Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
David Teigland [Tue, 29 May 2007 13:46:00 +0000 (08:46 -0500)]
[DLM] canceling deadlocked lock
Add a function that can be used through libdlm by a system daemon to cancel
another process's deadlocked lock. A completion ast with EDEADLK is returned
to the process waiting for the lock.
Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
David Teigland [Tue, 29 May 2007 13:44:23 +0000 (08:44 -0500)]
[DLM] timeout fixes
Various fixes related to the new timeout feature:
- add_timeout() missed setting TIMEWARN flag on lkb's when the
TIMEOUT flag was already set
- clear_proc_locks should remove a dead process's locks from the
timeout list
- the end-of-life calculation for user locks needs to consider that
ETIMEDOUT is equivalent to -DLM_ECANCEL
- make initial default timewarn_cs config value visible in configfs
- change bit position of TIMEOUT_CANCEL flag so it's not copied to
a remote master node
- set timestamp on remote lkb's so a lock dump will display the time
they've been waiting
Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
David Teigland [Fri, 18 May 2007 21:02:57 +0000 (16:02 -0500)]
[DLM] fix compile breakage
In the rush to get the previous patch set sent, a compilation bug I fixed
shortly before sending somehow got clobbered, probably by a missed quilt
refresh or something.
Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
David Teigland [Fri, 18 May 2007 14:03:35 +0000 (09:03 -0500)]
[DLM] wait for config check during join [6/6]
Joining the lockspace should wait for the initial round of inter-node
config checks to complete before returning. This way, if there's a
configuration mismatch between the joining node and the existing nodes,
the join can fail and return an error to the application.
Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
David Teigland [Fri, 18 May 2007 14:02:20 +0000 (09:02 -0500)]
[DLM] fix new_lockspace error exit [5/6]
Fix the error path when exiting new_lockspace(). It was kfree'ing the
lockspace struct at the end, but that's only valid if it exits before
kobject_register occured. After kobject_register we have to let the
kobject do the freeing.
Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
David Teigland [Fri, 18 May 2007 14:01:26 +0000 (09:01 -0500)]
[DLM] cancel in conversion deadlock [4/6]
When conversion deadlock is detected, cancel the conversion and return
EDEADLK to the application. This is a new default behavior where before
the dlm would allow the deadlock to exist indefinately.
The DLM_LKF_NODLCKWT flag can now be used in a conversion to prevent the
dlm from performing conversion deadlock detection/cancelation on it.
The DLM_LKF_CONVDEADLK flag can continue to be used as before to tell the
dlm to demote the granted mode of the lock being converted if it gets into
a conversion deadlock.
Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
David Teigland [Fri, 18 May 2007 14:00:32 +0000 (09:00 -0500)]
[DLM] dlm_device interface changes [3/6]
Change the user/kernel device interface used by libdlm:
- Add ability for userspace to check the version of the interface. libdlm
can now adapt to different versions of the kernel interface.
- Increase the size of the flags passed in a lock request so all possible
flags can be used from userspace.
- Add an opaque "xid" value for each lock. This "transaction id" will be
used later to associate locks with each other during deadlock detection.
- Add a "timeout" value for each lock. This is used along with the
DLM_LKF_TIMEOUT flag.
Also, remove a fragment of unused code in device_read().
This patch requires updating libdlm which is backward compatible with
older kernels.
Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
David Teigland [Fri, 18 May 2007 13:59:31 +0000 (08:59 -0500)]
[DLM] add lock timeouts and warnings [2/6]
New features: lock timeouts and time warnings. If the DLM_LKF_TIMEOUT
flag is set, then the request/conversion will be canceled after waiting
the specified number of centiseconds (specified per lock). This feature
is only available for locks requested through libdlm (can be enabled for
kernel dlm users if there's a use for it.)
If the new DLM_LSFL_TIMEWARN flag is set when creating the lockspace, then
a warning message will be sent to userspace (using genetlink) after a
request/conversion has been waiting for a given number of centiseconds
(configurable per node). The time warnings will be used in the future
to do deadlock detection in userspace.
Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Josef Bacik [Wed, 16 May 2007 19:56:13 +0000 (15:56 -0400)]
[DLM] keep dlm from panicing when traversing rsb list in debugfs
This problem was originally reported against GFS6.1, but the same issue exists
in upstream DLM. This patch keeps the rsb iterator assigning under the rsbtbl
list lock. Each time we process an rsb we grab a reference to it to make sure
it is not freed out from underneath us, and then put it when we get the next rsb
in the list or move onto another list.
Signed-off-by: Josef Bacik <jwhiter@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Abhijith Das [Wed, 16 May 2007 22:02:19 +0000 (17:02 -0500)]
[GFS2] Quotas non-functional - fix bug
This patch fixes an error in the quota code where a 'struct
gfs2_quota_lvb*' was being passed to gfs2_adjust_quota() instead of a
'struct gfs2_quota_data*'. Also moved 'struct gfs2_quota_lvb' from
fs/gfs2/incore.h to include/linux/gfs2_ondisk.h as per Steve's suggestion.
Signed-off-by: Abhijith Das <adas@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch cleans up the inode number handling code. The main difference
is that instead of looking up the inodes using a struct gfs2_inum_host
we now use just the no_addr member of this structure. The tests relating
to no_formal_ino can then be done by the calling code. This has
advantages in that we want to do different things in different code
paths if the no_formal_ino doesn't match. In the NFS patch we want to
return -ESTALE, but in the ->lookup() path, its a bug in the fs if the
no_formal_ino doesn't match and thus we can withdraw in this case.
In order to later fix bz #201012, we need to be able to look up an inode
without knowing no_formal_ino, as the only information that is known to
us is the on-disk location of the inode in question.
This patch will also help us to fix bz #236099 at a later date by
cleaning up a lot of the code in that area.
There are no user visible changes as a result of this patch and there
are no changes to the on-disk format either.
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This patch removes the completion (which is rather large) from struct
gdlm_lock in favour of using the wait_on_bit() functions. We don't need
to add any extra fields to the structure to do this, so we save 32 bytes
(on x86_64) per structure. This adds up to quite a lot when we may
potentially have millions of these lock structures,
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Acked-by: David Teigland <teigland@redhat.com>
Robert Peterson [Mon, 14 May 2007 17:42:18 +0000 (12:42 -0500)]
[GFS2] Addendum patch 2 for gfs2_grow
This addendum patch 2 corrects three things:
1. It fixes a stupid mistake in the previous addendum that broke gfs2.
Ref: https://www.redhat.com/archives/cluster-devel/2007-May/msg00162.html
2. It fixes a problem that Dave Teigland pointed out regarding the
external declarations in ops_address.h being in the wrong place.
3. It recasts a couple more %llu printks to (unsigned long long)
as requested by Steve Whitehouse.
I would have loved to put this all in one revised patch, but there was
a rush to get some patches for RHEL5. Therefore, the previous patches
were applied to the git tree "as is" and therefore, I'm posting another
addendum. Sorry.
Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Nate Diller [Fri, 11 May 2007 05:41:28 +0000 (22:41 -0700)]
[GFS2] use zero_user_page
Use zero_user_page() instead of open-coding it.
Signed-off-by: Nate Diller <nate.diller@gmail.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Robert Peterson [Thu, 10 May 2007 21:54:38 +0000 (16:54 -0500)]
[GFS2] Kernel changes to support new gfs2_grow command (part 2)
To avoid code redundancy, I separated out the operational "guts" into
a new function called read_rindex_entry. Then I made two functions:
the closer-to-original gfs2_ri_update (without the special condition
checks) and gfs2_ri_update_special that's designed with that condition
in mind. (I don't like the name, but if you have a suggestion, I'm
all ears).
Oh, and there's an added benefit: we don't need all the ugly gotos
anymore. ;)
This patch has been tested with gfs2_fsck_hellfire (which runs for
three and a half hours, btw).
Signed-off-By: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Robert Peterson [Wed, 9 May 2007 14:37:57 +0000 (09:37 -0500)]
[GFS2] kernel changes to support new gfs2_grow command
This is another revision of my gfs2 kernel patch that allows
gfs2_grow to function properly.
Steve Whitehouse expressed some concerns about the previous
patch and I restructured it based on his comments.
The previous patch was doing the statfs_change at file close time,
under its own transaction. The current patch does the statfs_change
inside the gfs2_commit_write function, which keeps it under the
umbrella of the inode transaction.
I can't call ri_update to re-read the rindex file during the
transaction because the transaction may have outstanding unwritten
buffers attached to the rgrps that would be otherwise blown away.
So instead, I created a new function, gfs2_ri_total, that will
re-read the rindex file just to total the file system space
for the sake of the statfs_change. The ri_update will happen
later, when gfs2 realizes the version number has changed, as it
happened before my patch.
Since the statfs_change is happening at write_commit time and there
may be multiple writes to the rindex file for one grow operation.
So one consequence of this restructuring is that instead of getting
one kernel message to indicate the change, you may see several.
For example, before when you did a gfs2_grow, you'd get a single
message like:
GFS2: File system extended by 247876 blocks (968MB)
Now you get something like:
GFS2: File system extended by 207896 blocks (812MB)
GFS2: File system extended by 39980 blocks (156MB)
This version has also been successfully run against the hours-long
"gfs2_fsck_hellfire" test that does several gfs2_grow and gfs2_fsck
while interjecting file system damage. It does this repeatedly
under a variety Resource Group conditions.
Signed-off-By: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Satyam Sharma [Tue, 8 May 2007 08:18:58 +0000 (09:18 +0100)]
[DLM] fix a couple of races
Fix two races in fs/dlm/config.c:
(1) Grab the configfs subsystem semaphore before calling
config_group_find_obj() in get_space(). This solves a potential race
between get_space() and concurrent mkdir(2) or rmdir(2).
(2) Grab a reference on the found config_item _while_ holding the configfs
subsystem semaphore in get_comm(), and not after it. This solves a
potential race between get_comm() and concurrent rmdir(2).
Signed-off-by: Satyam Sharma <ssatyam@cse.iitk.ac.in> Signed-off-by: David Teigland <teigland@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
[GFS2] flush the glock completely in inode_go_sync
Fix for bz #231910
When filemap_fdatawrite() is called on the inode mapping in data=ordered mode,
it will add the glock to the log. In inode_go_sync(), if you do the
gfs2_log_flush() before this, after the filemap_fdatawrite() call, the glock
and its associated data buffers will be on the log again. This means you can
demote a lock from exclusive, without having it flushed from the log. The
attached patch simply moves the gfs2_log_flush up to after the
filemap_fdatawrite() call.
Originally, I tried moving the gfs2_log_flush to after gfs2_meta_sync(), but
that caused me to trip the following assert.
GFS2: fsid=cypher-36:test.0: fatal: assertion "!buffer_busy(bh)" failed
GFS2: fsid=cypher-36:test.0: function = gfs2_ail_empty_gl, file = fs/gfs2/glops.c, line = 61
It appears that gfs2_log_flush() puts some of the glocks buffers in the busy
state and the filemap_fdatawrite() call is necessary to flush them. This makes
me worry slightly that a related problem could happen because of moving the
gfs2_log_flush() after the initial filemap_fdatawrite(), but I assume that
gfs2_ail_empty_gl() would catch that case as well.
Signed-off-by: Benjamin E. Marzinski <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Fix permission checking for the new utimensat() system call
Commit 1c710c896eb461895d3c399e15bb5f20b39c9073 added the utimensat()
system call, but didn't handle the case of checking for the writability
of the target right, when the target was a file descriptor, not a
filename.
We cannot use vfs_permission(MAY_WRITE) for that case, and need to
simply check whether the file descriptor is writable. The oops from
using the wrong function was noticed and narrowed down by Markus
Trippelsdorf.
Cc: Ulrich Drepper <drepper@redhat.com> Cc: Markus Trippelsdorf <markus@trippelsdorf.de> Cc: Andrew Morton <akpm@linux-foundation.org> Acked-by: Al Viro <viro@ftp.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
PIO4 is a maximum PIO mode supported by a driver. Using "255" as a max_mode
argument to ide_get_best_pio_mode() could result in wrong timings being used
by a driver (for "pio" equal to 5) or OOPS (for "pio" values > 5 && < 255).
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com> Reviewed-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
If the chipset is using this PCI-ID, the primary channel is connected to the
first PATA-port. The secondary channel is connected to SATA-ports in IDE
emulation mode. The legacy IO-ports are used.
The including of the PCI-ID into pata_sis is not sufficient, because the legacy
driver in drivers/ide is initialized before pata_sis.
Adrian Bunk [Sat, 7 Jul 2007 04:14:02 +0000 (06:14 +0200)]
DLM must depend on SYSFS
The dependency of DLM on SYSFS got lost in
commit 6ed7257b46709e87d79ac2b6b819b7e0c9184998 resulting in the
following compile error with CONFIG_DLM=y, CONFIG_SYSFS=n:
<-- snip -->
...
LD .tmp_vmlinux1
fs/built-in.o: In function `dlm_lockspace_init':
/home/bunk/linux/kernel-2.6/linux-2.6.22-rc6-mm1/fs/dlm/lockspace.c:231: undefined reference to `kernel_subsys'
fs/built-in.o: In function `configfs_init':
/home/bunk/linux/kernel-2.6/linux-2.6.22-rc6-mm1/fs/configfs/mount.c:143: undefined reference to `kernel_subsys'
make[1]: *** [.tmp_vmlinux1] Error 1
<-- snip -->
Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Adrian Bunk [Fri, 6 Jul 2007 22:54:09 +0000 (00:54 +0200)]
include/linux/kallsyms.h must #include <linux/errno.h>
This patch fixes the following 2.6.22 regression with CONFIG_KALLSYMS=n:
<-- snip -->
...
CC arch/m32r/kernel/traps.o
In file included from /home/bunk/linux/kernel-2.6/linux-2.6.22-rc6-mm1/arch/m32r/kernel/traps.c:14:
/home/bunk/linux/kernel-2.6/linux-2.6.22-rc6-mm1/include/linux/kallsyms.h: In function 'lookup_symbol_name':
/home/bunk/linux/kernel-2.6/linux-2.6.22-rc6-mm1/include/linux/kallsyms.h:66: error: 'ERANGE' undeclared (first use in this function)
/home/bunk/linux/kernel-2.6/linux-2.6.22-rc6-mm1/include/linux/kallsyms.h:66: error: (Each undeclared identifier is reported only once
/home/bunk/linux/kernel-2.6/linux-2.6.22-rc6-mm1/include/linux/kallsyms.h:66: error: for each function it appears in.)
/home/bunk/linux/kernel-2.6/linux-2.6.22-rc6-mm1/include/linux/kallsyms.h: In function 'lookup_symbol_attrs':
/home/bunk/linux/kernel-2.6/linux-2.6.22-rc6-mm1/include/linux/kallsyms.h:71: error: 'ERANGE' undeclared (first use in this function)
make[2]: *** [arch/m32r/kernel/traps.o] Error 1
<-- snip -->
Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Woodhouse [Sat, 7 Jul 2007 18:58:39 +0000 (14:58 -0400)]
Fix use-after-free oops in Bluetooth HID.
When cleaning up HIDP sessions, we currently close the ACL connection
before deregistering the input device. Closing the ACL connection
schedules a workqueue to remove the associated objects from sysfs, but
the input device still refers to them -- and if the workqueue happens to
run before the input device removal, the kernel will oops when trying to
look up PHYSDEVPATH for the removed input device.
Fix this by deregistering the input device before closing the
connections.
Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
* 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6:
[NETPOLL]: Fixups for 'fix soft lockup when removing module'
[NET]: net/core/netevent.c should #include <net/netevent.h>
[NETFILTER]: nf_conntrack_h323: add checking of out-of-range on choices' index values
[NET] skbuff: remove export of static symbol
SCTP: Add scope_id validation for link-local binds
SCTP: Check to make sure file is valid before setting timeout
SCTP: Fix thinko in sctp_copy_laddrs()
He correctly updated many of the function definitions that were using this
extra regs pointer parameter but forgot to update some caller sites of
those functions. The reason the modifications was not properly done on all
drivers is that some drivers were rarely compiled because they are for
AMIGA, or that some code sites were inside #ifdefs where the option is not
set or inside #if 0.
Here is the semantic patch that found the occurences
and fixed the problem.
arch/i386/kernel/built-in.o(.init.text+0x4fa9): In function `acpi_parse_madt':
: undefined reference to `acpi_madt_oem_check'
arch/i386/kernel/built-in.o(.init.text+0x7406): In function `smp_read_mpc':
: undefined reference to `mps_oem_check'
arch/i386/kernel/built-in.o(.init.text+0x8990): In function
`connect_bsp_APIC':
: undefined reference to `enable_apic_mode'
make: *** [.tmp_vmlinux1] Error 1
o Fix the build issue. Provided the definitions of missing functions.
o Don't have ES7000 machine. Only compile tested.
Cc: Len Brown <lenb@kernel.org> Cc: Natalie Protasevich <protasnb@gmail.com> Cc: Roland Dreier <rolandd@cisco.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
PNP SMCf010 quirk: work around Toshiba Portege 4000 ACPI issues
When we enable the SMCf010 IR device, the Toshiba Portege 4000 BIOS claims
the device is working, but it really isn't configured correctly. The BIOS
*will* configure it, but only if we call _SRS after (1) reversing the order
of the SIR and FIR I/O port regions and (2) changing the IRQ from
active-high to active-low.
This patch addresses the 2.6.22 regression:
"no irda0 interface (2.6.21 was OK), smsc does not find chip"
I tested this on a Portege 4000. The smsc-ircc2 driver correctly detects
the device, and "irattach irda0 -s && irdadump" shows transmitted and
received packets.
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Andrey Borzenkov <arvidjaar@mail.ru> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: "Linus Walleij (LD/EAB)" <linus.walleij@ericsson.com> Cc: Michal Piotrowski <michal.k.k.piotrowski@gmail.com> Cc: Adam Belay <ambx1@neo.rr.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Woodhouse [Fri, 6 Jul 2007 09:39:52 +0000 (02:39 -0700)]
x86_64: fix headers_install
A bug in headers_install for ARCH=x86_64 yields an asm/ directory full of
files all of which are using the same #ifdef guard, "__ASM_STUB_" with no
postfix. So the second and later asm files #included in the same C file
(often through standard headers like ioctl.h) yields no symbols.
Strangeness with the Ubuntu 'tell me if I support something that's not
explcitly mentioned in POSIX, and I'll strip it out' shell, I believe.
We don't need the 'export' but we do need a semicolon at the end of the
FNAME line:
Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Rob Landley <rob@landley.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
MTRR: Fix race causing set_mtrr to go into infinite loop
Processors synchronization in set_mtrr requires the .gate field to be set
after .count field is properly initialized. Without an explicit barrier,
the compiler was reordering those memory stores. That was sometimes
causing a processor (in ipi_handler) to see the .gate change and decrement
.count before the latter is set by set_mtrr() (which then hangs in a
infinite loop with irqs disabled).
Jason Wessel [Fri, 6 Jul 2007 09:39:50 +0000 (02:39 -0700)]
i386: fix regression, endless loop in ptrace singlestep over an int80
The commit 635cf99a80f4ebee59d70eb64bb85ce829e4591f introduced a
regression. Executing a ptrace single step after certain int80
accesses will infinitely loop and never advance the PC.
The TIF_SINGLESTEP check should be done on the return from the syscall
and not before it.
I loops on each single step on the pop right after the int80 which writes out
to the console. At that point you can issue as many single steps as you want
and it will not advance any further.
The test case is below:
/* Test whether singlestep through an int80 syscall works.
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <asm/user.h>
#include <string.h>
static int child, status;
static struct user_regs_struct regs;
Fix elf_core_dump() when writing arch specific notes (spu coredumps)
elf_core_dump() supports dumping arch specific ELF notes, via the #define
ELF_CORE_WRITE_EXTRA_NOTES. Currently the only user of this is the powerpc
spu coredump code.
There is a bug in the handling of foffset WRT the arch notes, which causes
us to erroneously increment foffset by the size of the arch notes, leaving
a block of zeroes in the file, and causing all subsequent data in the file
to be at <supposed position> + <arch note size>. eg:
LOAD 0x050000 0x00100000 0x00000000 0x20000 0x20000 R E 0x10000
Tells us we should have a chunk of data at 0x50000. The truth is the data
is at 0x90dbc = 0x50000 + 0x40dbc (the size of the arch notes).
This bug prevents gdb from reading the core file correctly.
The simplest fix is to simply remember the size of the arch notes, and add
it to foffset after we've written the arch notes. The only drawback is
that if the arch code doesn't write as many bytes as it said it would, we
end up with a broken core dump again. For now I think that's a reasonable
requirement.
Tested on a Cell blade, gdb no longer complains about the core file being
bogus.
While I'm here I should point out that the spu coredump code does not work
if we're dumping to a pipe - we'll have to wait for 23 to fix that.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Acked-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ralf Baechle [Wed, 20 Jun 2007 23:22:34 +0000 (00:22 +0100)]
[MIPS] Fix scheduling latency issue on 24K, 34K and 74K cores
The idle loop goes to sleep using the WAIT instruction if !need_resched().
This has is suffering from from a race condition that if if just after
need_resched has returned 0 an interrupt might set TIF_NEED_RESCHED but
we've just completed the test so go to sleep anyway. This would be
trivial to fix by just disabling interrupts during that sequence as in:
local_irq_disable();
if (!need_resched())
__asm__("wait");
local_irq_enable();
but the processor architecture leaves it undefined if a processor calling
WAIT with interrupts disabled will ever restart its pipeline and indeed
some processors have made use of the freedom provided by the architecture
definition. This has been resolved and the Config7.WII bit indicates that
the use of WAIT is safe on 24K, 24KE and 34K cores. It also is safe on
74K starting revision 2.1.0 so enable the use of WAIT with interrupts
disabled for 74K based on a c0_prid of at least that.
Older processors used to encode processor version and revision in two
4-bit bitfields, the 4K seems to simply count up and even newer MTI cores
have switched to use the 8-bits as 3:3:2 bitfield with the last field as
the patch number.
The RM7000 processors and the E9000 cores have a bug (though PMC-Sierra
opposes it being called that) where invalid instructions in the same
I-cache line worth of instructions being fetched may case spurious
exceptions.
The workaround for this was only enabled for E9000 cores; enable it also
for all RM7000-based platforms.
[NETPOLL]: Fixups for 'fix soft lockup when removing module'
>From my recent patch:
> > #1
> > Until kernel ver. 2.6.21 (including) cancel_rearming_delayed_work()
> > required a work function should always (unconditionally) rearm with
> > delay > 0 - otherwise it would endlessly loop. This patch replaces
> > this function with cancel_delayed_work(). Later kernel versions don't
> > require this, so here it's only for uniformity.
But Oleg Nesterov <oleg@tv-sign.ru> found:
> But 2.6.22 doesn't need this change, why it was merged?
>
> In fact, I suspect this change adds a race,
...
His description was right (thanks), so this patch reverts #1.
Signed-off-by: Jarek Poplawski <jarkao2@o2.pl> Signed-off-by: David S. Miller <davem@davemloft.net>
[NETFILTER]: nf_conntrack_h323: add checking of out-of-range on choices' index values
Choices' index values may be out of range while still encoded in the fixed
length bit-field. This bug may cause access to undefined types (NULL
pointers) and thus crashes (Reported by Zhongling Wen).
This patch also adds checking of decode flag when decoding SEQUENCEs.
Signed-off-by: Jing Min Zhao <zhaojingmin@vivecode.com> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
SCTP: Add scope_id validation for link-local binds
SCTP currently permits users to bind to link-local addresses,
but doesn't verify that the scope id specified at bind matches
the interface that the address is configured on. It was report
that this can hang a system.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
SCTP: Check to make sure file is valid before setting timeout
In-kernel sockets created with sock_create_kern don't usually
have a file and file descriptor allocated to them. As a result,
when SCTP tries to check the non-blocking flag, we Oops when
dereferencing a NULL file pointer.
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* master.kernel.org:/home/rmk/linux-2.6-arm:
[ARM] always allow dump_stack() to produce a backtrace
[ARM] Fix non-page aligned boot time mappings
[ARM] 4458/1: pxa: Fix CKEN usage and hence fix pxa suspend/resume
[ARM] 4454/1: Use word accesses in Versatile PCI config reads
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: document some of keycodes
Input: add a new EV_SW SW_RADIO event, for radio switches on laptops
Input: serio - take drv_mutex in serio_cleanup()
Input: atkbd - use printk_ratelimit for spurious ACK messages
Input: atkbd - throttle LED switching
Input: i8042 - add HP Pavilion ZT1000 to the MUX blacklist
Merge branch 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc:
[POWERPC] Update defconfigs
[POWERPC] Uninline and export virq_to_hw() for the pasemi_mac driver
[POWERPC] Fix PMI breakage in cbe_cbufreq driver
[POWERPC] Disable old EMAC driver in arch/powerpc
David Woodhouse [Thu, 5 Jul 2007 01:26:44 +0000 (21:26 -0400)]
Fix slab redzone alignment
Commit b46b8f19c9cd435ecac4d9d12b39d78c137ecd66 fixed a couple of bugs
by switching the redzone to 64 bits. Unfortunately, it neglected to
ensure that the _second_ redzone, after the slab object, is aligned
correctly. This caused illegal instruction faults on sparc32, which for
some reason not entirely clear to me are not trapped and fixed up.
Two things need to be done to fix this:
- increase the object size, rounding up to alignof(long long) so
that the second redzone can be aligned correctly.
- If SLAB_STORE_USER is set but alignof(long long)==8, allow a
full 64 bits of space for the user word at the end of the buffer,
even though we may not _use_ the whole 64 bits.
This patch should be a no-op on any 64-bit architecture or any 32-bit
architecture where alignof(long long) == 4. Of the others, it's tested
on ppc32 by myself and a very similar patch was tested on sparc32 by
Mark Fortescue, who reported the new problem.
Also, fix the conditions for FORCED_DEBUG, which hadn't been adjusted to
the new sizes. Again noticed by Mark.
Signed-off-by: David Woodhouse <dwmw2@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Yeah, we could have just disabled it, but there's work on a new one that
isn't as fundamentally broken, so there really doesn't seem to be any
point in keeping it around.
The recent timer cleanup broke the only valid use, and when I say
"valid", I obviously mean "totally broken". So it's not like it works,
or really even can work in the current format that uses the unsafe
"panic" LED blinking routines..
Russell King [Wed, 4 Jul 2007 20:16:33 +0000 (21:16 +0100)]
[ARM] Fix non-page aligned boot time mappings
AT91SAM9260 stopped booting with the recent changes to MM
initialisation - it was asking for a non-aligned virtual address
which caused loops to be non-terminal. Fix this by rounding
virtual addresses down, but remember to include the offset in
the length, and round the length up to the following page.
This means that asking for a mapping of 4K starting at 2K into
a page maps two pages as one would expect.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
projects / linux-2.6 / log