The problem is that when we write to a file, the copy from userspace to
pagecache is first done with preemption disabled, so if the source address is
not immediately available the copy fails *and* *zeros* *the* *destination*.

This is a problem because a concurrent read (which admittedly is an odd thing
to do) might see zeros rather that was there before the write, or what was
there after, or some mixture of the two (any of these being a reasonable thing
to see).

If the copy did fail, it will immediately be retried with preemption
re-enabled so any transient problem with accessing the source won't cause an
error.

The first copying does not need to zero any uncopied bytes, and doing so
causes the problem.  It uses copy_from_user_atomic rather than copy_from_user
so the simple expedient is to change copy_from_user_atomic to *not* zero out
bytes on failure.

The first of these two patches prepares for the change by fixing two places
which assume copy_from_user_atomic does zero the tail.  The two usages are
very similar pieces of code which copy from a userspace iovec into one or more
page-cache pages.  These are changed to remove the assumption.

The second patch changes __copy_from_user_inatomic* to not zero the tail.
Once these are accepted, I will look at similar patches of other architectures
where this is important (ppc, mips and sparc being the ones I can find).

This patch:

There is a problem with __copy_from_user_inatomic zeroing the tail of the
buffer in the case of an error.  As it is called in atomic context, the error
may be transient, so it results in zeros being written where maybe they
shouldn't be.

In the usage in filemap, this opens a window for a well timed read to see data
(zeros) which is not consistent with any ordering of reads and writes.

Most cases where __copy_from_user_inatomic is called, a failure results in
__copy_from_user being called immediately.  As long as the latter zeros the
tail, the former doesn't need to.  However in *copy_from_user_iovec
implementations (in both filemap and ntfs/file), it is assumed that
copy_from_user_inatomic will zero the tail.

This patch removes that assumption, so that after this patch it will
be safe for copy_from_user_inatomic to not zero the tail.

This patch also adds some commentary to filemap.h and asm-i386/uaccess.h.

After this patch, all architectures that might disable preempt when
kmap_atomic is called need to have their __copy_from_user_inatomic* "fixed".
This includes
 - powerpc
 - i386
 - mips
 - sparc
Signed-off-by: NNeil Brown <neilb@suse.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Anton Altaparmakov <aia21@cantab.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

constify a medium-large CRC code table.
Signed-off-by: NAndreas Mohr <andi@lisas.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NAndreas Mohr <andi@lisas.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This is redundant with check in wakeup_kswapd.
Signed-off-by: NChris Wright <chrisw@sous-sol.org>
Acked-by: NPaul Jackson <pj@sgi.com>
Acked-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Cc: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Do a *partial* CodingStyle cleanup, correct some spelling in printk()'s &&
convert C++ comments to C comments - in moxa driver.
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Remove pointless check of 'tty' argument vs NULL from moxa driver.
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>
Acked-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This was reported as Debian bug #336604.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The variable i is guaranteed to be the same as db_count given the previous
for loop.  So get rid of it since it's dead code.
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

If ext3 filesystem is larger than 2TB, and sector_t is a u32 (i.e.
CONFIG_LBD not defined in the kernel), the calculation of the disk sector
will overflow.  Add check at ext3_fill_super() and ext3_group_extend() to
prevent mount/remount/resize >2TB ext3 filesystem if sector_t size is 4
bytes.

Verified this patch on a 32 bit platform without CONFIG_LBD defined
(sector_t is 32 bits long), mount refuse to mount a 10TB ext3.

Signed-off-by: Mingming Cao<cmm@us.ibm.com>
Acked-by: NAndreas Dilger <adilger@clusterfs.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

schedule_on_each_cpu() presently does a large kmalloc - 96 kbytes on 1024 CPU
64-bit.

Rework it so that we do one 8192-byte allocation and then a pile of tiny ones,
via alloc_percpu().  This has a much higher chance of success (100% in the
current VM).

This also has the effect of reducing the memory requirements from NR_CPUS*n to
num_possible_cpus()*n.

Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Fix indentation.
Quote a brace '{' so that vi won't be fooled by it.
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Drop leading space of kernel-doc section contents.

"Section" data (contents) are split from the section header
(e.g., Note: below is a section header:
 * Note: list_empty on entry does not return true after this, the entry is
 * in an undefined state.
).

Currently the data/contents begins with a space and is left that way, which
causes it to look bad when printed (in text mode; see example below), so
just remove the leading space.

Note:

list_empty on entry does not return true after this, the entry is in an
undefined state.
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Lots of people use this.  Apparently RH has for over 18 months so lets
drop EXPERIMENTAL.
Signed-off-by: NChris Wedgwood <cw@f00f.org>
Cc: Matt Domsch <Matt_Domsch@dell.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

pdflush is carefully designed to ensure that all wakeups have some
corresponding work to do - if a woken-up pdflush thread discovers that it
hasn't been given any work to do then this is considered an error.

That all broke when swsusp came along - because a timer-delivered wakeup to a
frozen pdflush thread will just get lost.  This causes the pdflush thread to
get lost as well: the writeback timer is supposed to be re-armed by pdflush in
process context, but pdflush doesn't execute the callout which does this.

Fix that up by ignoring the return value from try_to_freeze(): jsut proceed,
see if we have any work pending and only go back to sleep if that is not the
case.
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

WARNING: drivers/block/cpqarray.o - Section mismatch: reference to .init.text: from .text between 'cpqarray_register_ctlr' (at offset 0xe98) and 'alloc_cpqarray_hba'
WARNING: drivers/block/cpqarray.o - Section mismatch: reference to .init.text: from .text between 'cpqarray_register_ctlr' (at offset 0xe9c) and 'alloc_cpqarray_hba'
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This is a patch from Alan that fixes a real ide-cd.c regression causing
bogus "Media Check" failures for perfectly valid Fedora install ISOs, on
certain CD-ROM drives.

This is a forward port to 2.6.16 (from RHEL) of the minimal changes for the
end of media problem.  It may not be sufficient for some controllers
(promise notably) and it does not touch the locking so the error path
locking is as horked as in mainstream.

From: Ingo Molnar <mingo@elte.hu>

I have ported the patch to 2.6.17-rc4 and tested it by provoking
end-of-media IO errors with an unaligned ISO image.  Unlike the vanilla
kernel, the patched kernel interpreted the error condition correctly with
512 byte granularity:

 hdc: command error: status=0x51 { DriveReady SeekComplete Error }
 hdc: command error: error=0x54 { AbortedCommand LastFailedSense=0x05 }
 ide: failed opcode was: unknown
 ATAPI device hdc:
   Error: Illegal request -- (Sense key=0x05)
   Illegal mode for this track or incompatible medium -- (asc=0x64, ascq=0x00)
   The failed "Read 10" packet command was:
   "28 00 00 04 fb 78 00 00 06 00 00 00 00 00 00 00 "
 end_request: I/O error, dev hdc, sector 1306080
 Buffer I/O error on device hdc, logical block 163260
 Buffer I/O error on device hdc, logical block 163261
 Buffer I/O error on device hdc, logical block 163262

the unpatched kernel produces an incorrect error dump:

 hdc: command error: status=0x51 { DriveReady SeekComplete Error }
 hdc: command error: error=0x54 { AbortedCommand LastFailedSense=0x05 }
 ide: failed opcode was: unknown
 end_request: I/O error, dev hdc, sector 1306080
 Buffer I/O error on device hdc, logical block 163260
 hdc: command error: status=0x51 { DriveReady SeekComplete Error }
 hdc: command error: error=0x54 { AbortedCommand LastFailedSense=0x05 }
 ide: failed opcode was: unknown
 end_request: I/O error, dev hdc, sector 1306088
 Buffer I/O error on device hdc, logical block 163261
 hdc: command error: status=0x51 { DriveReady SeekComplete Error }
 hdc: command error: error=0x54 { AbortedCommand LastFailedSense=0x05 }
 ide: failed opcode was: unknown
 end_request: I/O error, dev hdc, sector 1306096
 Buffer I/O error on device hdc, logical block 163262

I do not have the right type of CD-ROM drive to reproduce the end-of-media
data corruption bug myself, but this same patch in RHEL solved it.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
Cc: Jens Axboe <axboe@suse.de>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Use loop "cursor" instead of loop "counter" for list iterator descriptions.
They are not counters, they are pointers or positions.
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

kernel-doc:

Put all short function descriptions on one line or if they are too long,
omit the short description & add a Description: section for them.

Change some list iterator descriptions to use "current" point instead of
"existing" point.
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

nbd abuses file header as a changelog (and obsolete one, too), and fails to
mention GPL.  This fixes it.
Signed-off-by: NPavel Machek <pavel@suse.cz>
Cc: <Paul.Clements@steeleye.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

- proper prototypes for the following functions:
  - ctrl_alt_del()  (in include/linux/reboot.h)
  - getrusage()     (in include/linux/resource.h)
- make the following needlessly global functions static:
  - kernel_restart_prepare()
  - kernel_kexec()

[akpm@osdl.org: compile fix]
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Currently printk is no use for early debugging because it refuses to
actually print anything to the console unless
cpu_online(smp_processor_id()) is true.

The stated explanation is that console drivers may require per-cpu
resources, or otherwise barf, because the system is not yet setup
correctly.  Fair enough.

However some console drivers might be quite happy running early during
boot, in fact we have one, and so it'd be nice if printk understood that.

So I added a flag (which I would have called CON_BOOT, but that's taken)
called CON_ANYTIME, which indicates that a console is happy to be called
anytime, even if the cpu is not yet online.

Tested on a Power 5 machine, with both a CON_ANYTIME driver and a bogus
console driver that BUG()s if called while offline.  No problems AFAICT.
Built for i386 UP & SMP.
Signed-off-by: NMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add a driver for the ARM PL031 RTC found on some ARM SOCs.  The driver is
fairly trivial as the RTC only provides a read/write and alarm capability.

[akpm@osdl.org: compile fix]
Signed-off-by: NDeepak <dsaxena@plexity.net>
Acked-by: NAlessandro Zummo <a.zummo@towertech.it>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

In both the read and write cases it will return an error if
copy_{from/to}_user faults.  However, I let the driver try to read/write as
much as it can just as it normally would , then finally it returns an error
if there was one.  This was the most straight forward way to handle the
error , since there isn't a clear way to clean up the buffers on error .

I moved retval in idetape_chrdev_write() down into the actual code blocks
since it's really once used there, and it conflicted with my ret variable.

Fixes the following warning,

drivers/ide/ide-tape.c: In function ‘idetape_copy_stage_from_user’:
drivers/ide/ide-tape.c:2662: warning: ignoring return value of ‘copy_from_user’, declared with attribute warn_unused_result
drivers/ide/ide-tape.c: In function ‘idetape_copy_stage_to_user’:
drivers/ide/ide-tape.c:2689: warning: ignoring return value of ‘copy_to_user’, declared with attribute warn_unused_result
Signed-off-by: NDaniel Walker <dwalker@mvista.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Bartlomiej Zolnierkiewicz <B.Zolnierkiewicz@elka.pw.edu.pl>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

"Move" "common code" out to PTR_NOD, which does the conversion from private
pointer to node number.  This is to reduce potential casting/conversion errors
due to redundancy.  (The naming PTR_NOD follows PTR_ERR, turning a pointer
into xyz.)

[akpm@osdl.org: cleanups]
Signed-off-by: NJan Engelhardt <jengelh@gmx.de>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Remove unnecessary casts in fs/openpromfs/inode.c
Signed-off-by: NJan Engelhardt <jengelh@gmx.de>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

tchars is not '\0'-terminated so the strtoul may run into problems.  Fix that.
 Also make tchars as big as a long in hexadecimal form would take rather than
just 16.
Signed-off-by: NJan Engelhardt <jengelh@gmx.de>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Convert the driver to use module_{init,exit}.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Acked-by: NDavid Woodhouse <dwmw2@infradead.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Cc: Philippe Elie <phil.el@wanadoo.fr>
Cc: John Levon <levon@movementarian.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

WARNING: sound/oss/msnd.o - Section mismatch: reference to .init.text:msnd_register from __ksymtab between '__ksymtab_msnd_register' (at offset 0x0) and '__ksymtab_msnd_unregister'

This symbol is exported.  It'll oops if the driver is nonmodular and the
caller is modular.
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Make two needlessly global functions static.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

In ufs code there is function: ubh_ll_rw_block, it has parameter how many
ufs_buffer_head it should handle, but it always called with "1" on the place
of this parameter.  This patch removes unused parameter of "ubh_ll_wr_block".
Signed-off-by: NEvgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

ufs super block contains some statistic about file systems, like amount of
directories, free blocks, inodes and so on.

UFS1 hold this information in one location and uses 32bit integers for such
information, UFS2 hold statistic in another location and uses 64bit integers.

There is transition variant, if UFS1 has type 44BSD and flags field in super
block has some special value this mean that we work with statistic like UFS2
does.  and this also means that nobody care about old(UFS1) statistic.

So if start fsck against such file system, after usage linux ufs driver, it
found error: at now only UFS1 like statistic is updated.

This patch should fix this.  Also it contains some minor cleanup: CodingSytle
and remove unused variables.
Signed-off-by: NEvgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Presently ufs doesn't support "fsync", this make some applications unhappy,
for example vim.  This patch fixes this situation.
Signed-off-by: NEvgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Super block of UFS usually has size >512, because of fragment size may be 512,
this cause some problems.

Currently, there are two methods to work with ufs super block:

1) split structure which describes ufs super blocks into structures with
   size <=512

2) use one structure which describes ufs super block, and hope that array
   of "buffer_head" which holds "super block", has such construction:

	bh[n]->b_data + bh[n]->b_size == bh[n + 1]->b_data

The second variant may cause some problems in the future, and usage of two
variants cause unnecessary code duplication.

This patch remove the second variant.  Also patch contains some CodingStyle
fixes.
Signed-off-by: NEvgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch fixes two bugs, which introduced by previous patches:

1) Missed "brelse"

2) Sometimes "baseblk" may be wrongly calculated, if i_size is equal to
   zero, which lead infinite cycle in "mpage_writepages".
Signed-off-by: NEvgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

fs/ufs/super.c: In function `ufs_print_super_stuff':
fs/ufs/super.c:103: warning: unsigned int format, different type arg (arg 2)    fs/ufs/super.c: In function `ufs2_print_super_stuff':                           fs/ufs/super.c:147: warning: unsigned int format, different type arg (arg 2)    fs/ufs/super.c: In function `ufs_print_cylinder_stuff':
fs/ufs/super.c:175: warning: unsigned int format, different type arg (arg 2)

Cc: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Presently if we allocate several "metadata" blocks (pointers to indirect
blocks for example), we fill with zeroes only the first block.  This cause
some problems in "truncate" function.  Also this patch remove some unused
arguments from several functions and add comments.
Signed-off-by: NEvgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>