A deadlock can occur when user space uses a signal (autofs version 4 uses
SIGCHLD for this) to effect expire completion.
The order of events is:
Expire process completes, but before being able to send SIGCHLD to it's parent
...
Another process walks onto a different mount point and drops the directory
inode semaphore prior to sending the request to the daemon as it must ...
A third process does an lstat on on the expired mount point causing it to wait
on expire completion (unfortunately) holding the directory semaphore.
The mount request then arrives at the daemon which does an lstat and,
deadlock.
For some time I was concerned about releasing the directory semaphore around
the expire wait in autofs4_lookup as well as for the mount call back. I
finally realized that the last round of changes in this function made the
expiring dentry and the lookup dentry separate and distinct so the check and
possible wait can be done anywhere prior to the mount call back. This patch
moves the check to just before the mount call back and inside the directory
inode mutex release.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A significant portion of the autofs_dev_ioctl_expire() and
autofs4_expire_multi() functions is duplicated code. This patch cleans that
up.
Signed-off-by: Ian Kent <raven@themaw.net>
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=12843
"I use ramfs instead of tmpfs for /tmp because I don't use swap on my
laptop. Some apps need 1777 mode for /tmp directory, but ramfs does not
support 'mode=' mount option."
Reported-by: Avan Anishchuk <matimatik@gmail.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Introduce keyed event wakeups inside the eventfd code.
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: William Lee Irwin III <wli@movementarian.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use the events hint now sent by some devices, to avoid unnecessary wakeups
for events that are of no interest for the caller. This code handles both
devices that are sending keyed events, and the ones that are not (and
event the ones that sometimes send events, and sometimes don't).
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: William Lee Irwin III <wli@movementarian.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
People started using eventfd in a semaphore-like way where before they
were using pipes.
That is, counter-based resource access. Where a "wait()" returns
immediately by decrementing the counter by one, if counter is greater than
zero. Otherwise will wait. And where a "post(count)" will add count to
the counter releasing the appropriate amount of waiters. If eventfd the
"post" (write) part is fine, while the "wait" (read) does not dequeue 1,
but the whole counter value.
The problem with eventfd is that a read() on the fd returns and wipes the
whole counter, making the use of it as semaphore a little bit more
cumbersome. You can do a read() followed by a write() of COUNTER-1, but
IMO it's pretty easy and cheap to make this work w/out extra steps. This
patch introduces a new eventfd flag that tells eventfd to only dequeue 1
from the counter, allowing simple read/write to make it behave like a
semaphore. Simple test here:
http://www.xmailserver.org/eventfd-sem.c
To be back-compatible with earlier kernels, userspace applications should
probe for the availability of this feature via
#ifdef EFD_SEMAPHORE
fd = eventfd2 (CNT, EFD_SEMAPHORE);
if (fd == -1 && errno == EINVAL)
<fallback>
#else
<fallback>
#endif
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: <linux-api@vger.kernel.org>
Tested-by: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: Ulrich Drepper <drepper@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
eventpoll.c uses void * in one place for no obvious reason; change it to
use the real type instead.
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ep_modify() doesn't need to set event.data from within the ep->lock
spinlock as the comment suggests. The only place event.data is used is
ep_send_events_proc(), and this is protected by ep->mtx instead of
ep->lock. Also update the comment for mutex_lock() at the top of
ep_scan_ready_list(), which mentions epoll_ctl(EPOLL_CTL_DEL) but not
epoll_ctl(EPOLL_CTL_MOD).
ep_modify() can also use spin_lock_irq() instead of spin_lock_irqsave().
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
xchg in ep_unregister_pollwait() is unnecessary because it is protected by
either epmutex or ep->mtx (the same protection as ep_remove()).
If xchg was necessary, it would be insufficient to protect against
problems: if multiple concurrent calls to ep_unregister_pollwait() were
possible then a second caller that returns without doing anything because
nwait == 0 could return before the waitqueues are removed by the first
caller, which looks like it could lead to problematic races with
ep_poll_callback().
So remove xchg and add comments about the locking.
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If epoll_wait returns -EFAULT, the event that was being returned when the
fault was encountered will be forgotten. This is not a big deal since
EFAULT will happen only if a buggy userspace program passes in a bad
address, in which case what happens later usually doesn't matter.
However, it is easy to remember the event for later, and this patch makes
a simple change to do that.
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ep_call_nested() (formerly ep_poll_safewake()) uses "current" (without
dereferencing it) to detect callback recursion, but it may be called from
irq context where the use of current is generally discouraged. It would
be better to use get_cpu() and put_cpu() to detect the callback recursion.
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove debugging code from epoll. There's no need for it to be included
into mainline code.
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix a bug inside the epoll's f_op->poll() code, that returns POLLIN even
though there are no actual ready monitored fds. The bug shows up if you
add an epoll fd inside another fd container (poll, select, epoll).
The problem is that callback-based wake ups used by epoll does not carry
(patches will follow, to fix this) any information about the events that
actually happened. So the callback code, since it can't call the file*
->poll() inside the callback, chains the file* into a ready-list.
So, suppose you added an fd with EPOLLOUT only, and some data shows up on
the fd, the file* mapped by the fd will be added into the ready-list (via
wakeup callback). During normal epoll_wait() use, this condition is
sorted out at the time we're actually able to call the file*'s
f_op->poll().
Inside the old epoll's f_op->poll() though, only a quick check
!list_empty(ready-list) was performed, and this could have led to
reporting POLLIN even though no ready fds would show up at a following
epoll_wait(). In order to correctly report the ready status for an epoll
fd, the ready-list must be checked to see if any really available fd+event
would be ready in a following epoll_wait().
Operation (calling f_op->poll() from inside f_op->poll()) that, like wake
ups, must be handled with care because of the fact that epoll fds can be
added to other epoll fds.
Test code:
/*
* epoll_test by Davide Libenzi (Simple code to test epoll internals)
* Copyright (C) 2008 Davide Libenzi
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Davide Libenzi <davidel@xmailserver.org>
*
*/
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <limits.h>
#include <poll.h>
#include <sys/epoll.h>
#include <sys/wait.h>
#define EPWAIT_TIMEO (1 * 1000)
#ifndef POLLRDHUP
#define POLLRDHUP 0x2000
#endif
#define EPOLL_MAX_CHAIN 100L
#define EPOLL_TF_LOOP (1 << 0)
struct epoll_test_cfg {
long size;
long flags;
};
static int xepoll_create(int n) {
int epfd;
if ((epfd = epoll_create(n)) == -1) {
perror("epoll_create");
exit(2);
}
return epfd;
}
static void xepoll_ctl(int epfd, int cmd, int fd, struct epoll_event *evt) {
if (epoll_ctl(epfd, cmd, fd, evt) < 0) {
perror("epoll_ctl");
exit(3);
}
}
static void xpipe(int *fds) {
if (pipe(fds)) {
perror("pipe");
exit(4);
}
}
static pid_t xfork(void) {
pid_t pid;
if ((pid = fork()) == (pid_t) -1) {
perror("pipe");
exit(5);
}
return pid;
}
static int run_forked_proc(int (*proc)(void *), void *data) {
int status;
pid_t pid;
if ((pid = xfork()) == 0)
exit((*proc)(data));
if (waitpid(pid, &status, 0) != pid) {
perror("waitpid");
return -1;
}
return WIFEXITED(status) ? WEXITSTATUS(status): -2;
}
static int check_events(int fd, int timeo) {
struct pollfd pfd;
fprintf(stdout, "Checking events for fd %d\n", fd);
memset(&pfd, 0, sizeof(pfd));
pfd.fd = fd;
pfd.events = POLLIN | POLLOUT;
if (poll(&pfd, 1, timeo) < 0) {
perror("poll()");
return 0;
}
if (pfd.revents & POLLIN)
fprintf(stdout, "\tPOLLIN\n");
if (pfd.revents & POLLOUT)
fprintf(stdout, "\tPOLLOUT\n");
if (pfd.revents & POLLERR)
fprintf(stdout, "\tPOLLERR\n");
if (pfd.revents & POLLHUP)
fprintf(stdout, "\tPOLLHUP\n");
if (pfd.revents & POLLRDHUP)
fprintf(stdout, "\tPOLLRDHUP\n");
return pfd.revents;
}
static int epoll_test_tty(void *data) {
int epfd, ifd = fileno(stdin), res;
struct epoll_event evt;
if (check_events(ifd, 0) != POLLOUT) {
fprintf(stderr, "Something is cooking on STDIN (%d)\n", ifd);
return 1;
}
epfd = xepoll_create(1);
fprintf(stdout, "Created epoll fd (%d)\n", epfd);
memset(&evt, 0, sizeof(evt));
evt.events = EPOLLIN;
xepoll_ctl(epfd, EPOLL_CTL_ADD, ifd, &evt);
if (check_events(epfd, 0) & POLLIN) {
res = epoll_wait(epfd, &evt, 1, 0);
if (res == 0) {
fprintf(stderr, "Epoll fd (%d) is ready when it shouldn't!\n",
epfd);
return 2;
}
}
return 0;
}
static int epoll_wakeup_chain(void *data) {
struct epoll_test_cfg *tcfg = data;
int i, res, epfd, bfd, nfd, pfds[2];
pid_t pid;
struct epoll_event evt;
memset(&evt, 0, sizeof(evt));
evt.events = EPOLLIN;
epfd = bfd = xepoll_create(1);
for (i = 0; i < tcfg->size; i++) {
nfd = xepoll_create(1);
xepoll_ctl(bfd, EPOLL_CTL_ADD, nfd, &evt);
bfd = nfd;
}
xpipe(pfds);
if (tcfg->flags & EPOLL_TF_LOOP)
{
xepoll_ctl(bfd, EPOLL_CTL_ADD, epfd, &evt);
/*
* If we're testing for loop, we want that the wakeup
* triggered by the write to the pipe done in the child
* process, triggers a fake event. So we add the pipe
* read size with EPOLLOUT events. This will trigger
* an addition to the ready-list, but no real events
* will be there. The the epoll kernel code will proceed
* in calling f_op->poll() of the epfd, triggering the
* loop we want to test.
*/
evt.events = EPOLLOUT;
}
xepoll_ctl(bfd, EPOLL_CTL_ADD, pfds[0], &evt);
/*
* The pipe write must come after the poll(2) call inside
* check_events(). This tests the nested wakeup code in
* fs/eventpoll.c:ep_poll_safewake()
* By having the check_events() (hence poll(2)) happens first,
* we have poll wait queue filled up, and the write(2) in the
* child will trigger the wakeup chain.
*/
if ((pid = xfork()) == 0) {
sleep(1);
write(pfds[1], "w", 1);
exit(0);
}
res = check_events(epfd, 2000) & POLLIN;
if (waitpid(pid, NULL, 0) != pid) {
perror("waitpid");
return -1;
}
return res;
}
static int epoll_poll_chain(void *data) {
struct epoll_test_cfg *tcfg = data;
int i, res, epfd, bfd, nfd, pfds[2];
pid_t pid;
struct epoll_event evt;
memset(&evt, 0, sizeof(evt));
evt.events = EPOLLIN;
epfd = bfd = xepoll_create(1);
for (i = 0; i < tcfg->size; i++) {
nfd = xepoll_create(1);
xepoll_ctl(bfd, EPOLL_CTL_ADD, nfd, &evt);
bfd = nfd;
}
xpipe(pfds);
if (tcfg->flags & EPOLL_TF_LOOP)
{
xepoll_ctl(bfd, EPOLL_CTL_ADD, epfd, &evt);
/*
* If we're testing for loop, we want that the wakeup
* triggered by the write to the pipe done in the child
* process, triggers a fake event. So we add the pipe
* read size with EPOLLOUT events. This will trigger
* an addition to the ready-list, but no real events
* will be there. The the epoll kernel code will proceed
* in calling f_op->poll() of the epfd, triggering the
* loop we want to test.
*/
evt.events = EPOLLOUT;
}
xepoll_ctl(bfd, EPOLL_CTL_ADD, pfds[0], &evt);
/*
* The pipe write mush come before the poll(2) call inside
* check_events(). This tests the nested f_op->poll calls code in
* fs/eventpoll.c:ep_eventpoll_poll()
* By having the pipe write(2) happen first, we make the kernel
* epoll code to load the ready lists, and the following poll(2)
* done inside check_events() will test nested poll code in
* ep_eventpoll_poll().
*/
if ((pid = xfork()) == 0) {
write(pfds[1], "w", 1);
exit(0);
}
sleep(1);
res = check_events(epfd, 1000) & POLLIN;
if (waitpid(pid, NULL, 0) != pid) {
perror("waitpid");
return -1;
}
return res;
}
int main(int ac, char **av) {
int error;
struct epoll_test_cfg tcfg;
fprintf(stdout, "\n********** Testing TTY events\n");
error = run_forked_proc(epoll_test_tty, NULL);
fprintf(stdout, error == 0 ?
"********** OK\n": "********** FAIL (%d)\n", error);
tcfg.size = 3;
tcfg.flags = 0;
fprintf(stdout, "\n********** Testing short wakeup chain\n");
error = run_forked_proc(epoll_wakeup_chain, &tcfg);
fprintf(stdout, error == POLLIN ?
"********** OK\n": "********** FAIL (%d)\n", error);
tcfg.size = EPOLL_MAX_CHAIN;
tcfg.flags = 0;
fprintf(stdout, "\n********** Testing long wakeup chain (HOLD ON)\n");
error = run_forked_proc(epoll_wakeup_chain, &tcfg);
fprintf(stdout, error == 0 ?
"********** OK\n": "********** FAIL (%d)\n", error);
tcfg.size = 3;
tcfg.flags = 0;
fprintf(stdout, "\n********** Testing short poll chain\n");
error = run_forked_proc(epoll_poll_chain, &tcfg);
fprintf(stdout, error == POLLIN ?
"********** OK\n": "********** FAIL (%d)\n", error);
tcfg.size = EPOLL_MAX_CHAIN;
tcfg.flags = 0;
fprintf(stdout, "\n********** Testing long poll chain (HOLD ON)\n");
error = run_forked_proc(epoll_poll_chain, &tcfg);
fprintf(stdout, error == 0 ?
"********** OK\n": "********** FAIL (%d)\n", error);
tcfg.size = 3;
tcfg.flags = EPOLL_TF_LOOP;
fprintf(stdout, "\n********** Testing loopy wakeup chain (HOLD ON)\n");
error = run_forked_proc(epoll_wakeup_chain, &tcfg);
fprintf(stdout, error == 0 ?
"********** OK\n": "********** FAIL (%d)\n", error);
tcfg.size = 3;
tcfg.flags = EPOLL_TF_LOOP;
fprintf(stdout, "\n********** Testing loopy poll chain (HOLD ON)\n");
error = run_forked_proc(epoll_poll_chain, &tcfg);
fprintf(stdout, error == 0 ?
"********** OK\n": "********** FAIL (%d)\n", error);
return 0;
}
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The base versions handle constant folding now and are shorter than these
private wrappers, use them directly.
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Anton Altaparmakov <aia21@cantab.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that the filesystem freeze operation has been elevated to the VFS, and
is just an ioctl away, some sort of safety net for unintentionally frozen
root filesystems may be in order.
The timeout thaw originally proposed did not get merged, but perhaps
something like this would be useful in emergencies.
For example, freeze /path/to/mountpoint may freeze your root filesystem if
you forgot that you had that unmounted.
I chose 'j' as the last remaining character other than 'h' which is sort
of reserved for help (because help is generated on any unknown character).
I've tested this on a non-root fs with multiple (nested) freezers, as well
as on a system rendered unresponsive due to a frozen root fs.
[randy.dunlap@oracle.com: emergency thaw only if CONFIG_BLOCK enabled]
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Cc: Takashi Sato <t-sato@yk.jp.nec.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
try_to_free_pages() is used for the direct reclaim of up to
SWAP_CLUSTER_MAX pages when watermarks are low. The caller to
alloc_pages_nodemask() can specify a nodemask of nodes that are allowed to
be used but this is not passed to try_to_free_pages(). This can lead to
unnecessary reclaim of pages that are unusable by the caller and int the
worst case lead to allocation failure as progress was not been make where
it is needed.
This patch passes the nodemask used for alloc_pages_nodemask() to
try_to_free_pages().
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Instead of open-coding the lru-list-add pagevec batching when expanding a
file mapping from zero, defer to the appropriate page cache function that
also takes care of adding the page to the lru list.
This is cleaner, saves code and reduces the stack footprint by 16 words
worth of pagevec.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.com>
Cc: MinChan Kim <minchan.kim@gmail.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: Greg Ungerer <gerg@snapgear.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix warnings and return values in sysfs bin_page_mkwrite(), fixing
fs/sysfs/bin.c: In function `bin_page_mkwrite':
fs/sysfs/bin.c:250: warning: passing argument 2 of `bb->vm_ops->page_mkwrite' from incompatible pointer type
fs/sysfs/bin.c: At top level:
fs/sysfs/bin.c:280: warning: initialization from incompatible pointer type
Expects to have my [PATCH next] sysfs: fix some bin_vm_ops errors
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: "Eric W. Biederman" <ebiederm@aristanetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
page_mkwrite is called with neither the page lock nor the ptl held. This
means a page can be concurrently truncated or invalidated out from
underneath it. Callers are supposed to prevent truncate races themselves,
however previously the only thing they can do in case they hit one is to
raise a SIGBUS. A sigbus is wrong for the case that the page has been
invalidated or truncated within i_size (eg. hole punched). Callers may
also have to perform memory allocations in this path, where again, SIGBUS
would be wrong.
The previous patch ("mm: page_mkwrite change prototype to match fault")
made it possible to properly specify errors. Convert the generic buffer.c
code and btrfs to return sane error values (in the case of page removed
from pagecache, VM_FAULT_NOPAGE will cause the fault handler to exit
without doing anything, and the fault will be retried properly).
This fixes core code, and converts btrfs as a template/example. All other
filesystems defining their own page_mkwrite should be fixed in a similar
manner.
Acked-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change the page_mkwrite prototype to take a struct vm_fault, and return
VM_FAULT_xxx flags. There should be no functional change.
This makes it possible to return much more detailed error information to
the VM (and also can provide more information eg. virtual_address to the
driver, which might be important in some special cases).
This is required for a subsequent fix. And will also make it easier to
merge page_mkwrite() with fault() in future.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Artem Bityutskiy <dedekind@infradead.org>
Cc: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Allow non root users with sufficient mlock rlimits to be able to allocate
hugetlb backed shm for now. Deprecate this though. This is being
deprecated because the mlock based rlimit checks for SHM_HUGETLB is not
consistent with mmap based huge page allocations.
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Reviewed-by: Mel Gorman <mel@csn.ul.ie>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: Adam Litke <agl@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix hugetlb subsystem so that non root users belonging to
hugetlb_shm_group can actually allocate hugetlb backed shm.
Currently non root users cannot even map one large page using SHM_HUGETLB
when they belong to the gid in /proc/sys/vm/hugetlb_shm_group. This is
because allocation size is verified against RLIMIT_MEMLOCK resource limit
even if the user belongs to hugetlb_shm_group.
This patch
1. Fixes hugetlb subsystem so that users with CAP_IPC_LOCK and users
belonging to hugetlb_shm_group don't need to be restricted with
RLIMIT_MEMLOCK resource limits
2. This patch also disables mlock based rlimit checking (which will
be reinstated and marked deprecated in a subsequent patch).
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Reviewed-by: Mel Gorman <mel@csn.ul.ie>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: Adam Litke <agl@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a helper function account_page_dirtied(). Use that from two
callsites. reiser4 adds a function which adds a third callsite.
Signed-off-by: Edward Shishkin<edward.shishkin@gmail.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
struct tty_operations::proc_fops took it's place and there is one less
create_proc_read_entry() user now!
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Used for gradual switch of TTY drivers from using ->read_proc which helps
with gradual switch from ->read_proc for the whole tree.
As side effect, fix possible race condition when ->data initialized after
PDE is hooked into proc tree.
->proc_fops takes precedence over ->read_proc.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'proc-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/adobriyan/proc:
Revert "proc: revert /proc/uptime to ->read_proc hook"
proc 2/2: remove struct proc_dir_entry::owner
proc 1/2: do PDE usecounting even for ->read_proc, ->write_proc
proc: fix sparse warnings in pagemap_read()
proc: move fs/proc/inode-alloc.txt comment into a source file
Setting ->owner as done currently (pde->owner = THIS_MODULE) is racy
as correctly noted at bug #12454. Someone can lookup entry with NULL
->owner, thus not pinning enything, and release it later resulting
in module refcount underflow.
We can keep ->owner and supply it at registration time like ->proc_fops
and ->data.
But this leaves ->owner as easy-manipulative field (just one C assignment)
and somebody will forget to unpin previous/pin current module when
switching ->owner. ->proc_fops is declared as "const" which should give
some thoughts.
->read_proc/->write_proc were just fixed to not require ->owner for
protection.
rmmod'ed directories will be empty and return "." and ".." -- no harm.
And directories with tricky enough readdir and lookup shouldn't be modular.
We definitely don't want such modular code.
Removing ->owner will also make PDE smaller.
So, let's nuke it.
Kudos to Jeff Layton for reminding about this, let's say, oversight.
http://bugzilla.kernel.org/show_bug.cgi?id=12454
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
struct proc_dir_entry::owner is going to be removed. Now it's only necessary
to protect PDEs which are using ->read_proc, ->write_proc hooks.
However, ->owner assignments are racy and make it very easy for someone to switch
->owner on live PDE (as some subsystems do) without fixing refcounts and so on.
http://bugzilla.kernel.org/show_bug.cgi?id=12454
So, ->owner is on death row.
Proxy file operations exist already (proc_file_operations), just bump usecount
when necessary.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
fs/proc/task_mmu.c:696:12: warning: cast removes address space of expression
fs/proc/task_mmu.c:696:9: warning: incorrect type in assignment (different address spaces)
fs/proc/task_mmu.c:696:9: expected unsigned long long [noderef] [usertype] <asn:1>*out
fs/proc/task_mmu.c:696:9: got unsigned long long [usertype] *<noident>
fs/proc/task_mmu.c:697:12: warning: cast removes address space of expression
fs/proc/task_mmu.c:697:9: warning: incorrect type in assignment (different address spaces)
fs/proc/task_mmu.c:697:9: expected unsigned long long [noderef] [usertype] <asn:1>*end
fs/proc/task_mmu.c:697:9: got unsigned long long [usertype] *<noident>
fs/proc/task_mmu.c:723:12: warning: cast removes address space of expression
fs/proc/task_mmu.c:723:26: error: subtraction of different types can't work (different address spaces)
fs/proc/task_mmu.c:725:24: error: subtraction of different types can't work (different address spaces)
Signed-off-by: Milind Arun Choudhary <milindchoudhary@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
so that people will realize that it exists and can update it as needed.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
This patch renames n_, c_, etc variables to something more sane. This
is the sixth in a series of patches to rip out some of the awful
variable naming in reiserfs.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is a simple s/p_._//g to the reiserfs code. This is the
fifth in a series of patches to rip out some of the awful variable
naming in reiserfs.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is a simple s/p_s_tb/tb/g to the reiserfs code. This is the
fourth in a series of patches to rip out some of the awful variable
naming in reiserfs.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is a simple s/p_s_inode/inode/g to the reiserfs code. This
is the third in a series of patches to rip out some of the awful
variable naming in reiserfs.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is a simple s/p_s_bh/bh/g to the reiserfs code. This is the
second in a series of patches to rip out some of the awful variable
naming in reiserfs.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is a simple s/p_s_sb/sb/g to the reiserfs code. This is the
first in a series of patches to rip out some of the awful variable
naming in reiserfs.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch strips trailing whitespace from the reiserfs code.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch cleans up some redundancies in the reiserfs tree path code.
decrement_bcount() is essentially the same function as brelse(), so we use
that instead.
decrement_counters_in_path() is exactly the same function as pathrelse(), so
we kill that and use pathrelse() instead.
There's also a bit of cleanup that makes the code a bit more readable.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the first in a series of patches to make balance_leaf() not
quite so insane.
This patch factors out the open coded initializations of buffer_info
structures and defines a few initializers for the 4 cases they're used.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some time ago, some changes were made to make security inode attributes
be atomically written during inode creation. ReiserFS fell behind in
this area, but with the reworking of the xattr code, it's now fairly
easy to add.
The following patch adds the ability for security attributes to be added
automatically during inode creation.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current reiserfs xattr implementation open codes reiserfs_readdir
and frees the path before calling the filldir function. Typically, the
filldir function is something that modifies the file system, such as a
chown or an inode deletion that also require reading of an inode
associated with each direntry. Since the file system is modified, the
path retained becomes invalid for the next run. In addition, it runs
backwards in attempt to minimize activity.
This is clearly suboptimal from a code cleanliness perspective as well
as performance-wise.
This patch implements a generic reiserfs_for_each_xattr that uses the
generic readdir and a specific filldir routine that simply populates an
array of dentries and then performs a specific operation on them. When
all files have been operated on, it then calls the operation on the
directory itself.
The result is a noticable code reduction and better performance.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Deadlocks are possible in the xattr code between the journal lock and the
xattr sems.
This patch implements journalling for xattr operations. The benefit is
twofold:
* It gets rid of the deadlock possibility by always ensuring that xattr
write operations are initiated inside a transaction.
* It corrects the problem where xattr backing files aren't considered any
differently than normal files, despite the fact they are metadata.
I discussed the added journal load with Chris Mason, and we decided that
since xattrs (versus other journal activity) is fairly rare, the introduction
of larger transactions to support journaled xattrs wouldn't be too big a deal.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Christoph Hellwig had asked me quite some time ago to port the reiserfs
xattrs to the generic xattr interface.
This patch replaces the reiserfs-specific xattr handling code with the
generic struct xattr_handler.
However, since reiserfs doesn't split the prefix and name when accessing
xattrs, it can't leverage generic_{set,get,list,remove}xattr without
needlessly reconstructing the name on the back end.
Update 7/26/07: Added missing dput() to deletion path.
Update 8/30/07: Added missing mark_inode_dirty when i_mode is used to
represent an ACL and no previous ACL existed.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With the changes to xattr root locking, the i_has_xattr_dir flag
is no longer needed. This patch removes it.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Ian Kent