PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.
This promise never materialized. And unlikely will.
We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE. And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.
Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.
Let's stop pretending that pages in page cache are special. They are
not.
The changes are pretty straight-forward:
- <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
- <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
- PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};
- page_cache_get() -> get_page();
- page_cache_release() -> put_page();
This patch contains automated changes generated with coccinelle using
script below. For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.
The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.
There are few places in the code where coccinelle didn't reach. I'll
fix them manually in a separate patch. Comments and documentation also
will be addressed with the separate patch.
virtual patch
@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E
@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E
@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT
@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE
@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK
@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)
@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)
@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Running the following command:
busybox cat /sys/kernel/debug/tracing/trace_pipe > /dev/null
with any tracing enabled pretty very quickly leads to various NULL
pointer dereferences and VM BUG_ON()s, such as these:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
IP: [<ffffffff8119df6c>] generic_pipe_buf_release+0xc/0x40
Call Trace:
[<ffffffff811c48a3>] splice_direct_to_actor+0x143/0x1e0
[<ffffffff811c42e0>] ? generic_pipe_buf_nosteal+0x10/0x10
[<ffffffff811c49cf>] do_splice_direct+0x8f/0xb0
[<ffffffff81196869>] do_sendfile+0x199/0x380
[<ffffffff81197600>] SyS_sendfile64+0x90/0xa0
[<ffffffff8192cbee>] entry_SYSCALL_64_fastpath+0x12/0x6d
page dumped because: VM_BUG_ON_PAGE(atomic_read(&page->_count) == 0)
kernel BUG at include/linux/mm.h:367!
invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
RIP: [<ffffffff8119df9c>] generic_pipe_buf_release+0x3c/0x40
Call Trace:
[<ffffffff811c48a3>] splice_direct_to_actor+0x143/0x1e0
[<ffffffff811c42e0>] ? generic_pipe_buf_nosteal+0x10/0x10
[<ffffffff811c49cf>] do_splice_direct+0x8f/0xb0
[<ffffffff81196869>] do_sendfile+0x199/0x380
[<ffffffff81197600>] SyS_sendfile64+0x90/0xa0
[<ffffffff8192cd1e>] tracesys_phase2+0x84/0x89
(busybox's cat uses sendfile(2), unlike the coreutils version)
This is because tracing_splice_read_pipe() can call splice_to_pipe()
with spd->nr_pages == 0. spd_pages underflows in splice_to_pipe() and
we fill the page pointers and the other fields of the pipe_buffers with
garbage.
All other callers of splice_to_pipe() avoid calling it when nr_pages ==
0, and we could make tracing_splice_read_pipe() do that too, but it
seems reasonable to have splice_to_page() handle this condition
gracefully.
Cc: stable@vger.kernel.org
Signed-off-by: Rabin Vincent <rabin@rab.in>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This way we can set kiocb flags also from the sync read/write path for
the read_iter/write_iter operations. For now there is no way to pass
flags to plain read/write operations as there is no real need for that,
and all flags passed are explicitly rejected for these files.
Signed-off-by: Milosz Tanski <milosz@adfin.com>
[hch: rebased on top of my kiocb changes]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Stephen Bates <stephen.bates@pmcs.com>
Tested-by: Stephen Bates <stephen.bates@pmcs.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
During testing, I discovered that __generic_file_splice_read() returns
0 (EOF) when aops->readpage fails with AOP_TRUNCATED_PAGE on the first
page of a single/multi-page splice read operation. This EOF return code
causes the userspace test to (correctly) report a zero-length read error
when it was expecting otherwise.
The current strategy of returning a partial non-zero read when ->readpage
returns AOP_TRUNCATED_PAGE works only when the failed page is not the
first of the lot being processed.
This patch attempts to retry lookup and call ->readpage again on pages
that had previously failed with AOP_TRUNCATED_PAGE. With this patch, my
tests pass and I haven't noticed any unwanted side effects.
This version removes the thrice-retry loop and instead indefinitely
retries lookups on AOP_TRUNCATED_PAGE errors from ->readpage. This
behavior is now similar to do_generic_file_read().
Signed-off-by: Abhi Das <adas@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The following test program from Dmitry can cause softlockups or RCU
stalls as it copies 1GB from tmpfs into eventfd and we don't have any
scheduling point at that path in sendfile(2) implementation:
int r1 = eventfd(0, 0);
int r2 = memfd_create("", 0);
unsigned long n = 1<<30;
fallocate(r2, 0, 0, n);
sendfile(r1, r2, 0, n);
Add cond_resched() into __splice_from_pipe() to fix the problem.
CC: Dmitry Vyukov <dvyukov@google.com>
CC: stable@vger.kernel.org
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Commit 296291cdd1 (mm: make sendfile(2) killable) fixed an issue where
sendfile(2) was doing a lot of tiny writes into a filesystem and thus
was unkillable for a long time. However sendfile(2) can be (mis)used to
issue lots of writes into arbitrary file descriptor such as evenfd or
similar special file descriptors which never hit the standard filesystem
write path and thus are still unkillable. E.g. the following example
from Dmitry burns CPU for ~16s on my test system without possibility to
be killed:
int r1 = eventfd(0, 0);
int r2 = memfd_create("", 0);
unsigned long n = 1<<30;
fallocate(r2, 0, 0, n);
sendfile(r1, r2, 0, n);
There are actually quite a few tests for pending signals in sendfile
code however we data to write is always available none of them seems to
trigger. So fix the problem by adding a test for pending signal into
splice_from_pipe_next() also before the loop waiting for pipe buffers to
be available. This should fix all the lockup issues with sendfile of the
do-ton-of-tiny-writes nature.
CC: stable@vger.kernel.org
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
There are many places which use mapping_gfp_mask to restrict a more
generic gfp mask which would be used for allocations which are not
directly related to the page cache but they are performed in the same
context.
Let's introduce a helper function which makes the restriction explicit and
easier to track. This patch doesn't introduce any functional changes.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge first patchbomb from Andrew Morton:
- a few misc things
- ocfs2 udpates
- kernel/watchdog.c feature work (took ages to get right)
- most of MM. A few tricky bits are held up and probably won't make 4.2.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (91 commits)
mm: kmemleak_alloc_percpu() should follow the gfp from per_alloc()
mm, thp: respect MPOL_PREFERRED policy with non-local node
tmpfs: truncate prealloc blocks past i_size
mm/memory hotplug: print the last vmemmap region at the end of hot add memory
mm/mmap.c: optimization of do_mmap_pgoff function
mm: kmemleak: optimise kmemleak_lock acquiring during kmemleak_scan
mm: kmemleak: avoid deadlock on the kmemleak object insertion error path
mm: kmemleak: do not acquire scan_mutex in kmemleak_do_cleanup()
mm: kmemleak: fix delete_object_*() race when called on the same memory block
mm: kmemleak: allow safe memory scanning during kmemleak disabling
memcg: convert mem_cgroup->under_oom from atomic_t to int
memcg: remove unused mem_cgroup->oom_wakeups
frontswap: allow multiple backends
x86, mirror: x86 enabling - find mirrored memory ranges
mm/memblock: allocate boot time data structures from mirrored memory
mm/memblock: add extra "flags" to memblock to allow selection of memory based on attribute
mm: do not ignore mapping_gfp_mask in page cache allocation paths
mm/cma.c: fix typos in comments
mm/oom_kill.c: print points as unsigned int
mm/hugetlb: handle races in alloc_huge_page and hugetlb_reserve_pages
...
page_cache_read, do_generic_file_read, __generic_file_splice_read and
__ntfs_grab_cache_pages currently ignore mapping_gfp_mask when calling
add_to_page_cache_lru which might cause recursion into fs down in the
direct reclaim path if the mapping really relies on GFP_NOFS semantic.
This doesn't seem to be the case now because page_cache_read (page fault
path) doesn't seem to suffer from the reclaim recursion issues and
do_generic_file_read and __generic_file_splice_read also shouldn't be
called under fs locks which would deadlock in the reclaim path. Anyway it
is better to obey mapping gfp mask and prevent from later breakage.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Anton Altaparmakov <anton@tuxera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
unix_stream_recvmsg is refactored to unix_stream_read_generic in this
patch and enhanced to deal with pipe splicing. The refactoring is
inneglible, we mostly have to deal with a non-existing struct msghdr
argument.
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Using sendfile with below small program to get MD5 sums of some files,
it appear that big files (over 64kbytes with 4k pages system) get a
wrong MD5 sum while small files get the correct sum.
This program uses sendfile() to send a file to an AF_ALG socket
for hashing.
/* md5sum2.c */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <linux/if_alg.h>
int main(int argc, char **argv)
{
int sk = socket(AF_ALG, SOCK_SEQPACKET, 0);
struct stat st;
struct sockaddr_alg sa = {
.salg_family = AF_ALG,
.salg_type = "hash",
.salg_name = "md5",
};
int n;
bind(sk, (struct sockaddr*)&sa, sizeof(sa));
for (n = 1; n < argc; n++) {
int size;
int offset = 0;
char buf[4096];
int fd;
int sko;
int i;
fd = open(argv[n], O_RDONLY);
sko = accept(sk, NULL, 0);
fstat(fd, &st);
size = st.st_size;
sendfile(sko, fd, &offset, size);
size = read(sko, buf, sizeof(buf));
for (i = 0; i < size; i++)
printf("%2.2x", buf[i]);
printf(" %s\n", argv[n]);
close(fd);
close(sko);
}
exit(0);
}
Test below is done using official linux patch files. First result is
with a software based md5sum. Second result is with the program above.
root@vgoip:~# ls -l patch-3.6.*
-rw-r--r-- 1 root root 64011 Aug 24 12:01 patch-3.6.2.gz
-rw-r--r-- 1 root root 94131 Aug 24 12:01 patch-3.6.3.gz
root@vgoip:~# md5sum patch-3.6.*
b3ffb9848196846f31b2ff133d2d6443 patch-3.6.2.gz
c5e8f687878457db77cb7158c38a7e43 patch-3.6.3.gz
root@vgoip:~# ./md5sum2 patch-3.6.*
b3ffb9848196846f31b2ff133d2d6443 patch-3.6.2.gz
5fd77b24e68bb24dcc72d6e57c64790e patch-3.6.3.gz
After investivation, it appears that sendfile() sends the files by blocks
of 64kbytes (16 times PAGE_SIZE). The problem is that at the end of each
block, the SPLICE_F_MORE flag is missing, therefore the hashing operation
is reset as if it was the end of the file.
This patch adds SPLICE_F_MORE to the flags when more data is pending.
With the patch applied, we get the correct sums:
root@vgoip:~# md5sum patch-3.6.*
b3ffb9848196846f31b2ff133d2d6443 patch-3.6.2.gz
c5e8f687878457db77cb7158c38a7e43 patch-3.6.3.gz
root@vgoip:~# ./md5sum2 patch-3.6.*
b3ffb9848196846f31b2ff133d2d6443 patch-3.6.2.gz
c5e8f687878457db77cb7158c38a7e43 patch-3.6.3.gz
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Jens Axboe <axboe@fb.com>
The original dax patchset split the ext2/4_file_operations because of the
two NULL splice_read/splice_write in the dax case.
In the vfs if splice_read/splice_write are NULL we then call
default_splice_read/write.
What we do here is make generic_file_splice_read aware of IS_DAX() so the
original ext2/4_file_operations can be used as is.
For write it appears that iter_file_splice_write is just fine. It uses
the regular f_op->write(file,..) or new_sync_write(file, ...).
Signed-off-by: Boaz Harrosh <boaz@plexistor.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
struct kiocb now is a generic I/O container, so move it to fs.h.
Also do a #include diet for aio.h while we're at it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Simple helpers that pass an arbitrary iov_iter to filesystems.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
iter_file_splice_write() - a ->splice_write() instance that gathers the
pipe buffers, builds a bio_vec-based iov_iter covering those and feeds
it to ->write_iter(). A bunch of simple cases coverted to that...
[AV: fixed the braino spotted by Cyrill]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Commit 6130f5315e "switch vmsplice_to_user() to copy_page_to_iter()" in
v3.15-rc1 broke vmsplice(2).
This patch fixes two bugs:
- count is not initialized to a proper value, which resulted in no data
being copied
- if rw_copy_check_uvector() returns negative then the iov might be leaked.
Tested OK.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
For now, just use the same thing we pass to ->direct_IO() - it's all
iovec-based at the moment. Pass it explicitly to iov_iter_init() and
account for kvec vs. iovec in there, by the same kludge NFS ->direct_IO()
uses.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
I've switched the sanity checks on iovec to rw_copy_check_uvector();
we might need to do a local analog, if any behaviour differences are
not actually bugfixes here...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Having this struct in module memory could Oops when if the module is
unloaded while the buffer still persists in a pipe.
Since sock_pipe_buf_ops is essentially the same as fuse_dev_pipe_buf_steal
merge them into nosteal_pipe_buf_ops (this is the same as
default_pipe_buf_ops except stealing the page from the buffer is not
allowed).
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: stable@vger.kernel.org
Pull second set of VFS changes from Al Viro:
"Assorted f_pos race fixes, making do_splice_direct() safe to call with
i_mutex on parent, O_TMPFILE support, Jeff's locks.c series,
->d_hash/->d_compare calling conventions changes from Linus, misc
stuff all over the place."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (63 commits)
Document ->tmpfile()
ext4: ->tmpfile() support
vfs: export lseek_execute() to modules
lseek_execute() doesn't need an inode passed to it
block_dev: switch to fixed_size_llseek()
cpqphp_sysfs: switch to fixed_size_llseek()
tile-srom: switch to fixed_size_llseek()
proc_powerpc: switch to fixed_size_llseek()
ubi/cdev: switch to fixed_size_llseek()
pci/proc: switch to fixed_size_llseek()
isapnp: switch to fixed_size_llseek()
lpfc: switch to fixed_size_llseek()
locks: give the blocked_hash its own spinlock
locks: add a new "lm_owner_key" lock operation
locks: turn the blocked_list into a hashtable
locks: convert fl_link to a hlist_node
locks: avoid taking global lock if possible when waking up blocked waiters
locks: protect most of the file_lock handling with i_lock
locks: encapsulate the fl_link list handling
locks: make "added" in __posix_lock_file a bool
...
Fix new kernel-doc warning in fs/splice.c:
Warning(fs/splice.c:1298): No description found for parameter 'opos'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull VFS updates from Al Viro,
Misc cleanups all over the place, mainly wrt /proc interfaces (switch
create_proc_entry to proc_create(), get rid of the deprecated
create_proc_read_entry() in favor of using proc_create_data() and
seq_file etc).
7kloc removed.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits)
don't bother with deferred freeing of fdtables
proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h
proc: Make the PROC_I() and PDE() macros internal to procfs
proc: Supply a function to remove a proc entry by PDE
take cgroup_open() and cpuset_open() to fs/proc/base.c
ppc: Clean up scanlog
ppc: Clean up rtas_flash driver somewhat
hostap: proc: Use remove_proc_subtree()
drm: proc: Use remove_proc_subtree()
drm: proc: Use minor->index to label things, not PDE->name
drm: Constify drm_proc_list[]
zoran: Don't print proc_dir_entry data in debug
reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show()
proc: Supply an accessor for getting the data from a PDE's parent
airo: Use remove_proc_subtree()
rtl8192u: Don't need to save device proc dir PDE
rtl8187se: Use a dir under /proc/net/r8180/
proc: Add proc_mkdir_data()
proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h}
proc: Move PDE_NET() to fs/proc/proc_net.c
...
Pull compat cleanup from Al Viro:
"Mostly about syscall wrappers this time; there will be another pile
with patches in the same general area from various people, but I'd
rather push those after both that and vfs.git pile are in."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
syscalls.h: slightly reduce the jungles of macros
get rid of union semop in sys_semctl(2) arguments
make do_mremap() static
sparc: no need to sign-extend in sync_file_range() wrapper
ppc compat wrappers for add_key(2) and request_key(2) are pointless
x86: trim sys_ia32.h
x86: sys32_kill and sys32_mprotect are pointless
get rid of compat_sys_semctl() and friends in case of ARCH_WANT_OLD_COMPAT_IPC
merge compat sys_ipc instances
consolidate compat lookup_dcookie()
convert vmsplice to COMPAT_SYSCALL_DEFINE
switch getrusage() to COMPAT_SYSCALL_DEFINE
switch epoll_pwait to COMPAT_SYSCALL_DEFINE
convert sendfile{,64} to COMPAT_SYSCALL_DEFINE
switch signalfd{,4}() to COMPAT_SYSCALL_DEFINE
make SYSCALL_DEFINE<n>-generated wrappers do asmlinkage_protect
make HAVE_SYSCALL_WRAPPERS unconditional
consolidate cond_syscall and SYSCALL_ALIAS declarations
teach SYSCALL_DEFINE<n> how to deal with long long/unsigned long long
get rid of duplicate logics in __SC_....[1-6] definitions
it's used only as a flag to distinguish normal pipes/FIFOs from the
internal per-task one used by file-to-file splice. And pipe->files
would work just as well for that purpose...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
default_file_splice_from() ends up calling vfs_write() (via very convoluted
callchain). It's an overkill, since we already have done rw_verify_area()
in the caller by the time we call vfs_write() we are under set_fs(KERNEL_DS),
so access_ok() is also pointless. Add a new helper (__kernel_write()),
use it instead of kernel_write() in there.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
commit 35f9c09fe9 (tcp: tcp_sendpages() should call tcp_push() once)
added an internal flag : MSG_SENDPAGE_NOTLAST meant to be set on all
frags but the last one for a splice() call.
The condition used to set the flag in pipe_to_sendpage() relied on
splice() user passing the exact number of bytes present in the pipe,
or a smaller one.
But some programs pass an arbitrary high value, and the test fails.
The effect of this bug is a lack of tcp_push() at the end of a
splice(pipe -> socket) call, and possibly very slow or erratic TCP
sessions.
We should both test sd->total_len and fact that another fragment
is in the pipe (pipe->nrbufs > 1)
Many thanks to Willy for providing very clear bug report, bisection
and test programs.
Reported-by: Willy Tarreau <w@1wt.eu>
Bisected-by: Willy Tarreau <w@1wt.eu>
Tested-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There is no reason to pass the nr_pages_dirtied argument, because
nr_pages_dirtied value from the caller is unused in
balance_dirty_pages_ratelimited_nr().
Signed-off-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Vivek Trivedi <vtrivedi018@gmail.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are several entry points which dirty pages in a filesystem. mmap
(handled by block_page_mkwrite()), buffered write (handled by
__generic_file_aio_write()), splice write (generic_file_splice_write),
truncate, and fallocate (these can dirty last partial page - handled inside
each filesystem separately). Protect these places with sb_start_write() and
sb_end_write().
->page_mkwrite() calls are particularly complex since they are called with
mmap_sem held and thus we cannot use standard sb_start_write() due to lock
ordering constraints. We solve the problem by using a special freeze protection
sb_start_pagefault() which ranks below mmap_sem.
BugLink: https://bugs.launchpad.net/bugs/897421
Tested-by: Kamal Mostafa <kamal@canonical.com>
Tested-by: Peter M. Petrakis <peter.petrakis@canonical.com>
Tested-by: Dann Frazier <dann.frazier@canonical.com>
Tested-by: Massimo Morana <massimo.morana@canonical.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Dave Jones reported a kernel BUG at mm/slub.c:3474! triggered
by splice_shrink_spd() called from vmsplice_to_pipe()
commit 35f3d14dbb (pipe: add support for shrinking and growing pipes)
added capability to adjust pipe->buffers.
Problem is some paths don't hold pipe mutex and assume pipe->buffers
doesn't change for their duration.
Fix this by adding nr_pages_max field in struct splice_pipe_desc, and
use it in place of pipe->buffers where appropriate.
splice_shrink_spd() loses its struct pipe_inode_info argument.
Reported-by: Dave Jones <davej@redhat.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Tom Herbert <therbert@google.com>
Cc: stable <stable@vger.kernel.org> # 2.6.35
Tested-by: Dave Jones <davej@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull vfs changes from Al Viro.
"A lot of misc stuff. The obvious groups:
* Miklos' atomic_open series; kills the damn abuse of
->d_revalidate() by NFS, which was the major stumbling block for
all work in that area.
* ripping security_file_mmap() and dealing with deadlocks in the
area; sanitizing the neighborhood of vm_mmap()/vm_munmap() in
general.
* ->encode_fh() switched to saner API; insane fake dentry in
mm/cleancache.c gone.
* assorted annotations in fs (endianness, __user)
* parts of Artem's ->s_dirty work (jff2 and reiserfs parts)
* ->update_time() work from Josef.
* other bits and pieces all over the place.
Normally it would've been in two or three pull requests, but
signal.git stuff had eaten a lot of time during this cycle ;-/"
Fix up trivial conflicts in Documentation/filesystems/vfs.txt (the
'truncate_range' inode method was removed by the VM changes, the VFS
update adds an 'update_time()' method), and in fs/btrfs/ulist.[ch] (due
to sparse fix added twice, with other changes nearby).
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (95 commits)
nfs: don't open in ->d_revalidate
vfs: retry last component if opening stale dentry
vfs: nameidata_to_filp(): don't throw away file on error
vfs: nameidata_to_filp(): inline __dentry_open()
vfs: do_dentry_open(): don't put filp
vfs: split __dentry_open()
vfs: do_last() common post lookup
vfs: do_last(): add audit_inode before open
vfs: do_last(): only return EISDIR for O_CREAT
vfs: do_last(): check LOOKUP_DIRECTORY
vfs: do_last(): make ENOENT exit RCU safe
vfs: make follow_link check RCU safe
vfs: do_last(): use inode variable
vfs: do_last(): inline walk_component()
vfs: do_last(): make exit RCU safe
vfs: split do_lookup()
Btrfs: move over to use ->update_time
fs: introduce inode operation ->update_time
reiserfs: get rid of resierfs_sync_super
reiserfs: mark the superblock as dirty a bit later
...
Btrfs has to make sure we have space to allocate new blocks in order to modify
the inode, so updating time can fail. We've gotten around this by having our
own file_update_time but this is kind of a pain, and Christoph has indicated he
would like to make xfs do something different with atime updates. So introduce
->update_time, where we will deal with i_version an a/m/c time updates and
indicate which changes need to be made. The normal version just does what it
has always done, updates the time and marks the inode dirty, and then
filesystems can choose to do something different.
I've gone through all of the users of file_update_time and made them check for
errors with the exception of the fault code since it's complicated and I wasn't
quite sure what to do there, also Jan is going to be pushing the file time
updates into page_mkwrite for those who have it so that should satisfy btrfs and
make it not a big deal to check the file_update_time() return code in the
generic fault path. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
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Merge tag 'v3.4-rc5' into for-3.5/core
The core branch is behind driver commits that we want to build
on for 3.5, hence I'm pulling in a later -rc.
Linux 3.4-rc5
Conflicts:
Documentation/feature-removal-schedule.txt
Signed-off-by: Jens Axboe <axboe@kernel.dk>
It seems there is no fundamental reason to limit vmsplice()
SPLICE_F_GIFT to page aligned chunks.
All helpers are prepared to cope with offsets in page.
This limitation makes vmsplice() API very impractical in the zero-copy
land.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Miller <davem@davemloft.net>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hughd@google.com>
Cc: Changli Gao <xiaosuo@gmail.com>
Cc: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
commit 2f53384424 (tcp: allow splice() to build full TSO packets) added
a regression for splice() calls using SPLICE_F_MORE.
We need to call tcp_flush() at the end of the last page processed in
tcp_sendpages(), or else transmits can be deferred and future sends
stall.
Add a new internal flag, MSG_SENDPAGE_NOTLAST, acting like MSG_MORE, but
with different semantic.
For all sendpage() providers, its a transparent change. Only
sock_sendpage() and tcp_sendpages() can differentiate the two different
flags provided by pipe_to_sendpage()
Reported-by: Tom Herbert <therbert@google.com>
Cc: Nandita Dukkipati <nanditad@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: H.K. Jerry Chu <hkchu@google.com>
Cc: Maciej Żenczykowski <maze@google.com>
Cc: Mahesh Bandewar <maheshb@google.com>
Cc: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail>com>
Signed-off-by: David S. Miller <davem@davemloft.net>
"[PATCH 0/3] RFC - module.h usage cleanups in fs/ and lib/"
https://lkml.org/lkml/2012/2/29/589
--
Fix up files in fs/ and lib/ dirs to only use module.h if they really
need it.
These are trivial in scope vs. the work done previously. We now have
things where any few remaining cleanups can be farmed out to arch or
subsystem maintainers, and I have done so when possible. What is
remaining here represents the bits that don't clearly lie within a
single arch/subsystem boundary, like the fs dir and the lib dir.
Some duplicate includes arising from overlapping fixes from
independent subsystem maintainer submissions are also quashed.
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Merge tag 'module-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
Pull cleanup of fs/ and lib/ users of module.h from Paul Gortmaker:
"Fix up files in fs/ and lib/ dirs to only use module.h if they really
need it.
These are trivial in scope vs the work done previously. We now have
things where any few remaining cleanups can be farmed out to arch or
subsystem maintainers, and I have done so when possible. What is
remaining here represents the bits that don't clearly lie within a
single arch/subsystem boundary, like the fs dir and the lib dir.
Some duplicate includes arising from overlapping fixes from
independent subsystem maintainer submissions are also quashed."
Fix up trivial conflicts due to clashes with other include file cleanups
(including some due to the previous bug.h cleanup pull).
* tag 'module-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux:
lib: reduce the use of module.h wherever possible
fs: reduce the use of module.h wherever possible
includecheck: delete any duplicate instances of module.h
For files only using THIS_MODULE and/or EXPORT_SYMBOL, map
them onto including export.h -- or if the file isn't even
using those, then just delete the include. Fix up any implicit
include dependencies that were being masked by module.h along
the way.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Move invalidate_bdev, block_sync_page into fs/block_dev.c. Export
kill_bdev as well, so brd doesn't have to open code it. Reduce
buffer_head.h requirement accordingly.
Removed a rather large comment from invalidate_bdev, as it looked a bit
obsolete to bother moving. The small comment replacing it says enough.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Copy __generic_file_splice_read() and generic_file_splice_read() from
fs/splice.c to shmem_file_splice_read() in mm/shmem.c. Make
page_cache_pipe_buf_ops and spd_release_page() accessible to it.
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Jens Axboe <jaxboe@fusionio.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add and use wakeup_pipe_readers() to consolidate duplicated codes.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block: (43 commits)
block: ensure that completion error gets properly traced
blktrace: add missing probe argument to block_bio_complete
block cfq: don't use atomic_t for cfq_group
block cfq: don't use atomic_t for cfq_queue
block: trace event block fix unassigned field
block: add internal hd part table references
block: fix accounting bug on cross partition merges
kref: add kref_test_and_get
bio-integrity: mark kintegrityd_wq highpri and CPU intensive
block: make kblockd_workqueue smarter
Revert "sd: implement sd_check_events()"
block: Clean up exit_io_context() source code.
Fix compile warnings due to missing removal of a 'ret' variable
fs/block: type signature of major_to_index(int) to major_to_index(unsigned)
block: convert !IS_ERR(p) && p to !IS_ERR_NOR_NULL(p)
cfq-iosched: don't check cfqg in choose_service_tree()
fs/splice: Pull buf->ops->confirm() from splice_from_pipe actors
cdrom: export cdrom_check_events()
sd: implement sd_check_events()
sr: implement sr_check_events()
...
This patch pulls calls to buf->ops->confirm() from all actors passed
(also indirectly) to splice_from_pipe_feed().
Is avoiding the call to buf->ops->confirm() while splice()ing to
/dev/null is an intentional optimization? No other user does that
and this will remove this special case.
Against current linux.git 6313e3c217.
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
And in particular, use it in 'pipe_fcntl()'.
The other pipe functions do not need to use the 'careful' version, since
they are only ever called for things that are already known to be pipes.
The normal read/write/ioctl functions are called through the file
operations structures, so if a file isn't a pipe, they'd never get
called. But pipe_fcntl() is special, and called directly from the
generic fcntl code, and needs to use the same careful function that the
splice code is using.
Cc: Jens Axboe <jaxboe@fusionio.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
.. and change it to take the 'file' pointer instead of an inode, since
that's what all users want anyway.
The renaming is preparatory to exporting it to other users. The old
'pipe_info()' name was too generic and is already used elsewhere, so
before making the function public we need to use a more specific name.
Cc: Jens Axboe <jaxboe@fusionio.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
SPLICE_F_NONBLOCK is clearly documented to only affect blocking on the
pipe. In __generic_file_splice_read(), however, it causes an EAGAIN
if the page is currently being read.
This makes it impossible to write an application that only wants
failure if the pipe is full. For example if the same process is
handling both ends of a pipe and isn't otherwise able to determine
whether a splice to the pipe will fill it or not.
We could make the read non-blocking on O_NONBLOCK or some other splice
flag, but for now this is the simplest fix.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
CC: stable@kernel.org
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
No real bugs I believe, just some dead code, and some
shut up code.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Eric Paris <eparis@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
check f_mode for seekable file
As a seekable file is allowed without a llseek function, so the old way isn't
work any more.
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
----
fs/splice.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
mapping_gfp_mask() is not supposed to store allocation contex details,
only page location details. So mapping_gfp_mask should be applied to the
pagecache page allocation, wheras normal (kernel mapped) memory should be
used for surrounding allocations such as radix-tree nodes allocated by
add_to_page_cache. Context modifiers should be applied on a per-callsite
basis.
So change splice to follow this convention (which is followed in similar
code patterns in core code).
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This patch adds F_GETPIPE_SZ and F_SETPIPE_SZ fcntl() actions for
growing and shrinking the size of a pipe and adjusts pipe.c and splice.c
(and relay and network splice) usage to work with these larger (or smaller)
pipes.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
sendfile(2) was reworked with the splice infrastructure, but it still
checks f_op.sendpage() instead of f_op.splice_write() wrongly. Although
if f_op.sendpage() exists, f_op.splice_write() always exists at the same
time currently, the assumption will be broken in future silently. This
patch also brings a side effect: sendfile(2) can work with any output
file. Some security checks related to f_op are added too.
Signed-off-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* 'for-2.6.32' of git://git.kernel.dk/linux-2.6-block: (29 commits)
block: use blkdev_issue_discard in blk_ioctl_discard
Make DISCARD_BARRIER and DISCARD_NOBARRIER writes instead of reads
block: don't assume device has a request list backing in nr_requests store
block: Optimal I/O limit wrapper
cfq: choose a new next_req when a request is dispatched
Seperate read and write statistics of in_flight requests
aoe: end barrier bios with EOPNOTSUPP
block: trace bio queueing trial only when it occurs
block: enable rq CPU completion affinity by default
cfq: fix the log message after dispatched a request
block: use printk_once
cciss: memory leak in cciss_init_one()
splice: update mtime and atime on files
block: make blk_iopoll_prep_sched() follow normal 0/1 return convention
cfq-iosched: get rid of must_alloc flag
block: use interrupts disabled version of raise_softirq_irqoff()
block: fix comment in blk-iopoll.c
block: adjust default budget for blk-iopoll
block: fix long lines in block/blk-iopoll.c
block: add blk-iopoll, a NAPI like approach for block devices
...
Introduce new function for generic inode syncing (vfs_fsync_range) and use
it from fsync() path. Introduce also new helper for syncing after a sync
write (generic_write_sync) using the generic function.
Use these new helpers for syncing from generic VFS functions. This makes
O_SYNC writes to block devices acquire i_mutex for syncing. If we really
care about this, we can make block_fsync() drop the i_mutex and reacquire
it before it returns.
CC: Evgeniy Polyakov <zbr@ioremap.net>
CC: ocfs2-devel@oss.oracle.com
CC: Joel Becker <joel.becker@oracle.com>
CC: Felix Blyakher <felixb@sgi.com>
CC: xfs@oss.sgi.com
CC: Anton Altaparmakov <aia21@cantab.net>
CC: linux-ntfs-dev@lists.sourceforge.net
CC: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
CC: linux-ext4@vger.kernel.org
CC: tytso@mit.edu
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Splice should update the modification and access times on regular
files just like read and write. Not updating mtime will confuse
backup tools, etc...
This patch only adds the time updates for regular files. For pipes
and other special files that splice touches the need for updating the
times is less clear. Let's discuss and fix that separately.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Unfortunately multiple kmap() within a single thread are deadlockable,
so writing out multiple buffers with writev() isn't possible.
Change the implementation so that it does a separate write() for each
buffer. This actually simplifies the code a lot since the
splice_from_pipe() helper can be used.
This limitation is caused by HIGHMEM pages, and so only affects a
subset of architectures and configurations. In the future it may be
worth to implement default_file_splice_write() in a more efficient way
on configs that allow it.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
fs/splice.c: In function 'default_file_splice_read':
fs/splice.c:566: warning: 'error' may be used uninitialized in this function
which is sort-of true. The code will in fact return -ENOMEM instead of the
kernel_readv() return value.
Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
We cannot reliably map more than one page at the time, or we risk
deadlocking. Just allocate the pages from low mem instead.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
If f_op->splice_write() is not implemented, fall back to a plain write.
Use vfs_writev() to write from the pipe buffers.
This will allow splice on all filesystems and file types. This
includes "direct_io" files in fuse which bypass the page cache.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
If f_op->splice_read() is not implemented, fall back to a plain read.
Use vfs_readv() to read into previously allocated pages.
This will allow splice and functions using splice, such as the loop
device, to work on all filesystems. This includes "direct_io" files
in fuse which bypass the page cache.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Allow splice(2) to work when both the input and the output is a pipe.
Based on the impementation of the tee(2) syscall, but instead of
duplicating the buffer references move the buffers from the input pipe
to the output pipe.
Moving the whole buffer only succeeds if the full length of the buffer
is spliced. Otherwise duplicate the buffer, just like tee(2), set the
length of the output buffer and advance the offset on the input
buffer.
Since splice is operating on two pipes, special care needs to be taken
with locking to prevent AN ABBA deadlock. Again this is done
similarly to the tee(2) syscall, first preparing the input and output
pipes so there's data to consume and space for that data, and then
doing the move operation while holding both locks.
If other processes are doing I/O on the same pipes parallel to the
splice, then by the time both inodes are locked there might be no
buffers left to move, or no space to move them to. In this case retry
the whole operation, including the preparation phase. This could lead
to starvation, but I'm not sure if that's serious enough to worry
about.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
splice: fix kernel-doc warnings
Warning(fs/splice.c:617): bad line:
Warning(fs/splice.c:722): No description found for parameter 'sd'
Warning(fs/splice.c:722): Excess function parameter 'pipe' description in 'splice_from_pipe_begin'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are lots of sequences like this, especially in splice code:
if (pipe->inode)
mutex_lock(&pipe->inode->i_mutex);
/* do something */
if (pipe->inode)
mutex_unlock(&pipe->inode->i_mutex);
so introduce helpers which do the conditional locking and unlocking.
Also replace the inode_double_lock() call with a pipe_double_lock()
helper to avoid spreading the use of this functionality beyond the
pipe code.
This patch is just a cleanup, and should cause no behavioral changes.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Remove the now unused generic_file_splice_write_nolock() function.
It's conceptually broken anyway, because splice may need to wait for
pipe events so holding locks across the whole operation is wrong.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Rearrange locking of i_mutex on destination and call to
ocfs2_rw_lock() so locks are only held while buffers are copied with
the pipe_to_file() actor, and not while waiting for more data on the
pipe.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Rearrange locking of i_mutex on destination so it's only held while
buffers are copied with the pipe_to_file() actor, and not while
waiting for more data on the pipe.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
splice_from_pipe() is only called from two places:
- generic_splice_sendpage()
- splice_write_null()
Neither of these require i_mutex to be taken on the destination inode.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Split up __splice_from_pipe() into four helper functions:
splice_from_pipe_begin()
splice_from_pipe_next()
splice_from_pipe_feed()
splice_from_pipe_end()
splice_from_pipe_next() will wait (if necessary) for more buffers to
be added to the pipe. splice_from_pipe_feed() will feed the buffers
to the supplied actor and return when there's no more data available
(or if all of the requested data has been copied).
This is necessary so that implementations can do locking around the
non-waiting splice_from_pipe_feed().
This patch should not cause any change in behavior.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
There's a possible deadlock in generic_file_splice_write(),
splice_from_pipe() and ocfs2_file_splice_write():
- task A calls generic_file_splice_write()
- this calls inode_double_lock(), which locks i_mutex on both
pipe->inode and target inode
- ordering depends on inode pointers, can happen that pipe->inode is
locked first
- __splice_from_pipe() needs more data, calls pipe_wait()
- this releases lock on pipe->inode, goes to interruptible sleep
- task B calls generic_file_splice_write(), similarly to the first
- this locks pipe->inode, then tries to lock inode, but that is
already held by task A
- task A is interrupted, it tries to lock pipe->inode, but fails, as
it is already held by task B
- ABBA deadlock
Fix this by explicitly ordering locks: the outer lock must be on
target inode and the inner lock (which is later unlocked and relocked)
must be on pipe->inode. This is OK, pipe inodes and target inodes
form two nonoverlapping sets, generic_file_splice_write() and friends
are not called with a target which is a pipe.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: Mark Fasheh <mfasheh@suse.com>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Recruit a page flag to aid in cache management. The following extra flag is
defined:
(1) PG_fscache (PG_private_2)
The marked page is backed by a local cache and is pinning resources in the
cache driver.
If PG_fscache is set, then things that checked for PG_private will now also
check for that. This includes things like truncation and page invalidation.
The function page_has_private() had been added to make the checks for both
PG_private and PG_private_2 at the same time.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>
Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
A big patch for changing memcg's LRU semantics.
Now,
- page_cgroup is linked to mem_cgroup's its own LRU (per zone).
- LRU of page_cgroup is not synchronous with global LRU.
- page and page_cgroup is one-to-one and statically allocated.
- To find page_cgroup is on what LRU, you have to check pc->mem_cgroup as
- lru = page_cgroup_zoneinfo(pc, nid_of_pc, zid_of_pc);
- SwapCache is handled.
And, when we handle LRU list of page_cgroup, we do following.
pc = lookup_page_cgroup(page);
lock_page_cgroup(pc); .....................(1)
mz = page_cgroup_zoneinfo(pc);
spin_lock(&mz->lru_lock);
.....add to LRU
spin_unlock(&mz->lru_lock);
unlock_page_cgroup(pc);
But (1) is spin_lock and we have to be afraid of dead-lock with zone->lru_lock.
So, trylock() is used at (1), now. Without (1), we can't trust "mz" is correct.
This is a trial to remove this dirty nesting of locks.
This patch changes mz->lru_lock to be zone->lru_lock.
Then, above sequence will be written as
spin_lock(&zone->lru_lock); # in vmscan.c or swap.c via global LRU
mem_cgroup_add/remove/etc_lru() {
pc = lookup_page_cgroup(page);
mz = page_cgroup_zoneinfo(pc);
if (PageCgroupUsed(pc)) {
....add to LRU
}
spin_lock(&zone->lru_lock); # in vmscan.c or swap.c via global LRU
This is much simpler.
(*) We're safe even if we don't take lock_page_cgroup(pc). Because..
1. When pc->mem_cgroup can be modified.
- at charge.
- at account_move().
2. at charge
the PCG_USED bit is not set before pc->mem_cgroup is fixed.
3. at account_move()
the page is isolated and not on LRU.
Pros.
- easy for maintenance.
- memcg can make use of laziness of pagevec.
- we don't have to duplicated LRU/Active/Unevictable bit in page_cgroup.
- LRU status of memcg will be synchronized with global LRU's one.
- # of locks are reduced.
- account_move() is simplified very much.
Cons.
- may increase cost of LRU rotation.
(no impact if memcg is not configured.)
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nothing uses prepare_write or commit_write. Remove them from the tree
completely.
[akpm@linux-foundation.org: schedule simple_prepare_write() for unexporting]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is debatable, but while we're debating it, let's disallow the
combination of splice and an O_APPEND destination.
It's not entirely clear what the semantics of O_APPEND should be, and
POSIX apparently expects pwrite() to ignore O_APPEND, for example. So
we could make up any semantics we want, including the old ones.
But Miklos convinced me that we should at least give it some thought,
and that accepting writes at arbitrary offsets is wrong at least for
IS_APPEND() files (which always have O_APPEND set, even if the reverse
isn't true: you can obviously have O_APPEND set on a regular file).
So disallow O_APPEND entirely for now. I doubt anybody cares, and this
way we have one less gray area to worry about.
Reported-and-argued-for-by: Miklos Szeredi <miklos@szeredi.hu>
Acked-by: Jens Axboe <ens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Converting page lock to new locking bitops requires a change of page flag
operation naming, so we might as well convert it to something nicer
(!TestSetPageLocked_Lock => trylock_page, SetPageLocked => set_page_locked).
This also facilitates lockdeping of page lock.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
