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 169ebd9013 ("writeback: Avoid iput() from flusher thread")
removed iget-iput pair from inode writeback. As a side effect, inodes
that are dirty during iput_final() call won't be ever added to inode LRU
(iput_final() doesn't add dirty inodes to LRU and later when the inode
is cleaned there's noone to add the inode there). Thus inodes are
effectively unreclaimable until someone looks them up again.
The practical effect of this bug is limited by the fact that inodes are
pinned by a dentry for long enough that the inode gets cleaned. But
still the bug can have nasty consequences leading up to OOM conditions
under certain circumstances. Following can easily reproduce the
problem:
for (( i = 0; i < 1000; i++ )); do
mkdir $i
for (( j = 0; j < 1000; j++ )); do
touch $i/$j
echo 2 > /proc/sys/vm/drop_caches
done
done
then one needs to run 'sync; ls -lR' to make inodes reclaimable again.
We fix the issue by inserting unused clean inodes into the LRU after
writeback finishes in inode_sync_complete().
Signed-off-by: Jan Kara <jack@suse.cz>
Reported-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: <stable@vger.kernel.org> [3.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
...and fix up the callers. For do_file_open_root, just declare a
struct filename on the stack and fill out the .name field. For
do_filp_open, make it also take a struct filename pointer, and fix up its
callers to call it appropriately.
For filp_open, add a variant that takes a struct filename pointer and turn
filp_open into a wrapper around it.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Split inode_permission() into inode- and superblock-dependent parts.
This is aimed at unionmounts where the superblock from the upper layer has to
be checked rather than the superblock from the lower layer as the upper layer
may be writable, thus allowing an unwritable file from the lower layer to be
copied up and modified.
Original-author: Valerie Aurora <vaurora@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com> (Further development)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Just pass struct file *. Methods are happier that way...
There's no need to return struct file * from finish_open() now,
so let it return int. Next: saner prototypes for parts in
namei.c
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
All users of open intents have been converted to use ->atomic_{open,create}.
This patch gets rid of nd->intent.open and related infrastructure.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Add a new inode operation which is called on the last component of an open.
Using this the filesystem can look up, possibly create and open the file in one
atomic operation. If it cannot perform this (e.g. the file type turned out to
be wrong) it may signal this by returning NULL instead of an open struct file
pointer.
i_op->atomic_open() is only called if the last component is negative or needs
lookup. Handling cached positive dentries here doesn't add much value: these
can be opened using f_op->open(). If the cached file turns out to be invalid,
the open can be retried, this time using ->atomic_open() with a fresh dentry.
For now leave the old way of using open intents in lookup and revalidate in
place. This will be removed once all the users are converted.
David Howells noticed that if ->atomic_open() opens the file but does not create
it, handle_truncate() will be called on it even if it is not a regular file.
Fix this by checking the file type in this case too.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
it's enough to set ->mnt_ns of internal vfsmounts to something
distinct from all struct mnt_namespace out there; then we can
just use the check for ->mnt_ns != NULL in the fast path of
mntput_no_expire()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Split __dentry_open() into two functions:
do_dentry_open() - does most of the actual work, doesn't put file on failure
open_check_o_direct() - after a successful open, checks direct_IO method
This will allow i_op->atomic_open to do just the file initialization and leave
the direct_IO checking to the VFS.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
lglocks and brlocks are currently generated with some complicated macros
in lglock.h. But there's no reason to not just use common utility
functions and put all the data into a common data structure.
Since there are at least two users it makes sense to share this code in a
library. This is also easier maintainable than a macro forest.
This will also make it later possible to dynamically allocate lglocks and
also use them in modules (this would both still need some additional, but
now straightforward, code)
[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Currently remouting superblock read-only is racy in a major way.
With the per mount read-only infrastructure it is now possible to
prevent most races, which this patch attempts.
Before starting the remount read-only, iterate through all mounts
belonging to the superblock and if none of them have any pending
writes, set sb->s_readonly_remount. This indicates that remount is in
progress and no further write requests are allowed. If the remount
succeeds set MS_RDONLY and reset s_readonly_remount.
If the remounting is unsuccessful just reset s_readonly_remount.
This can result in transient EROFS errors, despite the fact the
remount failed. Unfortunately hodling off writes is difficult as
remount itself may touch the filesystem (e.g. through load_nls())
which would deadlock.
A later patch deals with delayed writes due to nlink going to zero.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
some stuff in there can actually become static; some belongs to pnode.h
as it's a private interface between namespace.c and pnode.c...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The per-sb shrinker has the same requirement as the writeback
threads of ensuring that the superblock is usable and pinned for the
time it takes to run the work. Both need to take a passive reference
to the sb, take a read lock on the s_umount lock and then only
continue if an unmount is not in progress.
pin_sb_for_writeback() does this exactly, so move it to fs/super.c
and rename it to grab_super_passive() and exporting it via
fs/internal.h for all the VFS code to be able to use.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
New helper (non-exported, fs/internal.h-only): __d_alloc(sb, name).
Allocates dentry, sets its ->d_sb to given superblock and sets
->d_op accordingly. Old d_alloc(NULL, name) callers are converted
to that (all of them know what superblock they want). d_alloc()
itself is left only for parent != NULl case; uses __d_alloc(),
inserts result into the list of parent's children.
Note that now ->d_sb is assign-once and never NULL *and*
->d_parent is never NULL either.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
