Steven Whitehouse 9fe55eea7e Fix race when checking i_size on direct i/o read ... So far I've had one ACK for this, and no other comments. So I think it is probably time to send this via some suitable tree. I'm guessing that the vfs tree would be the most appropriate route, but not sure that there is one at the moment (don't see anything recent at kernel.org) so in that case I think -mm is the "back up plan". Al, please let me know if you will take this? Steve. --------------------- Following on from the "Re: [PATCH v3] vfs: fix a bug when we do some dio reads with append dio writes" thread on linux-fsdevel, this patch is my current version of the fix proposed as option (b) in that thread. Removing the i_size test from the direct i/o read path at vfs level means that filesystems now have to deal with requests which are beyond i_size themselves. These I've divided into three sets: a) Those with "no op" ->direct_IO (9p, cifs, ceph) These are obviously not going to be an issue b) Those with "home brew" ->direct_IO (nfs, fuse) I've been told that NFS should not have any problem with the larger i_size, however I've added an extra test to FUSE to duplicate the original behaviour just to be on the safe side. c) Those using __blockdev_direct_IO() These call through to ->get_block() which should deal with the EOF condition correctly. I've verified that with GFS2 and I believe that Zheng has verified it for ext4. I've also run the test on XFS and it passes both before and after this change. The part of the patch in filemap.c looks a lot larger than it really is - there are only two lines of real change. The rest is just indentation of the contained code. There remains a test of i_size though, which was added for btrfs. It doesn't cause the other filesystems a problem as the test is performed after ->direct_IO has been called. It is possible that there is a race that does matter to btrfs, however this patch doesn't change that, so its still an overall improvement. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Reported-by: Zheng Liu <gnehzuil.liu@gmail.com> Cc: Jan Kara <jack@suse.cz> Cc: Dave Chinner <david@fromorbit.com> Acked-by: Miklos Szeredi <miklos@szeredi.hu> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <jbacik@fb.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>		2014-01-26 08:26:42 -05:00
..
9p	fs: make posix_acl_create more useful	2014-01-25 23:58:18 -05:00
adfs	adfs: delayed freeing of sbi	2013-10-24 23:43:27 -04:00
affs	affs: use ->kill_sb() to simplify ->put_super() and failure exits of ->mount()	2014-01-25 03:13:01 -05:00
afs	afs: get rid of junk in fs/afs/proc.c	2014-01-25 03:14:06 -05:00
autofs4	autofs4: make freeing sbi rcu-delayed	2013-10-24 23:43:27 -04:00
befs	befs: iget_locked() doesn't return an ERR_PTR	2014-01-25 03:14:38 -05:00
bfs	truncate: drop 'oldsize' truncate_pagecache() parameter	2013-09-12 15:38:02 -07:00
btrfs	btrfs: use generic posix ACL infrastructure	2014-01-25 23:58:18 -05:00
cachefiles	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-11-13 15:34:18 +09:00
ceph	ceph: Avoid data inconsistency due to d-cache aliasing in readpage()	2013-12-13 09:11:38 -08:00
cifs	cifs: set FILE_CREATED	2013-12-27 15:14:45 -06:00
coda	coda_revalidate_inode(): switch to passing inode...	2013-11-09 00:16:21 -05:00
configfs	configfs: fix race between dentry put and lookup	2013-11-21 16:42:27 -08:00
cramfs	cramfs: take headers to fs/cramfs	2014-01-25 03:13:02 -05:00
debugfs	debugfs: use list_next_entry() in debugfs_remove_recursive()	2013-11-13 12:09:24 +09:00
devpts	devpts: plug the memory leak in kill_sb	2013-11-13 12:09:36 +09:00
dlm	genetlink: only pass array to genl_register_family_with_ops()	2013-11-19 16:39:05 -05:00
ecryptfs	ecryptfs: fix failure handling in ->readlink()	2014-01-25 03:13:00 -05:00
efivarfs	consolidate simple ->d_delete() instances	2013-11-15 22:04:17 -05:00
efs	efs: get rid of ->put_super()	2014-01-25 03:13:02 -05:00
exofs	truncate: drop 'oldsize' truncate_pagecache() parameter	2013-09-12 15:38:02 -07:00
exportfs	exportfs: fix quadratic behavior in filehandle lookup	2013-11-09 00:16:38 -05:00
ext2	ext2/3/4: use generic posix ACL infrastructure	2014-01-25 23:58:19 -05:00
ext3	ext2/3/4: use generic posix ACL infrastructure	2014-01-25 23:58:19 -05:00
ext4	ext2/3/4: use generic posix ACL infrastructure	2014-01-25 23:58:19 -05:00
f2fs	f2fs: use generic posix ACL infrastructure	2014-01-25 23:58:19 -05:00
fat	fat: rcu-delay unloading nls and freeing sbi	2013-10-24 23:43:28 -04:00
freevxfs
fscache	Merge branch 'for-3.13/core' of git://git.kernel.dk/linux-block	2013-11-14 12:08:14 +09:00
fuse	Fix race when checking i_size on direct i/o read	2014-01-26 08:26:42 -05:00
gfs2	gfs2: use generic posix ACL infrastructure	2014-01-25 23:58:22 -05:00
hfs	fs/hfs/btree.h: remove duplicate defines	2013-11-13 12:09:32 +09:00
hfsplus	hfsplus: remove can_set_xattr	2014-01-26 08:26:41 -05:00
hostfs	consolidate simple ->d_delete() instances	2013-11-15 22:04:17 -05:00
hpfs	locks: break delegations on any attribute modification	2013-11-09 00:16:44 -05:00
hppfs	clean up scary strncpy(dst, src, strlen(src)) uses	2013-07-03 16:07:41 -07:00
hugetlbfs	cope with potentially long ->d_dname() output for shmem/hugetlb	2013-08-24 12:10:17 -04:00
isofs	isofs: don't pass dentry to isofs_hash{i,}_common()	2013-10-24 23:34:59 -04:00
jbd	jbd: Revert "jbd: remove dependency on __GFP_NOFAIL"	2013-10-31 20:37:15 +01:00
jbd2	jbd2: rename obsoleted msg JBD->JBD2	2013-12-08 21:14:59 -05:00
jffs2	jffs2: use generic posix ACL infrastructure	2014-01-25 23:58:20 -05:00
jfs	jfs: use generic posix ACL infrastructure	2014-01-25 23:58:22 -05:00
lockd	LOCKD: Don't call utsname()->nodename from nlmclnt_setlockargs	2013-08-05 15:03:46 -04:00
logfs	block: submit_bio_wait() conversions	2013-11-24 16:33:41 -07:00
minix	fs/minix: Drop dependency on H8300	2013-09-16 18:20:25 -07:00
ncpfs	ncpfs: rcu-delay unload_nls() and freeing ncp_server	2013-10-24 23:43:28 -04:00
nfs	nfs: use generic posix ACL infrastructure for v3 Posix ACLs	2014-01-26 08:26:20 -05:00
nfs_common
nfsd	nfsd: use get_acl and ->set_acl	2014-01-26 08:26:41 -05:00
nilfs2	nilfs2: fix segctor bug that causes file system corruption	2014-01-15 14:19:42 +07:00
nls	nls: have register_nls() set ->owner	2014-01-25 03:14:05 -05:00
notify	fsnotify: update comments concerning locking scheme	2013-07-09 10:33:20 -07:00
ntfs	iget/iget5: don't bother with ->i_lock until we find a match	2013-11-09 00:16:31 -05:00
ocfs2	ocfs2: use generic posix ACL infrastructure	2014-01-25 23:58:21 -05:00
omfs	truncate: drop 'oldsize' truncate_pagecache() parameter	2013-09-12 15:38:02 -07:00
openpromfs
proc	procfs: also fix proc_reg_get_unmapped_area() for !MMU case	2013-12-12 18:19:26 -08:00
pstore	pstore: Don't allow high traffic options on fragile devices	2013-12-20 13:12:01 -08:00
qnx4	qnx4: clean qnx4_fill_super() up	2014-01-25 03:13:03 -05:00
qnx6
quota	genetlink: make multicast groups const, prevent abuse	2013-11-19 16:39:06 -05:00
ramfs	initmpfs: move rootfs code from fs/ramfs/ to init/	2013-09-11 15:59:37 -07:00
reiserfs	reiserfs: use generic posix ACL infrastructure	2014-01-25 23:58:21 -05:00
romfs
squashfs	Squashfs: fix failure to unlock pages on decompress error	2013-11-24 01:02:50 +00:00
sysfs	sysfs: give different locking key to regular and bin files	2013-12-07 21:22:00 -08:00
sysv	sysv: Add forgotten superblock lock init for v7 fs	2013-09-29 22:02:02 -04:00
ubifs	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-11-13 15:34:18 +09:00
udf	udf: fix for pathetic mount times in case of invalid file system	2013-10-18 22:39:07 +02:00
ufs	truncate: drop 'oldsize' truncate_pagecache() parameter	2013-09-12 15:38:02 -07:00
xfs	xfs: use generic posix ACL infrastructure	2014-01-25 23:58:21 -05:00
aio.c	Merge git://git.kvack.org/~bcrl/aio-next	2013-12-22 11:03:49 -08:00
anon_inodes.c	... and kill anon_inode_getfile_private()	2013-11-09 00:16:28 -05:00
attr.c	locks: break delegations on any attribute modification	2013-11-09 00:16:44 -05:00
bad_inode.c	[readdir] ->readdir() is gone	2013-06-29 12:57:04 +04:00
binfmt_aout.c	dump_skip(): dump_seek() replacement taking coredump_params	2013-11-09 00:16:26 -05:00
binfmt_elf_fdpic.c	elf{,_fdpic} coredump: get rid of pointless if (siginfo->si_signo)	2013-11-09 00:16:30 -05:00
binfmt_elf.c	elf{,_fdpic} coredump: get rid of pointless if (siginfo->si_signo)	2013-11-09 00:16:30 -05:00
binfmt_em86.c	file->f_op is never NULL...	2013-10-24 23:34:54 -04:00
binfmt_flat.c
binfmt_misc.c
binfmt_script.c
binfmt_som.c
bio-integrity.c	Merge branch 'for-3.12/core' of git://git.kernel.dk/linux-block	2013-09-22 15:00:11 -07:00
bio.c	bio: fix argument of __bio_add_page() for max_sectors > 0xffff	2013-11-18 12:31:27 -07:00
block_dev.c	a trivial writeback fix	2013-09-13 23:06:40 -04:00
buffer.c	fs: buffer: move allocation failure loop into the allocator	2013-10-16 21:35:53 -07:00
char_dev.c	Merge branch 'for-3.13/core' of git://git.kernel.dk/linux-block	2013-11-14 12:08:14 +09:00
compat_binfmt_elf.c
compat_ioctl.c	file->f_op is never NULL...	2013-10-24 23:34:54 -04:00
compat.c	[readdir] constify ->actor	2013-06-29 12:57:05 +04:00
coredump.c	dump_emit(): use __kernel_write(), not vfs_write()	2013-11-15 22:04:09 -05:00
coredump.h
dcache.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace	2014-01-17 17:29:36 -08:00
dcookies.c
direct-io.c	direct-io: Use return from cmpxchg to decide of assignment happened	2013-09-09 10:47:42 -07:00
drop_caches.c	shrinker: add node awareness	2013-09-10 18:56:31 -04:00
eventfd.c	eventfd_ctx_fdget(): use fdget() instead of fget()	2014-01-25 03:13:04 -05:00
eventpoll.c	epoll: do not take the nested ep->mtx on EPOLL_CTL_DEL	2014-01-02 14:40:30 -08:00
exec.c	Merge git://git.infradead.org/users/eparis/audit	2013-11-21 19:18:14 -08:00
fcntl.c	file->f_op is never NULL...	2013-10-24 23:34:54 -04:00
fhandle.c
file_table.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-11-13 15:34:18 +09:00
file.c	fs: __fget_light() can use __fget() in slow path	2014-01-25 03:14:38 -05:00
filesystems.c
fs_struct.c	seqcount: Add lockdep functionality to seqcount/seqlock structures	2013-11-06 12:40:26 +01:00
fs-writeback.c	writeback: Fix data corruption on NFS	2013-12-14 04:21:26 +08:00
inode.c	locks: break delegations on any attribute modification	2013-11-09 00:16:44 -05:00
internal.h	get rid of s_files and files_lock	2013-11-09 00:16:20 -05:00
ioctl.c	file->f_op is never NULL...	2013-10-24 23:34:54 -04:00
ioprio.c
Kconfig	fs: remove generic_acl	2014-01-26 08:26:40 -05:00
Kconfig.binfmt
libfs.c	consolidate simple ->d_delete() instances	2013-11-15 22:04:17 -05:00
locks.c	locks: missing unlock on error in generic_add_lease()	2013-11-13 07:30:53 -05:00
Makefile	fs: remove generic_acl	2014-01-26 08:26:40 -05:00
mbcache.c	fs: convert fs shrinkers to new scan/count API	2013-09-10 18:56:31 -04:00
mount.h	RCU'd vfsmounts	2013-11-09 00:16:19 -05:00
mpage.c
namei.c	fs: add get_acl helper	2014-01-25 23:58:16 -05:00
namespace.c	vfs: Fix a regression in mounting proc	2013-11-26 20:54:52 -08:00
no-block.c
open.c	locks: break delegations on any attribute modification	2013-11-09 00:16:44 -05:00
pipe.c	vfs: fix subtle use-after-free of pipe_inode_info	2013-12-02 09:44:51 -08:00
pnode.c	split __lookup_mnt() in two functions	2013-10-24 23:35:00 -04:00
pnode.h	vfs: Don't copy mount bind mounts of /proc/<pid>/ns/mnt between namespaces	2013-08-26 18:42:15 -07:00
posix_acl.c	fs: remove generic_acl	2014-01-26 08:26:40 -05:00
proc_namespace.c	don't bother with vfsmount_lock in mounts_poll()	2013-10-24 23:34:59 -04:00
read_write.c	file->f_op is never NULL...	2013-10-24 23:34:54 -04:00
readdir.c	file->f_op is never NULL...	2013-10-24 23:34:54 -04:00
select.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2013-11-13 15:34:18 +09:00
seq_file.c	seq_file: always clear m->count when we free m->buf	2013-11-18 19:07:53 -08:00
signalfd.c
splice.c	file->f_op is never NULL...	2013-10-24 23:34:54 -04:00
stack.c
stat.c	vfs: split out vfs_getattr_nosec	2013-11-09 00:16:31 -05:00
statfs.c	vfs: allow O_PATH file descriptors for fstatfs()	2013-10-12 13:12:31 -07:00
super.c	get rid of s_files and files_lock	2013-11-09 00:16:20 -05:00
sync.c	Merge branch 'akpm' (patches from Andrew Morton)	2013-11-13 15:45:43 +09:00
timerfd.c
utimes.c	locks: break delegations on any attribute modification	2013-11-09 00:16:44 -05:00
xattr.c