linux/fs/ceph
Jeff Layton 321fe13c93 ceph: add buffered/direct exclusionary locking for reads and writes
xfstest generic/451 intermittently fails. The test does O_DIRECT writes
to a file, and then reads back the result using buffered I/O, while
running a separate set of tasks that are also doing buffered reads.

The client will invalidate the cache prior to a direct write, but it's
easy for one of the other readers' replies to race in and reinstantiate
the invalidated range with stale data.

To fix this, we must to serialize direct I/O writes and buffered reads.
We could just sprinkle in some shared locks on the i_rwsem for reads,
and increase the exclusive footprint on the write side, but that would
cause O_DIRECT writes to end up serialized vs. other direct requests.

Instead, borrow the scheme used by nfs.ko. Buffered writes take the
i_rwsem exclusively, but buffered reads take a shared lock, allowing
them to run in parallel.

O_DIRECT requests also take a shared lock, but we need for them to not
run in parallel with buffered reads.  A flag on the ceph_inode_info is
used to indicate whether it's in direct or buffered I/O mode. When a
conflicting request is submitted, it will block until the inode can be
flipped to the necessary mode.

Link: https://tracker.ceph.com/issues/40985
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2019-09-16 12:06:25 +02:00
..
acl.c ceph: rename struct ceph_acls_info to ceph_acl_sec_ctx 2019-07-08 14:01:42 +02:00
addr.c ceph: don't freeze during write page faults 2019-09-16 12:06:25 +02:00
cache.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 188 2019-05-30 11:29:21 -07:00
cache.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 188 2019-05-30 11:29:21 -07:00
caps.c ceph: remove incorrect comment above __send_cap 2019-09-16 12:06:24 +02:00
ceph_frag.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
debugfs.c ceph: don't return a value from void function 2019-09-16 12:06:25 +02:00
dir.c Merge branch 'work.dcache2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-07-20 09:15:51 -07:00
export.c ceph: fix indentation in __get_snap_name() 2019-09-16 12:06:24 +02:00
file.c ceph: add buffered/direct exclusionary locking for reads and writes 2019-09-16 12:06:25 +02:00
inode.c ceph: update the mtime when truncating up 2019-09-16 12:06:24 +02:00
io.c ceph: add buffered/direct exclusionary locking for reads and writes 2019-09-16 12:06:25 +02:00
io.h ceph: add buffered/direct exclusionary locking for reads and writes 2019-09-16 12:06:25 +02:00
ioctl.c libceph, ceph: move ceph_calc_file_object_mapping() to striper.c 2018-04-02 10:12:43 +02:00
ioctl.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig ceph: add selinux support 2019-07-08 14:01:42 +02:00
locks.c ceph: return -EIO if read/write against filp that lost file locks 2019-09-16 12:06:24 +02:00
Makefile ceph: add buffered/direct exclusionary locking for reads and writes 2019-09-16 12:06:25 +02:00
mds_client.c ceph: eliminate session->s_trim_caps 2019-09-16 12:06:24 +02:00
mds_client.h ceph: eliminate session->s_trim_caps 2019-09-16 12:06:24 +02:00
mdsmap.c ceph: have MDS map decoding use entity_addr_t decoder 2019-07-08 14:01:43 +02:00
quota.c ceph: fix infinite loop in get_quota_realm() 2019-07-08 14:01:42 +02:00
snap.c ceph: fix buffer free while holding i_ceph_lock in __ceph_build_xattrs_blob() 2019-08-22 10:47:41 +02:00
strings.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
super.c ceph: auto reconnect after blacklisted 2019-09-16 12:06:24 +02:00
super.h ceph: add buffered/direct exclusionary locking for reads and writes 2019-09-16 12:06:25 +02:00
xattr.c ceph: don't list vxattrs in listxattr() 2019-09-16 12:06:23 +02:00