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5 Commits

Author SHA1 Message Date
наб cc33149e5a libshare: nfs: don't leak nfs_lock_fd when lock fails
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #11886
2021-04-19 15:22:58 -07:00
наб 2453d0263d lib/: set O_CLOEXEC on all fds
As found by
  git grep -E '(open|setmntent|pipe2?)\(' |
    grep -vE '((zfs|zpool)_|fd|dl|lzc_re|pidfile_|g_)open\('

FreeBSD's pidfile_open() says nothing about the flags of the files it
opens, but we can't do anything about it anyway; the implementation does
open all files with O_CLOEXEC

Consider this output with zpool.d/media appended with
"pid=$$; (ls -l /proc/$pid/fd > /dev/tty)":
  $ /sbin/zpool iostat -vc media
  lrwx------ 0 -> /dev/pts/0
  l-wx------ 1 -> 'pipe:[3278500]'
  l-wx------ 2 -> /dev/null
  lrwx------ 3 -> /dev/zfs
  lr-x------ 4 -> /proc/31895/mounts
  lrwx------ 5 -> /dev/zfs
  lr-x------ 10 -> /usr/lib/zfs-linux/zpool.d/media
vs
  $ ./zpool iostat -vc vendor,upath,iostat,media
  lrwx------ 0 -> /dev/pts/0
  l-wx------ 1 -> 'pipe:[3279887]'
  l-wx------ 2 -> /dev/null
  lr-x------ 10 -> /usr/lib/zfs-linux/zpool.d/media

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ahelenia Ziemiańska <nabijaczleweli@nabijaczleweli.xyz>
Closes #11866
2021-04-14 13:23:07 -07:00
George Wilson bd76bcb36d
zpool command complains about /etc/exports.d
If the /etc/exports.d directory does not exist, then we should only
create it when we're performing an action which already requires root
privileges.

This commit moves the directory creation to the enable/disable code
path which ensures that we have the appropriate privileges.

Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed-by: Matthew Ahrens <mahrens@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Wilson <gwilson@delphix.com>
Closes #10785
Closes #10934
2020-09-25 13:09:40 -07:00
alaviss 75bf636cd0
libshare: Add missing headers for nfs.c
On musl libc, zfs failed to compile due to the missing <fcntl.h>
include, which is required for `open()` per POSIX.

This commit add the missing <fcntl.h> include.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Hiếu Lê <leorize+oss@disroot.org>
Closes #10880
2020-09-04 12:03:57 -07:00
George Wilson c15d36c674
Remove dependency on sharetab file and refactor sharing logic
== Motivation and Context

The current implementation of 'sharenfs' and 'sharesmb' relies on
the use of the sharetab file. The use of this file is os-specific
and not required by linux or freebsd. Currently the code must
maintain updates to this file which adds complexity and presents
a significant performance impact when sharing many datasets. In
addition, concurrently running 'zfs sharenfs' command results in
missing entries in the sharetab file leading to unexpected failures.

== Description

This change removes the sharetab logic from the linux and freebsd
implementation of 'sharenfs' and 'sharesmb'. It still preserves an
os-specific library which contains the logic required for sharing
NFS or SMB. The following entry points exist in the vastly simplified
libshare library:

- sa_enable_share -- shares a dataset but may not commit the change
- sa_disable_share -- unshares a dataset but may not commit the change
- sa_is_shared -- determine if a dataset is shared
- sa_commit_share -- notify NFS/SMB subsystem to commit the shares
- sa_validate_shareopts -- determine if sharing options are valid

The sa_commit_share entry point is provided as a performance enhancement
and is not required. The sa_enable_share/sa_disable_share may commit
the share as part of the implementation. Libshare provides a framework
for both NFS and SMB but some operating systems may not fully support
these protocols or all features of the protocol.

NFS Operation:
For linux, libshare updates /etc/exports.d/zfs.exports to add
and remove shares and then commits the changes by invoking
'exportfs -r'. This file, is automatically read by the kernel NFS
implementation which makes for better integration with the NFS systemd
service. For FreeBSD, libshare updates /etc/zfs/exports to add and
remove shares and then commits the changes by sending a SIGHUP to
mountd.

SMB Operation:
For linux, libshare adds and removes files in /var/lib/samba/usershares
by calling the 'net' command directly. There is no need to commit the
changes. FreeBSD does not support SMB.

== Performance Results

To test sharing performance we created a pool with an increasing number
of datasets and invoked various zfs actions that would enable and
disable sharing. The performance testing was limited to NFS sharing.
The following tests were performed on an 8 vCPU system with 128GB and
a pool comprised of 4 50GB SSDs:

Scale testing:
- Share all filesystems in parallel -- zfs sharenfs=on <dataset> &
- Unshare all filesystems in parallel -- zfs sharenfs=off <dataset> &

Functional testing:
- share each filesystem serially -- zfs share -a
- unshare each filesystem serially -- zfs unshare -a
- reset sharenfs property and unshare -- zfs inherit -r sharenfs <pool>

For 'zfs sharenfs=on' scale testing we saw an average reduction in time
of 89.43% and for 'zfs sharenfs=off' we saw an average reduction in time
of 83.36%.

Functional testing also shows a huge improvement:
- zfs share -- 97.97% reduction in time
- zfs unshare -- 96.47% reduction in time
- zfs inhert -r sharenfs -- 99.01% reduction in time

Reviewed-by: Matt Ahrens <matt@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Bryant G. Ly <bryangly@gmail.com>
Signed-off-by: George Wilson <gwilson@delphix.com>
External-Issue: DLPX-68690
Closes #1603
Closes #7692
Closes #7943
Closes #10300
2020-07-13 09:19:18 -07:00