glusterfs.git/xlators/mount/fuse/utils, branch v7.0alpha

mount.glusterfs: change the error message

2019-03-29T07:24:50+00:00

In scenarios where a mount fails before creating log file, doesn't
make sense to give message to 'check log file'. See below:

```
ERROR: failed to create logfile "/var/log/glusterfs/mnt.log" (No space left on device)
ERROR: failed to open logfile /var/log/glusterfs/mnt.log
Mount failed. Please check the log file for more details.
```

Fixes: bz#1688068
Change-Id: I1d837caa4f9bc9f1a37780783e95007e01ae4e3f
Signed-off-by: Amar Tumballi

core: implement a global thread pool

2019-02-18T02:58:24+00:00

This patch implements a thread pool that is wait-free for adding jobs to
the queue and uses a very small locked region to get jobs. This makes it
possible to decrease contention drastically. It's based on wfcqueue
structure provided by urcu library.

It automatically enables more threads when load demands it, and stops
them when not needed. There's a maximum number of threads that can be
used. This value can be configured.

Depending on the workload, the maximum number of threads plays an
important role. So it needs to be configured for optimal performance.
Currently the thread pool doesn't self adjust the maximum for the
workload, so this configuration needs to be changed manually.

For this reason, the global thread pool has been made optional, so that
volumes can still use the thread pool provided by io-threads.

To enable it for bricks, the following option needs to be set:

   config.global-threading = on

This option has no effect if bricks are already running. A restart is
required to activate it. It's recommended to also enable the following
option when running bricks with the global thread pool:

   performance.iot-pass-through = on

To enable it for a FUSE mount point, the option '--global-threading'
must be added to the mount command. To change it, an umount and remount
is needed. It's recommended to disable the following option when using
global threading on a mount point:

   performance.client-io-threads = off

To enable it for services managed by glusterd, glusterd needs to be
started with option '--global-threading'. In this case all daemons, like
self-heal, will be using the global thread pool.

Currently it can only be enabled for bricks, FUSE mounts and glusterd
services.

The maximum number of threads for clients and bricks can be configured
using the following options:

   config.client-threads
   config.brick-threads

These options can be applied online and its effect is immediate most of
the times. If one of them is set to 0, the maximum number of threads
will be calcutated as #cores * 2.

Some distributions use a very old userspace-rcu library (version 0.7)
for this reason, some header files from version 0.10 have been copied
into contrib/userspace-rcu and are used if the detected version is 0.7
or older.

An additional change has been made to io-threads to prevent that threads
are started when iot-pass-through is set.

Change-Id: I09d19e246b9e6d53c6247b29dfca6af6ee00a24b
updates: #532
Signed-off-by: Xavi Hernandez

mount/fuse: fix bug related to --auto-invalidation in mount script

2019-02-09T18:41:12+00:00

When "auto-invalidation" option was not specified for mount script,
glusterfs cmdline ended with "--auto-invalidation=" option. This patch
fixes that bug in mount script.

Thanks to Amar for reporting it.

Change-Id: Ie5cd4c6ffb3ac644d9d2b032035f914a935d05a8
Signed-off-by: Raghavendra Gowdappa 
updates: bz#1664934

mount/fuse: expose auto-invalidation as a mount option

2019-02-02T03:07:35+00:00

Auto invalidation is necessary when same (meta)data is shared/access
across multiple mounts. However, if (meta)data is not shared, all
relevant I/O goes through the cache of single mount and hence is
coherent with (meta)data on bricks always. So, fuse-auto-invalidation
can be disabled for this case which gives a huge performance boost for
workloads that write data and then immediately read the data they just
wrote.

From glusterfs --help,


      --auto-invalidation[=BOOL]   controls whether fuse-kernel can
                             auto-invalidate attribute, dentry and page-cache.
                             Disable this only if same files/directories are
                             not accessed across two different mounts
                             concurrently [default: "on"]


Details on how disabling auto-invalidation helped to reduce pgbench
init times can be found at [1]. Time taken for pgbench init of scale
8000 was 8340s. That will be an improvement of 86% (59280s vs 8340s)
with auto-invalidations turned off along with other
optimizations. Just disabling auto-invalidation contributed 56%
improvement by reducing the total time taken by 33260s.

[1] https://www.spinics.net/lists/gluster-devel/msg25907.html

Change-Id: I0ed730dba9064bd9c576ad1800170a21e100e1ce
Signed-off-by: Raghavendra Gowdappa 
updates: bz#1664934

fuse: add --lru-limit option

2018-12-14T17:34:28+00:00

The inode LRU mechanism is moot in fuse xlator (ie. there is no
limit for the LRU list), as fuse inodes are referenced from
kernel context, and thus they can only be dropped on request of
the kernel. This might results in a high number of passive
inodes which are useless for the glusterfs client, causing a
significant memory overhead.

This change tries to remedy this by extending the LRU semantics
and allowing to set a finite limit on the fuse inode LRU.

A brief history of problem:

When gluster's inode table was designed, fuse didn't have any
'invalidate' method, which means, userspace application could
never ask kernel to send a 'forget()' fop, instead had to wait
for kernel to send it based on kernel's parameters. Inode table
remembers the number of times kernel has cached the inode based
on the 'nlookup' parameter. And 'nlookup' field is not used by
no other entry points (like server-protocol, gfapi etc).

Hence the inode_table of fuse module always has to have lru-limit
as '0', which means no limit. GlusterFS always had to keep all
inodes in memory as kernel would have had a reference to it.
Again, the reason for this is, kernel's glusterfs inode reference
was pointer of 'inode_t' structure in glusterfs. As it is a
pointer, we could never free it (to prevent segfault, or memory
corruption).

Solution:

In the inode table, handle the prune case of inodes with 'nlookup'
differently, and call a 'invalidator' method, which in this case is
fuse_invalidate(), and it sends the request to kernel for getting
the forget request.

When the kernel sends the forget, it means, it has dropped all
the reference to the inode, and it will send the forget with the
'nlookup' parameter too. We just need to make sure to reduce the
'nlookup' value we have when we get forget. That automatically
cause the relevant prune to happen.

Credits: Csaba Henk, Xavier Hernandez, Raghavendra Gowdappa, Nithya B

fixes: bz#1560969
Change-Id: Ifee0737b23b12b1426c224ec5b8f591f487d83a2
Signed-off-by: Amar Tumballi

fuse: diagnostic FLUSH interrupt

2018-11-06T04:21:57+00:00

We add dummy interrupt handling for the FLUSH
fuse message. It can be enabled by the
"--fuse-flush-handle-interrupt" hidden command line
option, or "-ofuse-flush-handle-interrupt=yes"
mount option.

It serves no other than diagnostic & demonstational
purposes -- to exercise the interrupt handling framework
a bit and to give an usage example.

Documentation is also provided that showcases interrupt
handling via FLUSH.

Change-Id: I522f1e798501d06b74ac3592a5f73c1ab0590c60
updates: #465
Signed-off-by: Csaba Henk

mount.glusterfs: A more explicit check to avoid identical mounts

2018-10-24T10:18:58+00:00

Change check condition from
"[[:space:]+]${mount_point}[[:space:]+]fuse" to
"[[:space:]+]${mount_point}[[:space:]+]fuse.glusterfs". Fix false
postive check result for mount points of other FUSEes, such as "fuse.sshfs".

Change-Id: I13898b50a651a8f5ecc3a94d01b3b5de37ec4cbc
fixes: bz#1640026
Signed-off-by: Han Han

fuse: prevent error message "can't shift that many"

2018-10-01T04:26:45+00:00

On systems where /bin/sh is not Bash, running plain mount.glusterfs
gives the unhelpful error "can't shift that many".

The argument parsing can be a little improved. Adding a check for the
number of arguments, minimal two (Gluster ip:/volume, and mountpoint),
but possibly more (-o, -v etc.).

With the additional check, running 'mount.glusterfs -h' now shows the
following messags:

    Usage: /sbin/mount.glusterfs :  -o
    Options:
    man 8 mount.glusterfs
    To display the version number of the mount helper: /sbin/mount.glusterfs -V

Change-Id: I50e3ade0c6217fab4155f35ad8cb35d99d52e133
Fixes: bz#1564890
Reported-by: Alexander Zimmermann 
Signed-off-by: Niels de Vos

fuse: avoid using the which command

2018-06-21T05:44:26+00:00

In mount.glusterfs avoid using the which tool as it may not exist
on minimal system installs. Use the "command -v" builtin as
it is expected to be more portable.
Remove a extra semicolon while we're at it.

Change-Id: Ib682ed4955d5bad1beb94b65d10f4c44e9490767
fixes: bz#1593351
Signed-off-by: John Mulligan

mount,fuse: make fuse dumping available as mount option

2018-05-04T17:42:12+00:00

Updates: bz#1193929
Change-Id: I4dd4d0e607f89650ebb74b893b911b554472826d
Signed-off-by: Csaba Henk