glusterfs.git/xlators/mount/fuse/src/fuse-bridge.h, branch v5.3

fuse: add --lru-limit option

2019-01-16T15:59:03+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#1623107
Change-Id: Ifee0737b23b12b1426c224ec5b8f591f487d83a2
Signed-off-by: Amar Tumballi

Land clang-format changes

2018-09-12T11:52:48+00:00

Change-Id: I6f5d8140a06f3c1b2d196849299f8d483028d33b

fuse: add support for kernel writeback cache

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

- Added kernel-writeback-cache command line and xlator
  option for requesting utilisation of the writeback
  cache of the kernel in FUSE_INIT (see [1]).
- Added attr-times-granularity command line and xlator
  option via which granularity of the {a,m,c}time in
  stat (attr) data that we support can be indicated to
  kernel. This is a means to avoid divergence of the
  attr times between kernel and userspace that could
  occur with writeback-cache, while still maintaining
  maximum time precision the FUSE server is capable of
  (see [2]).
- Handling FATTR_CTIME flag in FUSE_SETATTR that
  indicates presence of ctime in setattr payload.
  Currently we cannot associate arbitrary ctimes to
  files on backend, so we just touch them to update
  their ctimes to current time. Having ctimes in setattr
  payload is also a side effect of writeback cache
  (see [3] and [4]).

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=4d99ff8,
     "fuse: Turn writeback cache on"
[2]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e27c9d3,
     "fuse: fuse: add time_gran to INIT_OUT"
[3]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1e18bda,
     "fuse: add .write_inode"
[4]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ab9e13f,
     "fuse: allow ctime flushing to userspace"

Updates: #435
Change-Id: Id174c8e0c815c4456c35f8c53e41a6a507d91855
Signed-off-by: Csaba Henk

mount/fuse: Add support for multi-threaded fuse readers

2018-04-02T06:10:30+00:00

Usage: Use 'reader-thread-count=' as command line option to
set the thread count at the time of mounting the volume.

Next task is to make these threads auto-scale based on the load,
instead of having the user remount the volume everytime to change
the thread count.

Updates #412

Change-Id: I94aa1505e5ae6a133683d473e0e4e0edd139b76b
Signed-off-by: Krutika Dhananjay

gfproxyd: Let glusterd manage gfproxy daemon

2017-10-18T14:15:05+00:00

Updates: #242
BUG: 1428063
Change-Id: Iaaf2edf99b2ecc75f6d30762c752a6d445c1c826
Signed-off-by: Poornima G

mount/fuse: Make event-history feature configurable

2017-09-24T06:22:07+00:00

... and disable it by default.

This is because having it disabled seems to improve performance.
This could be due to the lock contention by the different epoll threads
on the circular buff lock in the fop cbks just before writing their response
to /dev/fuse.

Just to provide some data - wrt ovirt-gluster hyperconverged
environment, I saw an increase in IOPs by 12K with event-history
disabled for randrom read workload.

Usage:
mount -t glusterfs -o event-history=on $HOSTNAME:$VOLNAME $MOUNTPOINT
OR
glusterfs --event-history=on --volfile-server=$HOSTNAME --volfile-id=$VOLNAME $MOUNTPOINT

Change-Id: Ia533788d309c78688a315dc8cd04d30fad9e9485
BUG: 1467614
Signed-off-by: Krutika Dhananjay

fuse: implement "-oauto_unmount"

2017-05-23T13:21:25+00:00

libfuse has an auto_unmount option which,
if enabled, ensures that the file system
is unmounted at FUSE server termination
by running a separate monitor process
that performs the unmount when that
occurs. (This feature would probably
better be called "robust auto-unmount",
as FUSE servers usually do try to unmount
their file systems upon termination,
it's just this mechanism is not crash
resilient.)

This change implements that option and
behavior for glusterfs.

Note that "auto unmount" (robust or not) is
a leaky abstraction, as the kernel cannot
guarantee that at the path where the FUSE
fs is mounted is actually the toplevel mount
at the time of the umount(2) call, for
multiple reasons, among others, see:

  fuse-devel: "fuse: feasible to distinguish between umount and abort?"
  http://fuse.996288.n3.nabble.com/fuse-feasible-to-distinguish-between-umount-and-abort-tt14358.html
  https://github.com/libfuse/libfuse/issues/122

Updates #153

Change-Id: Ia4432580c9fd2c156d9c73c3a44f4bfd42437599
Signed-off-by: Csaba Henk 
Reviewed-on: https://review.gluster.org/17230
Tested-by: Amar Tumballi 
CentOS-regression: Gluster Build System 
Smoke: Gluster Build System 
Reviewed-by: Amar Tumballi 
NetBSD-regression: NetBSD Build System

dict: Don't expose get_new_dict/dict_destroy

2016-07-26T06:47:33+00:00

get_new_dict/dict_destroy is causing confusion where, dict_new/dict_destroy or
get_new_dict/dict_unref are used instead of dict_new/dict_unref.

Change-Id: I4cc69f5b6711d720823395e20fd624a0c6c1168c
BUG: 1296043
Signed-off-by: Pranith Kumar K 
Reviewed-on: http://review.gluster.org/13183
Smoke: Gluster Build System 
CentOS-regression: Gluster Build System 
NetBSD-regression: NetBSD Build System 
Reviewed-by: Jeff Darcy 
Reviewed-by: Krutika Dhananjay

fuse: Address the review comments in the backport

2016-03-10T03:15:33+00:00

Backport @ http://review.gluster.org/#/c/13626/3

Fix a typo error, consolidate the selinux and capability
check in getxattr and setxattr.

Change-Id: I4303de3d4dd00853169b07577311e03cbb912ed7
BUG: 1316327
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/13653
NetBSD-regression: NetBSD Build System 
Tested-by: Vijay Bellur 
Smoke: Gluster Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Vijay Bellur

fuse: Add a new mount option capability

2016-03-08T05:57:28+00:00

Originally all security.* xattrs were forbidden if selinux is disabled,
which was causing Samba's acl_xattr module to not work, as it would
store the NTACL in security.NTACL. To fix this http://review.gluster.org/#/c/12826/
was sent, which forbid only security.selinux. This opened up a getxattr
call on security.capability before every write fop and others.

Capabilities can be used without selinux, hence if selinux is disabled,
security.capability cannot be forbidden. Hence adding a new mount
option called capability.

Only when "--capability" or "--selinux" mount option is used,
security.capability is sent to the brick, else it is forbidden.

Change-Id: I77f60e0fb541deaa416159e45c78dd2ae653105e
BUG: 1309462
Signed-off-by: Poornima G 
Reviewed-on: http://review.gluster.org/13540
Smoke: Gluster Build System 
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Raghavendra G