Bug 1523219 - fuse xlator uses block size and fragment size 128KB leading to rounding off in df output
Summary: fuse xlator uses block size and fragment size 128KB leading to rounding off i...
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: GlusterFS
Classification: Community
Component: fuse
Version: mainline
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
Assignee: bugs@gluster.org
QA Contact:
URL:
Whiteboard:
: 1566823 (view as bug list)
Depends On:
Blocks: 1523216
TreeView+ depends on / blocked
 
Reported: 2017-12-07 12:34 UTC by Raghavendra Talur
Modified: 2018-06-20 17:57 UTC (History)
2 users (show)

Fixed In Version: glusterfs-v4.1.0
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Environment:
Last Closed: 2018-06-20 17:57:42 UTC
Regression: ---
Mount Type: ---
Documentation: ---
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Description Raghavendra Talur 2017-12-07 12:34:19 UTC
Description of problem:
This difference is because FUSE uses a block size and fragment size of 128K instead of using the backend filesystem's block size.

When statvfs call is made, this is the statvfs buffer content

      blocks  bfree   bavail
gfapi 259584, 248433, 251028
brick 259584, 251028, 251028
fuse    8112,   7763,   7844


As you can see, gfapi and brick match in total blocks and bavail.
There is a difference in bfree because of posix xlator. Posix xlator deducts 1% of the total blocks from free blocks.

The numbers in fuse are the numbers in gfapi row divided by 32(because the numbers obtained from brick are for 4K blocks and fuse wants to communicate in terms of 128K blocks). Here, we are converting into a larger unit and value is rounded off.

df on a mount point would get data from fuse and hence the discrepancy.

Comment 1 Csaba Henk 2018-04-13 04:37:14 UTC
*** Bug 1566823 has been marked as a duplicate of this bug. ***

Comment 2 Worker Ant 2018-04-14 06:35:11 UTC
REVIEW: https://review.gluster.org/19873 (fuse: retire statvfs tweak) posted (#1) for review on master by Csaba Henk

Comment 3 Worker Ant 2018-04-16 08:41:13 UTC
COMMIT: https://review.gluster.org/19873 committed in master by "Raghavendra G" <rgowdapp> with a commit message- fuse: retire statvfs tweak

fuse xlator used to override the  filesystem
block size of the storage backend to indicate
its preferences. Now we retire this tweak and
pass on what we get from the backend.

This fixes the anomaly reported in the referred
BUG. For more background, see the following email,
which was sent out to gluster-devel and gluster-users
mailing lists to gauge if anyone sees any use of
this tweak:

http://lists.gluster.org/pipermail/gluster-devel/2018-March/054660.html
http://lists.gluster.org/pipermail/gluster-users/2018-March/033775.html

Noone vetoed the removal of it but it got endorsement:

http://lists.gluster.org/pipermail/gluster-devel/2018-March/054686.html

BUG: 1523219
Change-Id: I3b7111d3037a1b91a288c1589f407b2c48d81bfa
Signed-off-by: Csaba Henk <csaba>

Comment 4 Shyamsundar 2018-06-20 17:57:42 UTC
This bug is getting closed because a release has been made available that should address the reported issue. In case the problem is still not fixed with glusterfs-v4.1.0, please open a new bug report.

glusterfs-v4.1.0 has been announced on the Gluster mailinglists [1], packages for several distributions should become available in the near future. Keep an eye on the Gluster Users mailinglist [2] and the update infrastructure for your distribution.

[1] http://lists.gluster.org/pipermail/announce/2018-June/000102.html
[2] https://www.gluster.org/pipermail/gluster-users/


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