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convert gf_msg() to gf_smsg()
Change-Id: If540ca921b1cd8ca75b92b3d72eb9eb61bdaaa10
Updates: #657
Signed-off-by: yatip <ypadia@redhat.com>
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Change-Id: Ia84cc24c8924e6d22d02ac15f611c10e26db99b4
Signed-off-by: Nigel Babu <nigelb@redhat.com>
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Test case:
# while true; do uuid="`uuidgen`"; echo "some data" > "test$uuid"; mv
"test$uuid" "test" -f || break; echo "done:$uuid"; done
This script was run in parallel from multiple mountpoints
Along the course of getting the above usecase working, many issues
were found:
Issue 1:
=======
consider a case of rename (src, dst). We can encounter a situation
where,
* dst is a file present at the time of lookup
* dst is removed by the time rename fop reaches glusterfs
In this scenario, acquring inodelk on dst fails with ESTALE resulting
in failure of rename. However, as per POSIX irrespective of whether
dst is present or not, rename should be successful. Acquiring entrylk
provides synchronization even in races like this.
Algorithm:
1. Take inodelks on src and dst (if dst is present) on respective
cached subvols. These inodelks are done to preserve backward
compatibility with older clients, so that synchronization is
preserved when a volume is mounted by clients of different
versions. Once relevant older versions (3.10, 3.12, 3.13) reach
EOL, this code can be removed.
2. Ignore ENOENT/ESTALE errors of inodelk on dst.
3. protect namespace of src and dst. To protect namespace of a file,
take inodelk on parent on hashed subvol, then take entrylk on the
same subvol on parent with basename of file. inodelk on parent is
done to guard against changes to parent layout so that hashed
subvol won't change during rename.
4. <rest of rename continues>
5. unlock all locks
Issue 2:
========
linkfile creation in lookup codepath can race with a rename. Imagine
the following scenario:
* lookup finds a data-file with gfid - gfid-dst - without a
corresponding linkto file on hashed-subvol. It decides to create
linkto file with gfid - gfid-dst.
- Note that some codepaths of dht-rename deletes linkto file of
dst as first step. So, a lookup racing with an in-progress
rename can easily run into this situation.
* a rename (src-path:gfid-src, dst-path:gfid-dst) renames data-file
and hence gfid of data-file changes to gfid-src with path dst-path.
* lookup proceeds and creates linkto file - dst-path - with gfid -
dst-gfid - on hashed-subvol.
* rename tries to create a linkto file dst-path with src-gfid on
hashed-subvol, but it fails with EEXIST. But EEXIST is ignored
during linkto file creation.
Now we've ended with dst-path having different gfids - dst-gfid on
linkto file and src-gfid on data file. Future lookups on dst-path will
always fail with ESTALE, due to differing gfids.
The fix is to synchronize linkfile creation in lookup path with rename
using the same mechanism of protecting namespace explained in solution
of Issue 1. Once locks are acquired, before proceeding with linkfile
creation, we check whether conditions for linkto file creation are
still valid. If not, we skip linkto file creation.
Issue 3:
========
gfid of dst-path can change by the time locks are acquired. This
means, either another rename overwrote dst-path or dst-path was
deleted and recreated by a different client. When this happens,
cached-subvol for dst can change. If rename proceeds with old-gfid and
old-cached subvol, we'll end up in inconsistent state(s) like dst-path
with different gfids on different subvols, more than one data-file
being present etc.
Fix is to do the lookup with a new inode after protecting namespace of
dst. Post lookup, we've to compare gfids and correct local state
appropriately to be in sync with backend.
Issue 4:
========
During revalidate lookup, if following a linkto file doesn't lead to a
valid data-file, local->cached-subvol was not reset to NULL. This
means we would be operating on a stale state which can lead to
inconsistency. As a fix, reset it to NULL before proceeding with
lookup everywhere.
Issue 5:
========
Stale dentries left out in inode table on brick resulted in failures
of link fop even though the file/dentry didn't exist on backend fs. A
patch is submitted to fix this issue. Please check the dependency tree
of current patch on gerrit for details
In short, we fix the problem by not blindly trusting the
inode-table. Instead we validate whether dentry is present by doing
lookup on backend fs.
Change-Id: I832e5c47d232f90c4edb1fafc512bf19bebde165
updates: bz#1543279
BUG: 1543279
Signed-off-by: Raghavendra G <rgowdapp@redhat.com>
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Currently its passed in dht_blocking_inode(entry)lk, which would be a
global value for all the locks passed in the argument. This would
be a limitation for cases where we want to ignore failures on only few
locks and fail for others.
Change-Id: I02cfbcaafb593ad8140c0e5af725c866b630fb6b
BUG: 1543279
Signed-off-by: Raghavendra G <rgowdapp@redhat.com>
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dht_readdirp must unwind with list of entries only after
the entire buffer requested by kernel is filled to avoid
extra syscalls occuring when returning partially filled
buffer. Also wind readdir call to next subvol on reaching
EOD for directory on that subvol to avoid extra network call.
Change-Id: If2e1a2722f813d95457c7542bff25fef56c7a041
BUG: 1356453
Signed-off-by: Sakshi <sabansal@redhat.com>
Signed-off-by: Raghavendra G <rgowdapp@redhat.com>
Reviewed-on: https://review.gluster.org/12271
Smoke: Gluster Build System <jenkins@build.gluster.org>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Amar Tumballi <amarts@redhat.com>
Reviewed-by: Susant Palai <spalai@redhat.com>
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Design doc: https://review.gluster.org/16876
Directory creation is now synchronized with blocking inodelk of the
parent on the hashed subvolume followed by the entrylk on the hashed
subvolume between dht_mkdir, dht_rmdir, dht_rename_dir and lookup
selfheal mkdir.
To maintain internal consistency of directories across all subvols of
dht, we need locks. Specifically we are interested in:
1. Consistency of layout of a directory. Only one writer should modify
the layout at a time. A writer (layout setting during directory heal
as part of lookup) shouldn't modify the layout while there are
readers (all other fops like create, mkdir etc., which consume
layout) and readers shouldn't read the layout while a writer is in
progress. Readers can read the layout simultaneously. Writer takes
a WRITE inodelk on the directory (whose layout is being modified)
across ALL subvols. Reader takes a READ inodelk on the directory
(whose layout is being read) on ANY subvol.
2. Consistency of directory namespace across subvols. The path and
associated gfid should be same on all subvols. A gfid should not be
associated with more than one path on any subvol. All fops that can
change directory names (mkdir, rmdir, renamedir, directory creation
phase in lookup-heal) takes an entrylk on hashed subvol of the
directory.
NOTE1: In point 2 above, since dht takes entrylk on hashed subvol of a
directory, the transaction itself is a consumer of layout on
parent directory. So, the transaction is a reader of parent
layout and does an inodelk on parent directory just like any
other layout reader. So a mkdir (dir/subdir) would:
> Acquire a READ inodelk on "dir" on any subvol.
> Acquire an entrylk (dir, "subdir") on hashed subvol of "subdir".
> creates directory on hashed subvol and possibly on non-hashed subvols.
> UNLOCK (entrylk)
> UNLOCK (inodelk)
NOTE2: mkdir fop while setting the layout of the directory being created
is considered as a reader, but NOT a writer. The reason is for
a fop which can consume the layout of a directory to come either
of the following conditions has to be true:
> mkdir syscall from application has to complete. In this case no
need of synchronization.
> A lookup issued on the directory racing with mkdir has to complete.
Since layout setting by a lookup is considered as a writer, only
one of either mkdir or lookup will set the layout.
Code re-organization:
All the lock related routines are moved to "dht-lock.c" file.
New wrapper function is introduced to take blocking inodelk
followed by entrylk 'dht_protect_namespace'
Updates #191
Change-Id: I01569094dfbe1852de6f586475be79c1ba965a31
Signed-off-by: Kotresh HR <khiremat@redhat.com>
BUG: 1443373
Reviewed-on: https://review.gluster.org/15472
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
Smoke: Gluster Build System <jenkins@build.gluster.org>
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