To make the logs more readable such as for log likes:
ceph: will move 00000000a42b796b to split realm 100000003ed 000000007146df45
With this it will always show the inode numbers instead the inode
addresses.
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This will reduce very possible but unnecessary frequently memory
allocate/free in this loop.
URL: https://tracker.ceph.com/issues/44100
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
The global snaprealm would be created and then destroyed immediately
every time when updating it.
URL: https://tracker.ceph.com/issues/54362
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Use a list instead of recursion to avoid possible stack overflow.
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
We will only track the uppest parent snapshot realm from which we
need to rebuild the snapshot contexts _downward_ in hierarchy. For
all the others having no new snapshot we will do nothing.
This fix will avoid calling ceph_queue_cap_snap() on some inodes
inappropriately. For example, with the code in mainline, suppose there
are 2 directory hierarchies (with 6 directories total), like this:
/dir_X1/dir_X2/dir_X3/
/dir_Y1/dir_Y2/dir_Y3/
Firstly, make a snapshot under /dir_X1/dir_X2/.snap/snap_X2, then make a
root snapshot under /.snap/root_snap. Every time we make snapshots under
/dir_Y1/..., the kclient will always try to rebuild the snap context for
snap_X2 realm and finally will always try to queue cap snaps for dir_Y2
and dir_Y3, which makes no sense.
That's because the snap_X2's seq is 2 and root_snap's seq is 3. So when
creating a new snapshot under /dir_Y1/... the new seq will be 4, and
the mds will send the kclient a snapshot backtrace in _downward_
order: seqs 4, 3.
When ceph_update_snap_trace() is called, it will always rebuild the from
the last realm, that's the root_snap. So later when rebuilding the snap
context, the current logic will always cause it to rebuild the snap_X2
realm and then try to queue cap snaps for all the inodes related in that
realm, even though it's not necessary.
This is accompanied by a lot of these sorts of dout messages:
"ceph: queue_cap_snap 00000000a42b796b nothing dirty|writing"
Fix the logic to avoid this situation.
Also, the 'invalidate' word is not precise here. In actuality, it will
cause a rebuild of the existing snapshot contexts or just build
non-existent ones. Rename it to 'rebuild_snapcs'.
URL: https://tracker.ceph.com/issues/44100
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
There could be huge number of capsnaps around at any given time. On
x86_64 the structure is 248 bytes, which will be rounded up to 256 bytes
by kzalloc. Move this to a dedicated slabcache to save 8 bytes for each.
[ jlayton: use kmem_cache_zalloc ]
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Consolidate some fiddly code for changing an inode's snap_realm
into a new helper function, and change the callers to use it.
While we're in here, nothing uses the i_snap_realm_counter field, so
remove that from the inode.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Luis Henriques <lhenriques@suse.de>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
The ceph_cap_flush structures are usually dynamically allocated, but
the ceph_cap_snap has an embedded one.
When force umounting, the client will try to remove all the session
caps. During this, it will free them, but that should not be done
with the ones embedded in a capsnap.
Fix this by adding a new boolean that indicates that the cap flush is
embedded in a capsnap, and skip freeing it if that's set.
At the same time, switch to using list_del_init() when detaching the
i_list and g_list heads. It's possible for a forced umount to remove
these objects but then handle_cap_flushsnap_ack() races in and does the
list_del_init() again, corrupting memory.
Cc: stable@vger.kernel.org
URL: https://tracker.ceph.com/issues/52283
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
There is a race in ceph_put_snap_realm. The change to the nref and the
spinlock acquisition are not done atomically, so you could decrement
nref, and before you take the spinlock, the nref is incremented again.
At that point, you end up putting it on the empty list when it
shouldn't be there. Eventually __cleanup_empty_realms runs and frees
it when it's still in-use.
Fix this by protecting the 1->0 transition with atomic_dec_and_lock,
and just drop the spinlock if we can get the rwsem.
Because these objects can also undergo a 0->1 refcount transition, we
must protect that change as well with the spinlock. Increment locklessly
unless the value is at 0, in which case we take the spinlock, increment
and then take it off the empty list if it did the 0->1 transition.
With these changes, I'm removing the dout() messages from these
functions, as well as in __put_snap_realm. They've always been racy, and
it's better to not print values that may be misleading.
Cc: stable@vger.kernel.org
URL: https://tracker.ceph.com/issues/46419
Reported-by: Mark Nelson <mnelson@redhat.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Luis Henriques <lhenriques@suse.de>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Now that we don't need to hold session->s_mutex or the snap_rwsem when
calling ceph_check_caps, we can eliminate ceph_async_iput and just use
normal iput calls.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
They both say that the snap_rwsem must be held for write, but I don't
see any real reason for it, and it's not currently always called that
way.
The lookup is just walking the rbtree, so holding it for read should be
fine there. The "get" is bumping the refcount and (possibly) removing
it from the empty list. I see no need to hold the snap_rwsem for write
for that.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Currently ceph_update_snap_realm returns -EINVAL when it hits a decoding
error, which is the wrong error code. -EINVAL implies that the user gave
us a bogus argument to a syscall or something similar. -EIO is more
descriptive when we hit a decoding error.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
We need to use i_size_read(), which properly handles the torn read
case on 32-bit arches.
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
If the Fb cap is used it means the current inode is flushing the
dirty data to OSD, just defer flushing the capsnap.
URL: https://tracker.ceph.com/issues/48640
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Some messages sent by the MDS entail a session sequence number
increment, and the MDS will drop certain types of requests on the floor
when the sequence numbers don't match.
In particular, a REQUEST_CLOSE message can cross with one of the
sequence morphing messages from the MDS which can cause the client to
stall, waiting for a response that will never come.
Originally, this meant an up to 5s delay before the recurring workqueue
job kicked in and resent the request, but a recent change made it so
that the client would never resend, causing a 60s stall unmounting and
sometimes a blockisting event.
Add a new helper for incrementing the session sequence and then testing
to see whether a REQUEST_CLOSE needs to be resent, and move the handling
of CEPH_MDS_SESSION_CLOSING into that function. Change all of the
bare sequence counter increments to use the new helper.
Reorganize check_session_state with a switch statement. It should no
longer be called when the session is CLOSING, so throw a warning if it
ever is (but still handle that case sanely).
[ idryomov: whitespace, pr_err() call fixup ]
URL: https://tracker.ceph.com/issues/47563
Fixes: fa99677342 ("ceph: fix potential mdsc use-after-free crash")
Reported-by: Patrick Donnelly <pdonnell@redhat.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This will help simplify the code.
[ jlayton: fix minor merge conflict in quota.c ]
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Calling ceph_buffer_put() in __ceph_build_xattrs_blob() may result in
freeing the i_xattrs.blob buffer while holding the i_ceph_lock. This can
be fixed by having this function returning the old blob buffer and have
the callers of this function freeing it when the lock is released.
The following backtrace was triggered by fstests generic/117.
BUG: sleeping function called from invalid context at mm/vmalloc.c:2283
in_atomic(): 1, irqs_disabled(): 0, pid: 649, name: fsstress
4 locks held by fsstress/649:
#0: 00000000a7478e7e (&type->s_umount_key#19){++++}, at: iterate_supers+0x77/0xf0
#1: 00000000f8de1423 (&(&ci->i_ceph_lock)->rlock){+.+.}, at: ceph_check_caps+0x7b/0xc60
#2: 00000000562f2b27 (&s->s_mutex){+.+.}, at: ceph_check_caps+0x3bd/0xc60
#3: 00000000f83ce16a (&mdsc->snap_rwsem){++++}, at: ceph_check_caps+0x3ed/0xc60
CPU: 1 PID: 649 Comm: fsstress Not tainted 5.2.0+ #439
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-prebuilt.qemu.org 04/01/2014
Call Trace:
dump_stack+0x67/0x90
___might_sleep.cold+0x9f/0xb1
vfree+0x4b/0x60
ceph_buffer_release+0x1b/0x60
__ceph_build_xattrs_blob+0x12b/0x170
__send_cap+0x302/0x540
? __lock_acquire+0x23c/0x1e40
? __mark_caps_flushing+0x15c/0x280
? _raw_spin_unlock+0x24/0x30
ceph_check_caps+0x5f0/0xc60
ceph_flush_dirty_caps+0x7c/0x150
? __ia32_sys_fdatasync+0x20/0x20
ceph_sync_fs+0x5a/0x130
iterate_supers+0x8f/0xf0
ksys_sync+0x4f/0xb0
__ia32_sys_sync+0xa/0x10
do_syscall_64+0x50/0x1c0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fc6409ab617
Signed-off-by: Luis Henriques <lhenriques@suse.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
iput_final() may wait for reahahead pages. The wait can cause deadlock.
For example:
Workqueue: ceph-msgr ceph_con_workfn [libceph]
Call Trace:
schedule+0x36/0x80
io_schedule+0x16/0x40
__lock_page+0x101/0x140
truncate_inode_pages_range+0x556/0x9f0
truncate_inode_pages_final+0x4d/0x60
evict+0x182/0x1a0
iput+0x1d2/0x220
iterate_session_caps+0x82/0x230 [ceph]
dispatch+0x678/0xa80 [ceph]
ceph_con_workfn+0x95b/0x1560 [libceph]
process_one_work+0x14d/0x410
worker_thread+0x4b/0x460
kthread+0x105/0x140
ret_from_fork+0x22/0x40
Workqueue: ceph-msgr ceph_con_workfn [libceph]
Call Trace:
__schedule+0x3d6/0x8b0
schedule+0x36/0x80
schedule_preempt_disabled+0xe/0x10
mutex_lock+0x2f/0x40
ceph_check_caps+0x505/0xa80 [ceph]
ceph_put_wrbuffer_cap_refs+0x1e5/0x2c0 [ceph]
writepages_finish+0x2d3/0x410 [ceph]
__complete_request+0x26/0x60 [libceph]
handle_reply+0x6c8/0xa10 [libceph]
dispatch+0x29a/0xbb0 [libceph]
ceph_con_workfn+0x95b/0x1560 [libceph]
process_one_work+0x14d/0x410
worker_thread+0x4b/0x460
kthread+0x105/0x140
ret_from_fork+0x22/0x40
In above example, truncate_inode_pages_range() waits for readahead pages
while holding s_mutex. ceph_check_caps() waits for s_mutex and blocks
OSD dispatch thread. Later OSD replies (for readahead) can't be handled.
ceph_check_caps() also may lock snap_rwsem for read. So similar deadlock
can happen if iput_final() is called while holding snap_rwsem.
In general, it's not good to call iput_final() inside MDS/OSD dispatch
threads or while holding any mutex.
The fix is introducing ceph_async_iput(), which calls iput_final() in
workqueue.
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
We missed two places that i_wrbuffer_ref_head, i_wr_ref, i_dirty_caps
and i_flushing_caps may change. When they are all zeros, we should free
i_head_snapc.
Cc: stable@vger.kernel.org
Link: https://tracker.ceph.com/issues/38224
Reported-and-tested-by: Luis Henriques <lhenriques@suse.com>
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
ceph_getattr() return zero dev ID for head inodes and set dev ID to
snapid directly for snaphost inodes. This is not good because userspace
utilities may consider device ID of 0 as invalid, snapid may conflict
with other device's ID.
This patch introduces "snapids to anonymous bdev IDs" map. we create a
new mapping when we see a snapid for the first time. we trim unused
mapping after it is ilde for 5 minutes.
Link: http://tracker.ceph.com/issues/22353
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Since the vfs structures are all using timespec64, we can now
change the internal representation, using ceph_encode_timespec64 and
ceph_decode_timespec64.
In case of ceph_aux_inode however, we need to avoid doing a memcmp()
on uninitialized padding data, so the members of the i_mtime field get
copied individually into 64-bit integers.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Keep a pointer to the inode in struct ceph_snap_realm. This allows to
optimize functions that walk the realms hierarchy (e.g. in quotas).
Signed-off-by: Luis Henriques <lhenriques@suse.com>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3ae0bebc "ceph: queue cap snap only when snap realm's
context changes" introduced a regression: we may not call
queue_realm_cap_snaps() for newly created snap realm. This
regression allows unflushed snapshot data to be overwritten.
Link: http://tracker.ceph.com/issues/21483
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
If we create capsnap when snap realm's context does not change, the
new capsnap's snapc is equal to ci->i_head_snapc. Page writeback code
can't differentiates dirty pages associated with the new capsnap from
dirty pages associated with i_head_snapc.
Signed-off-by: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Dirty snapshot data needs to be flushed unconditionally. If they
were created before truncation, writeback should use old truncate
size/seq.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
This patch devide __ceph_flush_snaps() into two stags. In the first
stage, __ceph_flush_snaps() assign snapcaps flush TIDs and add them
to cap flush lists. __ceph_flush_snaps() keeps holding the
i_ceph_lock in this stagge. So inode's auth cap can not change. In
the second stage, __ceph_flush_snaps() send flushsnap cap messages.
i_ceph_lock is unlocked before sending each cap message. If auth cap
changes in the middle, __ceph_flush_snaps() just stops. This is OK
because kick_flushing_inode_caps() will re-send flushsnap cap messages
to inode's new auth MDS.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
This patch includes following changes
- Assign flush tid to snapcap flush
- Remove session's s_cap_snaps_flushing list. Add inode to session's
s_cap_flushing list instead. Inode is removed from the list when
there is no pending snapcap flush or cap flush.
- make __kick_flushing_caps() re-send both snapcap flushes and cap
flushes.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
ceph_empty_snapc->num_snaps == 0 at all times. Passing such a snapc to
ceph_osdc_alloc_request() (possibly through ceph_osdc_new_request()) is
equivalent to passing NULL, as ceph_osdc_alloc_request() uses it only
for sizing the request message.
Further, in all four cases the subsequent ceph_osdc_build_request() is
passed NULL for snapc, meaning that 0 is encoded for seq and num_snaps
and making ceph_empty_snapc entirely useless. The two cases where it
actually mattered were removed in commits 8605609049 ("ceph: avoid
sending unnessesary FLUSHSNAP message") and 23078637e0 ("ceph: fix
queuing inode to mdsdir's snaprealm").
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Yan, Zheng <zyan@redhat.com>
During MDS failovers, MClientSnap message may cause kclient to move
some inodes from root directory's snaprealm to mdsdir's snaprealm
and queue snapshots for these inodes. For a FS has never created any
snapshot, both root directory's snaprealm and mdsdir's snaprealm
share the same snapshot contexts (both are ceph_empty_snapc). This
confuses ceph_put_wrbuffer_cap_refs(), make it unable to distinguish
snapshot buffers from head buffers.
The fix is do not use ceph_empty_snapc as snaprealm's cached context.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
when a snap notification contains no new snapshot, we can avoid
sending FLUSHSNAP message to MDS. But we still need to create
cap_snap in some case because it's required by write path and
page writeback path
Signed-off-by: Yan, Zheng <zyan@redhat.com>
In most cases that snap context is needed, we are holding
reference of CEPH_CAP_FILE_WR. So we can set ceph inode's
i_head_snapc when getting the CEPH_CAP_FILE_WR reference,
and make codes get snap context from i_head_snapc. This makes
the code simpler.
Another benefit of this change is that we can handle snap
notification more elegantly. Especially when snap context
is updated while someone else is doing write. The old queue
cap_snap code may set cap_snap's context to ether the old
context or the new snap context, depending on if i_head_snapc
is set. The new queue capp_snap code always set cap_snap's
context to the old snap context.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Cached_context in ceph_snap_realm is directly accessed by
uninline_data() and get_pool_perm(). This is racy in theory.
both uninline_data() and get_pool_perm() do not modify existing
object, they only create new object. So we can pass the empty
snap context to them. Unlike cached_context in ceph_snap_realm,
we do not need to protect the empty snap context.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
When snaprealm is created, its initial reference count is zero.
But in some rare cases, the newly created snaprealm is not referenced
by anyone. This causes snaprealm with zero reference count not freed.
The fix is set reference count of newly snaprealm to 1. The reference
is return the function who requests to create the snaprealm. When the
function finishes its job, it releases the reference.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
After converting inline data to normal data, client need to flush
the new i_inline_version (CEPH_INLINE_NONE) to MDS. This commit makes
cap messages (sent to MDS) contain inline_version and inline_data.
Client always converts inline data to normal data before data write,
so the inline data length part is always zero.
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Current snaphost code does not properly handle moving inode from one
empty snap realm to another empty snap realm. After changing inode's
snap realm, some dirty pages' snap context can be not equal to inode's
i_head_snap. This can trigger BUG() in ceph_put_wrbuffer_cap_refs()
The fix is introduce a global empty snap context for all empty snap
realm. This avoids triggering the BUG() for filesystem with no snapshot.
Fixes: http://tracker.ceph.com/issues/9928
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Reviewed-by: Ilya Dryomov <idryomov@redhat.com>
