In the kernel 4.2 merge window we had a big changes to the implementation
of delayed references and qgroups which made the no_quota field of delayed
references not used anymore. More specifically the no_quota field is not
used anymore as of:
commit 0ed4792af0e8 ("btrfs: qgroup: Switch to new extent-oriented qgroup mechanism.")
Leaving the no_quota field actually prevents delayed references from
getting merged, which in turn cause the following BUG_ON(), at
fs/btrfs/extent-tree.c, to be hit when qgroups are enabled:
static int run_delayed_tree_ref(...)
{
(...)
BUG_ON(node->ref_mod != 1);
(...)
}
2) Ref2 bytenr X, action = BTRFS_DROP_DELAYED_REF, no_quota = 0, added.
It's not merged with Ref1 because Ref1->no_quota != Ref2->no_quota.
3) Ref3 bytenr X, action = BTRFS_ADD_DELAYED_REF, no_quota = 1, added.
It's not merged with the reference at the tail of the list of refs
for bytenr X because the reference at the tail, Ref2 is incompatible
due to Ref2->no_quota != Ref3->no_quota.
4) Ref4 bytenr X, action = BTRFS_DROP_DELAYED_REF, no_quota = 0, added.
It's not merged with the reference at the tail of the list of refs
for bytenr X because the reference at the tail, Ref3 is incompatible
due to Ref3->no_quota != Ref4->no_quota.
5) We run delayed references, trigger merging of delayed references,
through __btrfs_run_delayed_refs() -> btrfs_merge_delayed_refs().
6) Ref1 and Ref3 are merged as Ref1->no_quota = Ref3->no_quota and
all other conditions are satisfied too. So Ref1 gets a ref_mod
value of 2.
7) Ref2 and Ref4 are merged as Ref2->no_quota = Ref4->no_quota and
all other conditions are satisfied too. So Ref2 gets a ref_mod
value of 2.
8) Ref1 and Ref2 aren't merged, because they have different values
for their no_quota field.
9) Delayed reference Ref1 is picked for running (select_delayed_ref()
always prefers references with an action == BTRFS_ADD_DELAYED_REF).
So run_delayed_tree_ref() is called for Ref1 which triggers the
BUG_ON because Ref1->red_mod != 1 (equals 2).
So fix this by removing the no_quota field, as it's not used anymore as
of commit 0ed4792af0e8 ("btrfs: qgroup: Switch to new extent-oriented
qgroup mechanism.").
The use of no_quota was also buggy in at least two places:
1) At delayed-refs.c:btrfs_add_delayed_tree_ref() - we were setting
no_quota to 0 instead of 1 when the following condition was true:
is_fstree(ref_root) || !fs_info->quota_enabled
2) At extent-tree.c:__btrfs_inc_extent_ref() - we were attempting to
reset a node's no_quota when the condition "!is_fstree(root_objectid)
|| !root->fs_info->quota_enabled" was true but we did it only in
an unused local stack variable, that is, we never reset the no_quota
value in the node itself.
This fixes the remainder of problems several people have been having when
running delayed references, mostly while a balance is running in parallel,
on a 4.2+ kernel.
Very special thanks to Stéphane Lesimple for helping debugging this issue
and testing this fix on his multi terabyte filesystem (which took more
than one day to balance alone, plus fsck, etc).
Also, this fixes deadlock issue when using the clone ioctl with qgroups
enabled, as reported by Elias Probst in the mailing list. The deadlock
happens because after calling btrfs_insert_empty_item we have our path
holding a write lock on a leaf of the fs/subvol tree and then before
releasing the path we called check_ref() which did backref walking, when
qgroups are enabled, and tried to read lock the same leaf. The trace for
this case is the following:
The problem goes away by eleminating check_ref(), which no longer is
needed as its purpose was to get a value for the no_quota field of
a delayed reference (this patch removes the no_quota field as mentioned
earlier).
The cobalt driver should depend on VIDEO_V4L2_SUBDEV_API.
This fixes this kbuild error:
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 99bc7215bc60f6cd414cf1b85cd9d52cc596cccb
commit: 85756a069c55e0315ac5990806899cfb607b987f [media] cobalt: add new driver
config: x86_64-randconfig-s0-09201514 (attached as .config)
reproduce:
git checkout 85756a069c55e0315ac5990806899cfb607b987f
# save the attached .config to linux build tree
make ARCH=x86_64
All error/warnings (new ones prefixed by >>):
drivers/media/i2c/adv7604.c: In function 'adv76xx_get_format':
>> drivers/media/i2c/adv7604.c:1853:9: error: implicit declaration of function 'v4l2_subdev_get_try_format' [-Werror=implicit-function-declaration]
fmt = v4l2_subdev_get_try_format(sd, cfg, format->pad);
^
drivers/media/i2c/adv7604.c:1853:7: warning: assignment makes pointer from integer without a cast [-Wint-conversion]
fmt = v4l2_subdev_get_try_format(sd, cfg, format->pad);
^
drivers/media/i2c/adv7604.c: In function 'adv76xx_set_format':
drivers/media/i2c/adv7604.c:1882:7: warning: assignment makes pointer from integer without a cast [-Wint-conversion]
fmt = v4l2_subdev_get_try_format(sd, cfg, format->pad);
^
cc1: some warnings being treated as errors
create_request_message() computes the maximum length of a message,
but uses the wrong type for the time stamp: sizeof(struct timespec)
may be 8 or 16 depending on the architecture, while sizeof(struct
ceph_timespec) is always 8, and that is what gets put into the
message.
Found while auditing the uses of timespec for y2038 problems.
Fixes: b8e69066d8af ("ceph: include time stamp in every MDS request")
Signed-off-by: Arnd Bergmann <email address hidden>
Signed-off-by: Yan, Zheng <email address hidden>
Signed-off-by: Greg Kroah-Hartman <email address hidden>
If we pass in an empty nfs_fattr struct to nfs_update_inode, it will
(correctly) not update any of the attributes, but it then clears the
NFS_INO_INVALID_ATTR flag, which indicates that the attributes are
up to date. Don't clear the flag if the fattr struct has no valid
attrs to apply.
Reviewed-by: Steve French <email address hidden>
Signed-off-by: Jeff Layton <email address hidden>
Signed-off-by: Trond Myklebust <email address hidden>
Signed-off-by: Greg Kroah-Hartman <email address hidden>
1fa68c4...
by
Benjamin Coddington <email address hidden>
If clp->cl_cb_ident is zero, then nfs_cb_idr_remove_locked() skips removing
it when the nfs_client is freed. A decoding or server bug can then find
and try to put that first nfs_client which would lead to a crash.
In debugfs' start_creating(), we pin the file system to safely access
its root. When we failed to create a file, we unpin the file system via
failed_creating() to release the mount count and eventually the reference
of the vfsmount.
However, when we run into an error during lookup_one_len() when still
in start_creating(), we only release the parent's mutex but not so the
reference on the mount. Looks like it was done in the past, but after
splitting portions of __create_file() into start_creating() and
end_creating() via 190afd81e4a5 ("debugfs: split the beginning and the
end of __create_file() off"), this seemed missed. Noticed during code
review.
Fixes: 190afd81e4a5 ("debugfs: split the beginning and the end of __create_file() off")
Signed-off-by: Daniel Borkmann <email address hidden>
Signed-off-by: Al Viro <email address hidden>
Signed-off-by: Greg Kroah-Hartman <email address hidden>
We've observed the nfsd server in a state where there are
multiple delegations on the same nfs4_file for the same client.
The nfs client does attempt to DELEGRETURN these when they are presented to
it - but apparently under some (unknown) circumstances the client does not
manage to return all of them. This leads to the eventual
attempt to CB_RECALL more than one delegation with the same nfs
filehandle to the same client. The first recall will succeed, but the
next recall will fail with NFS4ERR_BADHANDLE. This leads to the server
having delegations on cl_revoked that the client has no way to FREE
or DELEGRETURN, with resulting inability to recover. The state manager
on the server will continually assert SEQ4_STATUS_RECALLABLE_STATE_REVOKED,
and the state manager on the client will be looping unable to satisfy
the server.
List discussion also reports a race between OPEN and DELEGRETURN that
will be avoided by only sending the delegation once to the
client. This is also logically in accordance with RFC5561 9.1.1 and 10.2.
So, let's:
1.) Not hand out duplicate delegations.
2.) Only send them to the client once.
RFC 5561:
9.1.1:
"Delegations and layouts, on the other hand, are not associated with a
specific owner but are associated with the client as a whole
(identified by a client ID)."
10.2:
"...the stateid for a delegation is associated with a client ID and may be
used on behalf of all the open-owners for the given client. A
delegation is made to the client as a whole and not to any specific
process or thread of control within it."
Reported-by: Eric Meddaugh <email address hidden>
Cc: Trond Myklebust <email address hidden>
Cc: Olga Kornievskaia <email address hidden>
Signed-off-by: Andrew Elble <email address hidden>
Signed-off-by: J. Bruce Fields <email address hidden>
Signed-off-by: Greg Kroah-Hartman <email address hidden>
