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  1. 17 Sep, 2012 3 commits
    • Simon Derr's avatar
      9P: fix test at the end of p9_write_work() · 1957b3a8
      Simon Derr authored 
      At the end of p9_write_work() we want to test if there is still data to send.
This means:
- either the current request still has data to send (wsize != 0)
- or there are requests in the unsent queue
Signed-off-by: default avatarSimon Derr <simon.derr@bull.net>
Signed-off-by: default avatarEric Van Hensbergen <ericvh@gmail.com>
      1957b3a8
    • Simon Derr's avatar
      9P: Fix race in p9_read_work() · 0462194d
      Simon Derr authored 
      Race scenario between p9_read_work() and p9_poll_mux()

Data arrive, Rworksched is set, p9_read_work() is called.

thread A                                thread B

                                        p9_read_work()
                                                .
                                        reads data
                                                .
                                        checks if new data ready. No.
                                                .
                                        gets preempted
                                                .
More data arrive, p9_poll_mux() is called.      .
                                                .
                                                .
p9_poll_mux()                                   .
                                                .
if (!test_and_set_bit(Rworksched,               .
                      &m->wsched)) {            .
  schedule_work(&m->rq);                        .
}                                               .
                                                .
-> does not schedule work because               .
   Rworksched is set                            .
                                                .
                                        clear_bit(Rworksched, &m->wsched);
                                        return;

No work has been scheduled, and yet data are waiting.

Currently p9_read_work() checks if there is data to read,
and if not, it clears Rworksched.

I think it should clear Rworksched first, and then check if there is data to read.
Signed-off-by: default avatarSimon Derr <simon.derr@bull.net>
Signed-off-by: default avatarEric Van Hensbergen <ericvh@gmail.com>
      0462194d
    • Jeff Layton's avatar
      9p: don't use __getname/__putname for uname/aname · e549c133
      Jeff Layton authored 
      These are generally very small strings. We don't need an entire 4k
allocation for each. Instead, just free and reallocate them on an
as-needed basis.

Note: This patch is untested since I don't have a 9p server available at
the moment. It's mainly something I noticed while doing some
getname/putname cleanup work.
Signed-off-by: default avatarJeff Layton <jlayton@redhat.com>
Signed-off-by: default avatarEric Van Hensbergen <ericvh@gmail.com>
      e549c133
  3. 06 Sep, 2012 2 commits
  5. 01 Sep, 2012 5 commits
  7. 30 Aug, 2012 5 commits
  9. 29 Aug, 2012 18 commits
  11. 28 Aug, 2012 7 commits
    • Stefan Behrens's avatar
      Btrfs: fix that repair code is spuriously executed for transid failures · 256dd1bb
      Stefan Behrens authored 
      If verify_parent_transid() fails for all mirrors, the current code
calls repair_io_failure() anyway which means:
- that the disk block is rewritten without repairing anything and
- that a kernel log message is printed which misleadingly claims
  that a read error was corrected.

This is an example:
parent transid verify failed on 615015833600 wanted 110423 found 110424
parent transid verify failed on 615015833600 wanted 110423 found 110424
btrfs read error corrected: ino 1 off 615015833600 (dev /dev/...)

It is wrong to ignore the results from verify_parent_transid() and to
call repair_eb_io_failure() when the verification of the transids failed.
This commit fixes the issue.
Signed-off-by: default avatarStefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
      256dd1bb
    • Liu Bo's avatar
      Btrfs: fix ordered extent leak when failing to start a transaction · d280e5be
      Liu Bo authored 
      We cannot just return error before freeing ordered extent and releasing reserved
space when we fail to start a transacion.
Signed-off-by: default avatarLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
      d280e5be
    • Liu Bo's avatar
      Btrfs: fix a dio write regression · 24c03fa5
      Liu Bo authored 
      This bug is introduced by commit 3b8bde746f6f9bd36a9f05f5f3b6e334318176a9
(Btrfs: lock extents as we map them in DIO).

In dio write, we should unlock the section which we didn't do IO on in case that
we fall back to buffered write.  But we need to not only unlock the section
but also cleanup reserved space for the section.

This bug was found while running xfstests 133, with this 133 no longer complains.
Signed-off-by: default avatarLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
      24c03fa5
    • Josef Bacik's avatar
      Btrfs: fix deadlock with freeze and sync V2 · bd7de2c9
      Josef Bacik authored 
      We can deadlock with freeze right now because we unconditionally start a
transaction in our ->sync_fs() call.  To fix this just check and see if we
have a running transaction to commit.  This saves us from the deadlock
because at this point we'll have the umount sem for the sb so we're safe
from freezes coming in after we've done our check.  With this patch the
freeze xfstests no longer deadlocks.  Thanks,
Signed-off-by: default avatarJosef Bacik <jbacik@fusionio.com>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
      bd7de2c9
    • Stefan Behrens's avatar
      Btrfs: revert checksum error statistic which can cause a BUG() · 5ee0844d
      Stefan Behrens authored 
      Commit 442a4f63 added btrfs device
statistic counters for detected IO and checksum errors to Linux 3.5.
The statistic part that counts checksum errors in
end_bio_extent_readpage() can cause a BUG() in a subfunction:
"kernel BUG at fs/btrfs/volumes.c:3762!"
That part is reverted with the current patch.
However, the counting of checksum errors in the scrub context remains
active, and the counting of detected IO errors (read, write or flush
errors) in all contexts remains active.

Cc: stable <stable@vger.kernel.org> # 3.5
Signed-off-by: default avatarStefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
      5ee0844d
    • Stefan Behrens's avatar
      Btrfs: remove superblock writing after fatal error · 68ce9682
      Stefan Behrens authored 
      With commit acce952b, btrfs was changed to flag the filesystem with
BTRFS_SUPER_FLAG_ERROR and switch to read-only mode after a fatal
error happened like a write I/O errors of all mirrors.
In such situations, on unmount, the superblock is written in
btrfs_error_commit_super(). This is done with the intention to be able
to evaluate the error flag on the next mount. A warning is printed
in this case during the next mount and the log tree is ignored.

The issue is that it is possible that the superblock points to a root
that was not written (due to write I/O errors).
The result is that the filesystem cannot be mounted. btrfsck also does
not start and all the other btrfs-progs tools fail to start as well.
However, mount -o recovery is working well and does the right things
to recover the filesystem (i.e., don't use the log root, clear the
free space cache and use the next mountable root that is stored in the
root backup array).

This patch removes the writing of the superblock when
BTRFS_SUPER_FLAG_ERROR is set, and removes the handling of the error
flag in the mount function.

These lines can be used to reproduce the issue (using /dev/sdm):
SCRATCH_DEV=/dev/sdm
SCRATCH_MNT=/mnt
echo 0 25165824 linear $SCRATCH_DEV 0 | dmsetup create foo
ls -alLF /dev/mapper/foo
mkfs.btrfs /dev/mapper/foo
mount /dev/mapper/foo $SCRATCH_MNT
echo bar > $SCRATCH_MNT/foo
sync
echo 0 25165824 error | dmsetup reload foo
dmsetup resume foo
ls -alF $SCRATCH_MNT
touch $SCRATCH_MNT/1
ls -alF $SCRATCH_MNT
sleep 35
echo 0 25165824 linear $SCRATCH_DEV 0 | dmsetup reload foo
dmsetup resume foo
sleep 1
umount $SCRATCH_MNT
btrfsck /dev/mapper/foo
dmsetup remove foo
Signed-off-by: default avatarStefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: default avatarJan Schmidt <list.btrfs@jan-o-sch.net>
      68ce9682
    • Josef Bacik's avatar
      Btrfs: allow delayed refs to be merged · ae1e206b
      Josef Bacik authored 
      Daniel Blueman reported a bug with fio+balance on a ramdisk setup.
Basically what happens is the balance relocates a tree block which will drop
the implicit refs for all of its children and adds a full backref.  Once the
block is relocated we have to add the implicit refs back, so when we cow the
block again we add the implicit refs for its children back.  The problem
comes when the original drop ref doesn't get run before we add the implicit
refs back.  The delayed ref stuff will specifically prefer ADD operations
over DROP to keep us from freeing up an extent that will have references to
it, so we try to add the implicit ref before it is actually removed and we
panic.  This worked fine before because the add would have just canceled the
drop out and we would have been fine.  But the backref walking work needs to
be able to freeze the delayed ref stuff in time so we have this ever
increasing sequence number that gets attached to all new delayed ref updates
which makes us not merge refs and we run into this issue.

So to fix this we need to merge delayed refs.  So everytime we run a
clustered ref we need to try and merge all of its delayed refs.  The backref
walking stuff locks the delayed ref head before processing, so if we have it
locked we are safe to merge any refs inside of the sequence number.  If
there is no sequence number we can merge all refs.  Doing this not only
fixes our bug but keeps the delayed ref code from adding and removing
useless refs and batching together multiple refs into one search instead of
one search per delayed ref, which will really help our commit times.  I ran
this with Daniels test and 276 and I haven't seen any problems.  Thanks,
Reported-by: default avatarDaniel J Blueman <daniel@quora.org>
Signed-off-by: default avatarJosef Bacik <jbacik@fusionio.com>
      ae1e206b
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