Commit graph

99 commits

Author SHA1 Message Date
Wang Shilong
cb7ab02156 Btrfs: wrap repeated code into scrub_blocked_if_needed()
Just wrap same code into one function scrub_blocked_if_needed().

This make a change that we will move waiting (@workers_pending = 0)
before we can wake up commiting transaction(atomic_inc(@scrub_paused)),
we must take carefully to not deadlock here.

Thread 1			Thread 2
				|->btrfs_commit_transaction()
					|->set trans type(COMMIT_DOING)
					|->btrfs_scrub_paused()(blocked)
|->join_transaction(blocked)

Move btrfs_scrub_paused() before setting trans type which means we can
still join a transaction when commiting_transaction is blocked.

Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Suggested-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
2014-01-28 13:19:53 -08:00
Wang Shilong
3cb0929ad2 Btrfs: fix wrong super generation mismatch when scrubbing supers
We came a race condition when scrubbing superblocks, the story is:

In commiting transaction, we will update @last_trans_commited after
writting superblocks, if scrubber start after writting superblocks
and before updating @last_trans_commited, generation mismatch happens!

We fix this by checking @scrub_pause_req, and we won't start a srubber
until commiting transaction is finished.(after btrfs_scrub_continue()
finished.)

Reported-by: Sebastian Ochmann <ochmann@informatik.uni-bonn.de>
Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
2014-01-28 13:19:52 -08:00
Valentina Giusti
ce3e7f1073 btrfs: remove unused variable from scrub_fixup_nodatasum
Signed-off-by: Valentina Giusti <valentina.giusti@microon.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <clm@fb.com>
2014-01-28 13:19:34 -08:00
Linus Torvalds
5ee540613d Merge branch 'for-linus' of git://git.kernel.dk/linux-block
Pull block layer fixes from Jens Axboe:
 "A small collection of fixes for the current series. It contains:

   - A fix for a use-after-free of a request in blk-mq.  From Ming Lei

   - A fix for a blk-mq bug that could attempt to dereference a NULL rq
     if allocation failed

   - Two xen-blkfront small fixes

   - Cleanup of submit_bio_wait() type uses in the kernel, unifying
     that.  From Kent

   - A fix for 32-bit blkg_rwstat reading.  I apologize for this one
     looking mangled in the shortlog, it's entirely my fault for missing
     an empty line between the description and body of the text"

* 'for-linus' of git://git.kernel.dk/linux-block:
  blk-mq: fix use-after-free of request
  blk-mq: fix dereference of rq->mq_ctx if allocation fails
  block: xen-blkfront: Fix possible NULL ptr dereference
  xen-blkfront: Silence pfn maybe-uninitialized warning
  block: submit_bio_wait() conversions
  Update of blkg_stat and blkg_rwstat may happen in bh context
2013-12-05 15:33:27 -08:00
Kent Overstreet
c170bbb45f block: submit_bio_wait() conversions
It was being open coded in a few places.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Joern Engel <joern@logfs.org>
Cc: Prasad Joshi <prasadjoshi.linux@gmail.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Chris Mason <chris.mason@fusionio.com>
Acked-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2013-11-24 16:33:41 -07:00
Ilya Dryomov
33ef30add1 Btrfs: do not inc uncorrectable_errors counter on ro scrubs
Currently if we discover an error when scrubbing in ro mode we a)
blindly increment the uncorrectable_errors counter, and b) spam the
dmesg with the 'unable to fixup (regular) error at ...' message, even
though a) we haven't tried to determine if the error is correctable or
not, and b) we haven't tried to fixup anything.  Fix this.

Cc: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-11-20 20:41:38 -05:00
Wang Shilong
3b7a016f44 Btrfs: avoid unnecessary scrub workers allocation
We only allocate scrub workers if we pass all the necessary
checks, for example, there are no operation in progress.

Besides, move mutex lock protection outside of scrub_workers_get()
/scrub_workers_put().

Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-11-11 22:12:58 -05:00
Wang Shilong
9b011adfe1 Btrfs: remove scrub_super_lock holding in btrfs_sync_log()
Originally, we introduced scrub_super_lock to synchronize
tree log code with scrubbing super.

However we can replace scrub_super_lock with device_list_mutex,
because writing super will hold this mutex, this will reduce an extra
lock holding when writing supers in sync log code.

Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-11-11 22:10:13 -05:00
Ilya Dryomov
539f358a30 Btrfs: fix the dev-replace suspend sequence
Replace progresses strictly from lower to higher offsets, and the
progress is tracked in chunks, by storing the physical offset of the
dev_extent which is being copied in the cursor_left field of
btrfs_dev_replace_item.  When we are done copying the chunk,
left_cursor is updated to point one byte past the dev_extent, so that
on resume we can skip the dev_extents that have already been copied.

There is a major bug (which goes all the way back to the inception of
dev-replace in 3.8) in the way left_cursor is bumped: the bump is done
unconditionally, without any regard to the scrub_chunk return value.
On suspend (and also on any kind of error) scrub_chunk returns early,
i.e. without completing the copy.  This leads to us skipping the chunk
that hasn't been fully copied yet when resuming.

Fix this by doing the cursor_left update only if scrub_chunk ret is 0.
(On suspend scrub_chunk returns with -ECANCELED, so this fix covers
both suspend and error cases.)

Cc: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-11-11 21:55:36 -05:00
Josef Bacik
652f25a292 Btrfs: improve replacing nocow extents
Various people have hit a deadlock when running btrfs/011.  This is because when
replacing nocow extents we will take the i_mutex to make sure nobody messes with
the file while we are replacing the extent.  The problem is we are already
holding a transaction open, which is a locking inversion, so instead we need to
save these inodes we find and then process them outside of the transaction.

Further we can't just lock the inode and assume we are good to go.  We need to
lock the extent range and then read back the extent cache for the inode to make
sure the extent really still points at the physical block we want.  If it
doesn't we don't have to copy it.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-09-21 11:05:26 -04:00
Stefan Behrens
23fa76b0ba Btrf: cleanup: don't check for root_refs == 0 twice
btrfs_read_fs_root_no_name() already checks if btrfs_root_refs()
is zero and returns ENOENT in this case. There is no need to do
it again in three more places.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-09-01 08:16:29 -04:00
Geert Uytterhoeven
118a0a2514 Btrfs: Format mirror_num as int
mirror_num is always "int", hence don't cast it to "unsigned long long" and
format it as a 64-bit number.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-09-01 08:16:11 -04:00
Geert Uytterhoeven
27f9f02357 Btrfs: Format PAGE_SIZE as unsigned long
PAGE_SIZE is "unsigned long" everywhere, so there's no need to cast it to
"unsigned long long" and format it as a 64-bit number.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-09-01 08:16:10 -04:00
Geert Uytterhoeven
c1c9ff7c94 Btrfs: Remove superfluous casts from u64 to unsigned long long
u64 is "unsigned long long" on all architectures now, so there's no need to
cast it when formatting it using the "ll" length modifier.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-09-01 08:16:08 -04:00
Qu Wenruo
3cae210fa5 btrfs: Cleanup for using BTRFS_SETGET_STACK instead of raw convert
Some codes still use the cpu_to_lexx instead of the
BTRFS_SETGET_STACK_FUNCS declared in ctree.h.

Also added some BTRFS_SETGET_STACK_FUNCS for btrfs_header btrfs_timespec
and other structures.

Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Miao Xie <miaoxie@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-09-01 07:57:37 -04:00
Stefan Behrens
115930cb2d Btrfs: fix wrong write offset when replacing a device
Miao Xie reported the following issue:

The filesystem was corrupted after we did a device replace.

Steps to reproduce:
 # mkfs.btrfs -f -m single -d raid10 <device0>..<device3>
 # mount <device0> <mnt>
 # btrfs replace start -rfB 1 <device4> <mnt>
 # umount <mnt>
 # btrfsck <device4>

The reason for the issue is that we changed the write offset by mistake,
introduced by commit 625f1c8dc.

We read the data from the source device at first, and then write the
data into the corresponding place of the new device. In order to
implement the "-r" option, the source location is remapped using
btrfs_map_block(). The read takes place on the mapped location, and
the write needs to take place on the unmapped location. Currently
the write is using the mapped location, and this commit changes it
back by undoing the change to the write address that the aforementioned
commit added by mistake.

Reported-by: Miao Xie <miaox@cn.fujitsu.com>
Cc: <stable@vger.kernel.org> # 3.10+
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-07-19 15:07:26 -04:00
Miao Xie
edd1400be9 Btrfs: fix several potential problems in copy_nocow_pages_for_inode
- It makes no sense that we deal with a inode in the dead tree.
- fix the race between dio and page copy by waiting the dio completion
- avoid the page copy vs truncate/punch hole
- check if the page is in the page cache or not

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-07-02 11:50:58 -04:00
Miao Xie
826aa0a82c Btrfs: cleanup the code of copy_nocow_pages_for_inode()
- It make no sense that we continue to do something after the error
  happened, just go back with this patch.
- remove some check of copy_nocow_pages_for_inode(), such as page check
  after write, inode check in the end of the function, because we are
  sure they exist.
- remove the unnecessary goto in the return value check of the write

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-07-02 11:50:56 -04:00
Miao Xie
26b2589190 Btrfs: fix oops when recovering the file data by scrub function
We get oops while running btrfs replace start test,
------------[ cut here ]------------
kernel BUG at mm/filemap.c:608!
[SNIP]
Call Trace:
  [<ffffffffa04b36c7>] copy_nocow_pages_for_inode+0x217/0x3f0 [btrfs]
  [<ffffffffa04b34b0>] ? scrub_print_warning_inode+0x230/0x230 [btrfs]
  [<ffffffffa04b34b0>] ? scrub_print_warning_inode+0x230/0x230 [btrfs]
  [<ffffffffa04bb8ce>] iterate_extent_inodes+0x1ae/0x300 [btrfs]
  [<ffffffffa04bbab2>] iterate_inodes_from_logical+0x92/0xb0 [btrfs]
  [<ffffffffa04b34b0>] ? scrub_print_warning_inode+0x230/0x230 [btrfs]
  [<ffffffffa04b3b07>] copy_nocow_pages_worker+0x97/0x150 [btrfs]
  [<ffffffffa048eed4>] worker_loop+0x134/0x540 [btrfs]
  [<ffffffff816274ea>] ? __schedule+0x3ca/0x7f0
  [<ffffffffa048eda0>] ? btrfs_queue_worker+0x300/0x300 [btrfs]
  [<ffffffff8106f2f0>] kthread+0xc0/0xd0
  [<ffffffff8106f230>] ? flush_kthread_worker+0x80/0x80
  [<ffffffff8163181c>] ret_from_fork+0x7c/0xb0
  [<ffffffff8106f230>] ? flush_kthread_worker+0x80/0x80
[SNIP]
 RIP  [<ffffffff8111f4c5>] unlock_page+0x35/0x40
  RSP <ffff88010316bb98>
 ---[ end trace 421e79ad0dd72c7d ]---

it is because we forgot to lock the page again after we read data to
the page. Fix it.

Signed-off-by: Lin Feng <linfeng@cn.fujitsu.com>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-07-02 11:50:55 -04:00
Miao Xie
f51a4a1826 Btrfs: remove btrfs_sector_sum structure
Using the structure btrfs_sector_sum to keep the checksum value is
unnecessary, because the extents that btrfs_sector_sum points to are
continuous, we can find out the expected checksums by btrfs_ordered_sum's
bytenr and the offset, so we can remove btrfs_sector_sum's bytenr. After
removing bytenr, there is only one member in the structure, so it makes
no sense to keep the structure, just remove it, and use a u32 array to
store the checksum value.

By this change, we don't use the while loop to get the checksums one by
one. Now, we can get several checksum value at one time, it improved the
performance by ~74% on my SSD (31MB/s -> 54MB/s).

test command:
 # dd if=/dev/zero of=/mnt/btrfs/file0 bs=1M count=1024 oflag=sync

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-07-02 11:50:47 -04:00
Josef Bacik
d88d46c6e0 Btrfs: free csums when we're done scrubbing an extent
A user reported scrub taking up an unreasonable amount of ram as it ran.  This
is because we lookup the csums for the extent we're scrubbing but don't free it
up until after we're done with the scrub, which means we can take up a whole lot
of ram.  This patch fixes this by dropping the csums once we're done with the
extent we've scrubbed.  The user reported this to fix their problem.  Thanks,

Reported-and-tested-by: Remco Hosman <remco@hosman.xs4all.nl>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-07-01 08:52:28 -04:00
Chris Mason
9be3395bcd Btrfs: use a btrfs bioset instead of abusing bio internals
Btrfs has been pointer tagging bi_private and using bi_bdev
to store the stripe index and mirror number of failed IOs.

As bios bubble back up through the call chain, we use these
to decide if and how to retry our IOs.  They are also used
to count IO failures on a per device basis.

Recently a bio tracepoint was added lead to crashes because
we were abusing bi_bdev.

This commit adds a btrfs bioset, and creates explicit fields
for the mirror number and stripe index.  The plan is to
extend this structure for all of the fields currently in
struct btrfs_bio, which will mean one less kmalloc in
our IO path.

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Reported-by: Tejun Heo <tj@kernel.org>
2013-05-17 21:52:52 -04:00
Liu Bo
625f1c8dc6 Btrfs: improve the loop of scrub_stripe
1) Right now scrub_stripe() is looping in some unnecessary cases:
* when the found extent item's objectid has been out of the dev extent's range
  but we haven't finish scanning all the range within the dev extent
* when all the items has been processed but we haven't finish scanning all the
  range within the dev extent

In both cases, we can just finish the loop to save costs.

2) Besides, when the found extent item's length is larger than the stripe
len(64k), we don't have to release the path and search again as it'll get at the
same key used in the last loop, we can instead increase the logical cursor in
place till all space of the extent is scanned.

3) And we use 0 as the key's offset to search btree, then get to previous item
to find a smaller item, and again have to move to the next one to get the right
item.  Setting offset=-1 and previous_item() is the correct way.

4) As we won't find any checksum at offset unless this 'offset' is in a data
extent, we can just find checksum when we're really going to scrub an extent.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-05-06 15:55:26 -04:00
Eric Sandeen
48a3b6366f btrfs: make static code static & remove dead code
Big patch, but all it does is add statics to functions which
are in fact static, then remove the associated dead-code fallout.

removed functions:

btrfs_iref_to_path()
__btrfs_lookup_delayed_deletion_item()
__btrfs_search_delayed_insertion_item()
__btrfs_search_delayed_deletion_item()
find_eb_for_page()
btrfs_find_block_group()
range_straddles_pages()
extent_range_uptodate()
btrfs_file_extent_length()
btrfs_scrub_cancel_devid()
btrfs_start_transaction_lflush()

btrfs_print_tree() is left because it is used for debugging.
btrfs_start_transaction_lflush() and btrfs_reada_detach() are
left for symmetry.

ulist.c functions are left, another patch will take care of those.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-05-06 15:55:23 -04:00
Josef Bacik
3173a18f70 Btrfs: add a incompatible format change for smaller metadata extent refs
We currently store the first key of the tree block inside the reference for the
tree block in the extent tree.  This takes up quite a bit of space.  Make a new
key type for metadata which holds the level as the offset and completely removes
storing the btrfs_tree_block_info inside the extent ref.  This reduces the size
from 51 bytes to 33 bytes per extent reference for each tree block.  In practice
this results in a 30-35% decrease in the size of our extent tree, which means we
COW less and can keep more of the extent tree in memory which makes our heavy
metadata operations go much faster.  This is not an automatic format change, you
must enable it at mkfs time or with btrfstune.  This patch deals with having
metadata stored as either the old format or the new format so it is easy to
convert.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-05-06 15:54:18 -04:00
Liu Bo
b0496686ba Btrfs: cleanup unused arguments of btrfs_csum_data
Argument 'root' is no more used in btrfs_csum_data().

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-05-06 15:54:14 -04:00
Josef Bacik
d8fe29e9de Btrfs: don't drop path when printing out tree errors in scrub
A user reported a panic where we were panicing somewhere in
tree_backref_for_extent from scrub_print_warning.  He only captured the trace
but looking at scrub_print_warning we drop the path right before we mess with
the extent buffer to print out a bunch of stuff, which isn't right.  So fix this
by dropping the path after we use the eb if we need to.  Thanks,

Cc: stable@vger.kernel.org
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-03-29 10:18:59 -04:00
Chris Mason
e942f883bc Merge branch 'raid56-experimental' into for-linus-3.9
Signed-off-by: Chris Mason <chris.mason@fusionio.com>

Conflicts:
	fs/btrfs/ctree.h
	fs/btrfs/extent-tree.c
	fs/btrfs/inode.c
	fs/btrfs/volumes.c
2013-02-20 14:06:05 -05:00
Miao Xie
87533c4751 Btrfs: use bit operation for ->fs_state
There is no lock to protect fs_info->fs_state, it will introduce
some problems, such as the value may be covered by the other task
when several tasks modify it. For example:
	Task0 - CPU0		Task1 - CPU1
	mov %fs_state rax
	or $0x1 rax
				mov %fs_state rax
				or $0x2 rax
	mov rax %fs_state
				mov rax %fs_state
The expected value is 3, but in fact, it is 2.

Though this problem doesn't happen now (because there is only one
flag currently), the code is error prone, if we add other flags,
the above problem will happen to a certainty.

Now we use bit operation for it to fix the above problem.
In this way, we can make the code more robust and be easy to
add new flags.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-20 12:59:09 -05:00
Liu Bo
6f1c36055f Btrfs: fix race between snapshot deletion and getting inode
While running snapshot testscript created by Mitch and David,
the race between autodefrag and snapshot deletion can lead to
corruption of dead_root list so that we can get crash on
btrfs_clean_old_snapshots().

And besides autodefrag, scrub also does the same thing, ie. read
root first and get inode.

Here is the story(take autodefrag as an example):
(1) when we delete a snapshot or subvolume, it will set its root's
refs to zero and do a iput() on its own inode, and if this inode happens
to be the only active in-meory one in root's inode rbtree, it will add
itself to the global dead_roots list for later cleanup.

(2) after (1), the autodefrag thread may read another inode for defrag
and the inode is just in the deleted snapshot/subvolume, but all of these
are without checking if the root is still valid(refs > 0).  So the end up
result is adding the deleted snapshot/subvolume's root to the global
dead_roots list AGAIN.

Fortunately, we already have a srcu lock to avoid the race, ie. subvol_srcu.

So all we need to do is to take the lock to protect 'read root and get inode',
since we synchronize to wait for the rcu grace period before adding something
to the global dead_roots list.

Reported-by: Mitch Harder <mitch.harder@sabayonlinux.org>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
2013-02-05 16:09:13 -05:00
David Woodhouse
53b381b3ab Btrfs: RAID5 and RAID6
This builds on David Woodhouse's original Btrfs raid5/6 implementation.
The code has changed quite a bit, blame Chris Mason for any bugs.

Read/modify/write is done after the higher levels of the filesystem have
prepared a given bio.  This means the higher layers are not responsible
for building full stripes, and they don't need to query for the topology
of the extents that may get allocated during delayed allocation runs.
It also means different files can easily share the same stripe.

But, it does expose us to incorrect parity if we crash or lose power
while doing a read/modify/write cycle.  This will be addressed in a
later commit.

Scrub is unable to repair crc errors on raid5/6 chunks.

Discard does not work on raid5/6 (yet)

The stripe size is fixed at 64KiB per disk.  This will be tunable
in a later commit.

Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2013-02-01 14:24:23 -05:00
Stefan Behrens
4ded4f6395 Btrfs: fix BUG() in scrub when first superblock reading gives EIO
This fixes a very special case that can be reproduced by just
disconnecting a disk at runtime, and without unmounting the
filesystem first, start scrub on the filesystem with the
disconnected disk. All read and write EIOs are handled
correctly, only the first superblock is an exception and gives
a BUG() in a subfunction. The BUG() is correct, it would crash
later otherwise. The subfunction must not be called for
superblocks and this is what the fix changes.

Reported-by: Joeri Vanthienen <mail@joerivanthienen.be>
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-12-16 20:46:28 -05:00
Stefan Behrens
af1be4f851 Btrfs: fix a scrub regression in case of write errors
This regression was introduced by the device-replace patches.
Scrub immediately stops checking those disks that have write errors.
This is nothing that happens in the real world, but it is wrong
since scrub is the tool to detect and repair defects. Fix it.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-12-16 20:46:14 -05:00
Stefan Behrens
29a8d9a0bc Btrfs: introduce GET_READ_MIRRORS functionality for btrfs_map_block()
Before this commit, btrfs_map_block() was called with REQ_WRITE
in order to retrieve the list of mirrors for a disk block.
This needs to be changed for the device replace procedure since
it makes a difference whether you are asking for read mirrors
or for locations to write to.
GET_READ_MIRRORS is introduced as a new interface to call
btrfs_map_block().
In the current commit, the functionality is not yet changed,
only the interface for GET_READ_MIRRORS is introduced and all
the places that should use this new interface are adapted.

The reason that REQ_WRITE cannot be abused anymore to retrieve
a list of read mirrors is that during a running dev replace
operation all write requests to the live filesystem are
duplicated to also write to the target drive.
Keep in mind that the target disk is only partially a valid
copy of the source disk while the operation is ongoing. All
writes go to the target disk, but not all reads would return
valid data on the target disk. Therefore it is not possible
anymore to abuse a REQ_WRITE interface to find valid mirrors
for a REQ_READ.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-12-12 17:15:43 -05:00
Stefan Behrens
8dabb7420f Btrfs: change core code of btrfs to support the device replace operations
This commit contains all the essential changes to the core code
of Btrfs for support of the device replace procedure.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-12-12 17:15:42 -05:00
Stefan Behrens
ff023aac31 Btrfs: add code to scrub to copy read data to another disk
The device replace procedure makes use of the scrub code. The scrub
code is the most efficient code to read the allocated data of a disk,
i.e. it reads sequentially in order to avoid disk head movements, it
skips unallocated blocks, it uses read ahead mechanisms, and it
contains all the code to detect and repair defects.
This commit adds code to scrub to allow the scrub code to copy read
data to another disk.
One goal is to be able to perform as fast as possible. Therefore the
write requests are collected until huge bios are built, and the
write process is decoupled from the read process with some kind of
flow control, of course, in order to limit the allocated memory.
The best performance on spinning disks could by reached when the
head movements are avoided as much as possible. Therefore a single
worker is used to interface the read process with the write process.
The regular scrub operation works as fast as before, it is not
negatively influenced and actually it is more or less unchanged.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-12-12 17:15:41 -05:00
Stefan Behrens
63a212abc2 Btrfs: disallow some operations on the device replace target device
This patch adds some code to disallow operations on the device that
is used as the target for the device replace operation.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-12-12 17:15:39 -05:00
Stefan Behrens
aa1b8cd409 Btrfs: pass fs_info instead of root
A small number of functions that are used in a device replace
procedure when the operation is resumed at mount time are unable
to pass the same root pointer that would be used in the regular
(ioctl) context. And since the root pointer is not required, only
the fs_info is, the root pointer argument is replaced with the
fs_info pointer argument.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-12-12 17:15:36 -05:00
Stefan Behrens
3ec706c831 Btrfs: pass fs_info to btrfs_map_block() instead of mapping_tree
This is required for the device replace procedure in a later step.
Two calling functions also had to be changed to have the fs_info
pointer: repair_io_failure() and scrub_setup_recheck_block().

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-12-12 17:15:34 -05:00
Stefan Behrens
b6bfebc132 Btrfs: cleanup scrub bio and worker wait code
Just move some code into functions to make everything more readable.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-12-12 17:15:32 -05:00
Stefan Behrens
34f5c8e90b Btrfs: in scrub repair code, simplify alloc error handling
In the scrub repair code, the code is changed to handle memory
allocation errors a little bit smarter. The change is to handle
it just like a read error. This simplifies the code and removes
a couple of lines of code, since the code to handle read errors
is there anyway.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-12-12 17:15:31 -05:00
Stefan Behrens
cb2ced73d8 Btrfs: in scrub repair code, optimize the reading of mirrors
In case that disk blocks need to be repaired (rewritten), the
current code at first (for simplicity reasons) reads all alternate
mirrors in the first step, afterwards selects the best one in a
second step. This is now changed to read one alternate mirror
after the other and to leave the loop early when a perfect mirror
is found.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-12-12 17:15:31 -05:00
Stefan Behrens
7a9e998768 Btrfs: make the scrub page array dynamically allocated
With the modified design (in order to support the devive replace
procedure) it is necessary to alloc the page array dynamically.
The reason is that pages are reused. At first a page is used for
the bio to read the data from the filesystem, then the same page
is reused for the bio that writes the data to the target disk.
Since the read process and the write process are completely
decoupled, this requires a new concept of refcounts and get/put
functions for pages, and it requires to use newly created pages
for each read bio which are freed after the write operation
is finished.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-12-12 17:15:30 -05:00
Stefan Behrens
a36cf8b893 Btrfs: remove the block device pointer from the scrub context struct
The block device is removed from the scrub context state structure.
The scrub code as it is used for the device replace procedure reads
the source data from whereever it is optimal. The source device might
even be gone (disconnected, for instance due to a hardware failure).
Or the drive can be so faulty so that the device replace procedure
tries to avoid access to the faulty source drive as much as possible,
and only if all other mirrors are damaged, as a last resort, the
source disk is accessed.
The modified scrub code operates as if it would handle the source
drive and thereby generates an exact copy of the source disk on the
target disk, even if the source disk is not present at all. Therefore
the block device pointer to the source disk is removed in the scrub
context struct and moved into the lower level scope of scrub_bio,
fixup and page structures where the block device context is known.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-12-12 17:15:30 -05:00
Stefan Behrens
d9d181c1ba Btrfs: rename the scrub context structure
The device replace procedure makes use of the scrub code. The scrub
code is the most efficient code to read the allocated data of a disk,
i.e. it reads sequentially in order to avoid disk head movements, it
skips unallocated blocks, it uses read ahead mechanisms, and it
contains all the code to detect and repair defects.
This commit is a first preparation step to adapt the scrub code to
be shareable for the device replace procedure.
The block device will be removed from the scrub context state
structure in a later step. It used to be the source block device.
The scrub code as it is used for the device replace procedure reads
the source data from whereever it is optimal. The source device might
even be gone (disconnected, for instance due to a hardware failure).
Or the drive can be so faulty so that the device replace procedure
tries to avoid access to the faulty source drive as much as possible,
and only if all other mirrors are damaged, as a last resort, the
source disk is accessed.
The modified scrub code operates as if it would handle the source
drive and thereby generates an exact copy of the source disk on the
target disk, even if the source disk is not present at all. Therefore
the block device pointer to the source disk is removed in a later
patch, and therefore the context structure is renamed (this is the
goal of the current patch) to reflect that no source block device
scope is there anymore.

Summary:
This first preparation step consists of a textual substitution of the
term "dev" to the term "ctx" whereever the scrub context is used.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
2012-12-12 17:15:29 -05:00
Kent Overstreet
be3940c0a9 btrfs: Kill some bi_idx references
For immutable bio vecs, I've been auditing and removing bi_idx
references. These were harmless, but removing them will make auditing
easier.

scrub_bio_end_io_worker() was open coding a bio_reset() - but this
doesn't appear to have been needed for anything as right after it does a
bio_put(), and perusing the code it doesn't appear anything else was
holding a reference to the bio.

The other use end_bio_extent_readpage() was just for a pr_debug() -
changed it to something that might be a bit more useful.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
CC: Chris Mason <chris.mason@oracle.com>
CC: Stefan Behrens <sbehrens@giantdisaster.de>
2012-10-01 15:19:21 -04:00
Liu Bo
69917e4312 Btrfs: fix a bug in parsing return value in logical resolve
In logical resolve, we parse extent_from_logical()'s 'ret' as a kind of flag.

It is possible to lose our errors because
(-EXXXX & BTRFS_EXTENT_FLAG_TREE_BLOCK) is true.

I'm not sure if it is on purpose, it just looks too hacky if it is.
I'd rather use a real flag and a 'ret' to catch errors.

Acked-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Signed-off-by: Liu Bo <liub.liubo@gmail.com>
2012-10-01 15:19:18 -04:00
Wei Yongjun
cf93dccea6 Btrfs: fix possible memory leak in scrub_setup_recheck_block()
bbio has been malloced in btrfs_map_block() and should be
freed before leaving from the error handling cases.

spatch with a semantic match is used to found this problem.
(http://coccinelle.lip6.fr/)

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
2012-10-01 15:19:09 -04:00
Josef Bacik
606686eeac Btrfs: use rcu to protect device->name
Al pointed out that we can just toss out the old name on a device and add a
new one arbitrarily, so anybody who uses device->name in printk could
possibly use free'd memory.  Instead of adding locking around all of this he
suggested doing it with RCU, so I've introduced a struct rcu_string that
does just that and have gone through and protected all accesses to
device->name that aren't under the uuid_mutex with rcu_read_lock().  This
protects us and I will use it for dealing with removing the device that we
used to mount the file system in a later patch.  Thanks,

Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Josef Bacik <josef@redhat.com>
2012-06-14 21:29:16 -04:00
Stefan Behrens
442a4f6308 Btrfs: add device counters for detected IO and checksum errors
The goal is to detect when drives start to get an increased error rate,
when drives should be replaced soon. Therefore statistic counters are
added that count IO errors (read, write and flush). Additionally, the
software detected errors like checksum errors and corrupted blocks are
counted.

Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
2012-05-30 10:23:39 -04:00