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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
Pull btrfs fixes from Chris Mason:
"The big ones here are a memory leak we introduced in rc1, and a
scheduling while atomic if the transid on disk doesn't match the
transid we expected. This happens for corrupt blocks, or out of date
disks.
It also fixes up the ioctl definition for our ioctl to resolve logical
inode numbers. The __u32 was a merging error and doesn't match what
we ship in the progs."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: avoid sleeping in verify_parent_transid while atomic
Btrfs: fix crash in scrub repair code when device is missing
btrfs: Fix mismatching struct members in ioctl.h
Btrfs: fix page leak when allocing extent buffers
Btrfs: Add properly locking around add_root_to_dirty_list
Fix that when scrub tries to repair an I/O or checksum error and one of
the devices containing the mirror is missing, it crashes in bio_add_page
because the bdev is a NULL pointer for missing devices.
Reported-by: Marco L. Crociani <marco.crociani@gmail.com>
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Pull btrfs fixes from Chris Mason:
"This has our collection of bug fixes. I missed the last rc because I
thought our patches were making NFS crash during my xfs test runs.
Turns out it was an NFS client bug fixed by someone else while I tried
to bisect it.
All of these fixes are small, but some are fairly high impact. The
biggest are fixes for our mount -o remount handling, a deadlock due to
GFP_KERNEL allocations in readdir, and a RAID10 error handling bug.
This was tested against both 3.3 and Linus' master as of this morning."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (26 commits)
Btrfs: reduce lock contention during extent insertion
Btrfs: avoid deadlocks from GFP_KERNEL allocations during btrfs_real_readdir
Btrfs: Fix space checking during fs resize
Btrfs: fix block_rsv and space_info lock ordering
Btrfs: Prevent root_list corruption
Btrfs: fix repair code for RAID10
Btrfs: do not start delalloc inodes during sync
Btrfs: fix that check_int_data mount option was ignored
Btrfs: don't count CRC or header errors twice while scrubbing
Btrfs: fix btrfs_ioctl_dev_info() crash on missing device
btrfs: don't return EINTR
Btrfs: double unlock bug in error handling
Btrfs: always store the mirror we read the eb from
fs/btrfs/volumes.c: add missing free_fs_devices
btrfs: fix early abort in 'remount'
Btrfs: fix max chunk size check in chunk allocator
Btrfs: add missing read locks in backref.c
Btrfs: don't call free_extent_buffer twice in iterate_irefs
Btrfs: Make free_ipath() deal gracefully with NULL pointers
Btrfs: avoid possible use-after-free in clear_extent_bit()
...
Pull the minimal btrfs branch from Chris Mason:
"We have a use-after-free in there, along with errors when mount -o
discard is enabled, and a BUG_ON(we should compile with UP more
often)."
* 'for-linus-min' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: use commit root when loading free space cache
Btrfs: fix use-after-free in __btrfs_end_transaction
Btrfs: check return value of bio_alloc() properly
Btrfs: remove lock assert from get_restripe_target()
Btrfs: fix eof while discarding extents
Btrfs: fix uninit variable in repair_eb_io_failure
Revert "Btrfs: increase the global block reserve estimates"
bio_alloc() has the possibility of returning NULL.
So, it is necessary to check the return value.
Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Pull btrfs fixes and features from Chris Mason:
"We've merged in the error handling patches from SuSE. These are
already shipping in the sles kernel, and they give btrfs the ability
to abort transactions and go readonly on errors. It involves a lot of
churn as they clarify BUG_ONs, and remove the ones we now properly
deal with.
Josef reworked the way our metadata interacts with the page cache.
page->private now points to the btrfs extent_buffer object, which
makes everything faster. He changed it so we write an whole extent
buffer at a time instead of allowing individual pages to go down,,
which will be important for the raid5/6 code (for the 3.5 merge
window ;)
Josef also made us more aggressive about dropping pages for metadata
blocks that were freed due to COW. Overall, our metadata caching is
much faster now.
We've integrated my patch for metadata bigger than the page size.
This allows metadata blocks up to 64KB in size. In practice 16K and
32K seem to work best. For workloads with lots of metadata, this cuts
down the size of the extent allocation tree dramatically and fragments
much less.
Scrub was updated to support the larger block sizes, which ended up
being a fairly large change (thanks Stefan Behrens).
We also have an assortment of fixes and updates, especially to the
balancing code (Ilya Dryomov), the back ref walker (Jan Schmidt) and
the defragging code (Liu Bo)."
Fixed up trivial conflicts in fs/btrfs/scrub.c that were just due to
removal of the second argument to k[un]map_atomic() in commit
7ac687d9e0.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (75 commits)
Btrfs: update the checks for mixed block groups with big metadata blocks
Btrfs: update to the right index of defragment
Btrfs: do not bother to defrag an extent if it is a big real extent
Btrfs: add a check to decide if we should defrag the range
Btrfs: fix recursive defragment with autodefrag option
Btrfs: fix the mismatch of page->mapping
Btrfs: fix race between direct io and autodefrag
Btrfs: fix deadlock during allocating chunks
Btrfs: show useful info in space reservation tracepoint
Btrfs: don't use crc items bigger than 4KB
Btrfs: flush out and clean up any block device pages during mount
btrfs: disallow unequal data/metadata blocksize for mixed block groups
Btrfs: enhance superblock sanity checks
Btrfs: change scrub to support big blocks
Btrfs: minor cleanup in scrub
Btrfs: introduce common define for max number of mirrors
Btrfs: fix infinite loop in btrfs_shrink_device()
Btrfs: fix memory leak in resolver code
Btrfs: allow dup for data chunks in mixed mode
Btrfs: validate target profiles only if we are going to use them
...
Scrub used to be coded for nodesize == leafsize == sectorsize == PAGE_SIZE.
This is now changed to support sizes for nodesize and leafsize which are
N * PAGE_SIZE.
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Just a minor cleanup commit in preparation for the big block changes.
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
In commit 4692cf58 we introduced new backref walking code for btrfs. This
assumes we're searching live roots, which requires a transaction context.
While scrubbing, however, we must not join a transaction because this could
deadlock with the commit path. Additionally, what scrub really wants to do
is resolving a logical address in the commit root it's currently checking.
This patch adds support for logical to path resolving on commit roots and
makes scrub use that.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
btrfs currently handles most errors with BUG_ON. This patch is a work-in-
progress but aims to handle most errors other than internal logic
errors and ENOMEM more gracefully.
This iteration prevents most crashes but can run into lockups with
the page lock on occasion when the timing "works out."
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Because scrub enumerates the dev extent tree to find the chunks to scrub,
it currently finds each DUP chunk twice and also scrubs it twice. This
patch makes sure that scrub_chunk only checks that part of the chunk the
dev extent has been found for. This only changes the behaviour for DUP
chunks.
Reported-and-tested-by: Stefan Behrens <sbehrens@giantdisaster.de>
Signed-off-by: Arne Jansen <sensille@gmx.net>
The old backref iteration code could only safely be used on commit roots.
Besides this limitation, it had bugs in finding the roots for these
references. This commit replaces large parts of it by btrfs_find_all_roots()
which a) really finds all roots and the correct roots, b) works correctly
under heavy file system load, c) considers delayed refs.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
This is the last part of the patch series. It modifies the btrfs
code to use the integrity check module if configured to do so
with the define BTRFS_FS_CHECK_INTEGRITY. If this define is not set,
the only effective change is that code is added that handles the
mount option to activate the integrity check. If the mount option is
set and the define BTRFS_FS_CHECK_INTEGRITY is not set, that code
complains in the log and the mount fails with EINVAL.
Add the mount option to activate the usage of the integrity check
code.
Add invocation of btrfs integrity check code init and cleanup
function on mount and umount, respectively.
Add hook to call btrfs integrity check code version of
submit_bh/submit_bio.
Signed-off-by: Stefan Behrens <sbehrens@giantdisaster.de>
Al pointed out we have some random problems with the way we account for
num_workers_starting in the async thread stuff. First of all we need to make
sure to decrement num_workers_starting if we fail to start the worker, so make
__btrfs_start_workers do this. Also fix __btrfs_start_workers so that it
doesn't call btrfs_stop_workers(), there is no point in stopping everybody if we
failed to create a worker. Also check_pending_worker_creates needs to call
__btrfs_start_work in it's work function since it already increments
num_workers_starting.
People only start one worker at a time, so get rid of the num_workers argument
everywhere, and make btrfs_queue_worker a void since it will always succeed.
Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
This patch casts to unsigned long before casting to a pointer and fixes
the following warnings:
fs/btrfs/extent_io.c:2289:20: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
fs/btrfs/ioctl.c:2933:37: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
fs/btrfs/ioctl.c:2937:21: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
fs/btrfs/ioctl.c:3020:21: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
fs/btrfs/scrub.c:275:4: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
fs/btrfs/backref.c:686:27: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Currently scrub fails with ENOMEM when bio_add_page fails. Unfortunately
dm based targets accept only one page per bio, thus making scrub always
fails. This patch just submits the current bio when an error is encountered
and starts a new one.
Signed-off-by: Arne Jansen <sensille@gmx.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
In case we were able to map less than we wanted (length < PAGE_SIZE
clause is true) btrfs_bio is still allocated and we have to free it.
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The new ioctls to follow backrefs are not clean for 32/64 bit
compat. This reworks them for u64s everywhere. They are brand new, so
there are no problems with changing the interface now.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
fs_info has now ~9kb, more than fits into one page. This will cause
mount failure when memory is too fragmented. Top space consumers are
super block structures super_copy and super_for_commit, ~2.8kb each.
Allocate them dynamically. fs_info will be ~3.5kb. (measured on x86_64)
Add a wrapper for freeing fs_info and all of it's dynamically allocated
members.
Signed-off-by: David Sterba <dsterba@suse.cz>
Scrub uses a simple tree-enumeration to bring the relevant portions
of the extent- and csum-tree into the page cache before starting the
scrub-I/O. This is now replaced by using the new readahead-API.
During readahead the scrub is being accounted as paused, so it won't
hold off transaction commits.
This change raises the average disk bandwith utilisation on my test
volume from 70% to 90%. On another volume, the time for a test run
went down from 89s to 43s.
Changes v5:
- reada1/2 are now of type struct reada_control *
Signed-off-by: Arne Jansen <sensille@gmx.net>
This ties nodatasum fixup in scrub together with raid repair patches. While
both series are working fine alone, scrub will report uncorrectable errors
if they occur in a nodatasum extent *and* the page is in the page cache.
Previously, we would have triggered readpage to find good data and do the
repair. However, readpage wouldn't read anything in the case where the page
is up to date in the cache. So, we simply take that good data we have and
call repair_io_failure directly (unless the page in the cache is dirty).
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
btrfs_bio is a bio abstraction able to split and not complete after the last
bio has returned (like the old btrfs_multi_bio). Additionally, btrfs_bio
tracks the mirror_num used to read data which can be used for error
correction purposes.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
This removes a FIXME comment and introduces the first part of nodatasum
fixup: It gets the corresponding inode for a logical address and triggers a
regular readpage for the corrupted sector.
Once we have on-the-fly error correction our error will be automatically
corrected. The correction code is expected to clear the newly introduced
EXTENT_DAMAGED flag, making scrub report that error as "corrected" instead
of "uncorrectable" eventually.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Fix the mirror_num determination in scrub_stripe. The rest of the scrub code
did not use mirror_num for anything important and that error went unnoticed.
The nodatasum fixup patch of this set depends on a correct mirror_num.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
While scrubbing, we may encounter various errors. Previously, a logical
address was printed to the log only. Now, all paths belonging to that
address are resolved and printed separately. That should work for hardlinks
as well as reflinks.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
In normal operation, scrub is reading data sequentially in large portions.
In case of an i/o error, we try to find the corrupted area(s) by issuing
page sized read requests. With this commit we increment the
unverified_errors counter if all of the small size requests succeed.
Userland patches carrying such conspicous events to the administrator should
already be around.
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Scrub starts the workers each time a scrub starts and stops them after it
finished. This patch adds an initialization for the workers before each
start, otherwise the workers behave strangely.
Signed-off-by: Arne Jansen <sensille@gmx.net>
due to the semantics of btrfs_search_slot the path can point to an
invalid slot when ret > 0. This condition went unnoticed, which in
turn could have led to an incomplete scrubbing.
Signed-off-by: Arne Jansen <sensille@gmx.net>
With the removal of the implicit plugging scrub ends up doing more and
smaller I/O than necessary. This patch adds explicit plugging per chunk.
Signed-off-by: Arne Jansen <sensille@gmx.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The current scrub implementation reuses bios and pages as often as possible,
allocating them only on start and releasing them when finished. This leads
to more problems with the block layer than it's worth. The elevator gets
confused when there are more pages added to the bio than bi_size suggests.
This patch completely rips out the reuse of bios and pages and allocates
them freshly for each submit.
Signed-off-by: Arne Jansen <sensille@gmx.net>
Signed-off-by: Chris Maosn <chris.mason@oracle.com>
scrub_page collects several pages into one bio as long as they are physically
contiguous. As we only save one logical address for the whole bio, don't
collect pages that are physically contiguous but logically discontiguous.
Signed-off-by: Arne Jansen <sensille@gmx.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
btrfs scrub - make fixups sync, don't reuse fixup bios
Fixups are already sync for csum failures, this patch makes them sync
for EIO case as well.
Fixups are now sharing pages with the parent sbio - instead of
allocating a separate page to do a fixup we grab the page from the sbio
buffer.
Fixup bios are no longer reused.
struct fixup is no longer needed, instead pass [sbio pointer, index].
Originally this was added to look at the possibility of sharing the code
between drive swap and scrub, but it actually fixes a serious bug in
scrub code where errors that could be corrected were ignored and
reported as uncorrectable.
btrfs scrub - restore bios properly after media errors
The current code reallocates a bio after a media error. This is a
temporary measure introduced in v3 after a serious problem related to
bio reuse was found in v2 of scrub patchset.
Basically we did not reset bv_offset and bv_len fields of the bio_vec
structure. They are changed in case I/O error happens, for example, at
offset 512 or 1024 into the page. Also bi_flags field wasn't properly
setup before reusing the bio.
Signed-off-by: Arne Jansen <sensille@gmx.net>
This adds an initial implementation for scrub. It works quite
straightforward. The usermode issues an ioctl for each device in the
fs. For each device, it enumerates the allocated device chunks. For
each chunk, the contained extents are enumerated and the data checksums
fetched. The extents are read sequentially and the checksums verified.
If an error occurs (checksum or EIO), a good copy is searched for. If
one is found, the bad copy will be rewritten.
All enumerations happen from the commit roots. During a transaction
commit, the scrubs get paused and afterwards continue from the new
roots.
This commit is based on the series originally posted to linux-btrfs
with some improvements that resulted from comments from David Sterba,
Ilya Dryomov and Jan Schmidt.
Signed-off-by: Arne Jansen <sensille@gmx.net>
