commit d96b34248c upstream.
We don't allow send and balance/relocation to run in parallel in order
to prevent send failing or silently producing some bad stream. This is
because while send is using an extent (specially metadata) or about to
read a metadata extent and expecting it belongs to a specific parent
node, relocation can run, the transaction used for the relocation is
committed and the extent gets reallocated while send is still using the
extent, so it ends up with a different content than expected. This can
result in just failing to read a metadata extent due to failure of the
validation checks (parent transid, level, etc), failure to find a
backreference for a data extent, and other unexpected failures. Besides
reallocation, there's also a similar problem of an extent getting
discarded when it's unpinned after the transaction used for block group
relocation is committed.
The restriction between balance and send was added in commit 9e967495e0
("Btrfs: prevent send failures and crashes due to concurrent relocation"),
kernel 5.3, while the more general restriction between send and relocation
was added in commit 1cea5cf0e6 ("btrfs: ensure relocation never runs
while we have send operations running"), kernel 5.14.
Both send and relocation can be very long running operations. Relocation
because it has to do a lot of IO and expensive backreference lookups in
case there are many snapshots, and send due to read IO when operating on
very large trees. This makes it inconvenient for users and tools to deal
with scheduling both operations.
For zoned filesystem we also have automatic block group relocation, so
send can fail with -EAGAIN when users least expect it or send can end up
delaying the block group relocation for too long. In the future we might
also get the automatic block group relocation for non zoned filesystems.
This change makes it possible for send and relocation to run in parallel.
This is achieved the following way:
1) For all tree searches, send acquires a read lock on the commit root
semaphore;
2) After each tree search, and before releasing the commit root semaphore,
the leaf is cloned and placed in the search path (struct btrfs_path);
3) After releasing the commit root semaphore, the changed_cb() callback
is invoked, which operates on the leaf and writes commands to the pipe
(or file in case send/receive is not used with a pipe). It's important
here to not hold a lock on the commit root semaphore, because if we did
we could deadlock when sending and receiving to the same filesystem
using a pipe - the send task blocks on the pipe because it's full, the
receive task, which is the only consumer of the pipe, triggers a
transaction commit when attempting to create a subvolume or reserve
space for a write operation for example, but the transaction commit
blocks trying to write lock the commit root semaphore, resulting in a
deadlock;
4) Before moving to the next key, or advancing to the next change in case
of an incremental send, check if a transaction used for relocation was
committed (or is about to finish its commit). If so, release the search
path(s) and restart the search, to where we were before, so that we
don't operate on stale extent buffers. The search restarts are always
possible because both the send and parent roots are RO, and no one can
add, remove of update keys (change their offset) in RO trees - the
only exception is deduplication, but that is still not allowed to run
in parallel with send;
5) Periodically check if there is contention on the commit root semaphore,
which means there is a transaction commit trying to write lock it, and
release the semaphore and reschedule if there is contention, so as to
avoid causing any significant delays to transaction commits.
This leaves some room for optimizations for send to have less path
releases and re searching the trees when there's relocation running, but
for now it's kept simple as it performs quite well (on very large trees
with resulting send streams in the order of a few hundred gigabytes).
Test case btrfs/187, from fstests, stresses relocation, send and
deduplication attempting to run in parallel, but without verifying if send
succeeds and if it produces correct streams. A new test case will be added
that exercises relocation happening in parallel with send and then checks
that send succeeds and the resulting streams are correct.
A final note is that for now this still leaves the mutual exclusion
between send operations and deduplication on files belonging to a root
used by send operations. A solution for that will be slightly more complex
but it will eventually be built on top of this change.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit b4be6aefa7 upstream.
We hit a bug with a recovering relocation on mount for one of our file
systems in production. I reproduced this locally by injecting errors
into snapshot delete with balance running at the same time. This
presented as an error while looking up an extent item
WARNING: CPU: 5 PID: 1501 at fs/btrfs/extent-tree.c:866 lookup_inline_extent_backref+0x647/0x680
CPU: 5 PID: 1501 Comm: btrfs-balance Not tainted 5.16.0-rc8+ #8
RIP: 0010:lookup_inline_extent_backref+0x647/0x680
RSP: 0018:ffffae0a023ab960 EFLAGS: 00010202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 000000000000000c RDI: 0000000000000000
RBP: ffff943fd2a39b60 R08: 0000000000000000 R09: 0000000000000001
R10: 0001434088152de0 R11: 0000000000000000 R12: 0000000001d05000
R13: ffff943fd2a39b60 R14: ffff943fdb96f2a0 R15: ffff9442fc923000
FS: 0000000000000000(0000) GS:ffff944e9eb40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1157b1fca8 CR3: 000000010f092000 CR4: 0000000000350ee0
Call Trace:
<TASK>
insert_inline_extent_backref+0x46/0xd0
__btrfs_inc_extent_ref.isra.0+0x5f/0x200
? btrfs_merge_delayed_refs+0x164/0x190
__btrfs_run_delayed_refs+0x561/0xfa0
? btrfs_search_slot+0x7b4/0xb30
? btrfs_update_root+0x1a9/0x2c0
btrfs_run_delayed_refs+0x73/0x1f0
? btrfs_update_root+0x1a9/0x2c0
btrfs_commit_transaction+0x50/0xa50
? btrfs_update_reloc_root+0x122/0x220
prepare_to_merge+0x29f/0x320
relocate_block_group+0x2b8/0x550
btrfs_relocate_block_group+0x1a6/0x350
btrfs_relocate_chunk+0x27/0xe0
btrfs_balance+0x777/0xe60
balance_kthread+0x35/0x50
? btrfs_balance+0xe60/0xe60
kthread+0x16b/0x190
? set_kthread_struct+0x40/0x40
ret_from_fork+0x22/0x30
</TASK>
Normally snapshot deletion and relocation are excluded from running at
the same time by the fs_info->cleaner_mutex. However if we had a
pending balance waiting to get the ->cleaner_mutex, and a snapshot
deletion was running, and then the box crashed, we would come up in a
state where we have a half deleted snapshot.
Again, in the normal case the snapshot deletion needs to complete before
relocation can start, but in this case relocation could very well start
before the snapshot deletion completes, as we simply add the root to the
dead roots list and wait for the next time the cleaner runs to clean up
the snapshot.
Fix this by setting a bit on the fs_info if we have any DEAD_ROOT's that
had a pending drop_progress key. If they do then we know we were in the
middle of the drop operation and set a flag on the fs_info. Then
balance can wait until this flag is cleared to start up again.
If there are DEAD_ROOT's that don't have a drop_progress set then we're
safe to start balance right away as we'll be properly protected by the
cleaner_mutex.
CC: stable@vger.kernel.org # 5.10+
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 960a3166ae upstream
Now that we use a dedicated block group and regular writes for data
relocation, we can preallocate the space needed for a relocated inode,
just like we do in regular mode.
Essentially this reverts commit 32430c6148 ("btrfs: zoned: enable
relocation on a zoned filesystem") as it is not needed anymore.
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 37f00a6d2e upstream
There are several places in our codebase where we check if a root is the
root of the data reloc tree and subsequent patches will introduce more.
Factor out the check into a small helper function instead of open coding
it multiple times.
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[BUG]
When using the following script, btrfs will report data corruption after
one data balance with subpage support:
mkfs.btrfs -f -s 4k $dev
mount $dev -o nospace_cache $mnt
$fsstress -w -n 8 -s 1620948986 -d $mnt/ -v > /tmp/fsstress
sync
btrfs balance start -d $mnt
btrfs scrub start -B $mnt
Similar problem can be easily observed in btrfs/028 test case, there
will be tons of balance failure with -EIO.
[CAUSE]
Above fsstress will result the following data extents layout in extent
tree:
item 10 key (13631488 EXTENT_ITEM 98304) itemoff 15889 itemsize 82
refs 2 gen 7 flags DATA
extent data backref root FS_TREE objectid 259 offset 1339392 count 1
extent data backref root FS_TREE objectid 259 offset 647168 count 1
item 11 key (13631488 BLOCK_GROUP_ITEM 8388608) itemoff 15865 itemsize 24
block group used 102400 chunk_objectid 256 flags DATA
item 12 key (13733888 EXTENT_ITEM 4096) itemoff 15812 itemsize 53
refs 1 gen 7 flags DATA
extent data backref root FS_TREE objectid 259 offset 729088 count 1
Then when creating the data reloc inode, the data reloc inode will look
like this:
0 32K 64K 96K 100K 104K
|<------ Extent A ----->| |<- Ext B ->|
Then when we first try to relocate extent A, we setup the data reloc
inode with i_size 96K, then read both page [0, 64K) and page [64K, 128K).
For page 64K, since the i_size is just 96K, we fill range [96K, 128K)
with 0 and set it uptodate.
Then when we come to extent B, we update i_size to 104K, then try to read
page [64K, 128K).
Then we find the page is already uptodate, so we skip the read.
But range [96K, 128K) is filled with 0, not the real data.
Then we writeback the data reloc inode to disk, with 0 filling range
[96K, 128K), corrupting the content of extent B.
The behavior is caused by the fact that we still do full page read for
subpage case.
The bug won't really happen for regular sectorsize, as one page only
contains one sector.
[FIX]
This patch will fix the problem by invalidating range [i_size, PAGE_END]
in prealloc_file_extent_cluster().
So that if above example happens, when we preallocate the file extent
for extent B, we will clear the uptodate bits for range [96K, 128K),
allowing later relocate_one_page() to re-read the needed range.
There is a special note for the invalidating part.
Since we're not calling real btrfs_invalidatepage(), but just clearing
the subpage and page uptodate bits, we can leave a page half dirty and
half out of date.
Reading such page can cause a deadlock, as we normally expect a dirty
page to be fully uptodate.
Thus here we flush and wait the data reloc inode before doing the hacked
invalidating. This won't cause extra overhead, as we're going to
writeback the data later anyway.
Reported-by: Ritesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For subpage case, one page of data reloc inode can contain several file
extents, like this:
|<--- File extent A --->| FE B | FE C |<--- File extent D -->|
|<--------- Page --------->|
We can no longer use PAGE_SIZE directly for various operations.
This patch will relocate_one_page() to handle subpage case by:
- Iterating through all extents of a cluster when marking pages
When marking pages dirty and delalloc, we need to check the cluster
extent boundary.
Now we introduce a loop to go extent by extent of a page, until we
either finished the last extent, or reach the page end.
By this, regular sectorsize == PAGE_SIZE can still work as usual, since
we will do that loop only once.
- Iteration start from max(page_start, extent_start)
Since we can have the following case:
| FE B | FE C |<--- File extent D -->|
|<--------- Page --------->|
Thus we can't always start from page_start, but do a
max(page_start, extent_start)
- Iteration end when the cluster is exhausted
Similar to previous case, the last file extent can end before the page
end:
|<--- File extent A --->| FE B | FE C |
|<--------- Page --------->|
In this case, we need to manually exit the loop after we have finished
the last extent of the cluster.
- Reserve metadata space for each extent range
Since now we can hit multiple ranges in one page, we should reserve
metadata for each range, not simply PAGE_SIZE.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In function relocate_file_extent_cluster(), we have a big loop for
marking all involved page delalloc.
That part is long enough to be contained in one function, so this patch
will move that code chunk into a new function, relocate_one_page().
This also provides enough space for later subpage work.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Relocation and send do not play well together because while send is
running a block group can be relocated, a transaction committed and
the respective disk extents get re-allocated and written to or discarded
while send is about to do something with the extents.
This was explained in commit 9e967495e0 ("Btrfs: prevent send failures
and crashes due to concurrent relocation"), which prevented balance and
send from running in parallel but it did not address one remaining case
where chunk relocation can happen: shrinking a device (and device deletion
which shrinks a device's size to 0 before deleting the device).
We also have now one more case where relocation is triggered: on zoned
filesystems partially used block groups get relocated by a background
thread, introduced in commit 18bb8bbf13 ("btrfs: zoned: automatically
reclaim zones").
So make sure that instead of preventing balance from running when there
are ongoing send operations, we prevent relocation from happening.
This uses the infrastructure recently added by a patch that has the
subject: "btrfs: add cancellable chunk relocation support".
Also it adds a spinlock used exclusively for the exclusivity between
send and relocation, as before fs_info->balance_mutex was used, which
would make an attempt to run send to block waiting for balance to
finish, which can take a lot of time on large filesystems.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Add support code that will allow canceling relocation on the chunk
granularity. This is different and independent of balance, that also
uses relocation but is a higher level operation and manages it's own
state and pause/cancellation requests.
Relocation is used for resize (shrink) and device deletion so this will
be a common point to implement cancellation for both. The context is
entirely in btrfs_relocate_block_group and btrfs_recover_relocation,
enclosing one chunk relocation. The status bit is set and unset between
the chunks. As relocation can take long, the effects may not be
immediate and the request and actual action can slightly race.
The fs_info::reloc_cancel_req is only supposed to be increased and does
not pair with decrement like fs_info::balance_cancel_req.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are a few places where we don't check the return value of
btrfs_commit_transaction in relocation.c. Thankfully all these places
have straightforward error handling, so simply change all of the sites
at once.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have a BUG_ON() if we get an error back from btrfs_get_fs_root().
This honestly should never fail, as at this point we have a solid
coordination of fs root to reloc root, and these roots will all be in
memory. But in the name of killing BUG_ON()'s remove these and handle
the error condition properly, ASSERT()'ing for developers.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In corruption cases we could have paths from a block up to no root at
all, and thus we'll BUG_ON(!root) in select_one_root. Handle this by
adding an ASSERT() for developers, and returning an error for normal
users.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This probably can't happen even with a corrupt file system, because we
would have failed much earlier on than here. However there's no reason
we can't just check and bail out as appropriate, so do that and convert
the correctness BUG_ON() to an ASSERT().
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
If we have a duplicate entry for a reloc root then we could have fs
corruption that resulted in a double allocation. Since this shouldn't
happen unless there is corruption, add an ASSERT(ret != -EEXIST) to all
of the callers of __add_reloc_root() to catch any logic mistakes for
developers, otherwise normal error handling will happen for normal
users.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We can already handle errors appropriately from this function, deal with
an error coming from __add_reloc_root appropriately.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
We already handle some errors in this function, and the callers do the
correct error handling, so clean up the rest of the function to do the
appropriate error handling.
There's a little extra work that needs to be done here, as we create the
inode item before we create the orphan item. We could potentially add
the orphan item, but if we failed to create the inode item we would have
to abort the transaction.
Instead add a helper to delete the inode item we created in the case
that we're unable to look up the inode (this would likely be caused by
an ENOMEM), which if it succeeds means we can avoid a transaction abort
in this particular error case.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
These checks are all taken care of for us by the tree checker code:
- the flags don't change or are updated consistently
- the v0 extent item format is invalid and caught in many other places
too
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
We can already deal with errors appropriately from do_relocation, simply
handle any errors that come from changing the refs at this point
cleanly. We have to abort the transaction if we fail here as we've
modified metadata at this point.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If any of the reference count manipulation stuff fails in replace_path
we need to abort the transaction, as we've modified the blocks already.
We can simply break at this point and everything will be cleaned up.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The search can fail for various reasons, in case of errors there's no
cleanup to be done so we can pass the error to the caller, adjusting for
the case where the key is not found and search slot returns 1.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
If we error out COWing the root node when doing a replace_path then we
simply unlock and free the buffer and return the error.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A few BUG_ON()'s in replace_path are purely to keep us from making
logical mistakes, so replace them with ASSERT()'s.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We call btrfs_update_root in btrfs_update_reloc_root, which can fail for
all sorts of reasons, including IO errors. Instead of panicing the box
lets return the error, now that all callers properly handle those
errors.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_update_reloc_root will will return errors in the future, so handle
an error properly in prepare_to_merge.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_update_reloc_root will will return errors in the future, so handle
the error properly in insert_dirty_subvol.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This will be able to return errors in the future, so change it to return
an error and handle the errors appropriately.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we fail to setup a root->reloc_root in a different thread that path
will error out, however it still leaves root->reloc_root NULL but would
still appear set up in the transaction. Subsequent calls to
btrfs_record_root_in_transaction would succeed without attempting to
create the reloc root, as the transid has already been updated.
Handle this case by making sure we have a root->reloc_root set after a
btrfs_record_root_in_transaction call so we don't end up dereferencing a
NULL pointer.
Reported-by: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We do memory allocations here, read blocks from disk, all sorts of
operations that could easily fail at any given point. Instead of
panicing the box, simply return the error back up the chain, all callers
at this point have proper error handling.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
create_reloc_root will return errors in the future, and __add_reloc_root
can return ENOMEM or EEXIST, so handle these errors properly.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add comment ]
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_record_root_in_trans will return errors in the future, so handle
the error properly in relocate_tree_block.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Generally speaking this shouldn't ever fail, the corresponding fs root
for the reloc root will already be in memory, so we won't get ENOMEM
here.
However if there is no corresponding root for the reloc root then we
could get ENOMEM when we try to allocate it or we could get ENOENT
when we look it up and see that it doesn't exist.
Convert these BUG_ON()'s into ASSERT()'s and add proper error handling
for the case of corruption.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We will record the fs root or the reloc root in the trans in
select_reloc_root. These will actually return errors in the following
patches, so check their return value here and return it up the stack.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have several BUG_ON()'s in select_reloc_root() that can be tripped if
there is an extent tree corruption. Convert these to ASSERT()'s, because
if we hit it during testing it really is bad, or could indicate a
problem with the backref walking code.
However if users hit these problems it generally indicates corruption,
I've hit a few machines in the fleet that trip over these with clearly
corrupted extent trees, so be nice and print out an error message and
return an error instead of bringing the whole box down.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently select_reloc_root() doesn't return an error, but followup
patches will make it possible for it to return an error. We do have
proper error recovery in do_relocation however, so handle the
possibility of select_reloc_root() having an error properly instead of
BUG_ON(!root).
I've also adjusted select_reloc_root() to return ERR_PTR(-ENOENT) if we
don't find a root, instead of NULL, to make the error case easier to
deal with. I've replaced the BUG_ON(!root) with an ASSERT(0) for this
case as it indicates we messed up the backref walking code, but it could
also indicate corruption.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have a couple of BUG_ON()'s in relocate_tree_block() that can be
tripped if we have file system corruption. Convert these to ASSERT()'s
so developers still get yelled at when they break the backref code, but
error out nicely for users so the whole box doesn't go down.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A few of these are checking for correctness, and won't be triggered by
corrupted file systems, so convert them to ASSERT() instead of BUG_ON()
and add a comment explaining their existence.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
A few places we intermix btrfs_inode_lock with a inode_unlock, and some
places we just use inode_lock/inode_unlock instead of btrfs_inode_lock.
None of these places are using this incorrectly, but as we adjust some
of these callers it would be nice to keep everything consistent, so
convert everybody to use btrfs_inode_lock/btrfs_inode_unlock.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently fallocate() is disabled on a zoned filesystem. Since current
relocation process relies on preallocation to move file data extents, it
must be handled differently.
On a zoned filesystem, we just truncate the inode to the size that we
wanted to pre-allocate. Then, we flush dirty pages on the file before
finishing the relocation process. run_delalloc_zoned() will handle all
the allocations and submit IOs to the underlying layers.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
To support subpage sector size, data also need extra info to make sure
which sectors in a page are uptodate/dirty/...
This patch will make pages for data inodes get btrfs_subpage structure
attached, and detached when the page is freed.
This patch also slightly changes the timing when
set_page_extent_mapped() is called to make sure:
- We have page->mapping set
page->mapping->host is used to grab btrfs_fs_info, thus we can only
call this function after page is mapped to an inode.
One call site attaches pages to inode manually, thus we have to modify
the timing of set_page_extent_mapped() a bit.
- As soon as possible, before other operations
Since memory allocation can fail, we have to do extra error handling.
Calling set_page_extent_mapped() as soon as possible can simply the
error handling for several call sites.
The idea is pretty much the same as iomap_page, but with more bitmaps
for btrfs specific cases.
Currently the plan is to switch iomap if iomap can provide sector
aligned write back (only write back dirty sectors, but not the full
page, data balance require this feature).
So we will stick to btrfs specific bitmap for now.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When recovering a relocation, if we run into a reloc root that has 0
refs we simply add it to the reloc_control->reloc_roots list, and then
clean it up later. The problem with this is __del_reloc_root() doesn't
do anything if the root isn't in the radix tree, which in this case it
won't be because we never call __add_reloc_root() on the reloc_root.
This exit condition simply isn't correct really. During normal
operation we can remove ourselves from the rb tree and then we're meant
to clean up later at merge_reloc_roots() time, and this happens
correctly. During recovery we're depending on free_reloc_roots() to
drop our references, but we're short-circuiting.
Fix this by continuing to check if we're on the list and dropping
ourselves from the reloc_control root list and dropping our reference
appropriately. Change the corresponding BUG_ON() to an ASSERT() that
does the correct thing if we aren't in the rb tree.
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
While testing the error paths in relocation, I hit the following lockdep
splat:
======================================================
WARNING: possible circular locking dependency detected
5.10.0-rc3+ #206 Not tainted
------------------------------------------------------
btrfs-balance/1571 is trying to acquire lock:
ffff8cdbcc8f77d0 (&head_ref->mutex){+.+.}-{3:3}, at: btrfs_lookup_extent_info+0x156/0x3b0
but task is already holding lock:
ffff8cdbc54adbf8 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_lock+0x27/0x100
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (btrfs-tree-00){++++}-{3:3}:
down_write_nested+0x43/0x80
__btrfs_tree_lock+0x27/0x100
btrfs_search_slot+0x248/0x890
relocate_tree_blocks+0x490/0x650
relocate_block_group+0x1ba/0x5d0
kretprobe_trampoline+0x0/0x50
-> #1 (btrfs-csum-01){++++}-{3:3}:
down_read_nested+0x43/0x130
__btrfs_tree_read_lock+0x27/0x100
btrfs_read_lock_root_node+0x31/0x40
btrfs_search_slot+0x5ab/0x890
btrfs_del_csums+0x10b/0x3c0
__btrfs_free_extent+0x49d/0x8e0
__btrfs_run_delayed_refs+0x283/0x11f0
btrfs_run_delayed_refs+0x86/0x220
btrfs_start_dirty_block_groups+0x2ba/0x520
kretprobe_trampoline+0x0/0x50
-> #0 (&head_ref->mutex){+.+.}-{3:3}:
__lock_acquire+0x1167/0x2150
lock_acquire+0x116/0x3e0
__mutex_lock+0x7e/0x7b0
btrfs_lookup_extent_info+0x156/0x3b0
walk_down_proc+0x1c3/0x280
walk_down_tree+0x64/0xe0
btrfs_drop_subtree+0x182/0x260
do_relocation+0x52e/0x660
relocate_tree_blocks+0x2ae/0x650
relocate_block_group+0x1ba/0x5d0
kretprobe_trampoline+0x0/0x50
other info that might help us debug this:
Chain exists of:
&head_ref->mutex --> btrfs-csum-01 --> btrfs-tree-00
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(btrfs-tree-00);
lock(btrfs-csum-01);
lock(btrfs-tree-00);
lock(&head_ref->mutex);
*** DEADLOCK ***
5 locks held by btrfs-balance/1571:
#0: ffff8cdb89749ff8 (&fs_info->delete_unused_bgs_mutex){+.+.}-{3:3}, at: btrfs_balance+0x563/0xf40
#1: ffff8cdb89748838 (&fs_info->cleaner_mutex){+.+.}-{3:3}, at: btrfs_relocate_block_group+0x156/0x300
#2: ffff8cdbc2c16650 (sb_internal#2){.+.+}-{0:0}, at: start_transaction+0x413/0x5c0
#3: ffff8cdbc135f538 (btrfs-treloc-01){+.+.}-{3:3}, at: __btrfs_tree_lock+0x27/0x100
#4: ffff8cdbc54adbf8 (btrfs-tree-00){++++}-{3:3}, at: __btrfs_tree_lock+0x27/0x100
stack backtrace:
CPU: 1 PID: 1571 Comm: btrfs-balance Not tainted 5.10.0-rc3+ #206
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014
Call Trace:
dump_stack+0x8b/0xb0
check_noncircular+0xcf/0xf0
? trace_call_bpf+0x139/0x260
__lock_acquire+0x1167/0x2150
lock_acquire+0x116/0x3e0
? btrfs_lookup_extent_info+0x156/0x3b0
__mutex_lock+0x7e/0x7b0
? btrfs_lookup_extent_info+0x156/0x3b0
? btrfs_lookup_extent_info+0x156/0x3b0
? release_extent_buffer+0x124/0x170
? _raw_spin_unlock+0x1f/0x30
? release_extent_buffer+0x124/0x170
btrfs_lookup_extent_info+0x156/0x3b0
walk_down_proc+0x1c3/0x280
walk_down_tree+0x64/0xe0
btrfs_drop_subtree+0x182/0x260
do_relocation+0x52e/0x660
relocate_tree_blocks+0x2ae/0x650
? add_tree_block+0x149/0x1b0
relocate_block_group+0x1ba/0x5d0
elfcorehdr_read+0x40/0x40
? elfcorehdr_read+0x40/0x40
? btrfs_balance+0x796/0xf40
? __kthread_parkme+0x66/0x90
? btrfs_balance+0xf40/0xf40
? balance_kthread+0x37/0x50
? kthread+0x137/0x150
? __kthread_bind_mask+0x60/0x60
? ret_from_fork+0x1f/0x30
As you can see this is bogus, we never take another tree's lock under
the csum lock. This happens because sometimes we have to read tree
blocks from disk without knowing which root they belong to during
relocation. We defaulted to an owner of 0, which translates to an fs
tree. This is fine as all fs trees have the same class, but obviously
isn't fine if the block belongs to a COW only tree.
Thankfully COW only trees only have their owners root as a reference to
them, and since we already look up the extent information during
relocation, go ahead and check and see if this block might belong to a
COW only tree, and if so save the owner in the tree_block struct. This
allows us to read_tree_block with the proper owner, which gets rid of
this lockdep splat.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I was attempting to reproduce a problem that Zygo hit, but my error
injection wasn't firing for a few of the common calls to
btrfs_should_cancel_balance. This is because the compiler decided to
inline it at these spots. Keep this from happening by explicitly
marking the function as noinline so that error injection will always
work.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This better reflects the semantics of the function i.e no search is
performed whatsoever.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
There are several bug reports about recent kernel unable to relocate
certain data block groups.
Sometimes the error just goes away, but there is one reporter who can
reproduce it reliably.
The dmesg would look like:
[438.260483] BTRFS info (device dm-10): balance: start -dvrange=34625344765952..34625344765953
[438.269018] BTRFS info (device dm-10): relocating block group 34625344765952 flags data|raid1
[450.439609] BTRFS info (device dm-10): found 167 extents, stage: move data extents
[463.501781] BTRFS info (device dm-10): balance: ended with status: -2
[CAUSE]
The ENOENT error is returned from the following call chain:
add_data_references()
|- delete_v1_space_cache();
|- if (!found)
return -ENOENT;
The variable @found is set to true if we find a data extent whose
disk bytenr matches parameter @data_bytes.
With extra debugging, the offending tree block looks like this:
leaf bytenr = 42676709441536, data_bytenr = 34626327621632
ctime 1567904822.739884119 (2019-09-08 03:07:02)
mtime 0.0 (1970-01-01 01:00:00)
otime 0.0 (1970-01-01 01:00:00)
item 27 key (51933 EXTENT_DATA 0) itemoff 9854 itemsize 53
generation 1517381 type 2 (prealloc)
prealloc data disk byte 34626327621632 nr 262144 <<<
prealloc data offset 0 nr 262144
item 28 key (52262 ROOT_ITEM 0) itemoff 9415 itemsize 439
generation 2618893 root_dirid 256 bytenr 42677048360960 level 3 refs 1
lastsnap 2618893 byte_limit 0 bytes_used 5557338112 flags 0x0(none)
uuid d0d4361f-d231-6d40-8901-fe506e4b2b53
Although item 27 has disk bytenr 34626327621632, which matches the
data_bytenr, its type is prealloc, not reg.
This makes the existing code skip that item, and return ENOENT.
[FIX]
The code is modified in commit 19b546d7a1 ("btrfs: relocation: Use
btrfs_find_all_leafs to locate data extent parent tree leaves"), before
that commit, we use something like
"if (type == BTRFS_FILE_EXTENT_INLINE) continue;"
But in that offending commit, we use (type == BTRFS_FILE_EXTENT_REG),
ignoring BTRFS_FILE_EXTENT_PREALLOC.
Fix it by also checking BTRFS_FILE_EXTENT_PREALLOC.
Reported-by: Stéphane Lesimple <stephane_btrfs2@lesimple.fr>
Link: https://lore.kernel.org/linux-btrfs/505cabfa88575ed6dbe7cb922d8914fb@lesimple.fr
Fixes: 19b546d7a1 ("btrfs: relocation: Use btrfs_find_all_leafs to locate data extent parent tree leaves")
CC: stable@vger.kernel.org # 5.6+
Tested-By: Stéphane Lesimple <stephane_btrfs2@lesimple.fr>
Reviewed-by: Su Yue <l@damenly.su>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
It's been deprecated since commit b547a88ea5 ("btrfs: start
deprecation of mount option inode_cache") which enumerates the reasons.
A filesystem that uses the feature (mount -o inode_cache) tracks the
inode numbers in bitmaps, that data stay on the filesystem after this
patch. The size is roughly 5MiB for 1M inodes [1], which is considered
small enough to be left there. Removal of the change can be implemented
in btrfs-progs if needed.
[1] https://lore.kernel.org/linux-btrfs/20201127145836.GZ6430@twin.jikos.cz/
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
It simply gets assigned to 'ret' in case of errors. The flow of the
while loop is not changed by this commit since the few call sites
that 'goto next' will simply break from the loop.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In most cases when an error is returned from a function 'ret' is simply
assigned to 'err'. There is only one case where walk_up_reloc_tree can
return a positive value - in this case the code breaks from the loop and
ret is going to get its return value from btrfs_cow_block - either 0 or
negative. This retains the old logic of how 'err' used to be set at
this call site.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we've plumbed all of the callers to have the owner root and the
level, plumb it down into alloc_extent_buffer().
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In order to properly set the lockdep class of a newly allocated block we
need to know the owner of the block. For non-refcounted trees this is
straightforward, we always know in advance what tree we're reading from.
For refcounted trees we don't necessarily know, however all refcounted
trees share the same lockdep class name, tree-<level>.
Fix all the callers of read_tree_block() to pass in the root objectid
we're using. In places like relocation and backref we could probably
unconditionally use 0, but just in case use the root when we have it,
otherwise use 0 in the cases we don't have the root as it's going to be
a refcounted tree anyway.
This is a preparation patch for further changes.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We're open-coding btrfs_read_node_slot() here, replace with the helper.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
