If force_bio_submit, submit_extent_page simply calls submit_one_bio as
the first thing. This can just be moved to the only caller that sets
force_bio_submit to true.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When read_extent_buffer_subpage calls submit_extent_page, it does
so on a freshly initialized btrfs_bio_ctrl structure that can't have
a valid bio to submit. Clear the force_bio_submit parameter to false
as there is nothing to submit.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_bin_search() is a simple wrapper that searches for the whole slots
by calling btrfs_generic_bin_search() with the starting slot/first_slot
preset to 0.
This simple wrapper can be open coded as btrfs_bin_search().
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
Although dev replace ioctl has a way to specify the mode on whether we
should read from the source device, it's not properly followed.
# mkfs.btrfs -f -d raid1 -m raid1 $dev1 $dev2
# mount $dev1 $mnt
# xfs_io -f -c "pwrite 0 32M" $mnt/file
# sync
# btrfs replace start -r -f 1 $dev3 $mnt
And one extra trace is added to scrub_submit(), showing the detail about
the bio:
btrfs-11569 [005] ... 37.0270: scrub_submit.part.0: devid=1 logical=22036480 phy=22036480 len=16384
btrfs-11569 [005] ... 37.0273: scrub_submit.part.0: devid=1 logical=30457856 phy=30457856 len=32768
btrfs-11569 [005] ... 37.0274: scrub_submit.part.0: devid=1 logical=30507008 phy=30507008 len=49152
btrfs-11569 [005] ... 37.0274: scrub_submit.part.0: devid=1 logical=30605312 phy=30605312 len=32768
btrfs-11569 [005] ... 37.0275: scrub_submit.part.0: devid=1 logical=30703616 phy=30703616 len=65536
btrfs-11569 [005] ... 37.0281: scrub_submit.part.0: devid=1 logical=298844160 phy=298844160 len=131072
...
btrfs-11569 [005] ... 37.0762: scrub_submit.part.0: devid=1 logical=322961408 phy=322961408 len=131072
btrfs-11569 [005] ... 37.0762: scrub_submit.part.0: devid=1 logical=323092480 phy=323092480 len=131072
One can see that all the reads are submitted to devid 1, even if we have
specified "-r" option to avoid reading from the source device.
[CAUSE]
The dev-replace read mode is only set but not followed by scrub code at
all. In fact, only common read path is properly following the read
mode, but scrub itself has its own read path, thus not following the
mode.
[FIX]
Here we enhance scrub_find_good_copy() to also follow the read mode.
The idea is pretty simple, in the first loop, we avoid the following
devices:
- Missing devices
This is the existing condition
- The source device if the replace wants to avoid it.
And if above loop found no candidate (e.g. replace a single device),
then we discard the 2nd condition, and try again.
Since we're here, also enhance the function scrub_find_good_copy() by:
- Remove the forward declaration
- Makes it return int
To indicates errors, e.g. no good mirror found.
- Add extra error messages
Now with the same trace, "btrfs replace start -r" works as expected:
btrfs-1213 [000] ... 991.9059: scrub_submit.part.0: devid=2 logical=22036480 phy=1064960 len=16384
btrfs-1213 [000] ... 991.9062: scrub_submit.part.0: devid=2 logical=30457856 phy=9486336 len=32768
btrfs-1213 [000] ... 991.9063: scrub_submit.part.0: devid=2 logical=30507008 phy=9535488 len=49152
btrfs-1213 [000] ... 991.9064: scrub_submit.part.0: devid=2 logical=30605312 phy=9633792 len=32768
btrfs-1213 [000] ... 991.9065: scrub_submit.part.0: devid=2 logical=30703616 phy=9732096 len=65536
btrfs-1213 [000] ... 991.9073: scrub_submit.part.0: devid=2 logical=298844160 phy=277872640 len=131072
btrfs-1213 [000] ... 991.9075: scrub_submit.part.0: devid=2 logical=298975232 phy=278003712 len=131072
btrfs-1213 [000] ... 991.9078: scrub_submit.part.0: devid=2 logical=299106304 phy=278134784 len=131072
...
btrfs-1213 [000] ... 991.9474: scrub_submit.part.0: devid=2 logical=318504960 phy=297533440 len=131072
btrfs-1213 [000] ... 991.9476: scrub_submit.part.0: devid=2 logical=318636032 phy=297664512 len=131072
btrfs-1213 [000] ... 991.9479: scrub_submit.part.0: devid=2 logical=318767104 phy=297795584 len=131072
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Fold finish_compressed_bio_write into its only caller as there is no
reason to keep them separate.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
No one ever set ->mapping on these pages, so don't bother clearing it.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Share the code to free the compressed pages and the array to hold them
into a common helper.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Factor out a common helper to add the compressed_bio pages to the
bio that is shared by the compressed read and write path.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
struct btrfs_bio now has a file_offset field set up by all submitters.
Use that value combined with the bio size in add_ra_bio_pages to
calculate the last offset in the bio.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
struct btrfs_bio now has a file_offset field set up by all submitters.
Use that in btrfs_submit_compressed_read instead of recalculating the
value.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
em can't be non-NULL after the free_extent_map label. Also remove
the now pointless clearing of em to NULL after freeing it.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Embed a btrfs_bio into struct compressed_bio. This avoids potential
(so far theoretical) deadlocks due to nesting of btrfs_bioset allocations
for the original read bio and the compressed bio, and avoids an extra
memory allocation in the I/O path.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In btrfs_io_context structure, we have a pointer raid_map, which
indicates the logical bytenr for each stripe.
But considering we always call sort_parity_stripes(), the result
raid_map[] is always sorted, thus raid_map[0] is always the logical
bytenr of the full stripe.
So why we waste the space and time (for sorting) for raid_map?
This patch will replace btrfs_io_context::raid_map with a single u64
number, full_stripe_start, by:
- Replace btrfs_io_context::raid_map with full_stripe_start
- Replace call sites using raid_map[0] to use full_stripe_start
- Replace call sites using raid_map[i] to compare with nr_data_stripes.
The benefits are:
- Less memory wasted on raid_map
It's sizeof(u64) * num_stripes vs sizeof(u64).
It'll always save at least one u64, and the benefit grows larger with
num_stripes.
- No more weird alloc_btrfs_io_context() behavior
As there is only one fixed size + one variable length array.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For btrfs dev-replace, we have to duplicate writes to the source
device into the target device.
For non-RAID56, all writes into the same mapped ranges are sharing the
same content, thus they don't really need to bother anything.
(E.g. in btrfs_submit_bio() for non-RAID56 range we just submit the
same write to all involved devices).
But for RAID56, all stripes contain different content, thus we must
have a clear mapping of which stripe is duplicated from which original
stripe.
Currently we use a complex way using tgtdev_map[] array, e.g:
num_tgtdevs = 1
tgtdev_map[0] = 0 <- Means stripes[0] is not involved in replace.
tgtdev_map[1] = 3 <- Means stripes[1] is involved in replace,
and it's duplicated to stripes[3].
tgtdev_map[2] = 0 <- Means stripes[2] is not involved in replace.
But this is wasting some space, and ignores one important thing for
dev-replace, there is at most one running replace.
Thus we can change it to a fixed array to represent the mapping:
replace_nr_stripes = 1
replace_stripe_src = 1 <- Means stripes[1] is involved in replace.
thus the extra stripe is a copy of
stripes[1]
By this we can save some space for bioc on RAID56 chunks with many
devices. And we get rid of one variable sized array from bioc.
Thus the patch involves the following changes:
- Replace @num_tgtdevs and @tgtdev_map[] with @replace_nr_stripes
and @replace_stripe_src.
@num_tgtdevs is just renamed to @replace_nr_stripes.
While the mapping is completely changed.
- Add extra ASSERT()s for RAID56 code
- Only add two more extra stripes for dev-replace cases.
As we have an upper limit on how many dev-replace stripes we can have.
- Unify the behavior of handle_ops_on_dev_replace()
Previously handle_ops_on_dev_replace() go two different paths for
WRITE and GET_READ_MIRRORS.
Now unify them by always going the WRITE path first (with at most 2
replace stripes), then if we're doing GET_READ_MIRRORS and we have 2
extra stripes, just drop one stripe.
- Remove the @real_stripes argument from alloc_btrfs_io_context()
As we don't need the old variable length array any more.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
That structure is our ultimate object for all __btrfs_map_block()
related functions. We have some hard to understand members, like
tgtdev_map, but without any comments.
This patch will improve the situation:
- Add extra comments for num_stripes, mirror_num, num_tgtdevs and
tgtdev_map[]
Especially for the last two members, add a dedicated (thus very long)
comments for them, with example to explain it.
- Shrink those int members to u16.
In fact our on-disk format is only using u16 for num_stripes, thus
no need to use int at all.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There is no memory re-allocation for handle_ops_on_dev_replace(), thus
we don't need to pass a btrfs_io_context pointer.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are quite some div64 calls inside btrfs_map_block() and its
variants.
Such calls are for @stripe_nr, where @stripe_nr is the number of
stripes before our logical bytenr inside a chunk.
However we can eliminate such div64 calls by just reducing the width of
@stripe_nr from 64 to 32.
This can be done because our chunk size limit is already 10G, with fixed
stripe length 64K.
Thus a U32 is definitely enough to contain the number of stripes.
With such width reduction, we can get rid of slower div64, and extra
warning for certain 32bit arch.
This patch would do:
- Add a new tree-checker chunk validation on chunk length
Make sure no chunk can reach 256G, which can also act as a bitflip
checker.
- Reduce the width from u64 to u32 for @stripe_nr variables
- Replace unnecessary div64 calls with regular modulo and division
32bit division and modulo are much faster than 64bit operations, and
we are finally free of the div64 fear at least in those involved
functions.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently btrfs doesn't support stripe lengths other than 64KiB.
This is already set in the tree-checker.
There is really no meaning to record that fixed value in map_lookup for
now, and can all be replaced with BTRFS_STRIPE_LEN.
Furthermore we can use the fix stripe length to do the following
optimization:
- Use BTRFS_STRIPE_LEN_SHIFT to replace some 64bit division
Now we only need to do a right shift.
And the value of BTRFS_STRIPE_LEN itself is already too large for bit
shift, thus if we accidentally use BTRFS_STRIPE_LEN to do bit shift,
a compiler warning would be triggered.
Thus this bit shift optimization would be safe.
- Use BTRFS_STRIPE_LEN_MASK to calculate the offset inside a stripe
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Move the remaining code that deals with initializing the btree
inode into btrfs_init_btree_inode instead of splitting it between
that helpers and its only caller.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Function search_file_offset_in_bio() finds the file offset in the
file_offset_ret, and we use the return value to indicate if it is
successful, so use bool.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The function btrfs_lookup_bio_sums() and a nested if statement declare
ret respectively as blk_status_t and int.
There is no need to store the return value of
search_file_offset_in_bio() to ret as this is a one-time call.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Remove btrfs_csum_ptr() and fold it into it's only caller.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
These days all the operations that take locks in the raid56.c code are
run from user context (mostly workqueues). Drop all the irqsafe locking
that is not required any more.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We were seeing weird errors when we were testing our btrfs backports
before we had the incorrect level check fix. These errors appeared to
be improper error handling, but error injection testing uncovered that
the errors were a result of corruption that occurred from improper error
handling during snapshot delete.
With snapshot delete if we encounter any errors during walk_down or
walk_up we'll simply return an error, we won't abort the transaction.
This is problematic because we will be dropping references for nodes and
leaves along the way, and if we fail in the middle we will leave the
file system corrupt because we don't know where we left off in the drop.
Fix this by making sure we abort if we hit any errors during the walk
down or walk up operations, as we have no idea what operations could
have been left half done 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>
We can get errors in walk_down_proc as we try and lookup extent info for
the snapshot dropping to act on. However if we get an error we simply
return 1 which indicates we're done with walking down, which will lead
us to improperly continue with the snapshot drop with the incorrect
information. Instead break if we get any error from walk_down_proc or
do_walk_down, and handle the case of ret == 1 by returning 0, otherwise
return the ret value that we have.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When we mount the file system we do something like this:
while (1) {
lookup fs roots;
for (i = 0; i < num_roots; i++) {
ret = btrfs_orphan_cleanup(roots[i]);
if (ret)
break;
btrfs_put_root(roots[i]);
}
}
for (; i < num_roots; i++)
btrfs_put_root(roots[i]);
As you can see if we break in that inner loop we just go back to the
outer loop and lose the fact that we have to drop references on the
remaining roots we looked up. Fix this by making an out label and
jumping to that on error so we don't leak a reference to the roots we
looked up.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.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 missed a couple of iput()s in the orphan cleanup failure paths, add
them so we don't get refcount errors. The iput needs to be done in the
check and not under a common label due to the way the code is
structured.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
While investigating a problem with error injection I tripped over
curious behavior in the node/leaf splitting code. If we get an EIO when
trying to read either the left or right leaf/node for splitting we'll
simply treat the node as if it were full and continue on. The end
result of this isn't too bad, we simply end up allocating a block when
we may have pushed items into the adjacent blocks.
However this does essentially allow us to continue to modify a file
system that we've gotten errors on, either from a bad disk or csum
mismatch or other corruption. This isn't particularly safe, so instead
handle these btrfs_read_node_slot() usages differently. We allow you to
pass in any slot, the idea being that we save some code if the slot
number is outside of the range of the parent. This means we treat all
errors the same, when in reality we only want to ignore -ENOENT.
Fix this by changing how we call btrfs_read_node_slot(), which is to
only call it for slots we know are valid. This way if we get an error
back from reading the block we can properly pass the error up the chain.
This was validated with the error injection testing I was doing.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In btrfs_read_node_slot() we have a BUG_ON() that can be converted to an
ASSERT(), it's from an extent buffer and the level is validated at the
time it's read from disk.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
While trying to track down a lost EIO problem I hit the following
assertion while doing my error injection testing
BTRFS warning (device nvme1n1): transaction 1609 (with 180224 dirty metadata bytes) is not committed
assertion failed: !found, in fs/btrfs/disk-io.c:4456
------------[ cut here ]------------
kernel BUG at fs/btrfs/messages.h:169!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 1445 Comm: mount Tainted: G W 6.2.0-rc5+ #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014
RIP: 0010:btrfs_assertfail.constprop.0+0x18/0x1a
RSP: 0018:ffffb95fc3b0bc68 EFLAGS: 00010286
RAX: 0000000000000034 RBX: ffff9941c2ac2000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffffb6741f7d RDI: 00000000ffffffff
RBP: ffff9941c2ac2428 R08: 0000000000000000 R09: ffffb95fc3b0bb38
R10: 0000000000000003 R11: ffffffffb71438a8 R12: ffff9941c2ac2428
R13: ffff9941c2ac2450 R14: ffff9941c2ac2450 R15: 000000000002c000
FS: 00007fcea2d07800(0000) GS:ffff9941fbc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f00cc7c83a8 CR3: 000000010c686000 CR4: 0000000000350ef0
Call Trace:
<TASK>
close_ctree+0x426/0x48f
btrfs_mount_root.cold+0x7e/0xee
? legacy_parse_param+0x2b/0x220
legacy_get_tree+0x2b/0x50
vfs_get_tree+0x29/0xc0
vfs_kern_mount.part.0+0x73/0xb0
btrfs_mount+0x11d/0x3d0
? legacy_parse_param+0x2b/0x220
legacy_get_tree+0x2b/0x50
vfs_get_tree+0x29/0xc0
path_mount+0x438/0xa40
__x64_sys_mount+0xe9/0x130
do_syscall_64+0x3e/0x90
entry_SYSCALL_64_after_hwframe+0x72/0xdc
This is because the error injection did an EIO for the root inode lookup
and we simply jumped to closing the ctree. However because we didn't
mark the file system as having an error we skipped all of the broken
transaction cleanup stuff, and thus triggered this ASSERT(). Fix this
by calling btrfs_handle_fs_error() in this case so we have the error set
on the file system.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
-----BEGIN PGP SIGNATURE-----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=WIDR
-----END PGP SIGNATURE-----
Merge tag 'for-6.3-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- fix fast checksum detection, this affects filesystems with non-crc32c
checksum, calculation would not be offloaded to worker threads
- restore thread_pool mount option behaviour for endio workers, the new
value for maximum active threads would not be set to the actual work
queues
* tag 'for-6.3-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix fast csum implementation detection
btrfs: restore the thread_pool= behavior in remount for the end I/O workqueues
The BTRFS_FS_CSUM_IMPL_FAST flag is currently set whenever a non-generic
crc32c is detected, which is the incorrect check if the file system uses
a different checksumming algorithm. Refactor the code to only check
this if crc32c is actually used. Note that in an ideal world the
information if an algorithm is hardware accelerated or not should be
provided by the crypto API instead, but that's left for another day.
CC: stable@vger.kernel.org # 5.4.x: c8a5f8ca9a: btrfs: print checksum type and implementation at mount time
CC: stable@vger.kernel.org # 5.4.x
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Commit d7b9416fe5 ("btrfs: remove btrfs_end_io_wq") converted the read
and I/O handling from btrfs_workqueues to Linux workqueues, and as part
of that lost the code to apply the thread_pool= based max_active limit
on remount. Restore it.
Fixes: d7b9416fe5 ("btrfs: remove btrfs_end_io_wq")
CC: stable@vger.kernel.org # 6.0+
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
-----BEGIN PGP SIGNATURE-----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=v7ZW
-----END PGP SIGNATURE-----
Merge tag 'for-6.3-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
- scan block devices in non-exclusive mode to avoid temporary mkfs
failures
- fix race between quota disable and quota assign ioctls
- fix deadlock when aborting transaction during relocation with scrub
- ignore fiemap path cache when there are multiple paths for a node
* tag 'for-6.3-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: ignore fiemap path cache when there are multiple paths for a node
btrfs: fix deadlock when aborting transaction during relocation with scrub
btrfs: scan device in non-exclusive mode
btrfs: fix race between quota disable and quota assign ioctls
During fiemap, when walking backreferences to determine if a b+tree
node/leaf is shared, we may find a tree block (leaf or node) for which
two parents were added to the references ulist. This happens if we get
for example one direct ref (shared tree block ref) and one indirect ref
(non-shared tree block ref) for the tree block at the current level,
which can happen during relocation.
In that case the fiemap path cache can not be used since it's meant for
a single path, with one tree block at each possible level, so having
multiple references for a tree block at any level may result in getting
the level counter exceed BTRFS_MAX_LEVEL and eventually trigger the
warning:
WARN_ON_ONCE(level >= BTRFS_MAX_LEVEL)
at lookup_backref_shared_cache() and at store_backref_shared_cache().
This is harmless since the code ignores any level >= BTRFS_MAX_LEVEL, the
warning is there just to catch any unexpected case like the one described
above. However if a user finds this it may be scary and get reported.
So just ignore the path cache once we find a tree block for which there
are more than one reference, which is the less common case, and update
the cache with the sharedness check result for all levels below the level
for which we found multiple references.
Reported-by: Jarno Pelkonen <jarno.pelkonen@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CAKv8qLmDNAGJGCtsevxx_VZ_YOvvs1L83iEJkTgyA4joJertng@mail.gmail.com/
Fixes: 12a824dc67 ("btrfs: speedup checking for extent sharedness during fiemap")
CC: stable@vger.kernel.org # 6.1+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This fixes mkfs/mount/check failures due to race with systemd-udevd
scan.
During the device scan initiated by systemd-udevd, other user space
EXCL operations such as mkfs, mount, or check may get blocked and result
in a "Device or resource busy" error. This is because the device
scan process opens the device with the EXCL flag in the kernel.
Two reports were received:
- btrfs/179 test case, where the fsck command failed with the -EBUSY
error
- LTP pwritev03 test case, where mkfs.vfs failed with
the -EBUSY error, when mkfs.vfs tried to overwrite old btrfs filesystem
on the device.
In both cases, fsck and mkfs (respectively) were racing with a
systemd-udevd device scan, and systemd-udevd won, resulting in the
-EBUSY error for fsck and mkfs.
Reproducing the problem has been difficult because there is a very
small window during which these userspace threads can race to
acquire the exclusive device open. Even on the system where the problem
was observed, the problem occurrences were anywhere between 10 to 400
iterations and chances of reproducing decreases with debug printk()s.
However, an exclusive device open is unnecessary for the scan process,
as there are no write operations on the device during scan. Furthermore,
during the mount process, the superblock is re-read in the below
function call chain:
btrfs_mount_root
btrfs_open_devices
open_fs_devices
btrfs_open_one_device
btrfs_get_bdev_and_sb
So, to fix this issue, removes the FMODE_EXCL flag from the scan
operation, and add a comment.
The case where mkfs may still write to the device and a scan is running,
the btrfs signature is not written at that time so scan will not
recognize such device.
Reported-by: Sherry Yang <sherry.yang@oracle.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/oe-lkp/202303170839.fdf23068-oliver.sang@intel.com
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
-----BEGIN PGP SIGNATURE-----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=XuDt
-----END PGP SIGNATURE-----
Merge tag 'for-6.3-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"A few more fixes, the zoned accounting fix is spread across a few
patches, preparatory and the actual fixes:
- zoned mode:
- fix accounting of unusable zone space
- fix zone activation condition for DUP profile
- preparatory patches
- improved error handling of missing chunks
- fix compiler warning"
* tag 'for-6.3-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: zoned: drop space_info->active_total_bytes
btrfs: zoned: count fresh BG region as zone unusable
btrfs: use temporary variable for space_info in btrfs_update_block_group
btrfs: rename BTRFS_FS_NO_OVERCOMMIT to BTRFS_FS_ACTIVE_ZONE_TRACKING
btrfs: zoned: fix btrfs_can_activate_zone() to support DUP profile
btrfs: fix compiler warning on SPARC/PA-RISC handling fscrypt_setup_filename
btrfs: handle missing chunk mapping more gracefully
The space_info->active_total_bytes is no longer necessary as we now
count the region of newly allocated block group as zone_unusable. Drop
its usage.
Fixes: 6a921de589 ("btrfs: zoned: introduce space_info->active_total_bytes")
CC: stable@vger.kernel.org # 6.1+
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The naming of space_info->active_total_bytes is misleading. It counts
not only active block groups but also full ones which are previously
active but now inactive. That confusion results in a bug not counting
the full BGs into active_total_bytes on mount time.
For a background, there are three kinds of block groups in terms of
activation.
1. Block groups never activated
2. Block groups currently active
3. Block groups previously active and currently inactive (due to fully
written or zone finish)
What we really wanted to exclude from "total_bytes" is the total size of
BGs #1. They seem empty and allocatable but since they are not activated,
we cannot rely on them to do the space reservation.
And, since BGs #1 never get activated, they should have no "used",
"reserved" and "pinned" bytes.
OTOH, BGs #3 can be counted in the "total", since they are already full
we cannot allocate from them anyway. For them, "total_bytes == used +
reserved + pinned + zone_unusable" should hold.
Tracking #2 and #3 as "active_total_bytes" (current implementation) is
confusing. And, tracking #1 and subtract that properly from "total_bytes"
every time you need space reservation is cumbersome.
Instead, we can count the whole region of a newly allocated block group as
zone_unusable. Then, once that block group is activated, release
[0 .. zone_capacity] from the zone_unusable counters. With this, we can
eliminate the confusing ->active_total_bytes and the code will be common
among regular and the zoned mode. Also, no additional counter is needed
with this approach.
Fixes: 6a921de589 ("btrfs: zoned: introduce space_info->active_total_bytes")
CC: stable@vger.kernel.org # 6.1+
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We do
cache->space_info->counter += num_bytes;
everywhere in here. This is makes the lines longer than they need to
be, and will be especially noticeable when we add the active tracking in,
so add a temp variable for the space_info so this is cleaner.
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.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 flag only gets set when we're doing active zone tracking, and we're
going to need to use this flag for things related to this behavior.
Rename the flag to represent what it actually means for the file system
so it can be used in other ways and still make sense.
Reviewed-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.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_can_activate_zone() returns true if at least one device has one zone
available for activation. This is OK for the single profile, but not OK for
DUP profile. We need two zones to create a DUP block group. Fix it by
properly handling the case with the profile flags.
Fixes: 265f7237dd ("btrfs: zoned: allow DUP on meta-data block groups")
CC: stable@vger.kernel.org # 6.1+
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Commit 1ec49744ba ("btrfs: turn on -Wmaybe-uninitialized") exposed
that on SPARC and PA-RISC, gcc is unaware that fscrypt_setup_filename()
only returns negative error values or 0. This ultimately results in a
maybe-uninitialized warning in btrfs_lookup_dentry().
Change to only return negative error values or 0 from
fscrypt_setup_filename() at the relevant call site, and assert that no
positive error codes are returned (which would have wider implications
involving other users).
Reported-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/all/481b19b5-83a0-4793-b4fd-194ad7b978c3@roeck-us.net/
Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
[BUG]
During my scrub rework, I did a stupid thing like this:
bio->bi_iter.bi_sector = stripe->logical;
btrfs_submit_bio(fs_info, bio, stripe->mirror_num);
Above bi_sector assignment is using logical address directly, which
lacks ">> SECTOR_SHIFT".
This results a read on a range which has no chunk mapping.
This results the following crash:
BTRFS critical (device dm-1): unable to find logical 11274289152 length 65536
assertion failed: !IS_ERR(em), in fs/btrfs/volumes.c:6387
Sure this is all my fault, but this shows a possible problem in real
world, that some bit flip in file extents/tree block can point to
unmapped ranges, and trigger above ASSERT(), or if CONFIG_BTRFS_ASSERT
is not configured, cause invalid pointer access.
[PROBLEMS]
In the above call chain, we just don't handle the possible error from
btrfs_get_chunk_map() inside __btrfs_map_block().
[FIX]
The fix is straightforward, replace the ASSERT() with proper error
handling (callers handle errors already).
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
-----BEGIN PGP SIGNATURE-----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=rJlY
-----END PGP SIGNATURE-----
Merge tag 'for-6.3-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux
Pull btrfs fixes from David Sterba:
"First batch of fixes. Among them there are two updates to sysfs and
ioctl which are not strictly fixes but are used for testing so there's
no reason to delay them.
- fix block group item corruption after inserting new block group
- fix extent map logging bit not cleared for split maps after
dropping range
- fix calculation of unusable block group space reporting bogus
values due to 32/64b division
- fix unnecessary increment of read error stat on write error
- improve error handling in inode update
- export per-device fsid in DEV_INFO ioctl to distinguish seeding
devices, needed for testing
- allocator size classes:
- fix potential dead lock in size class loading logic
- print sysfs stats for the allocation classes"
* tag 'for-6.3-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
btrfs: fix block group item corruption after inserting new block group
btrfs: fix extent map logging bit not cleared for split maps after dropping range
btrfs: fix percent calculation for bg reclaim message
btrfs: fix unnecessary increment of read error stat on write error
btrfs: handle btrfs_del_item errors in __btrfs_update_delayed_inode
btrfs: ioctl: return device fsid from DEV_INFO ioctl
btrfs: fix potential dead lock in size class loading logic
btrfs: sysfs: add size class stats
We can often end up inserting a block group item, for a new block group,
with a wrong value for the used bytes field.
This happens if for the new allocated block group, in the same transaction
that created the block group, we have tasks allocating extents from it as
well as tasks removing extents from it.
For example:
1) Task A creates a metadata block group X;
2) Two extents are allocated from block group X, so its "used" field is
updated to 32K, and its "commit_used" field remains as 0;
3) Transaction commit starts, by some task B, and it enters
btrfs_start_dirty_block_groups(). There it tries to update the block
group item for block group X, which currently has its "used" field with
a value of 32K. But that fails since the block group item was not yet
inserted, and so on failure update_block_group_item() sets the
"commit_used" field of the block group back to 0;
4) The block group item is inserted by task A, when for example
btrfs_create_pending_block_groups() is called when releasing its
transaction handle. This results in insert_block_group_item() inserting
the block group item in the extent tree (or block group tree), with a
"used" field having a value of 32K, but without updating the
"commit_used" field in the block group, which remains with value of 0;
5) The two extents are freed from block X, so its "used" field changes
from 32K to 0;
6) The transaction commit by task B continues, it enters
btrfs_write_dirty_block_groups() which calls update_block_group_item()
for block group X, and there it decides to skip the block group item
update, because "used" has a value of 0 and "commit_used" has a value
of 0 too.
As a result, we end up with a block item having a 32K "used" field but
no extents allocated from it.
When this issue happens, a btrfs check reports an error like this:
[1/7] checking root items
[2/7] checking extents
block group [1104150528 1073741824] used 39796736 but extent items used 0
ERROR: errors found in extent allocation tree or chunk allocation
(...)
Fix this by making insert_block_group_item() update the block group's
"commit_used" field.
Fixes: 7248e0cebb ("btrfs: skip update of block group item if used bytes are the same")
CC: stable@vger.kernel.org # 6.2+
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
At btrfs_drop_extent_map_range() we are clearing the EXTENT_FLAG_LOGGING
bit on a 'flags' variable that was not initialized. This makes static
checkers complain about it, so initialize the 'flags' variable before
clearing the bit.
In practice this has no consequences, because EXTENT_FLAG_LOGGING should
not be set when btrfs_drop_extent_map_range() is called, as an fsync locks
the inode in exclusive mode, locks the inode's mmap semaphore in exclusive
mode too and it always flushes all delalloc.
Also add a comment about why we clear EXTENT_FLAG_LOGGING on a copy of the
flags of the split extent map.
Reported-by: Dan Carpenter <error27@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/Y%2FyipSVozUDEZKow@kili/
Fixes: db21370bff ("btrfs: drop extent map range more efficiently")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have a report, that the info message for block-group reclaim is
crossing the 100% used mark.
This is happening as we were truncating the divisor for the division
(the block_group->length) to a 32bit value.
Fix this by using div64_u64() to not truncate the divisor.
In the worst case, it can lead to a div by zero error and should be
possible to trigger on 4 disks RAID0, and each device is large enough:
$ mkfs.btrfs -f /dev/test/scratch[1234] -m raid1 -d raid0
btrfs-progs v6.1
[...]
Filesystem size: 40.00GiB
Block group profiles:
Data: RAID0 4.00GiB <<<
Metadata: RAID1 256.00MiB
System: RAID1 8.00MiB
Reported-by: Forza <forza@tnonline.net>
Link: https://lore.kernel.org/linux-btrfs/e99483.c11a58d.1863591ca52@tnonline.net/
Fixes: 5f93e776c6 ("btrfs: zoned: print unusable percentage when reclaiming block groups")
CC: stable@vger.kernel.org # 5.15+
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ add Qu's note ]
Signed-off-by: David Sterba <dsterba@suse.com>
