There are many places where kmap/memove/kunmap patterns occur.

This pattern exists in the core common function copy_highpage().

Use copy_highpage to avoid open coding the use of kmap and leverages the
core functions use of kmap_local_page().

Development of this patch was aided by the following coccinelle script:

// <smpl>
// SPDX-License-Identifier: GPL-2.0-only
// Find kmap/copypage/kunmap pattern and replace with copy_highpage calls
//
// NOTE: The expressions in the copy page version of this kmap pattern are
// overly complex and so these all need individual attention.
//
// Confidence: Low
// Copyright: (C) 2021 Intel Corporation
// URL: http://coccinelle.lip6.fr/
// Comments:
// Options:

//
// Then a copy_page where we have 2 pages involved.
//
@ copy_page_rule @
expression page, page2, To, From, Size;
identifier ptr, ptr2;
type VP, VP2;
@@

/* kmap */
(
-VP ptr = kmap(page);
...
-VP2 ptr2 = kmap(page2);
|
-VP ptr = kmap_atomic(page);
...
-VP2 ptr2 = kmap_atomic(page2);
|
-ptr = kmap(page);
...
-ptr2 = kmap(page2);
|
-ptr = kmap_atomic(page);
...
-ptr2 = kmap_atomic(page2);
)

// 1 or more copy versions of the entire page
<+...
(
-copy_page(To, From);
+copy_highpage(To, From);
|
-memmove(To, From, Size);
+memmoveExtra(To, From, Size);
)
...+>

/* kunmap */
(
-kunmap(page2);
...
-kunmap(page);
|
-kunmap(page);
...
-kunmap(page2);
|
-kmap_atomic(ptr2);
...
-kmap_atomic(ptr);
)

// Remove any pointers left unused
@
depends on copy_page_rule
@
identifier copy_page_rule.ptr;
identifier copy_page_rule.ptr2;
type VP, VP1;
type VP2, VP21;
@@

-VP ptr;
	... when != ptr;
? VP1 ptr;
-VP2 ptr2;
	... when != ptr2;
? VP21 ptr2;

// </smpl>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NIra Weiny <ira.weiny@intel.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

There are many places where the pattern kmap/memcpy/kunmap occurs.

This pattern was lifted to the core common functions
memcpy_[to|from]_page().

Use these new functions to reduce the code, eliminate direct uses of
kmap, and leverage the new core functions use of kmap_local_page().

Also, there is 1 place where a kmap/memcpy is followed by an
optional memset.  Here we leave the kmap open coded to avoid remapping
the page but use kmap_local_page() directly.

Development of this patch was aided by the coccinelle script:

// <smpl>
// SPDX-License-Identifier: GPL-2.0-only
// Find kmap/memcpy/kunmap pattern and replace with memcpy*page calls
//
// NOTE: Offsets and other expressions may be more complex than what the script
// will automatically generate.  Therefore a catchall rule is provided to find
// the pattern which then must be evaluated by hand.
//
// Confidence: Low
// Copyright: (C) 2021 Intel Corporation
// URL: http://coccinelle.lip6.fr/
// Comments:
// Options:

//
// simple memcpy version
//
@ memcpy_rule1 @
expression page, T, F, B, Off;
identifier ptr;
type VP;
@@

(
-VP ptr = kmap(page);
|
-ptr = kmap(page);
|
-VP ptr = kmap_atomic(page);
|
-ptr = kmap_atomic(page);
)
<+...
(
-memcpy(ptr + Off, F, B);
+memcpy_to_page(page, Off, F, B);
|
-memcpy(ptr, F, B);
+memcpy_to_page(page, 0, F, B);
|
-memcpy(T, ptr + Off, B);
+memcpy_from_page(T, page, Off, B);
|
-memcpy(T, ptr, B);
+memcpy_from_page(T, page, 0, B);
)
...+>
(
-kunmap(page);
|
-kunmap_atomic(ptr);
)

// Remove any pointers left unused
@
depends on memcpy_rule1
@
identifier memcpy_rule1.ptr;
type VP, VP1;
@@

-VP ptr;
	... when != ptr;
? VP1 ptr;

//
// Some callers kmap without a temp pointer
//
@ memcpy_rule2 @
expression page, T, Off, F, B;
@@

<+...
(
-memcpy(kmap(page) + Off, F, B);
+memcpy_to_page(page, Off, F, B);
|
-memcpy(kmap(page), F, B);
+memcpy_to_page(page, 0, F, B);
|
-memcpy(T, kmap(page) + Off, B);
+memcpy_from_page(T, page, Off, B);
|
-memcpy(T, kmap(page), B);
+memcpy_from_page(T, page, 0, B);
)
...+>
-kunmap(page);
// No need for the ptr variable removal

//
// Catch all
//
@ memcpy_rule3 @
expression page;
expression GenTo, GenFrom, GenSize;
identifier ptr;
type VP;
@@

(
-VP ptr = kmap(page);
|
-ptr = kmap(page);
|
-VP ptr = kmap_atomic(page);
|
-ptr = kmap_atomic(page);
)
<+...
(
//
// Some call sites have complex expressions within the memcpy
// match a catch all to be evaluated by hand.
//
-memcpy(GenTo, GenFrom, GenSize);
+memcpy_to_pageExtra(page, GenTo, GenFrom, GenSize);
+memcpy_from_pageExtra(GenTo, page, GenFrom, GenSize);
)
...+>
(
-kunmap(page);
|
-kunmap_atomic(ptr);
)

// Remove any pointers left unused
@
depends on memcpy_rule3
@
identifier memcpy_rule3.ptr;
type VP, VP1;
@@

-VP ptr;
	... when != ptr;
? VP1 ptr;

// <smpl>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NIra Weiny <ira.weiny@intel.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Rename generic_file_buffered_read to match the naming of filemap_fault,
also update the written parameter to a more descriptive name and improve
the kerneldoc comment.

Link: https://lkml.kernel.org/r/20210122160140.223228-18-willy@infradead.orgSigned-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: NKent Overstreet <kent.overstreet@gmail.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Lockdep with fstests test case btrfs/041 detected a unsafe locking
scenario when we allocate the log node on a zoned filesystem.

btrfs/041
 ============================================
 WARNING: possible recursive locking detected
 5.11.0-rc7+ #939 Not tainted
 --------------------------------------------
 xfs_io/698 is trying to acquire lock:
 ffff88810cd673a0 (&root->log_mutex){+.+.}-{3:3}, at: btrfs_sync_log+0x3d1/0xee0 [btrfs]

 but task is already holding lock:
 ffff88810b0fc3a0 (&root->log_mutex){+.+.}-{3:3}, at: btrfs_sync_log+0x313/0xee0 [btrfs]

 other info that might help us debug this:
  Possible unsafe locking scenario:

        CPU0
        ----
   lock(&root->log_mutex);
   lock(&root->log_mutex);

  *** DEADLOCK ***

  May be due to missing lock nesting notation

 2 locks held by xfs_io/698:
  #0: ffff88810cd66620 (sb_internal){.+.+}-{0:0}, at: btrfs_sync_file+0x2c3/0x570 [btrfs]
  #1: ffff88810b0fc3a0 (&root->log_mutex){+.+.}-{3:3}, at: btrfs_sync_log+0x313/0xee0 [btrfs]

 stack backtrace:
 CPU: 0 PID: 698 Comm: xfs_io Not tainted 5.11.0-rc7+ #939
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.13.0-0-gf21b5a4-rebuilt.opensuse.org 04/01/2014
 Call Trace:
  dump_stack+0x77/0x97
  __lock_acquire.cold+0xb9/0x32a
  lock_acquire+0xb5/0x400
  ? btrfs_sync_log+0x3d1/0xee0 [btrfs]
  __mutex_lock+0x7b/0x8d0
  ? btrfs_sync_log+0x3d1/0xee0 [btrfs]
  ? btrfs_sync_log+0x3d1/0xee0 [btrfs]
  ? find_first_extent_bit+0x9f/0x100 [btrfs]
  ? __mutex_unlock_slowpath+0x35/0x270
  btrfs_sync_log+0x3d1/0xee0 [btrfs]
  btrfs_sync_file+0x3a8/0x570 [btrfs]
  __x64_sys_fsync+0x34/0x60
  do_syscall_64+0x33/0x40
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

This happens, because we are taking the ->log_mutex albeit it has already
been locked.

Also while at it, fix the bogus unlock of the tree_log_mutex in the error
handling.

Fixes: 3ddebf27 ("btrfs: zoned: reorder log node allocation on zoned filesystem")
Reviewed-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

It's wrong calling btrfs_put_block_group in
__btrfs_return_cluster_to_free_space if the block group passed is
different than the block group the cluster represents. As this means the
cluster doesn't have a reference to the passed block group. This results
in double put and a use-after-free bug.

Fix this by simply bailing if the block group we passed in does not
match the block group on the cluster.

Fixes: fa9c0d79 ("Btrfs: rework allocation clustering")
CC: stable@vger.kernel.org # 4.4+
Signed-off-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: NDavid Sterba <dsterba@suse.com>

When using the NO_HOLES feature, if we clone a file range that spans only
a hole into a range that is at or beyond the current i_size of the
destination file, we end up not setting the full sync runtime flag on the
inode. As a result, if we then fsync the destination file and have a power
failure, after log replay we can end up exposing stale data instead of
having a hole for that range.

The conditions for this to happen are the following:

1) We have a file with a size of, for example, 1280K;

2) There is a written (non-prealloc) extent for the file range from 1024K
   to 1280K with a length of 256K;

3) This particular file extent layout is durably persisted, so that the
   existing superblock persisted on disk points to a subvolume root where
   the file has that exact file extent layout and state;

4) The file is truncated to a smaller size, to an offset lower than the
   start offset of its last extent, for example to 800K. The truncate sets
   the full sync runtime flag on the inode;

6) Fsync the file to log it and clear the full sync runtime flag;

7) Clone a region that covers only a hole (implicit hole due to NO_HOLES)
   into the file with a destination offset that starts at or beyond the
   256K file extent item we had - for example to offset 1024K;

8) Since the clone operation does not find extents in the source range,
   we end up in the if branch at the bottom of btrfs_clone() where we
   punch a hole for the file range starting at offset 1024K by calling
   btrfs_replace_file_extents(). There we end up not setting the full
   sync flag on the inode, because we don't know we are being called in
   a clone context (and not fallocate's punch hole operation), and
   neither do we create an extent map to represent a hole because the
   requested range is beyond eof;

9) A further fsync to the file will be a fast fsync, since the clone
   operation did not set the full sync flag, and therefore it relies on
   modified extent maps to correctly log the file layout. But since
   it does not find any extent map marking the range from 1024K (the
   previous eof) to the new eof, it does not log a file extent item
   for that range representing the hole;

10) After a power failure no hole for the range starting at 1024K is
   punched and we end up exposing stale data from the old 256K extent.

Turning this into exact steps:

  $ mkfs.btrfs -f -O no-holes /dev/sdi
  $ mount /dev/sdi /mnt

  # Create our test file with 3 extents of 256K and a 256K hole at offset
  # 256K. The file has a size of 1280K.
  $ xfs_io -f -s \
              -c "pwrite -S 0xab -b 256K 0 256K" \
              -c "pwrite -S 0xcd -b 256K 512K 256K" \
              -c "pwrite -S 0xef -b 256K 768K 256K" \
              -c "pwrite -S 0x73 -b 256K 1024K 256K" \
              /mnt/sdi/foobar

  # Make sure it's durably persisted. We want the last committed super
  # block to point to this particular file extent layout.
  sync

  # Now truncate our file to a smaller size, falling within a position of
  # the second extent. This sets the full sync runtime flag on the inode.
  # Then fsync the file to log it and clear the full sync flag from the
  # inode. The third extent is no longer part of the file and therefore
  # it is not logged.
  $ xfs_io -c "truncate 800K" -c "fsync" /mnt/foobar

  # Now do a clone operation that only clones the hole and sets back the
  # file size to match the size it had before the truncate operation
  # (1280K).
  $ xfs_io \
        -c "reflink /mnt/foobar 256K 1024K 256K" \
        -c "fsync" \
        /mnt/foobar

  # File data before power failure:
  $ od -A d -t x1 /mnt/foobar
  0000000 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab
  *
  0262144 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  *
  0524288 cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd
  *
  0786432 ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef
  *
  0819200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  *
  1310720

  <power fail>

  # Mount the fs again to replay the log tree.
  $ mount /dev/sdi /mnt

  # File data after power failure:
  $ od -A d -t x1 /mnt/foobar
  0000000 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab
  *
  0262144 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  *
  0524288 cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd cd
  *
  0786432 ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef ef
  *
  0819200 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  *
  1048576 73 73 73 73 73 73 73 73 73 73 73 73 73 73 73 73
  *
  1310720

The range from 1024K to 1280K should correspond to a hole but instead it
points to stale data, to the 256K extent that should not exist after the
truncate operation.

The issue does not exists when not using NO_HOLES, because for that case
we use file extent items to represent holes, these are found and copied
during the loop that iterates over extents at btrfs_clone(), and that
causes btrfs_replace_file_extents() to be called with a non-NULL
extent_info argument and therefore set the full sync runtime flag on the
inode.

So fix this by making the code that deals with a trailing hole during
cloning, at btrfs_clone(), to set the full sync flag on the inode, if the
range starts at or beyond the current i_size.

A test case for fstests will follow soon.

Backporting notes: for kernel 5.4 the change goes to ioctl.c into
btrfs_clone before the last call to btrfs_punch_hole_range.

CC: stable@vger.kernel.org # 5.4+
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The tree checker checks the extent ref hash at read and write time to
make sure we do not corrupt the file system.  Generally extent
references go inline, but if we have enough of them we need to make an
item, which looks like

key.objectid	= <bytenr>
key.type	= <BTRFS_EXTENT_DATA_REF_KEY|BTRFS_TREE_BLOCK_REF_KEY>
key.offset	= hash(tree, owner, offset)

However if key.offset collide with an unrelated extent reference we'll
simply key.offset++ until we get something that doesn't collide.
Obviously this doesn't match at tree checker time, and thus we error
while writing out the transaction.  This is relatively easy to
reproduce, simply do something like the following

  xfs_io -f -c "pwrite 0 1M" file
  offset=2

  for i in {0..10000}
  do
	  xfs_io -c "reflink file 0 ${offset}M 1M" file
	  offset=$(( offset + 2 ))
  done

  xfs_io -c "reflink file 0 17999258914816 1M" file
  xfs_io -c "reflink file 0 35998517829632 1M" file
  xfs_io -c "reflink file 0 53752752058368 1M" file

  btrfs filesystem sync

And the sync will error out because we'll abort the transaction.  The
magic values above are used because they generate hash collisions with
the first file in the main subvol.

The fix for this is to remove the hash value check from tree checker, as
we have no idea which offset ours should belong to.
Reported-by: NTuomas Lähdekorpi <tuomas.lahdekorpi@gmail.com>
Fixes: 0785a9aa ("btrfs: tree-checker: Add EXTENT_DATA_REF check")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
[ add comment]
Signed-off-by: NDavid Sterba <dsterba@suse.com>

When creating a snapshot we check if the current number of swap files, in
the root, is non-zero, and if it is, we error out and warn that we can not
create the snapshot because there are active swap files.

However this is racy because when a task started activation of a swap
file, another task might have started already snapshot creation and might
have seen the counter for the number of swap files as zero. This means
that after the swap file is activated we may end up with a snapshot of the
same root successfully created, and therefore when the first write to the
swap file happens it has to fall back into COW mode, which should never
happen for active swap files.

Basically what can happen is:

1) Task A starts snapshot creation and enters ioctl.c:create_snapshot().
   There it sees that root->nr_swapfiles has a value of 0 so it continues;

2) Task B enters btrfs_swap_activate(). It is not aware that another task
   started snapshot creation but it did not finish yet. It increments
   root->nr_swapfiles from 0 to 1;

3) Task B checks that the file meets all requirements to be an active
   swap file - it has NOCOW set, there are no snapshots for the inode's
   root at the moment, no file holes, no reflinked extents, etc;

4) Task B returns success and now the file is an active swap file;

5) Task A commits the transaction to create the snapshot and finishes.
   The swap file's extents are now shared between the original root and
   the snapshot;

6) A write into an extent of the swap file is attempted - there is a
   snapshot of the file's root, so we fall back to COW mode and therefore
   the physical location of the extent changes on disk.

So fix this by taking the snapshot lock during swap file activation before
locking the extent range, as that is the order in which we lock these
during buffered writes.

Fixes: ed46ff3d ("Btrfs: support swap files")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

When we active a swap file, at btrfs_swap_activate(), we acquire the
exclusive operation lock to prevent the physical location of the swap
file extents to be changed by operations such as balance and device
replace/resize/remove. We also call there can_nocow_extent() which,
among other things, checks if the block group of a swap file extent is
currently RO, and if it is we can not use the extent, since a write
into it would result in COWing the extent.

However we have no protection against a scrub operation running after we
activate the swap file, which can result in the swap file extents to be
COWed while the scrub is running and operating on the respective block
group, because scrub turns a block group into RO before it processes it
and then back again to RW mode after processing it. That means an attempt
to write into a swap file extent while scrub is processing the respective
block group, will result in COWing the extent, changing its physical
location on disk.

Fix this by making sure that block groups that have extents that are used
by active swap files can not be turned into RO mode, therefore making it
not possible for a scrub to turn them into RO mode. When a scrub finds a
block group that can not be turned to RO due to the existence of extents
used by swap files, it proceeds to the next block group and logs a warning
message that mentions the block group was skipped due to active swap
files - this is the same approach we currently use for balance.

Fixes: ed46ff3d ("Btrfs: support swap files")
CC: stable@vger.kernel.org # 5.4+
Reviewed-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

During the nocow writeback path, we currently iterate the rbtree of block
groups twice: once for checking if the target block group is RO with the
call to btrfs_extent_readonly()), and once again for getting a nocow
reference on the block group with a call to btrfs_inc_nocow_writers().

Since btrfs_inc_nocow_writers() already returns false when the target
block group is RO, remove the call to btrfs_extent_readonly(). Not only
we avoid searching the blocks group rbtree twice, it also helps reduce
contention on the lock that protects it (specially since it is a spin
lock and not a read-write lock). That may make a noticeable difference
on very large filesystems, with thousands of allocated block groups.
Reviewed-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

During allocation the allocator will try to allocate an extent using
cluster policy. Once the current cluster is exhausted it will remove the
entry under btrfs_free_cluster::lock and subsequently acquire
btrfs_free_space_ctl::tree_lock to dispose of the already-deleted entry
and adjust btrfs_free_space_ctl::total_bitmap. This poses a problem
because there exists a race condition between removing the entry under
one lock and doing the necessary accounting holding a different lock
since extent freeing only uses the 2nd lock. This can result in the
following situation:

T1:                                    T2:
btrfs_alloc_from_cluster               insert_into_bitmap <holds tree_lock>
 if (entry->bytes == 0)                   if (block_group && !list_empty(&block_group->cluster_list)) {
    rb_erase(entry)

 spin_unlock(&cluster->lock);
   (total_bitmaps is still 4)           spin_lock(&cluster->lock);
                                         <doesn't find entry in cluster->root>
 spin_lock(&ctl->tree_lock);             <goes to new_bitmap label, adds
<blocked since T2 holds tree_lock>       <a new entry and calls add_new_bitmap>
					    recalculate_thresholds  <crashes,
                                              due to total_bitmaps
					      becoming 5 and triggering
					      an ASSERT>

To fix this ensure that once depleted, the cluster entry is deleted when
both cluster lock and tree locks are held in the allocator (T1), this
ensures that even if there is a race with a concurrent
insert_into_bitmap call it will correctly find the entry in the cluster
and add the new space to it.

CC: <stable@vger.kernel.org> # 4.4+
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Currently check_compressed_csum() completely relies on sectorsize ==
PAGE_SIZE to do checksum verification for compressed extents.

To make it subpage compatible, this patch will:
- Do extra calculation for the csum range
  Since we have multiple sectors inside a page, we need to only hash
  the range we want, not the full page anymore.

- Do sector-by-sector hash inside the page

With this patch and previous conversion on
btrfs_submit_compressed_read(), now we can read subpage compressed
extents properly, and do proper csum verification.
Reviewed-by: NAnand Jain <anand.jain@oracle.com>
Signed-off-by: NQu Wenruo <wqu@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

For compressed read, we always submit page read using page size.  This
doesn't work well with subpage, as for subpage one page can contain
several sectors.  Such submission will read range out of what we want,
and cause problems.

Thankfully to make it subpage compatible, we only need to change how the
last page of the compressed extent is read.

Instead of always adding a full page to the compressed read bio, if we're
at the last page, calculate the size using compressed length, so that we
only add part of the range into the compressed read bio.

Since we are here, also change the PAGE_SIZE used in
lookup_extent_mapping() to sectorsize.
This modification won't cause any functional change, as
lookup_extent_mapping() can handle the case where the search range is
larger than found extent range.
Reviewed-by: NAnand Jain <anand.jain@oracle.com>
Signed-off-by: NQu Wenruo <wqu@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

When a qstripe is required an extra page is allocated and mapped.  There
were 3 problems:

1) There is no corresponding call of kunmap() for the qstripe page.
2) There is no reason to map the qstripe page more than once if the
   number of bits set in rbio->dbitmap is greater than one.
3) There is no reason to map the parity page and unmap it each time
   through the loop.

The page memory can continue to be reused with a single mapping on each
iteration by raid6_call.gen_syndrome() without remapping.  So map the
page for the duration of the loop.

Similarly, improve the algorithm by mapping the parity page just 1 time.

Fixes: 5a6ac9ea ("Btrfs, raid56: support parity scrub on raid56")
CC: stable@vger.kernel.org # 4.4.x: c17af965: btrfs: raid56: simplify tracking of Q stripe presence
CC: stable@vger.kernel.org # 4.4.x
Signed-off-by: NIra Weiny <ira.weiny@intel.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

User reported that btrfs-progs misc-tests/028-superblock-recover fails:

      [TEST/misc]   028-superblock-recover
  unexpected success: mounted fs with corrupted superblock
  test failed for case 028-superblock-recover

The test case expects that a broken image with bad superblock will be
rejected to be mounted. However, the test image just passed csum check
of superblock and was successfully mounted.

Commit 55fc29be ("btrfs: use cached value of fs_info::csum_size
everywhere") replaces all calls to btrfs_super_csum_size by
fs_info::csum_size. The calls include the place where fs_info->csum_size
is not initialized. So btrfs_check_super_csum() passes because memcmp()
with len 0 always returns 0.

Fix it by caching csum size in btrfs_fs_info::csum_size once we know the
csum type in superblock is valid in open_ctree().

Link: https://github.com/kdave/btrfs-progs/issues/250
Fixes: 55fc29be ("btrfs: use cached value of fs_info::csum_size everywhere")
Signed-off-by: NSu Yue <l@damenly.su>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This final patch adds the ZONED incompat flag to the supported flags
and enables to mount ZONED flagged file system.
Reviewed-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Since the zoned filesystem requires sequential write out of metadata, we
cannot proceed with a hole in tree-log pages. When such a hole exists,
btree_write_cache_pages() will return -EAGAIN. This happens when someone,
e.g., a concurrent transaction commit, writes a dirty extent in this
tree-log commit.

If we are not going to wait for the extents, we can hope the concurrent
writing fills the hole for us. So, we can ignore the error in this case and
hope the next write will succeed.

If we want to wait for them and got the error, we cannot wait for them
because it will cause a deadlock. So, let's bail out to a full commit in
this case.
Reviewed-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This is the 3/3 patch to enable tree-log on zoned filesystems.

The allocation order of nodes of "fs_info->log_root_tree" and nodes of
"root->log_root" is not the same as the writing order of them. So, the
writing causes unaligned write errors.

Reorder the allocation of them by delaying allocation of the root node of
"fs_info->log_root_tree," so that the node buffers can go out sequentially
to devices.

Cc: Filipe Manana <fdmanana@gmail.com>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This is the 2/3 patch to enable tree-log on zoned filesystems.

Since we can start more than one log transactions per subvolume
simultaneously, nodes from multiple transactions can be allocated
interleaved. Such mixed allocation results in non-sequential writes at
the time of a log transaction commit. The nodes of the global log root
tree (fs_info->log_root_tree), also have the same problem with mixed
allocation.

Serializes log transactions by waiting for a committing transaction when
someone tries to start a new transaction, to avoid the mixed allocation
problem. We must also wait for running log transactions from another
subvolume, but there is no easy way to detect which subvolume root is
running a log transaction. So, this patch forbids starting a new log
transaction when other subvolumes already allocated the global log root
tree.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Reviewed-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This is the 1/3 patch to enable tree log on zoned filesystems.

The tree-log feature does not work on a zoned filesystem as is. Blocks for
a tree-log tree are allocated mixed with other metadata blocks and btrfs
writes and syncs the tree-log blocks to devices at the time of fsync(),
which has a different timing than a global transaction commit. As a
result, both writing tree-log blocks and writing other metadata blocks
become non-sequential writes that zoned filesystems must avoid.

Introduce a dedicated block group for tree-log blocks, so that tree-log
blocks and other metadata blocks can be separate write streams.  As a
result, each write stream can now be written to devices separately.
"fs_info->treelog_bg" tracks the dedicated block group and assigns
"treelog_bg" on-demand on tree-log block allocation time.

This commit extends the zoned block allocator to use the block group.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This is a preparation patch for the next patch. Split alloc_log_tree()
into two parts. The first one allocating the tree structure, remains in
alloc_log_tree() and the second part allocating the tree node, which is
moved into btrfs_alloc_log_tree_node().

Also export the latter part is to be used in the next patch.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

When a bad checksum is found and if the filesystem has a mirror of the
damaged data, we read the correct data from the mirror and writes it to
damaged blocks. This however, violates the sequential write constraints
of a zoned block device.

We can consider three methods to repair an IO failure in zoned filesystems:

(1) Reset and rewrite the damaged zone
(2) Allocate new device extent and replace the damaged device extent to
    the new extent
(3) Relocate the corresponding block group

Method (1) is most similar to a behavior done with regular devices.
However, it also wipes non-damaged data in the same device extent, and
so it unnecessary degrades non-damaged data.

Method (2) is much like device replacing but done in the same device. It
is safe because it keeps the device extent until the replacing finish.
However, extending device replacing is non-trivial. It assumes
"src_dev->physical == dst_dev->physical". Also, the extent mapping
replacing function should be extended to support replacing device extent
position in one device.

Method (3) invokes relocation of the damaged block group and is
straightforward to implement. It relocates all the mirrored device
extents, so it potentially is a more costly operation than method (1) or
(2). But it relocates only used extents which reduce the total IO size.

Let's apply method (3) for now. In the future, we can extend device-replace
and apply method (2).

For protecting a block group gets relocated multiple time with multiple
IO errors, this commit introduces "relocating_repair" bit to show it's
now relocating to repair IO failures. Also it uses a new kthread
"btrfs-relocating-repair", not to block IO path with relocating process.

This commit also supports repairing in the scrub process.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: NDavid 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: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This is 4/4 patch to implement device-replace on zoned filesystems.

Even after the copying is done, the write pointers of the source device
and the destination device may not be synchronized. For example, when
the last allocated extent is freed before device-replace process, the
extent is not copied, leaving a hole there.

Synchronize the write pointers by writing zeroes to the destination
device.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This is 3/4 patch to implement device-replace on zoned filesystems.

This commit implements copying. To do this, it tracks the write pointer
during the device replace process. As device-replace's copy process is
smart enough to only copy used extents on the source device, we have to
fill the gap to honor the sequential write requirement in the target
device.

The device-replace process on zoned filesystems must copy or clone all
the extents in the source device exactly once. So, we need to ensure
allocations started just before the dev-replace process to have their
corresponding extent information in the B-trees.
finish_extent_writes_for_zoned() implements that functionality, which
basically is the removed code in the commit 042528f8 ("Btrfs: fix
block group remaining RO forever after error during device replace").
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This is 2/4 patch to implement device replace for zoned filesystems.

In zoned mode, a block group must be either copied (from the source
device to the target device) or cloned (to both devices).

Implement the cloning part. If a block group targeted by an IO is marked
to copy, we should not clone the IO to the destination device, because
the block group is eventually copied by the replace process.

This commit also handles cloning of device reset.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This is the 1/4 patch to support device-replace on zoned filesystems.

We have two types of IOs during the device replace process. One is an IO
to "copy" (by the scrub functions) all the device extents from the source
device to the destination device. The other one is an IO to "clone" (by
handle_ops_on_dev_replace()) new incoming write IOs from users to the
source device into the target device.

Cloning incoming IOs can break the sequential write rule in on target
device. When a write is mapped in the middle of a block group, the IO is
directed to the middle of a target device zone, which breaks the
sequential write requirement.

However, the cloning function cannot be disabled since incoming IOs
targeting already copied device extents must be cloned so that the IO is
executed on the target device.

We cannot use dev_replace->cursor_{left,right} to determine whether a bio
is going to a not yet copied region. Since we have a time gap between
finishing btrfs_scrub_dev() and rewriting the mapping tree in
btrfs_dev_replace_finishing(), we can have a newly allocated device extent
which is never cloned nor copied.

So the point is to copy only already existing device extents. This patch
introduces mark_block_group_to_copy() to mark existing block groups as a
target of copying. Then, handle_ops_on_dev_replace() and dev-replace can
check the flag to do their job.

Also, btrfs_finish_block_group_to_copy() will check if the copied stripe
is the last stripe in the block group. With the last stripe copied,
the to_copy flag is finally disabled. Afterwards we can safely clone
incoming IOs on this block group.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

On zoned filesystems, btrfs uses per-fs zoned_meta_io_lock to serialize
the metadata write IOs.

Even with this serialization, write bios sent from btree_write_cache_pages
can be reordered by async checksum workers as these workers are per CPU
and not per zone.

To preserve write bio ordering, we disable async metadata checksum on a
zoned filesystem. This does not result in lower performance with HDDs as
a single CPU core is fast enough to do checksum for a single zone write
stream with the maximum possible bandwidth of the device. If multiple
zones are being written simultaneously, HDD seek overhead lowers the
achievable maximum bandwidth, resulting again in a per zone checksum
serialization not affecting the performance.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

When truncating a file, file buffers which have already been allocated
but not yet written may be truncated. Truncating these buffers could
cause breakage of a sequential write pattern in a block group if the
truncated blocks are for example followed by blocks allocated to another
file. To avoid this problem, always wait for write out of all unwritten
buffers before proceeding with the truncate execution.
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

We cannot use zone append for writing metadata, because the B-tree nodes
have references to each other using logical address. Without knowing
the address in advance, we cannot construct the tree in the first place.
So we need to serialize write IOs for metadata.

We cannot add a mutex around allocation and submission because metadata
blocks are allocated in an earlier stage to build up B-trees.

Add a zoned_meta_io_lock and hold it during metadata IO submission in
btree_write_cache_pages() to serialize IOs.

Furthermore, this adds a per-block group metadata IO submission pointer
"meta_write_pointer" to ensure sequential writing, which can break when
attempting to write back blocks in an unfinished transaction. If the
writing out failed because of a hole and the write out is for data
integrity (WB_SYNC_ALL), it returns EAGAIN.

A caller like fsync() code should handle this properly e.g. by falling
back to a full transaction commit.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

If more than one IO is issued for one file extent, these IO can be
written to separate regions on a device. Since we cannot map one file
extent to such a separate area on a zoned filesystem, we need to follow
the "one IO == one ordered extent" rule.

The normal buffered, uncompressed and not pre-allocated write path (used
by cow_file_range()) sometimes does not follow this rule. It can write a
part of an ordered extent when specified a region to write e.g., when
its called from fdatasync().

Introduce a dedicated (uncompressed buffered) data write path for zoned
filesystems, that will COW the region and write it at once.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Likewise to buffered IO, enable zone append writing for direct IO when
its used on a zoned block device.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Enable zone append writing for zoned mode. When using zone append, a
bio is issued to the start of a target zone and the device decides to
place it inside the zone. Upon completion the device reports the actual
written position back to the host.

Three parts are necessary to enable zone append mode. First, modify the
bio to use REQ_OP_ZONE_APPEND in btrfs_submit_bio_hook() and adjust the
bi_sector to point the beginning of the zone.

Second, record the returned physical address (and disk/partno) to the
ordered extent in end_bio_extent_writepage() after the bio has been
completed. We cannot resolve the physical address to the logical address
because we can neither take locks nor allocate a buffer in this end_bio
context. So, we need to record the physical address to resolve it later
in btrfs_finish_ordered_io().

And finally, rewrite the logical addresses of the extent mapping and
checksum data according to the physical address using btrfs_rmap_block.
If the returned address matches the originally allocated address, we can
skip this rewriting process.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

A following patch will add another caller of
btrfs_lookup_ordered_extent(), but from a bio's endio context.

btrfs_lookup_ordered_extent() uses spin_lock_irq() which unconditionally
disables interrupts. Change this to spin_lock_irqsave() so interrupts
aren't disabled and re-enabled unconditionally.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

On a zoned filesystem, cache if a block group is on a sequential write
only zone.

On sequential write only zones, we can use REQ_OP_ZONE_APPEND for
writing data, therefore provide btrfs_use_zone_append() to figure out if
IO is targeting a sequential write only zone and we can use
REQ_OP_ZONE_APPEND for data writing.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

btrfs_rmap_block currently reverse-maps the physical addresses on all
devices to the corresponding logical addresses.

Extend the function to match to a specified device. The old functionality
of querying all devices is left intact by specifying NULL as target
device.

A block_device instead of a btrfs_device is passed into btrfs_rmap_block,
as this function is intended to reverse-map the result of a bio, which
only has a block_device.

Also export the function for later use.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

To ensure that an ordered extent maps to a contiguous region on disk, we
need to maintain a "one bio == one ordered extent" rule.

Ensure that constructing bio does not span more than an ordered extent.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

For a zone append write, the device decides the location the data is being
written to. Therefore we cannot ensure that two bios are written
consecutively on the device. In order to ensure that an ordered extent
maps to a contiguous region on disk, we need to maintain a "one bio ==
one ordered extent" rule.

Implement splitting of an ordered extent and extent map on bio submission
to adhere to the rule.

extract_ordered_extent() hooks into btrfs_submit_data_bio() and splits the
corresponding ordered extent so that the ordered extent's region fits into
one bio and the corresponding device limits.

Several sanity checks need to be done in extract_ordered_extent() e.g.

- We cannot split once end_bio'd ordered extent because we cannot divide
  ordered->bytes_left for the split ones
- We do not expect a compressed ordered extent
- We should not have checksum list because we omit the list splitting.
  Since the function is called before btrfs_wq_submit_bio() or
  btrfs_csum_one_bio(), this should be always ensured.

We also need to split an extent map by creating a new one. If not,
unpin_extent_cache() complains about the difference between the start of
the extent map and the file's logical offset.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Zoned filesystems use REQ_OP_ZONE_APPEND bios for writing to actual
devices.

Let btrfs_end_bio() and btrfs_op be aware of it, by mapping
REQ_OP_ZONE_APPEND to BTRFS_MAP_WRITE and using btrfs_op() instead of
bio_op().
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

A zoned device has its own hardware restrictions e.g. max_zone_append_size
when using REQ_OP_ZONE_APPEND. To follow these restrictions, use
bio_add_zone_append_page() instead of bio_add_page(). We need target device
to use bio_add_zone_append_page(), so this commit reads the chunk
information to cache the target device to btrfs_io_bio(bio)->device.

Caching only the target device is sufficient here as zoned filesystems
only supports the single profile at the moment. Once more profiles will be
supported btrfs_io_bio can hold an extent_map to be able to check for the
restrictions of all devices the btrfs_bio will be mapped to.
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NNaohiro Aota <naohiro.aota@wdc.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>