Signed-off-by: NDavid Sterba <dsterba@suse.com>

Remove parameters not used by any of the callbacks.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Remove parameters not used by any of the callbacks.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The called function name is self explanatory.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The current implementation of btrfs_page_exists_in_range() gives the
wrong answer if the workingset code has stored a shadow entry in the
page cache.  The filemap_range_has_page() function does not have this
problem, and it's shared code, so use it instead.
eigned-off-by: NMatthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Previously, btrfs_inode_by_name() returned 0 which left caller to check
objectid of location even location if the type was invalid.

Let btrfs_inode_by_name() return -EUCLEAN if a corrupted location of a
dir entry is found.  Removal of label out_err also simplifies the
function.
Signed-off-by: NSu Yue <suy.fnst@cn.fujitsu.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
[ drop unlikely ]
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This argument is always set to the root of the inode, which is also
passed. So let's get a reference inside the function and simplify
the arg list.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

When we truncate a file to the same size and that size is not aligned
with the sector size, we end up triggering writeback (and wait for it to
complete) of the last page. This is unncessary as we can not have delayed
allocation beyond the inode's i_size and the goal of truncating a file
to its own size is to discard prealloc extents (allocated via the
fallocate(2) system call). Besides the unnecessary IO start and wait, it
also breaks the oppurtunity for larger contiguous extents on disk, as
before the last dirty page there might be other dirty pages.

This scenario is probably not very common in general, however it is
common for btrfs receive implementations because currently the send
stream always issues a truncate operation for each processed inode as
the last operation for that inode (this truncate operation is not
always needed and the send implementation will be addressed to avoid
them).

So improve this by not starting and waiting for writeback of the inode's
last page when we are truncating to exactly the same size.

The following script was used to quickly measure the time a receive
operation takes:

 $ cat test_send.sh
 #!/bin/bash

 SRC_DEV=/dev/sdc
 DST_DEV=/dev/sdd
 SRC_MNT=/mnt/sdc
 DST_MNT=/mnt/sdd

 mkfs.btrfs -f $SRC_DEV >/dev/null
 mkfs.btrfs -f $DST_DEV >/dev/null
 mount $SRC_DEV $SRC_MNT
 mount $DST_DEV $DST_MNT

 echo "Creating source filesystem"
 for ((t = 0; t < 10; t++)); do
     (
         for ((i = 1; i <= 20000; i++)); do
             xfs_io -f -c "pwrite -S 0xab 0 5000" \
                $SRC_MNT/file_$i > /dev/null
         done
     ) &
     worker_pids[$t]=$!
 done
 wait ${worker_pids[@]}

 echo "Creating and sending snapshot"
 btrfs subvolume snapshot -r $SRC_MNT $SRC_MNT/snap1 >/dev/null
 /usr/bin/time -f "send took %e seconds"    \
     btrfs send -f $SRC_MNT/send_file $SRC_MNT/snap1
 /usr/bin/time -f "receive took %e seconds" \
     btrfs receive -f $SRC_MNT/send_file $DST_MNT

 umount $SRC_MNT
 umount $DST_MNT

The results for 5 runs were the following:

* Without this change

average receive time was 26.49 seconds
standard deviation of 2.53 seconds

* With this change

average receive time was 12.51 seconds
standard deviation of 0.32 seconds
Reported-by: NRobbie Ko <robbieko@synology.com>
Signed-off-by: NFilipe Manana <fdmanana@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Using any kind of memory barriers around atomic operations which have
a return value is redundant, since those operations themselves are
fully ordered. atomic_t.txt states:

    - RMW operations that have a return value are fully ordered;

    Fully ordered primitives are ordered against everything prior and
    everything subsequent. Therefore a fully ordered primitive is like
    having an smp_mb() before and an smp_mb() after the primitive.

Given this let's replace the extra memory barriers with comments.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The __cold functions are placed to a special section, as they're
expected to be called rarely. This could help i-cache prefetches or help
compiler to decide which branches are more/less likely to be taken
without any other annotations needed.

Though we can't add more __exit annotations, it's still possible to add
__cold (that's also added with __exit). That way the following function
categories are tagged:

- printf wrappers, error messages
- exit helpers
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Fstests generic/475 provides a way to fail metadata reads while
checking if checksum exists for the inode inside run_delalloc_nocow(),
and csum_exist_in_range() interprets error (-EIO) as inode having
checksum and makes its caller enter the cow path.

In case of free space inode, this ends up with a warning in
cow_file_range().

The same problem applies to btrfs_cross_ref_exist() since it may also
read metadata in between.

With this, run_delalloc_nocow() bails out when errors occur at the two
places.

cc: <stable@vger.kernel.org> v2.6.28+
Fixes: 17d217fe ("Btrfs: fix nodatasum handling in balancing code")
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The custom crc32 init code was introduced in
14a958e6 ("Btrfs: fix btrfs boot when compiled as built-in") to
enable using btrfs as a built-in. However, later as pointed out by
60efa5eb ("Btrfs: use late_initcall instead of module_init") this
wasn't enough and finally btrfs was switched to late_initcall which
comes after the generic crc32c implementation is initiliased. The
latter commit superseeded the former. Now that we don't have to
maintain our own code let's just remove it and switch to using the
generic implementation.

Despite touching a lot of files the patch is really simple. Here is the gist of
the changes:

1. Select LIBCRC32C rather than the low-level modules.
2. s/btrfs_crc32c/crc32c/g
3. replace hash.h with linux/crc32c.h
4. Move the btrfs namehash funcs to ctree.h and change the tree accordingly.

I've tested this with btrfs being both a module and a built-in and xfstest
doesn't complain.

Does seem to fix the longstanding problem of not automatically selectiong
the crc32c module when btrfs is used. Possibly there is a workaround in
dracut.

The modinfo confirms that now all the module dependencies are there:

before:
depends:        zstd_compress,zstd_decompress,raid6_pq,xor,zlib_deflate

after:
depends:        libcrc32c,zstd_compress,zstd_decompress,raid6_pq,xor,zlib_deflate
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
[ add more info to changelog from mails ]
Signed-off-by: NDavid Sterba <dsterba@suse.com>

delayed_iput_count wa supposed to be used to implement, well, delayed
iput. The idea is that we keep accumulating the number of iputs we do
until eventually the inode is deleted. Turns out we never really
switched the delayed_iput_count from 0 to 1, hence all conditional
code relying on the value of that member being different than 0 was
never executed. This, as it turns out, didn't cause any problem due
to the simple fact that the generic inode's i_count member was always
used to count the number of iputs. So let's just remove the unused
member and all unused code. This patch essentially provides no
functional changes. While at it, also add proper documentation for
btrfs_add_delayed_iput
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
[ reformat comment ]
Signed-off-by: NDavid Sterba <dsterba@suse.com>

It's not necessary to hold ->orphan_lock when checking inode's runtime
flags.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Use ASSERT to report logical error in cow_file_range(), also move it a
bit closer to when the num_bytes is derived.

The extent start could be (u64)-1 in some cases, the assert should catch
that we do not accidentally pass it to cow_file_range.
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This patch deletes local variable disk_num_bytes as its value
is same as num_bytes in the function cow_file_range().
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

add_pending_csums was added as part of the new data=ordered
implementation in e6dcd2dc ("Btrfs: New data=ordered
implementation"). Even back then it called the btrfs_csum_file_blocks
which can fail but it never bothered handling the failure. In ENOMEM
situation this could lead to the filesystem failing to write the
checksums for a particular extent and not detect this. On read this
could lead to the filesystem erroring out due to crc mismatch. Fix it by
propagating failure from add_pending_csums and handling them.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

I got these from running generic/475,

WARNING: CPU: 0 PID: 26384 at fs/btrfs/inode.c:3326 btrfs_orphan_commit_root+0x1ac/0x2b0 [btrfs]
BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
IP: btrfs_block_rsv_release+0x1c/0x70 [btrfs]
Call Trace:
  btrfs_orphan_release_metadata+0x9f/0x200 [btrfs]
  btrfs_orphan_del+0x10d/0x170 [btrfs]
  btrfs_setattr+0x500/0x640 [btrfs]
  notify_change+0x7ae/0x870
  do_truncate+0xca/0x130
  vfs_truncate+0x2ee/0x3d0
  do_sys_truncate+0xaf/0xf0
  SyS_truncate+0xe/0x10
  entry_SYSCALL_64_fastpath+0x1f/0x96

The race is between btrfs_orphan_commit_root and btrfs_orphan_del,
        t1                                        t2
btrfs_orphan_commit_root                     btrfs_orphan_del
   spin_lock
   check (&root->orphan_inodes)
   root->orphan_block_rsv = NULL;
   spin_unlock
                                             atomic_dec(&root->orphan_inodes);
                                             access root->orphan_block_rsv

Accessing root->orphan_block_rsv must be done before decreasing
root->orphan_inodes.

cc: <stable@vger.kernel.org> v3.12+
Fixes: 703c88e0 ("Btrfs: fix tracking of orphan inode count")
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This regression is introduced in
commit 3d48d981 ("btrfs: Handle uninitialised inode eviction").

There are two problems,

a) it is ->destroy_inode() that does the final free on inode, not
   ->evict_inode(),
b) clear_inode() must be called before ->evict_inode() returns.

This could end up hitting BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
in evict() because I_CLEAR is set in clear_inode().

Fixes: commit 3d48d981 ("btrfs: Handle uninitialised inode eviction")
Cc: <stable@vger.kernel.org> # v4.7-rc6+
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

@cur_offset is not set back to what it should be (@cow_start) if
btrfs_next_leaf() returns something wrong, and the range [cow_start,
cur_offset) remains locked forever.

cc: <stable@vger.kernel.org>
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

At this point, we know that "now" and the file times may differ, and we
suspect that the i_version has been flagged to be bumped. Attempt to
bump the i_version, and only mark the inode dirty if that actually
occurred or if one of the times was updated.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Acked-by: NDavid Sterba <dsterba@suse.com>
Reviewed-by: NLiu Bo <bo.li.liu@oracle.com>

Signed-off-by: NJeff Layton <jlayton@redhat.com>
Acked-by: NDavid Sterba <dsterba@suse.com>

Add a documentation blob that explains what the i_version field is, how
it is expected to work, and how it is currently implemented by various
filesystems.

We already have inode_inc_iversion. Add several other functions for
manipulating and accessing the i_version counter. For now, the
implementation is trivial and basically works the way that all of the
open-coded i_version accesses work today.

Future patches will convert existing users of i_version to use the new
API, and then convert the backend implementation to do things more
efficiently.
Signed-off-by: NJeff Layton <jlayton@redhat.com>
Reviewed-by: NJan Kara <jack@suse.cz>

No functional changes, just makes the code more readable
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NQu Wenruo <wqu@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

These helpers are extent map specific, move them to extent_map.c.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This is a prepare work for the following extent map selftest, which
runs tests against em merge logic.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This fixes a corner case that is caused by a race of dio write vs dio
read/write.

Here is how the race could happen.

Suppose that no extent map has been loaded into memory yet.
There is a file extent [0, 32K), two jobs are running concurrently
against it, t1 is doing dio write to [8K, 32K) and t2 is doing dio
read from [0, 4K) or [4K, 8K).

t1 goes ahead of t2 and splits em [0, 32K) to em [0K, 8K) and [8K 32K).

------------------------------------------------------
             t1                                t2
      btrfs_get_blocks_direct()         btrfs_get_blocks_direct()
       -> btrfs_get_extent()              -> btrfs_get_extent()
           -> lookup_extent_mapping()
           -> add_extent_mapping()            -> lookup_extent_mapping()
              # load [0, 32K)
       -> btrfs_new_extent_direct()
           -> btrfs_drop_extent_cache()
              # split [0, 32K) and
	      # drop [8K, 32K)
           -> add_extent_mapping()
              # add [8K, 32K)
                                              -> add_extent_mapping()
                                                 # handle -EEXIST when adding
                                                 # [0, 32K)
------------------------------------------------------
About how t2(dio read/write) runs into -EEXIST:

a) add_extent_mapping() gets -EEXIST for adding em [0, 32k),

b) search_extent_mapping() then returns [0, 8k) as the existing em,
   even though start == existing->start, em is [0, 32k) so that
   extent_map_end(em) > extent_map_end(existing), i.e. 32k > 8k,

c) then it goes thru merge_extent_mapping() which tries to add a [8k, 8k)
   (with a length 0) and returns -EEXIST as [8k, 32k) is already in tree,

d) so btrfs_get_extent() ends up returning -EEXIST to dio read/write,
   which is confusing applications.

Here I conclude all the possible situations,
1) start < existing->start

            +-----------+em+-----------+
+--prev---+ |     +-------------+      |
|         | |     |             |      |
+---------+ +     +---+existing++      ++
                +
                |
                +
             start

2) start == existing->start

      +------------em------------+
      |     +-------------+      |
      |     |             |      |
      +     +----existing-+      +
            |
            |
            +
         start

3) start > existing->start && start < (existing->start + existing->len)

      +------------em------------+
      |     +-------------+      |
      |     |             |      |
      +     +----existing-+      +
               |
               |
               +
             start

4) start >= (existing->start + existing->len)

+-----------+em+-----------+
|     +-------------+      | +--next---+
|     |             |      | |         |
+     +---+existing++      + +---------+
                      +
                      |
                      +
                   start

As we can see, it turns out that if start is within existing em (front
inclusive), then the existing em should be returned as is, otherwise,
we try our best to merge candidate em with sibling ems to form a
larger em (in order to reduce the total number of em).
Reported-by: NDavid Vallender <david.vallender@landmark.co.uk>
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

%block_len could be checked on deciding if two em are mergeable.

merge_extent_mapping() has only added the front pad if the front part
of em gets truncated, but it's possible that the end part gets
truncated.

For both compressed extent and inline extent, em->block_len is not
adjusted accordingly, and for regular extent, em->block_len always
equals to em->len, hence this sets em->block_len with em->len.
Signed-off-by: NLiu Bo <bo.li.liu@oracle.com>
Reviewed-by: NJosef Bacik <jbacik@fb.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

There is no function named btrfs_get_inode_index_count.
Explanation for magic number index_cnt=2 in btrfs_new_inode() is
actually located in btrfs_set_inode_index_count().

So replace 'btrfs_get_inode_index_count' in the comment by
'btrfs_set_inode_index_count'.
Signed-off-by: NSu Yue <suy.fnst@cn.fujitsu.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

All callers pass either GFP_NOFS or GFP_KERNEL now, so we can sink the
parameter to the function, though we lose some of the slightly better
semantics of GFP_KERNEL in some places, it's worth cleaning up the
callchains.
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The bio is not referenced after it has been submitted and the endio is
going to consume the sole reference on successful submission. On error,
the callers of __btrfs_submit_dio_bio do invoke bio_put so we don't
leak it either.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The bio that is passsed is the newly created repair bio which already
has a reference count of 1, which is going to be consumed by the
endio routine on successful submission. On error the handler also
calls bio_put.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The tree argument passed to extent_write_full_page is referenced from
the page being passed to the same function. Since we already have
enough information to get the reference, remove the function parameter.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This function is called only from submit_compressed_extents and the
io tree being passed is always that of the inode. But we are also
passing the inode, so just move getting the io tree pointer in
extent_write_locked_range to simplify the signature.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

This function was introduced by 247e743c ("Btrfs: Use async helpers
to deal with pages that have been improperly dirtied") and it didn't do
any error handling then. This function might very well fail in ENOMEM
situation, yet it's not handled, this could lead to inconsistent state.
So let's handle the failure by setting the mapping error bit.

Cc: stable@vger.kernel.org
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NQu Wenruo <wqu@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Before returning hole_em in btrfs_get_fiemap_extent we check if it's different
than null. However, by the time this null check is triggered we already know
hole_em is not null because it means it points to the em we found and it
has already been dereferenced.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

trans was statically assigned to NULL and this never changed over the
course of btrfs_get_extent. So remove any code which checks whether
trans != NULL and just hardcode the fact trans is always NULL.

Resolves-coverity-id: 112806
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

We need to call extent_range_clear_dirty_for_io()
on compression range to prevent application from changing
page content, while pages compressing.

extent_range_clear_dirty_for_io() runs on each loop iteration,
"(end - start)" can be much (up to 1024 times) bigger
then compression range (BTRFS_MAX_UNCOMPRESSED).

The start pointer is advanced each time we manage to compress part of
the range. The end pointer does not change so we could redirty the
remaining parts repeatedly.

Fix that behaviour by call extent_range_clear_dirty_for_io()
only once, the first time it happens.

This is the safest but probably not the best behaviour. Previous
iterations of the patch tried to redirty only the range that we were not
able to compress. This has been refused by David for safety reasons, the
writeout callchain is complex and there could be some path that relies
on redirtying the entire unwritten range.
Signed-off-by: NTimofey Titovets <nefelim4ag@gmail.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
[ enhance changelog, the history and safety concerns, add comment ]
Signed-off-by: NDavid Sterba <dsterba@suse.com>

Commit 9036c102 ("Btrfs: update hole handling v2") added the
FLAG_VACANCY to denote holes, however there was already a consistent way
of flagging extents which represent hole - ->block_start =
EXTENT_MAP_HOLE. And also the only place where this flag is checked is
in the fiemap code, but the block_start value is also checked and every
other place in the filesystem detects holes by using block_start
value's. So remove the extra flag. This survived a full xfstest run.
Signed-off-by: NNikolay Borisov <nborisov@suse.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

The semantics of adding_csums matches bool, 'short' was most likely used
to save space in a698d075 ("Btrfs: add a type field for the
transaction handle").
Signed-off-by: NDavid Sterba <dsterba@suse.com>