The use_count is a reference counter, we can use the refcount_t type,
though we don't use the atomicity. This is not a performance critical
code and we could catch the underflows. The type is changed from long,
but the number of references will fit an int.
Signed-off-by: David Sterba <dsterba@suse.com>

Last user was removed in a monster commit a22285a6
("Btrfs: Integrate metadata reservation with start_transaction") in
2010.
Signed-off-by: David 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: David Sterba <dsterba@suse.com>

Due to new_inline logic, the create == 0 is always true at this
point in the code, so the create != 0 branch can be removed.
Signed-off-by: Edmund Nadolski <enadolski@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Replace hardcoded numeric argument values for inode_only with the
constants defined for that use.
Signed-off-by: Edmund Nadolski <enadolski@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

The maximum size of a checksum buffer is known, BTRFS_CSUM_SIZE, and we
don't have to allocate it dynamically. This code path is not used at all
as we have only the crc32c and use an on-stack buffer already.
Signed-off-by: David Sterba <dsterba@suse.com>

Setting plug can merge adjacent IOs before dispatching IOs to the disk
driver.

Without plug, it'd not be a problem for single disk usecases, but for
multiple disks using raid profile, a large IO can be split to several
IOs of stripe length, and plug can be helpful to bring them together
for each disk so that we can save several disk access.

Moreover, fsync issues synchronous writes, so plug can really take
effect.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

No functional changes, create btrfs_open_one_device() from
__btrfs_open_devices(). This is a preparatory work to add dynamic
device scan.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
[ minor whitespace fixes ]
Signed-off-by: David Sterba <dsterba@suse.com>

No functional changes. This helps to move the entire section into
a new function.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

This is in preparation to move a section of code in __btrfs_open_devices()
into a new function so that it can be reused. As we set seeding if any of
the device is having SB flag BTRFS_SUPER_FLAG_SEEDING, so do it in the
device list loop itself. No functional changes.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

With gcc-4.1.2:

    fs/btrfs/ref-verify.c: In function ‘btrfs_build_ref_tree’:
    fs/btrfs/ref-verify.c:1017: warning: ‘root’ is used uninitialized in this function

The variable is indeed passed uninitialized, but it is never used by the
callee.  However, not all versions of gcc are smart enough to notice.

Hence remove the unused parameter from walk_up_tree() to silence the
compiler warning.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David Sterba <dsterba@suse.com>

All callers pass btree_get_extent, which needs to be exported.
Signed-off-by: David Sterba <dsterba@suse.com>

All callers pass btrfs_get_extent.
Signed-off-by: David Sterba <dsterba@suse.com>

All callers pass btrfs_get_extent.
Signed-off-by: David Sterba <dsterba@suse.com>

There's only one caller that passes btrfs_get_extent.
Signed-off-by: David Sterba <dsterba@suse.com>

All callers pass btrfs_get_extent_fiemap and get_extent_skip_holes
itself is used only as a fiemap helper.
Signed-off-by: David Sterba <dsterba@suse.com>

All callers pass btrfs_get_extent_fiemap and we don't expect anything
else in the context of extent_fiemap.
Signed-off-by: David Sterba <dsterba@suse.com>

Previous patches cleaned up all places where
extent_page_data::get_extent was set and it was btrfs_get_extent all the
time, so we can simply call that instead.

This also reduces size of extent_page_data by 8 bytes which has positive
effect on stack consumption on various functions on the write out path.
Signed-off-by: David Sterba <dsterba@suse.com>

There's only one caller.
Signed-off-by: David Sterba <dsterba@suse.com>

There's only one caller.
Signed-off-by: David Sterba <dsterba@suse.com>

There's only one caller.
Signed-off-by: David Sterba <dsterba@suse.com>

Since tree-checker has verified leaf when reading from disk, we don't
need the existing verify_dir_item() or btrfs_is_name_len_valid() checks.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Add checker for dir item, for key types DIR_ITEM, DIR_INDEX and
XATTR_ITEM.

This checker does comprehensive checks for:

1) dir_item header and its data size
   Against item boundary and maximum name/xattr length.
   This part is mostly the same as old verify_dir_item().

2) dir_type
   Against maximum file types, and against key type.
   Since XATTR key should only have FT_XATTR dir item, and normal dir
   item type should not have XATTR key.

   The check between key->type and dir_type is newly introduced by this
   patch.

3) name hash
   For XATTR and DIR_ITEM key, key->offset is name hash (crc32c).
   Check the hash of the name against the key to ensure it's correct.

   The name hash check is only found in btrfs-progs before this patch.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Su Yue <suy.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

This callback is called directly from VFS, no locks are held at the
allocation time.
Signed-off-by: David Sterba <dsterba@suse.com>

There's only one callsite with GFP_NOFS.
Signed-off-by: David Sterba <dsterba@suse.com>

All callers use GFP_NOFS, we don't have to pass it as an argument. The
built-in tests pass GFP_KERNEL, but they run only at module load time
and NOFS works there as well.
Signed-off-by: David Sterba <dsterba@suse.com>

Use __clear_extent_bit directly in case we want to pass unknown
gfp flags. Otherwise all clear_extent_bit callers use GFP_NOFS, so we
can sink them to the function and reduce argument count, at the cost
that __clear_extent_bit has to be exported.
Signed-off-by: David Sterba <dsterba@suse.com>

We take the fs_devices::device_list_mutex mutex in write_all_supers
which will prevent any add/del changes to the device list. Therefore we
don't need to use the RCU variant list_for_each_entry_rcu in any of the
called functions.
Signed-off-by: David Sterba <dsterba@suse.com>

We don't need to use the mutex as we do not modify the devices nor the
list itself and just read information about device counts.
Move copying fsid out of the protected section, not applicable to RCU
same as the rest of the retrieved information.
Signed-off-by: David Sterba <dsterba@suse.com>

We don't need to use the mutex as we do not modify the devices nor the
list itself and just read some information:

does not change during device lifetime:
- devid
- uuid
- name (ie. the path)

may change in parallel to the ioctl call, but can lead only to reporting
inacurracy:
- bytes_used
- total_bytes
Signed-off-by: David Sterba <dsterba@suse.com>

Split the conditions a bit.
Signed-off-by: David Sterba <dsterba@suse.com>

Overview of the main locks protecting various device-related structures.
Signed-off-by: David Sterba <dsterba@suse.com>

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

A helper to free a device and all it's dynamically allocated members,
like the rcu_string name or flush_bio. This is going to replace all
open coded places.
Signed-off-by: David Sterba <dsterba@suse.com>

Make it clear that it is an RCU helper, we want to use the name
free_device for a wrapper freeing all device members.
Signed-off-by: David Sterba <dsterba@suse.com>

These rules have been hidden in several if-else and are not
straightforward to follow, for example, dio submit hook's nocsum case
has a bug , i.e. doing async submit instead of sync submit, which has
been fixed recently.

This is documenting the rules for reference.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>

After commit 996478ca ("btrfs: change how we decide to commit
transactions during flushing") there is no need to hold the delayed_rsv
during the percpu_counter_compare call since we get the byte's snapshot
earlier. So hold the lock only while reading delayed_rsv.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Adding __init macro gives kernel a hint that this function is only used
during the initialization phase and its memory resources can be freed up
after.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Function btrfs_add_device() is adding the device item so rename to
reflect that in the function. Similarly we have btrfs_rm_dev_item().
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>