linux.git/fs/btrfs/export.c, branch v6.16

btrfs: make btrfs_iget() return a btrfs inode instead

2025-03-18T19:35:50+00:00

It's an internal function and most of the time the callers are doing a lot
of BTRFS_I() calls on the returned VFS inode to get the btrfs inode, so
change the return type to struct btrfs_inode instead.

Signed-off-by: Filipe Manana 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: use BTRFS_PATH_AUTO_FREE in btrfs_get_name()

2025-03-18T19:35:48+00:00

This is the trivial pattern for path auto free, initialize at the
beginning and free at the end with some return simplifications.

Reviewed-by: Johannes Thumshirn 
Signed-off-by: David Sterba

btrfs: use struct btrfs_inode inside btrfs_get_name()

2025-03-18T19:35:44+00:00

Use a struct btrfs_inode in btrfs_get_name() as it's an internal
helper, allowing to remove some use of BTRFS_I.

Reviewed-by: Johannes Thumshirn 
Signed-off-by: David Sterba

btrfs: use struct btrfs_inode inside btrfs_get_parent()

2025-03-18T19:35:44+00:00

Use a struct btrfs_inode to btrfs_get_parent() as it's an internal
helper, allowing to remove some use of BTRFS_I.

Reviewed-by: Johannes Thumshirn 
Signed-off-by: David Sterba

btrfs: unify ordering of btrfs_key initializations

2025-03-18T19:35:42+00:00

The btrfs_key is defined as objectid/type/offset and the keys are also
printed like that. For better readability, update all key
initializations to match this order.

Signed-off-by: David Sterba

btrfs: remove super block argument from btrfs_iget()

2024-07-11T13:33:25+00:00

It's pointless to pass a super block argument to btrfs_iget() because we
always pass a root and from it we can get the super block through:

   root->fs_info->sb

So remove the super block argument.

Reviewed-by: Johannes Thumshirn 
Reviewed-by: Josef Bacik 
Reviewed-by: Qu Wenruo 
Signed-off-by: Filipe Manana 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: remove objectid from struct btrfs_inode on 64 bits platforms

2024-07-11T13:33:17+00:00

On 64 bits platforms we don't really need to have a dedicated member (the
objectid field) for the inode's number since we store in the VFS inode's
i_ino member, which is an unsigned long and this type is 64 bits wide on
64 bits platforms. We only need that field in case we are on a 32 bits
platform because the unsigned long type is 32 bits wide on such platforms
See commit 33345d01522f ("Btrfs: Always use 64bit inode number") regarding
this 64/32 bits detail.

The objectid field of struct btrfs_inode is also used to store the ID of
a root for directories that are stubs for unreferenced roots. In such
cases the inode is a directory and has the BTRFS_INODE_ROOT_STUB runtime
flag set.

So in order to reduce the size of btrfs_inode structure on 64 bits
platforms we can remove the objectid member and use the VFS inode's i_ino
member instead whenever we need to get the inode number. In case the inode
is a root stub (BTRFS_INODE_ROOT_STUB set) we can use the member
last_reflink_trans to store the ID of the unreferenced root, since such
inode is a directory and reflinks can't be done against directories.

So remove the objectid fields for 64 bits platforms and alias the
last_reflink_trans field with a name of ref_root_id in a union.
On a release kernel config, this reduces the size of struct btrfs_inode
from 1040 bytes down to 1032 bytes.

Signed-off-by: Filipe Manana 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: remove location key from struct btrfs_inode

2024-07-11T13:33:17+00:00

Currently struct btrfs_inode has a key member, named "location", that is
either:

1) The key of the inode's item. In this case the objectid is the number
   of the inode;

2) A key stored in a dir entry with a type of BTRFS_ROOT_ITEM_KEY, for
   the case where we have a root that is a snapshot of a subvolume that
   points to other subvolumes. In this case the objectid is the ID of
   a subvolume inside the snapshotted parent subvolume.

The key is only used to lookup the inode item for the first case, while
for the second it's never used since it corresponds to directory stubs
created with new_simple_dir() and which are marked as dummy, so there's
no actual inode item to ever update. In the second case we only check
the key type at btrfs_ino() for 32 bits platforms and its objectid is
only needed for unlink.

Instead of using a key we can do fine with just the objectid, since we
can generate the key whenever we need it having only the objectid, as
in all use cases the type is always BTRFS_INODE_ITEM_KEY and the offset
is always 0.

So use only an objectid instead of a full key. This reduces the size of
struct btrfs_inode from 1048 bytes down to 1040 bytes on a release kernel.

Signed-off-by: Filipe Manana 
Reviewed-by: David Sterba 
Signed-off-by: David Sterba

btrfs: change root->root_key.objectid to btrfs_root_id()

2024-05-07T19:31:06+00:00

A comment from Filipe on one of my previous cleanups brought my
attention to a new helper we have for getting the root id of a root,
which makes it easier to read in the code.

The changes where made with the following Coccinelle semantic patch:

// 
@@
expression E,E1;
@@
(
 E->root_key.objectid = E1
|
- E->root_key.objectid
+ btrfs_root_id(E)
)
// 

Reviewed-by: Filipe Manana 
Signed-off-by: Josef Bacik 
Reviewed-by: David Sterba 
[ minor style fixups ]
Signed-off-by: David Sterba

btrfs: add helper to get fs_info from struct inode pointer

2024-03-04T15:24:49+00:00

Add a convenience helper to get a fs_info from a VFS inode pointer
instead of open coding the chain or using btrfs_sb() that in some cases
does one more pointer hop.  This is implemented as a macro (still with
type checking) so we don't need full definitions of struct btrfs_inode,
btrfs_root or btrfs_fs_info.

Reviewed-by: Johannes Thumshirn 
Reviewed-by: Anand Jain 
Signed-off-by: David Sterba