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btrfs: simplify fsid and metadata_uuid comparisons
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Refactor the functions find_fsid() and find_fsid_with_metadata_uuid(),
as they currently share a common set of code to compare the fsid and
metadata_uuid. Create a common helper function, match_fsid_fs_devices().

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Anand Jain authored and David Sterba committed Jun 19, 2023
1 parent 413fb1b commit 1a89834
Showing 1 changed file with 23 additions and 15 deletions.
38 changes: 23 additions & 15 deletions fs/btrfs/volumes.c
Original file line number Diff line number Diff line change
Expand Up @@ -427,6 +427,21 @@ void __exit btrfs_cleanup_fs_uuids(void)
}
}

static bool match_fsid_fs_devices(const struct btrfs_fs_devices *fs_devices,
const u8 *fsid, const u8 *metadata_fsid)
{
if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) != 0)
return false;

if (!metadata_fsid)
return true;

if (memcmp(metadata_fsid, fs_devices->metadata_uuid, BTRFS_FSID_SIZE) != 0)
return false;

return true;
}

static noinline struct btrfs_fs_devices *find_fsid(
const u8 *fsid, const u8 *metadata_fsid)
{
Expand All @@ -436,15 +451,8 @@ static noinline struct btrfs_fs_devices *find_fsid(

/* Handle non-split brain cases */
list_for_each_entry(fs_devices, &fs_uuids, fs_list) {
if (metadata_fsid) {
if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0
&& memcmp(metadata_fsid, fs_devices->metadata_uuid,
BTRFS_FSID_SIZE) == 0)
return fs_devices;
} else {
if (memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE) == 0)
return fs_devices;
}
if (match_fsid_fs_devices(fs_devices, fsid, metadata_fsid))
return fs_devices;
}
return NULL;
}
Expand All @@ -462,14 +470,14 @@ static struct btrfs_fs_devices *find_fsid_with_metadata_uuid(
* at all and the CHANGING_FSID_V2 flag set.
*/
list_for_each_entry(fs_devices, &fs_uuids, fs_list) {
if (fs_devices->fsid_change &&
memcmp(disk_super->metadata_uuid, fs_devices->fsid,
BTRFS_FSID_SIZE) == 0 &&
memcmp(fs_devices->fsid, fs_devices->metadata_uuid,
BTRFS_FSID_SIZE) == 0) {
if (!fs_devices->fsid_change)
continue;

if (match_fsid_fs_devices(fs_devices, disk_super->metadata_uuid,
fs_devices->fsid))
return fs_devices;
}
}

/*
* Handle scanned device having completed its fsid change but
* belonging to a fs_devices that was created by a device that
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