btrfs: document BTRFS_MAX_MIRRORS

The real meaning of that constant is not clear from the context due to
the target device inclusion.

Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2019-05-31 17:22:59 +02:00
parent a07e8a468e
commit 71a9c4885e
1 changed files with 10 additions and 1 deletions

View File

@ -46,7 +46,16 @@ struct btrfs_ref;
#define BTRFS_MAGIC 0x4D5F53665248425FULL /* ascii _BHRfS_M, no null */
#define BTRFS_MAX_MIRRORS 3
/*
* Maximum number of mirrors that can be available for all profiles counting
* the target device of dev-replace as one. During an active device replace
* procedure, the target device of the copy operation is a mirror for the
* filesystem data as well that can be used to read data in order to repair
* read errors on other disks.
*
* Current value is derived from RAID1 with 2 copies.
*/
#define BTRFS_MAX_MIRRORS (2 + 1)
#define BTRFS_MAX_LEVEL 8