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| author | Lars Ellenberg | 2013-03-19 18:16:43 +0100 |
|---|---|---|
| committer | Jens Axboe | 2013-03-23 01:13:59 +0100 |
| commit | ae8bf312e97d554b6aa32e7b2ceb993812ad0835 (patch) | |
| tree | 7ed6d4fcf6385c1dbc694cf4f43f884436ae104a /drivers/block/drbd/drbd_main.c | |
| parent | drbd: cleanup bogus assert message (diff) | |
| download | kernel-qcow2-linux-ae8bf312e97d554b6aa32e7b2ceb993812ad0835.tar.gz kernel-qcow2-linux-ae8bf312e97d554b6aa32e7b2ceb993812ad0835.tar.xz kernel-qcow2-linux-ae8bf312e97d554b6aa32e7b2ceb993812ad0835.zip | |
drbd: cleanup ondisk meta data layout calculations and defines
Add a comment about our meta data layout variants,
and rename a few defines (e.g. MD_RESERVED_SECT -> MD_128MB_SECT)
to make it clear that they are short hand for fixed constants,
and not arbitrarily to be redefined as one may see fit.
Properly pad struct meta_data_on_disk to 4kB,
and initialize to zero not only the first 512 Byte,
but all of it in drbd_md_sync().
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block/drbd/drbd_main.c')
| -rw-r--r-- | drivers/block/drbd/drbd_main.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c index 731a28eedc56..76faeab40c8f 100644 --- a/drivers/block/drbd/drbd_main.c +++ b/drivers/block/drbd/drbd_main.c @@ -2834,6 +2834,7 @@ void conn_md_sync(struct drbd_tconn *tconn) rcu_read_unlock(); } +/* aligned 4kByte */ struct meta_data_on_disk { u64 la_size; /* last agreed size. */ u64 uuid[UI_SIZE]; /* UUIDs. */ @@ -2843,13 +2844,13 @@ struct meta_data_on_disk { u32 magic; u32 md_size_sect; u32 al_offset; /* offset to this block */ - u32 al_nr_extents; /* important for restoring the AL */ + u32 al_nr_extents; /* important for restoring the AL (userspace) */ /* `-- act_log->nr_elements <-- ldev->dc.al_extents */ u32 bm_offset; /* offset to the bitmap, from here */ u32 bm_bytes_per_bit; /* BM_BLOCK_SIZE */ u32 la_peer_max_bio_size; /* last peer max_bio_size */ - u32 reserved_u32[3]; + u8 reserved_u8[4096 - (7*8 + 8*4)]; } __packed; /** @@ -2862,6 +2863,10 @@ void drbd_md_sync(struct drbd_conf *mdev) sector_t sector; int i; + /* Don't accidentally change the DRBD meta data layout. */ + BUILD_BUG_ON(UI_SIZE != 4); + BUILD_BUG_ON(sizeof(struct meta_data_on_disk) != 4096); + del_timer(&mdev->md_sync_timer); /* timer may be rearmed by drbd_md_mark_dirty() now. */ if (!test_and_clear_bit(MD_DIRTY, &mdev->flags)) @@ -2876,7 +2881,7 @@ void drbd_md_sync(struct drbd_conf *mdev) if (!buffer) goto out; - memset(buffer, 0, 512); + memset(buffer, 0, sizeof(*buffer)); buffer->la_size = cpu_to_be64(drbd_get_capacity(mdev->this_bdev)); for (i = UI_CURRENT; i < UI_SIZE; i++) |