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authorBoaz Harrosh <bharrosh@panasas.com>2011-10-12 20:42:22 +0400
committerBoaz Harrosh <bharrosh@panasas.com>2011-10-25 03:55:36 +0400
commita1fec1dbbc8db974d2582e4040590cebe72171e4 (patch)
tree9dcbe1933b7f40256f40393f3c86dbb16e8fb953 /fs/exofs/ore_raid.h
parent3e335672e018c06e007f85a5d54afd721fb3d6d5 (diff)
downloadlinux-a1fec1dbbc8db974d2582e4040590cebe72171e4.tar.xz
ore: RAID5 read
This patch introduces the first stage of RAID5 support mainly the skip-over-raid-units when reading. For writes it inserts BLANK units, into where XOR blocks should be calculated and written to. It introduces the new "general raid maths", and the main additional parameters and components needed for raid5. Since at this stage it could corrupt future version that actually do support raid5. The enablement of raid5 mounting and setting of parity-count > 0 is disabled. So the raid5 code will never be used. Mounting of raid5 is only enabled later once the basic XOR write is also in. But if the patch "enable RAID5" is applied this code has been tested to be able to properly read raid5 volumes and is according to standard. Also it has been tested that the new maths still properly supports RAID0 and grouping code just as before. (BTW: I have found more bugs in the pnfs-obj RAID math fixed here) The ore.c file is getting too big, so new ore_raid.[hc] files are added that will include the special raid stuff that are not used in striping and mirrors. In future write support these will get bigger. When adding the ore_raid.c to Kbuild file I was forced to rename ore.ko to libore.ko. Is it possible to keep source file, say ore.c and module file ore.ko the same even if there are multiple files inside ore.ko? Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Diffstat (limited to 'fs/exofs/ore_raid.h')
-rw-r--r--fs/exofs/ore_raid.h64
1 files changed, 64 insertions, 0 deletions
diff --git a/fs/exofs/ore_raid.h b/fs/exofs/ore_raid.h
new file mode 100644
index 000000000000..c21080b4407f
--- /dev/null
+++ b/fs/exofs/ore_raid.h
@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) from 2011
+ * Boaz Harrosh <bharrosh@panasas.com>
+ *
+ * This file is part of the objects raid engine (ore).
+ *
+ * It is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with "ore". If not, write to the Free Software Foundation, Inc:
+ * "Free Software Foundation <info@fsf.org>"
+ */
+
+#include <scsi/osd_ore.h>
+
+#define ORE_ERR(fmt, a...) printk(KERN_ERR "ore: " fmt, ##a)
+
+#ifdef CONFIG_EXOFS_DEBUG
+#define ORE_DBGMSG(fmt, a...) \
+ printk(KERN_NOTICE "ore @%s:%d: " fmt, __func__, __LINE__, ##a)
+#else
+#define ORE_DBGMSG(fmt, a...) \
+ do { if (0) printk(fmt, ##a); } while (0)
+#endif
+
+/* u64 has problems with printk this will cast it to unsigned long long */
+#define _LLU(x) (unsigned long long)(x)
+
+#define ORE_DBGMSG2(M...) do {} while (0)
+/* #define ORE_DBGMSG2 ORE_DBGMSG */
+
+/* Calculate the component order in a stripe. eg the logical data unit
+ * address within the stripe of @dev given the @par_dev of this stripe.
+ */
+static inline unsigned _dev_order(unsigned devs_in_group, unsigned mirrors_p1,
+ unsigned par_dev, unsigned dev)
+{
+ unsigned first_dev = dev - dev % devs_in_group;
+
+ dev -= first_dev;
+ par_dev -= first_dev;
+
+ if (devs_in_group == par_dev) /* The raid 0 case */
+ return dev / mirrors_p1;
+ /* raid4/5/6 case */
+ return ((devs_in_group + dev - par_dev - mirrors_p1) % devs_in_group) /
+ mirrors_p1;
+}
+
+/* ios_raid.c stuff needed by ios.c */
+int _ore_post_alloc_raid_stuff(struct ore_io_state *ios);
+void _ore_free_raid_stuff(struct ore_io_state *ios);
+
+void _ore_add_sg_seg(struct ore_per_dev_state *per_dev, unsigned cur_len,
+ bool not_last);
+int _ore_add_parity_unit(struct ore_io_state *ios, struct ore_striping_info *si,
+ struct ore_per_dev_state *per_dev, unsigned cur_len);
+
+/* ios.c stuff needed by ios_raid.c */
+int _ore_add_stripe_unit(struct ore_io_state *ios, unsigned *cur_pg,
+ unsigned pgbase, struct page **pages,
+ struct ore_per_dev_state *per_dev, int cur_len);