staging: add Lustre file system client support

Lustre is the most deployed distributed file system
in the HPC (High Performance Computing) world. The patch
adds its client side support.

The code is not very clean and needs to live in drivers/staging
for some time for continuing cleanup work. See
drivers/staging/lustre/TODO for details.

The code is based on Lustre master commit faefbfc04

commit faefbfc0460bc00f2ee4c1c1c86aa1e39b9eea49
Author: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Date:   Tue Apr 30 23:05:21 2013 +0400

    LU-3244 utils: tunefs.lustre should preserve virgin label

Plus a few under-review patches on Whamcloud gerrit:
3.8 kernel support:
http://review.whamcloud.com/#change,5973
http://review.whamcloud.com/#change,5974
http://review.whamcloud.com/#change,5768
http://review.whamcloud.com/#change,5781
http://review.whamcloud.com/#change,5763
http://review.whamcloud.com/#change,5613
http://review.whamcloud.com/#change,5655

3.9 kernel support:
http://review.whamcloud.com/#change,5898
http://review.whamcloud.com/#change,5899

Kconfig/Kbuild:
http://review.whamcloud.com/#change,4646
http://review.whamcloud.com/#change,4644

libcfs cleanup:
http://review.whamcloud.com/#change,2831
http://review.whamcloud.com/#change,4775
http://review.whamcloud.com/#change,4776
http://review.whamcloud.com/#change,4777
http://review.whamcloud.com/#change,4778
http://review.whamcloud.com/#change,4779
http://review.whamcloud.com/#change,4780

All starting/trailing whitespaces are removed, to match kernel
coding style. Also ran scripts/cleanfile on all lustre source files.

[maked the Kconfig depend on BROKEN as the recent procfs changes causes
this to fail - gregkh]

Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 267 insertions, 0 deletions

diff --git a/drivers/staging/lustre/lustre/lov/lov_offset.c b/drivers/staging/lustre/lustre/lov/lov_offset.c
new file mode 100644
index 0000000..f62b7e5
--- /dev/null
+++ b/drivers/staging/lustre/lustre/lov/lov_offset.c
@@ -0,0 +1,267 @@
+/*
+ * GPL HEADER START
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Use is subject to license terms.
+ *
+ * Copyright (c) 2011, Intel Corporation.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
+ */
+
+#define DEBUG_SUBSYSTEM S_LOV
+
+#include <linux/libcfs/libcfs.h>
+
+#include <obd_class.h>
+#include <obd_lov.h>
+
+#include "lov_internal.h"
+
+/* compute object size given "stripeno" and the ost size */
+obd_size lov_stripe_size(struct lov_stripe_md *lsm, obd_size ost_size,
+			 int stripeno)
+{
+	unsigned long ssize = lsm->lsm_stripe_size;
+	unsigned long stripe_size;
+	obd_off swidth;
+	obd_size lov_size;
+	int magic = lsm->lsm_magic;
+	ENTRY;
+
+	if (ost_size == 0)
+		RETURN(0);
+
+	LASSERT(lsm_op_find(magic) != NULL);
+	lsm_op_find(magic)->lsm_stripe_by_index(lsm, &stripeno, NULL, &swidth);
+
+	/* lov_do_div64(a, b) returns a % b, and a = a / b */
+	stripe_size = lov_do_div64(ost_size, ssize);
+	if (stripe_size)
+		lov_size = ost_size * swidth + stripeno * ssize + stripe_size;
+	else
+		lov_size = (ost_size - 1) * swidth + (stripeno + 1) * ssize;
+
+	RETURN(lov_size);
+}
+
+/* we have an offset in file backed by an lov and want to find out where
+ * that offset lands in our given stripe of the file.  for the easy
+ * case where the offset is within the stripe, we just have to scale the
+ * offset down to make it relative to the stripe instead of the lov.
+ *
+ * the harder case is what to do when the offset doesn't intersect the
+ * stripe.  callers will want start offsets clamped ahead to the start
+ * of the nearest stripe in the file.  end offsets similarly clamped to the
+ * nearest ending byte of a stripe in the file:
+ *
+ * all this function does is move offsets to the nearest region of the
+ * stripe, and it does its work "mod" the full length of all the stripes.
+ * consider a file with 3 stripes:
+ *
+ *	     S					      E
+ * ---------------------------------------------------------------------
+ * |    0    |     1     |     2     |    0    |     1     |     2     |
+ * ---------------------------------------------------------------------
+ *
+ * to find stripe 1's offsets for S and E, it divides by the full stripe
+ * width and does its math in the context of a single set of stripes:
+ *
+ *	     S	 E
+ * -----------------------------------
+ * |    0    |     1     |     2     |
+ * -----------------------------------
+ *
+ * it'll notice that E is outside stripe 1 and clamp it to the end of the
+ * stripe, then multiply it back out by lov_off to give the real offsets in
+ * the stripe:
+ *
+ *   S		   E
+ * ---------------------------------------------------------------------
+ * |    1    |     1     |     1     |    1    |     1     |     1     |
+ * ---------------------------------------------------------------------
+ *
+ * it would have done similarly and pulled S forward to the start of a 1
+ * stripe if, say, S had landed in a 0 stripe.
+ *
+ * this rounding isn't always correct.  consider an E lov offset that lands
+ * on a 0 stripe, the "mod stripe width" math will pull it forward to the
+ * start of a 1 stripe, when in fact it wanted to be rounded back to the end
+ * of a previous 1 stripe.  this logic is handled by callers and this is why:
+ *
+ * this function returns < 0 when the offset was "before" the stripe and
+ * was moved forward to the start of the stripe in question;  0 when it
+ * falls in the stripe and no shifting was done; > 0 when the offset
+ * was outside the stripe and was pulled back to its final byte. */
+int lov_stripe_offset(struct lov_stripe_md *lsm, obd_off lov_off,
+		      int stripeno, obd_off *obdoff)
+{
+	unsigned long ssize  = lsm->lsm_stripe_size;
+	obd_off stripe_off, this_stripe, swidth;
+	int magic = lsm->lsm_magic;
+	int ret = 0;
+
+	if (lov_off == OBD_OBJECT_EOF) {
+		*obdoff = OBD_OBJECT_EOF;
+		return 0;
+	}
+
+	LASSERT(lsm_op_find(magic) != NULL);
+
+	lsm_op_find(magic)->lsm_stripe_by_index(lsm, &stripeno, &lov_off,
+						&swidth);
+
+	/* lov_do_div64(a, b) returns a % b, and a = a / b */
+	stripe_off = lov_do_div64(lov_off, swidth);
+
+	this_stripe = (obd_off)stripeno * ssize;
+	if (stripe_off < this_stripe) {
+		stripe_off = 0;
+		ret = -1;
+	} else {
+		stripe_off -= this_stripe;
+
+		if (stripe_off >= ssize) {
+			stripe_off = ssize;
+			ret = 1;
+		}
+	}
+
+	*obdoff = lov_off * ssize + stripe_off;
+	return ret;
+}
+
+/* Given a whole-file size and a stripe number, give the file size which
+ * corresponds to the individual object of that stripe.
+ *
+ * This behaves basically in the same was as lov_stripe_offset, except that
+ * file sizes falling before the beginning of a stripe are clamped to the end
+ * of the previous stripe, not the beginning of the next:
+ *
+ *					       S
+ * ---------------------------------------------------------------------
+ * |    0    |     1     |     2     |    0    |     1     |     2     |
+ * ---------------------------------------------------------------------
+ *
+ * if clamped to stripe 2 becomes:
+ *
+ *				   S
+ * ---------------------------------------------------------------------
+ * |    0    |     1     |     2     |    0    |     1     |     2     |
+ * ---------------------------------------------------------------------
+ */
+obd_off lov_size_to_stripe(struct lov_stripe_md *lsm, obd_off file_size,
+			   int stripeno)
+{
+	unsigned long ssize  = lsm->lsm_stripe_size;
+	obd_off stripe_off, this_stripe, swidth;
+	int magic = lsm->lsm_magic;
+
+	if (file_size == OBD_OBJECT_EOF)
+		return OBD_OBJECT_EOF;
+
+	LASSERT(lsm_op_find(magic) != NULL);
+	lsm_op_find(magic)->lsm_stripe_by_index(lsm, &stripeno, &file_size,
+						&swidth);
+
+	/* lov_do_div64(a, b) returns a % b, and a = a / b */
+	stripe_off = lov_do_div64(file_size, swidth);
+
+	this_stripe = (obd_off)stripeno * ssize;
+	if (stripe_off < this_stripe) {
+		/* Move to end of previous stripe, or zero */
+		if (file_size > 0) {
+			file_size--;
+			stripe_off = ssize;
+		} else {
+			stripe_off = 0;
+		}
+	} else {
+		stripe_off -= this_stripe;
+
+		if (stripe_off >= ssize) {
+			/* Clamp to end of this stripe */
+			stripe_off = ssize;
+		}
+	}
+
+	return (file_size * ssize + stripe_off);
+}
+
+/* given an extent in an lov and a stripe, calculate the extent of the stripe
+ * that is contained within the lov extent.  this returns true if the given
+ * stripe does intersect with the lov extent. */
+int lov_stripe_intersects(struct lov_stripe_md *lsm, int stripeno,
+			  obd_off start, obd_off end,
+			  obd_off *obd_start, obd_off *obd_end)
+{
+	int start_side, end_side;
+
+	start_side = lov_stripe_offset(lsm, start, stripeno, obd_start);
+	end_side = lov_stripe_offset(lsm, end, stripeno, obd_end);
+
+	CDEBUG(D_INODE, "["LPU64"->"LPU64"] -> [(%d) "LPU64"->"LPU64" (%d)]\n",
+	       start, end, start_side, *obd_start, *obd_end, end_side);
+
+	/* this stripe doesn't intersect the file extent when neither
+	 * start or the end intersected the stripe and obd_start and
+	 * obd_end got rounded up to the save value. */
+	if (start_side != 0 && end_side != 0 && *obd_start == *obd_end)
+		return 0;
+
+	/* as mentioned in the lov_stripe_offset commentary, end
+	 * might have been shifted in the wrong direction.  This
+	 * happens when an end offset is before the stripe when viewed
+	 * through the "mod stripe size" math. we detect it being shifted
+	 * in the wrong direction and touch it up.
+	 * interestingly, this can't underflow since end must be > start
+	 * if we passed through the previous check.
+	 * (should we assert for that somewhere?) */
+	if (end_side != 0)
+		(*obd_end)--;
+
+	return 1;
+}
+
+/* compute which stripe number "lov_off" will be written into */
+int lov_stripe_number(struct lov_stripe_md *lsm, obd_off lov_off)
+{
+	unsigned long ssize  = lsm->lsm_stripe_size;
+	obd_off stripe_off, swidth;
+	int magic = lsm->lsm_magic;
+
+	LASSERT(lsm_op_find(magic) != NULL);
+	lsm_op_find(magic)->lsm_stripe_by_offset(lsm, NULL, &lov_off, &swidth);
+
+	stripe_off = lov_do_div64(lov_off, swidth);
+
+	/* Puts stripe_off/ssize result into stripe_off */
+	lov_do_div64(stripe_off, ssize);
+
+	return stripe_off;
+}