diff options
Diffstat (limited to 'drivers/staging/lustre/lustre/lov/lov_offset.c')
| -rw-r--r-- | drivers/staging/lustre/lustre/lov/lov_offset.c | 271 |
1 files changed, 0 insertions, 271 deletions
diff --git a/drivers/staging/lustre/lustre/lov/lov_offset.c b/drivers/staging/lustre/lustre/lov/lov_offset.c deleted file mode 100644 index 3e16e647b334..000000000000 --- a/drivers/staging/lustre/lustre/lov/lov_offset.c +++ /dev/null @@ -1,271 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * 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.gnu.org/licenses/gpl-2.0.html - * - * GPL HEADER END - */ -/* - * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. - * Use is subject to license terms. - * - * Copyright (c) 2011, 2015, 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 "lov_internal.h" - -/* compute object size given "stripeno" and the ost size */ -u64 lov_stripe_size(struct lov_stripe_md *lsm, u64 ost_size, int stripeno) -{ - unsigned long ssize = lsm->lsm_stripe_size; - unsigned long stripe_size; - u64 swidth; - u64 lov_size; - int magic = lsm->lsm_magic; - - if (ost_size == 0) - return 0; - - 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; -} - -/** - * Compute file level page index by stripe level page offset - */ -pgoff_t lov_stripe_pgoff(struct lov_stripe_md *lsm, pgoff_t stripe_index, - int stripe) -{ - loff_t offset; - - offset = lov_stripe_size(lsm, (stripe_index << PAGE_SHIFT) + 1, stripe); - return offset >> PAGE_SHIFT; -} - -/* 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, u64 lov_off, - int stripeno, u64 *obdoff) -{ - unsigned long ssize = lsm->lsm_stripe_size; - u64 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; - } - - 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 = (u64)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 | - * --------------------------------------------------------------------- - */ -u64 lov_size_to_stripe(struct lov_stripe_md *lsm, u64 file_size, - int stripeno) -{ - unsigned long ssize = lsm->lsm_stripe_size; - u64 stripe_off, this_stripe, swidth; - int magic = lsm->lsm_magic; - - if (file_size == OBD_OBJECT_EOF) - return OBD_OBJECT_EOF; - - 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 = (u64)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, - u64 start, u64 end, u64 *obd_start, u64 *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, "[%llu->%llu] -> [(%d) %llu->%llu (%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, u64 lov_off) -{ - unsigned long ssize = lsm->lsm_stripe_size; - u64 stripe_off, swidth; - int magic = lsm->lsm_magic; - - 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; -} |