--- /dev/null
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * reservations.c
+ *
+ * Allocation reservations implementation
+ *
+ * Some code borrowed from fs/ext3/balloc.c and is:
+ *
+ * Copyright (C) 1992, 1993, 1994, 1995
+ * Remy Card (card@masi.ibp.fr)
+ * Laboratoire MASI - Institut Blaise Pascal
+ * Universite Pierre et Marie Curie (Paris VI)
+ *
+ * The rest is copyright (C) 2010 Novell. All rights reserved.
+ *
+ * This program 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.
+ *
+ * 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 for more details.
+ */
+
+#include <linux/fs.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/highmem.h>
+#include <linux/bitops.h>
+#include <linux/list.h>
+
+#define MLOG_MASK_PREFIX ML_RESERVATIONS
+#include <cluster/masklog.h>
+
+#include "ocfs2.h"
+
+#ifdef CONFIG_OCFS2_DEBUG_FS
+#define OCFS2_CHECK_RESERVATIONS
+#endif
+
+DEFINE_SPINLOCK(resv_lock);
+
+#define OCFS2_MIN_RESV_WINDOW_BITS 8
+#define OCFS2_MAX_RESV_WINDOW_BITS 1024
+
+static unsigned int ocfs2_resv_window_bits(struct ocfs2_reservation_map *resmap,
+ struct ocfs2_alloc_reservation *resv)
+{
+ struct ocfs2_super *osb = resmap->m_osb;
+ unsigned int bits;
+
+ /* 8, 16, 32, 64, 128, 256, 512, 1024 */
+ bits = 4 << osb->osb_resv_level;
+
+ return bits;
+}
+
+static inline unsigned int ocfs2_resv_end(struct ocfs2_alloc_reservation *resv)
+{
+ if (resv->r_len)
+ return resv->r_start + resv->r_len - 1;
+ return resv->r_start;
+}
+
+static inline int ocfs2_resv_empty(struct ocfs2_alloc_reservation *resv)
+{
+ return !!(resv->r_len == 0);
+}
+
+static inline int ocfs2_resmap_disabled(struct ocfs2_reservation_map *resmap)
+{
+ if (resmap->m_osb->osb_resv_level == 0)
+ return 1;
+ return 0;
+}
+
+static void ocfs2_dump_resv(struct ocfs2_reservation_map *resmap)
+{
+ struct ocfs2_super *osb = resmap->m_osb;
+ struct rb_node *node;
+ struct ocfs2_alloc_reservation *resv;
+ int i = 0;
+
+ mlog(ML_NOTICE, "Dumping resmap for device %s. Bitmap length: %u\n",
+ osb->dev_str, resmap->m_bitmap_len);
+
+ node = rb_first(&resmap->m_reservations);
+ while (node) {
+ resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);
+
+ mlog(ML_NOTICE, "start: %u\tend: %u\tlen: %u\tlast_start: %u"
+ "\tlast_len: %u\n", resv->r_start,
+ ocfs2_resv_end(resv), resv->r_len, resv->r_last_start,
+ resv->r_last_len);
+
+ node = rb_next(node);
+ i++;
+ }
+
+ mlog(ML_NOTICE, "%d reservations found. LRU follows\n", i);
+
+ i = 0;
+ list_for_each_entry(resv, &resmap->m_lru, r_lru) {
+ mlog(ML_NOTICE, "LRU(%d) start: %u\tend: %u\tlen: %u\t"
+ "last_start: %u\tlast_len: %u\n", i, resv->r_start,
+ ocfs2_resv_end(resv), resv->r_len, resv->r_last_start,
+ resv->r_last_len);
+
+ i++;
+ }
+}
+
+#ifdef OCFS2_CHECK_RESERVATIONS
+static int ocfs2_validate_resmap_bits(struct ocfs2_reservation_map *resmap,
+ int i,
+ struct ocfs2_alloc_reservation *resv)
+{
+ char *disk_bitmap = resmap->m_disk_bitmap;
+ unsigned int start = resv->r_start;
+ unsigned int end = ocfs2_resv_end(resv);
+
+ while (start <= end) {
+ if (ocfs2_test_bit(start, disk_bitmap)) {
+ mlog(ML_ERROR,
+ "reservation %d covers an allocated area "
+ "starting at bit %u!\n", i, start);
+ return 1;
+ }
+
+ start++;
+ }
+ return 0;
+}
+
+static void ocfs2_check_resmap(struct ocfs2_reservation_map *resmap)
+{
+ unsigned int off = 0;
+ int i = 0;
+ struct rb_node *node;
+ struct ocfs2_alloc_reservation *resv;
+
+ node = rb_first(&resmap->m_reservations);
+ while (node) {
+ resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);
+
+ if (i > 0 && resv->r_start <= off) {
+ mlog(ML_ERROR, "reservation %d has bad start off!\n",
+ i);
+ goto bad;
+ }
+
+ if (resv->r_len == 0) {
+ mlog(ML_ERROR, "reservation %d has no length!\n",
+ i);
+ goto bad;
+ }
+
+ if (resv->r_start > ocfs2_resv_end(resv)) {
+ mlog(ML_ERROR, "reservation %d has invalid range!\n",
+ i);
+ goto bad;
+ }
+
+ if (ocfs2_resv_end(resv) >= resmap->m_bitmap_len) {
+ mlog(ML_ERROR, "reservation %d extends past bitmap!\n",
+ i);
+ goto bad;
+ }
+
+ if (ocfs2_validate_resmap_bits(resmap, i, resv))
+ goto bad;
+
+ off = ocfs2_resv_end(resv);
+ node = rb_next(node);
+
+ i++;
+ }
+ return;
+
+bad:
+ ocfs2_dump_resv(resmap);
+ BUG();
+}
+#else
+static inline void ocfs2_check_resmap(struct ocfs2_reservation_map *resmap)
+{
+
+}
+#endif
+
+void ocfs2_resv_init_once(struct ocfs2_alloc_reservation *resv)
+{
+ memset(resv, 0, sizeof(*resv));
+ INIT_LIST_HEAD(&resv->r_lru);
+}
+
+void ocfs2_resv_set_type(struct ocfs2_alloc_reservation *resv,
+ unsigned int flags)
+{
+ BUG_ON(flags & ~OCFS2_RESV_TYPES);
+
+ resv->r_flags |= flags;
+}
+
+int ocfs2_resmap_init(struct ocfs2_super *osb,
+ struct ocfs2_reservation_map *resmap)
+{
+ memset(resmap, 0, sizeof(*resmap));
+
+ resmap->m_osb = osb;
+ resmap->m_reservations = RB_ROOT;
+ /* m_bitmap_len is initialized to zero by the above memset. */
+ INIT_LIST_HEAD(&resmap->m_lru);
+
+ return 0;
+}
+
+static void ocfs2_resv_mark_lru(struct ocfs2_reservation_map *resmap,
+ struct ocfs2_alloc_reservation *resv)
+{
+ assert_spin_locked(&resv_lock);
+
+ if (!list_empty(&resv->r_lru))
+ list_del_init(&resv->r_lru);
+
+ list_add_tail(&resv->r_lru, &resmap->m_lru);
+}
+
+static void __ocfs2_resv_trunc(struct ocfs2_alloc_reservation *resv)
+{
+ resv->r_len = 0;
+ resv->r_start = 0;
+}
+
+static void ocfs2_resv_remove(struct ocfs2_reservation_map *resmap,
+ struct ocfs2_alloc_reservation *resv)
+{
+ if (resv->r_flags & OCFS2_RESV_FLAG_INUSE) {
+ list_del_init(&resv->r_lru);
+ rb_erase(&resv->r_node, &resmap->m_reservations);
+ resv->r_flags &= ~OCFS2_RESV_FLAG_INUSE;
+ }
+}
+
+static void __ocfs2_resv_discard(struct ocfs2_reservation_map *resmap,
+ struct ocfs2_alloc_reservation *resv)
+{
+ assert_spin_locked(&resv_lock);
+
+ __ocfs2_resv_trunc(resv);
+ /*
+ * last_len and last_start no longer make sense if
+ * we're changing the range of our allocations.
+ */
+ resv->r_last_len = resv->r_last_start = 0;
+
+ ocfs2_resv_remove(resmap, resv);
+}
+
+/* does nothing if 'resv' is null */
+void ocfs2_resv_discard(struct ocfs2_reservation_map *resmap,
+ struct ocfs2_alloc_reservation *resv)
+{
+ if (resv) {
+ spin_lock(&resv_lock);
+ __ocfs2_resv_discard(resmap, resv);
+ spin_unlock(&resv_lock);
+ }
+}
+
+static void ocfs2_resmap_clear_all_resv(struct ocfs2_reservation_map *resmap)
+{
+ struct rb_node *node;
+ struct ocfs2_alloc_reservation *resv;
+
+ assert_spin_locked(&resv_lock);
+
+ while ((node = rb_last(&resmap->m_reservations)) != NULL) {
+ resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);
+
+ __ocfs2_resv_discard(resmap, resv);
+ }
+}
+
+void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap,
+ unsigned int clen, char *disk_bitmap)
+{
+ if (ocfs2_resmap_disabled(resmap))
+ return;
+
+ spin_lock(&resv_lock);
+
+ ocfs2_resmap_clear_all_resv(resmap);
+ resmap->m_bitmap_len = clen;
+ resmap->m_disk_bitmap = disk_bitmap;
+
+ spin_unlock(&resv_lock);
+}
+
+void ocfs2_resmap_uninit(struct ocfs2_reservation_map *resmap)
+{
+ /* Does nothing for now. Keep this around for API symmetry */
+}
+
+static void ocfs2_resv_insert(struct ocfs2_reservation_map *resmap,
+ struct ocfs2_alloc_reservation *new)
+{
+ struct rb_root *root = &resmap->m_reservations;
+ struct rb_node *parent = NULL;
+ struct rb_node **p = &root->rb_node;
+ struct ocfs2_alloc_reservation *tmp;
+
+ assert_spin_locked(&resv_lock);
+
+ mlog(0, "Insert reservation start: %u len: %u\n", new->r_start,
+ new->r_len);
+
+ while (*p) {
+ parent = *p;
+
+ tmp = rb_entry(parent, struct ocfs2_alloc_reservation, r_node);
+
+ if (new->r_start < tmp->r_start) {
+ p = &(*p)->rb_left;
+
+ /*
+ * This is a good place to check for
+ * overlapping reservations.
+ */
+ BUG_ON(ocfs2_resv_end(new) >= tmp->r_start);
+ } else if (new->r_start > ocfs2_resv_end(tmp)) {
+ p = &(*p)->rb_right;
+ } else {
+ /* This should never happen! */
+ mlog(ML_ERROR, "Duplicate reservation window!\n");
+ BUG();
+ }
+ }
+
+ rb_link_node(&new->r_node, parent, p);
+ rb_insert_color(&new->r_node, root);
+ new->r_flags |= OCFS2_RESV_FLAG_INUSE;
+
+ ocfs2_resv_mark_lru(resmap, new);
+
+ ocfs2_check_resmap(resmap);
+}
+
+/**
+ * ocfs2_find_resv_lhs() - find the window which contains goal
+ * @resmap: reservation map to search
+ * @goal: which bit to search for
+ *
+ * If a window containing that goal is not found, we return the window
+ * which comes before goal. Returns NULL on empty rbtree or no window
+ * before goal.
+ */
+static struct ocfs2_alloc_reservation *
+ocfs2_find_resv_lhs(struct ocfs2_reservation_map *resmap, unsigned int goal)
+{
+ struct ocfs2_alloc_reservation *resv = NULL;
+ struct ocfs2_alloc_reservation *prev_resv = NULL;
+ struct rb_node *node = resmap->m_reservations.rb_node;
+ struct rb_node *prev = NULL;
+
+ assert_spin_locked(&resv_lock);
+
+ if (!node)
+ return NULL;
+
+ node = rb_first(&resmap->m_reservations);
+ while (node) {
+ resv = rb_entry(node, struct ocfs2_alloc_reservation, r_node);
+
+ if (resv->r_start <= goal && ocfs2_resv_end(resv) >= goal)
+ break;
+
+ /* Check if we overshot the reservation just before goal? */
+ if (resv->r_start > goal) {
+ resv = prev_resv;
+ break;
+ }
+
+ prev_resv = resv;
+ prev = node;
+ node = rb_next(node);
+ }
+
+ return resv;
+}
+
+/*
+ * We are given a range within the bitmap, which corresponds to a gap
+ * inside the reservations tree (search_start, search_len). The range
+ * can be anything from the whole bitmap, to a gap between
+ * reservations.
+ *
+ * The start value of *rstart is insignificant.
+ *
+ * This function searches the bitmap range starting at search_start
+ * with length csearch_len for a set of contiguous free bits. We try
+ * to find up to 'wanted' bits, but can sometimes return less.
+ *
+ * Returns the length of allocation, 0 if no free bits are found.
+ *
+ * *cstart and *clen will also be populated with the result.
+ */
+static int ocfs2_resmap_find_free_bits(struct ocfs2_reservation_map *resmap,
+ unsigned int wanted,
+ unsigned int search_start,
+ unsigned int search_len,
+ unsigned int *rstart,
+ unsigned int *rlen)
+{
+ void *bitmap = resmap->m_disk_bitmap;
+ unsigned int best_start, best_len = 0;
+ int offset, start, found;
+
+ mlog(0, "Find %u bits within range (%u, len %u) resmap len: %u\n",
+ wanted, search_start, search_len, resmap->m_bitmap_len);
+
+ found = best_start = best_len = 0;
+
+ start = search_start;
+ while ((offset = ocfs2_find_next_zero_bit(bitmap, resmap->m_bitmap_len,
+ start)) != -1) {
+ /* Search reached end of the region */
+ if (offset >= (search_start + search_len))
+ break;
+
+ if (offset == start) {
+ /* we found a zero */
+ found++;
+ /* move start to the next bit to test */
+ start++;
+ } else {
+ /* got a zero after some ones */
+ found = 1;
+ start = offset + 1;
+ }
+ if (found > best_len) {
+ best_len = found;
+ best_start = start - found;
+ }
+
+ if (found >= wanted)
+ break;
+ }
+
+ if (best_len == 0)
+ return 0;
+
+ if (best_len >= wanted)
+ best_len = wanted;
+
+ *rlen = best_len;
+ *rstart = best_start;
+
+ mlog(0, "Found start: %u len: %u\n", best_start, best_len);
+
+ return *rlen;
+}
+
+static void __ocfs2_resv_find_window(struct ocfs2_reservation_map *resmap,
+ struct ocfs2_alloc_reservation *resv,
+ unsigned int goal, unsigned int wanted)
+{
+ struct rb_root *root = &resmap->m_reservations;
+ unsigned int gap_start, gap_end, gap_len;
+ struct ocfs2_alloc_reservation *prev_resv, *next_resv;
+ struct rb_node *prev, *next;
+ unsigned int cstart, clen;
+ unsigned int best_start = 0, best_len = 0;
+
+ /*
+ * Nasty cases to consider:
+ *
+ * - rbtree is empty
+ * - our window should be first in all reservations
+ * - our window should be last in all reservations
+ * - need to make sure we don't go past end of bitmap
+ */
+
+ mlog(0, "resv start: %u resv end: %u goal: %u wanted: %u\n",
+ resv->r_start, ocfs2_resv_end(resv), goal, wanted);
+
+ assert_spin_locked(&resv_lock);
+
+ if (RB_EMPTY_ROOT(root)) {
+ /*
+ * Easiest case - empty tree. We can just take
+ * whatever window of free bits we want.
+ */
+
+ mlog(0, "Empty root\n");
+
+ clen = ocfs2_resmap_find_free_bits(resmap, wanted, goal,
+ resmap->m_bitmap_len - goal,
+ &cstart, &clen);
+
+ /*
+ * This should never happen - the local alloc window
+ * will always have free bits when we're called.
+ */
+ BUG_ON(goal == 0 && clen == 0);
+
+ if (clen == 0)
+ return;
+
+ resv->r_start = cstart;
+ resv->r_len = clen;
+
+ ocfs2_resv_insert(resmap, resv);
+ return;
+ }
+
+ prev_resv = ocfs2_find_resv_lhs(resmap, goal);
+
+ if (prev_resv == NULL) {
+ mlog(0, "Goal on LHS of leftmost window\n");
+
+ /*
+ * A NULL here means that the search code couldn't
+ * find a window that starts before goal.
+ *
+ * However, we can take the first window after goal,
+ * which is also by definition, the leftmost window in
+ * the entire tree. If we can find free bits in the
+ * gap between goal and the LHS window, then the
+ * reservation can safely be placed there.
+ *
+ * Otherwise we fall back to a linear search, checking
+ * the gaps in between windows for a place to
+ * allocate.
+ */
+
+ next = rb_first(root);
+ next_resv = rb_entry(next, struct ocfs2_alloc_reservation,
+ r_node);
+
+ /*
+ * The search should never return such a window. (see
+ * comment above
+ */
+ if (next_resv->r_start <= goal) {
+ mlog(ML_ERROR, "goal: %u next_resv: start %u len %u\n",
+ goal, next_resv->r_start, next_resv->r_len);
+ ocfs2_dump_resv(resmap);
+ BUG();
+ }
+
+ clen = ocfs2_resmap_find_free_bits(resmap, wanted, goal,
+ next_resv->r_start - goal,
+ &cstart, &clen);
+ if (clen) {
+ best_len = clen;
+ best_start = cstart;
+ if (best_len == wanted)
+ goto out_insert;
+ }
+
+ prev_resv = next_resv;
+ next_resv = NULL;
+ }
+
+ prev = &prev_resv->r_node;
+
+ /* Now we do a linear search for a window, starting at 'prev_rsv' */
+ while (1) {
+ next = rb_next(prev);
+ if (next) {
+ mlog(0, "One more resv found in linear search\n");
+ next_resv = rb_entry(next,
+ struct ocfs2_alloc_reservation,
+ r_node);
+
+ gap_start = ocfs2_resv_end(prev_resv) + 1;
+ gap_end = next_resv->r_start - 1;
+ gap_len = gap_end - gap_start + 1;
+ } else {
+ mlog(0, "No next node\n");
+ /*
+ * We're at the rightmost edge of the
+ * tree. See if a reservation between this
+ * window and the end of the bitmap will work.
+ */
+ gap_start = ocfs2_resv_end(prev_resv) + 1;
+ gap_len = resmap->m_bitmap_len - gap_start;
+ gap_end = resmap->m_bitmap_len - 1;
+ }
+
+ /*
+ * No need to check this gap if we have already found
+ * a larger region of free bits.
+ */
+ if (gap_len <= best_len)
+ goto next_resv;
+
+ clen = ocfs2_resmap_find_free_bits(resmap, wanted, gap_start,
+ gap_len, &cstart, &clen);
+ if (clen == wanted) {
+ best_len = clen;
+ best_start = cstart;
+ goto out_insert;
+ } else if (clen > best_len) {
+ best_len = clen;
+ best_start = cstart;
+ }
+
+next_resv:
+ if (!next)
+ break;
+
+ prev = next;
+ prev_resv = rb_entry(prev, struct ocfs2_alloc_reservation,
+ r_node);
+ }
+
+out_insert:
+ if (best_len) {
+ resv->r_start = best_start;
+ resv->r_len = best_len;
+ ocfs2_resv_insert(resmap, resv);
+ }
+}
+
+static void ocfs2_cannibalize_resv(struct ocfs2_reservation_map *resmap,
+ struct ocfs2_alloc_reservation *resv,
+ unsigned int wanted)
+{
+ struct ocfs2_alloc_reservation *lru_resv;
+ int tmpwindow = !!(resv->r_flags & OCFS2_RESV_FLAG_TMP);
+ unsigned int min_bits;
+
+ if (!tmpwindow)
+ min_bits = ocfs2_resv_window_bits(resmap, resv) >> 1;
+ else
+ min_bits = wanted; /* We at know the temp window will use all
+ * of these bits */
+
+ /*
+ * Take the first reservation off the LRU as our 'target'. We
+ * don't try to be smart about it. There might be a case for
+ * searching based on size but I don't have enough data to be
+ * sure. --Mark (3/16/2010)
+ */
+ lru_resv = list_first_entry(&resmap->m_lru,
+ struct ocfs2_alloc_reservation, r_lru);
+
+ mlog(0, "lru resv: start: %u len: %u end: %u\n", lru_resv->r_start,
+ lru_resv->r_len, ocfs2_resv_end(lru_resv));
+
+ /*
+ * Cannibalize (some or all) of the target reservation and
+ * feed it to the current window.
+ */
+ if (lru_resv->r_len <= min_bits) {
+ /*
+ * Discard completely if size is less than or equal to a
+ * reasonable threshold - 50% of window bits for non temporary
+ * windows.
+ */
+ resv->r_start = lru_resv->r_start;
+ resv->r_len = lru_resv->r_len;
+
+ __ocfs2_resv_discard(resmap, lru_resv);
+ } else {
+ unsigned int shrink;
+ if (tmpwindow)
+ shrink = min_bits;
+ else
+ shrink = lru_resv->r_len / 2;
+
+ lru_resv->r_len -= shrink;
+
+ resv->r_start = ocfs2_resv_end(lru_resv) + 1;
+ resv->r_len = shrink;
+ }
+
+ mlog(0, "Reservation now looks like: r_start: %u r_end: %u "
+ "r_len: %u r_last_start: %u r_last_len: %u\n",
+ resv->r_start, ocfs2_resv_end(resv), resv->r_len,
+ resv->r_last_start, resv->r_last_len);
+
+ ocfs2_resv_insert(resmap, resv);
+}
+
+static void ocfs2_resv_find_window(struct ocfs2_reservation_map *resmap,
+ struct ocfs2_alloc_reservation *resv,
+ unsigned int wanted)
+{
+ unsigned int goal = 0;
+
+ BUG_ON(!ocfs2_resv_empty(resv));
+
+ /*
+ * Begin by trying to get a window as close to the previous
+ * one as possible. Using the most recent allocation as a
+ * start goal makes sense.
+ */
+ if (resv->r_last_len) {
+ goal = resv->r_last_start + resv->r_last_len;
+ if (goal >= resmap->m_bitmap_len)
+ goal = 0;
+ }
+
+ __ocfs2_resv_find_window(resmap, resv, goal, wanted);
+
+ /* Search from last alloc didn't work, try once more from beginning. */
+ if (ocfs2_resv_empty(resv) && goal != 0)
+ __ocfs2_resv_find_window(resmap, resv, 0, wanted);
+
+ if (ocfs2_resv_empty(resv)) {
+ /*
+ * Still empty? Pull oldest one off the LRU, remove it from
+ * tree, put this one in it's place.
+ */
+ ocfs2_cannibalize_resv(resmap, resv, wanted);
+ }
+
+ BUG_ON(ocfs2_resv_empty(resv));
+}
+
+int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap,
+ struct ocfs2_alloc_reservation *resv,
+ int *cstart, int *clen)
+{
+ unsigned int wanted = *clen;
+
+ if (resv == NULL || ocfs2_resmap_disabled(resmap))
+ return -ENOSPC;
+
+ spin_lock(&resv_lock);
+
+ /*
+ * We don't want to over-allocate for temporary
+ * windows. Otherwise, we run the risk of fragmenting the
+ * allocation space.
+ */
+ wanted = ocfs2_resv_window_bits(resmap, resv);
+ if ((resv->r_flags & OCFS2_RESV_FLAG_TMP) || wanted < *clen)
+ wanted = *clen;
+
+ if (ocfs2_resv_empty(resv)) {
+ mlog(0, "empty reservation, find new window\n");
+
+ /*
+ * Try to get a window here. If it works, we must fall
+ * through and test the bitmap . This avoids some
+ * ping-ponging of windows due to non-reserved space
+ * being allocation before we initialize a window for
+ * that inode.
+ */
+ ocfs2_resv_find_window(resmap, resv, wanted);
+ }
+
+ BUG_ON(ocfs2_resv_empty(resv));
+
+ *cstart = resv->r_start;
+ *clen = resv->r_len;
+
+ spin_unlock(&resv_lock);
+ return 0;
+}
+
+static void
+ ocfs2_adjust_resv_from_alloc(struct ocfs2_reservation_map *resmap,
+ struct ocfs2_alloc_reservation *resv,
+ unsigned int start, unsigned int end)
+{
+ unsigned int lhs = 0, rhs = 0;
+
+ BUG_ON(start < resv->r_start);
+
+ /*
+ * Completely used? We can remove it then.
+ */
+ if (ocfs2_resv_end(resv) <= end && resv->r_start >= start) {
+ __ocfs2_resv_discard(resmap, resv);
+ return;
+ }
+
+ if (end < ocfs2_resv_end(resv))
+ rhs = end - ocfs2_resv_end(resv);
+
+ if (start > resv->r_start)
+ lhs = start - resv->r_start;
+
+ /*
+ * This should have been trapped above. At the very least, rhs
+ * should be non zero.
+ */
+ BUG_ON(rhs == 0 && lhs == 0);
+
+ if (rhs >= lhs) {
+ unsigned int old_end = ocfs2_resv_end(resv);
+
+ resv->r_start = end + 1;
+ resv->r_len = old_end - resv->r_start + 1;
+ } else {
+ resv->r_len = start - resv->r_start;
+ }
+}
+
+void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap,
+ struct ocfs2_alloc_reservation *resv,
+ u32 cstart, u32 clen)
+{
+ unsigned int cend = cstart + clen - 1;
+
+ if (resmap == NULL || ocfs2_resmap_disabled(resmap))
+ return;
+
+ if (resv == NULL)
+ return;
+
+ spin_lock(&resv_lock);
+
+ mlog(0, "claim bits: cstart: %u cend: %u clen: %u r_start: %u "
+ "r_end: %u r_len: %u, r_last_start: %u r_last_len: %u\n",
+ cstart, cend, clen, resv->r_start, ocfs2_resv_end(resv),
+ resv->r_len, resv->r_last_start, resv->r_last_len);
+
+ BUG_ON(cstart < resv->r_start);
+ BUG_ON(cstart > ocfs2_resv_end(resv));
+ BUG_ON(cend > ocfs2_resv_end(resv));
+
+ ocfs2_adjust_resv_from_alloc(resmap, resv, cstart, cend);
+ resv->r_last_start = cstart;
+ resv->r_last_len = clen;
+
+ /*
+ * May have been discarded above from
+ * ocfs2_adjust_resv_from_alloc().
+ */
+ if (!ocfs2_resv_empty(resv))
+ ocfs2_resv_mark_lru(resmap, resv);
+
+ mlog(0, "Reservation now looks like: r_start: %u r_end: %u "
+ "r_len: %u r_last_start: %u r_last_len: %u\n",
+ resv->r_start, ocfs2_resv_end(resv), resv->r_len,
+ resv->r_last_start, resv->r_last_len);
+
+ ocfs2_check_resmap(resmap);
+
+ spin_unlock(&resv_lock);
+}
--- /dev/null
+/* -*- mode: c; c-basic-offset: 8; -*-
+ * vim: noexpandtab sw=8 ts=8 sts=0:
+ *
+ * reservations.h
+ *
+ * Allocation reservations function prototypes and structures.
+ *
+ * Copyright (C) 2010 Novell. All rights reserved.
+ *
+ * This program 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.
+ *
+ * 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 for more details.
+ */
+
+#ifndef OCFS2_RESERVATIONS_H
+#define OCFS2_RESERVATIONS_H
+
+#include <linux/rbtree.h>
+
+#define OCFS2_DEFAULT_RESV_LEVEL 4
+#define OCFS2_MAX_RESV_LEVEL 9
+#define OCFS2_MIN_RESV_LEVEL 0
+
+struct ocfs2_alloc_reservation {
+ struct rb_node r_node;
+
+ unsigned int r_start; /* Begining of current window */
+ unsigned int r_len; /* Length of the window */
+
+ unsigned int r_last_len; /* Length of most recent alloc */
+ unsigned int r_last_start; /* Start of most recent alloc */
+ struct list_head r_lru; /* LRU list head */
+
+ unsigned int r_flags;
+};
+
+#define OCFS2_RESV_FLAG_INUSE 0x01 /* Set when r_node is part of a btree */
+#define OCFS2_RESV_FLAG_TMP 0x02 /* Temporary reservation, will be
+ * destroyed immedately after use */
+
+struct ocfs2_reservation_map {
+ struct rb_root m_reservations;
+ char *m_disk_bitmap;
+
+ struct ocfs2_super *m_osb;
+
+ /* The following are not initialized to meaningful values until a disk
+ * bitmap is provided. */
+ u32 m_bitmap_len; /* Number of valid
+ * bits available */
+
+ struct list_head m_lru; /* LRU of reservations
+ * structures. */
+
+};
+
+void ocfs2_resv_init_once(struct ocfs2_alloc_reservation *resv);
+
+#define OCFS2_RESV_TYPES (OCFS2_RESV_FLAG_TMP)
+void ocfs2_resv_set_type(struct ocfs2_alloc_reservation *resv,
+ unsigned int flags);
+
+/**
+ * ocfs2_resv_discard() - truncate a reservation
+ * @resmap:
+ * @resv: the reservation to truncate.
+ *
+ * After this function is called, the reservation will be empty, and
+ * unlinked from the rbtree.
+ */
+void ocfs2_resv_discard(struct ocfs2_reservation_map *resmap,
+ struct ocfs2_alloc_reservation *resv);
+
+
+/**
+ * ocfs2_resmap_init() - Initialize fields of a reservations bitmap
+ * @resmap: struct ocfs2_reservation_map to initialize
+ * @obj: unused for now
+ * @ops: unused for now
+ * @max_bitmap_bytes: Maximum size of the bitmap (typically blocksize)
+ *
+ * Only possible return value other than '0' is -ENOMEM for failure to
+ * allocation mirror bitmap.
+ */
+int ocfs2_resmap_init(struct ocfs2_super *osb,
+ struct ocfs2_reservation_map *resmap);
+
+/**
+ * ocfs2_resmap_restart() - "restart" a reservation bitmap
+ * @resmap: reservations bitmap
+ * @clen: Number of valid bits in the bitmap
+ * @disk_bitmap: the disk bitmap this resmap should refer to.
+ *
+ * Re-initialize the parameters of a reservation bitmap. This is
+ * useful for local alloc window slides.
+ *
+ * This function will call ocfs2_trunc_resv against all existing
+ * reservations. A future version will recalculate existing
+ * reservations based on the new bitmap.
+ */
+void ocfs2_resmap_restart(struct ocfs2_reservation_map *resmap,
+ unsigned int clen, char *disk_bitmap);
+
+/**
+ * ocfs2_resmap_uninit() - uninitialize a reservation bitmap structure
+ * @resmap: the struct ocfs2_reservation_map to uninitialize
+ */
+void ocfs2_resmap_uninit(struct ocfs2_reservation_map *resmap);
+
+/**
+ * ocfs2_resmap_resv_bits() - Return still-valid reservation bits
+ * @resmap: reservations bitmap
+ * @resv: reservation to base search from
+ * @cstart: start of proposed allocation
+ * @clen: length (in clusters) of proposed allocation
+ *
+ * Using the reservation data from resv, this function will compare
+ * resmap and resmap->m_disk_bitmap to determine what part (if any) of
+ * the reservation window is still clear to use. If resv is empty,
+ * this function will try to allocate a window for it.
+ *
+ * On success, zero is returned and the valid allocation area is set in cstart
+ * and clen.
+ *
+ * Returns -ENOSPC if reservations are disabled.
+ */
+int ocfs2_resmap_resv_bits(struct ocfs2_reservation_map *resmap,
+ struct ocfs2_alloc_reservation *resv,
+ int *cstart, int *clen);
+
+/**
+ * ocfs2_resmap_claimed_bits() - Tell the reservation code that bits were used.
+ * @resmap: reservations bitmap
+ * @resv: optional reservation to recalulate based on new bitmap
+ * @cstart: start of allocation in clusters
+ * @clen: end of allocation in clusters.
+ *
+ * Tell the reservation code that bits were used to fulfill allocation in
+ * resmap. The bits don't have to have been part of any existing
+ * reservation. But we must always call this function when bits are claimed.
+ * Internally, the reservations code will use this information to mark the
+ * reservations bitmap. If resv is passed, it's next allocation window will be
+ * calculated.
+ */
+void ocfs2_resmap_claimed_bits(struct ocfs2_reservation_map *resmap,
+ struct ocfs2_alloc_reservation *resv,
+ u32 cstart, u32 clen);
+
+#endif /* OCFS2_RESERVATIONS_H */
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff