#include "buffer_head_io.h"
+/*
+ * The extent caching implementation is intentionally trivial.
+ *
+ * We only cache a small number of extents stored directly on the
+ * inode, so linear order operations are acceptable. If we ever want
+ * to increase the size of the extent map, then these algorithms must
+ * get smarter.
+ */
+
+void ocfs2_extent_map_init(struct inode *inode)
+{
+ struct ocfs2_inode_info *oi = OCFS2_I(inode);
+
+ oi->ip_extent_map.em_num_items = 0;
+ INIT_LIST_HEAD(&oi->ip_extent_map.em_list);
+}
+
+static void __ocfs2_extent_map_lookup(struct ocfs2_extent_map *em,
+ unsigned int cpos,
+ struct ocfs2_extent_map_item **ret_emi)
+{
+ unsigned int range;
+ struct ocfs2_extent_map_item *emi;
+
+ *ret_emi = NULL;
+
+ list_for_each_entry(emi, &em->em_list, ei_list) {
+ range = emi->ei_cpos + emi->ei_clusters;
+
+ if (cpos >= emi->ei_cpos && cpos < range) {
+ list_move(&emi->ei_list, &em->em_list);
+
+ *ret_emi = emi;
+ break;
+ }
+ }
+}
+
+static int ocfs2_extent_map_lookup(struct inode *inode, unsigned int cpos,
+ unsigned int *phys, unsigned int *len,
+ unsigned int *flags)
+{
+ unsigned int coff;
+ struct ocfs2_inode_info *oi = OCFS2_I(inode);
+ struct ocfs2_extent_map_item *emi;
+
+ spin_lock(&oi->ip_lock);
+
+ __ocfs2_extent_map_lookup(&oi->ip_extent_map, cpos, &emi);
+ if (emi) {
+ coff = cpos - emi->ei_cpos;
+ *phys = emi->ei_phys + coff;
+ if (len)
+ *len = emi->ei_clusters - coff;
+ if (flags)
+ *flags = emi->ei_flags;
+ }
+
+ spin_unlock(&oi->ip_lock);
+
+ if (emi == NULL)
+ return -ENOENT;
+
+ return 0;
+}
+
+/*
+ * Forget about all clusters equal to or greater than cpos.
+ */
+void ocfs2_extent_map_trunc(struct inode *inode, unsigned int cpos)
+{
+ struct ocfs2_extent_map_item *emi, *n;
+ struct ocfs2_inode_info *oi = OCFS2_I(inode);
+ struct ocfs2_extent_map *em = &oi->ip_extent_map;
+ LIST_HEAD(tmp_list);
+ unsigned int range;
+
+ spin_lock(&oi->ip_lock);
+ list_for_each_entry_safe(emi, n, &em->em_list, ei_list) {
+ if (emi->ei_cpos >= cpos) {
+ /* Full truncate of this record. */
+ list_move(&emi->ei_list, &tmp_list);
+ BUG_ON(em->em_num_items == 0);
+ em->em_num_items--;
+ continue;
+ }
+
+ range = emi->ei_cpos + emi->ei_clusters;
+ if (range > cpos) {
+ /* Partial truncate */
+ emi->ei_clusters = cpos - emi->ei_cpos;
+ }
+ }
+ spin_unlock(&oi->ip_lock);
+
+ list_for_each_entry_safe(emi, n, &tmp_list, ei_list) {
+ list_del(&emi->ei_list);
+ kfree(emi);
+ }
+}
+
+/*
+ * Is any part of emi2 contained within emi1
+ */
+static int ocfs2_ei_is_contained(struct ocfs2_extent_map_item *emi1,
+ struct ocfs2_extent_map_item *emi2)
+{
+ unsigned int range1, range2;
+
+ /*
+ * Check if logical start of emi2 is inside emi1
+ */
+ range1 = emi1->ei_cpos + emi1->ei_clusters;
+ if (emi2->ei_cpos >= emi1->ei_cpos && emi2->ei_cpos < range1)
+ return 1;
+
+ /*
+ * Check if logical end of emi2 is inside emi1
+ */
+ range2 = emi2->ei_cpos + emi2->ei_clusters;
+ if (range2 > emi1->ei_cpos && range2 <= range1)
+ return 1;
+
+ return 0;
+}
+
+static void ocfs2_copy_emi_fields(struct ocfs2_extent_map_item *dest,
+ struct ocfs2_extent_map_item *src)
+{
+ dest->ei_cpos = src->ei_cpos;
+ dest->ei_phys = src->ei_phys;
+ dest->ei_clusters = src->ei_clusters;
+ dest->ei_flags = src->ei_flags;
+}
+
+/*
+ * Try to merge emi with ins. Returns 1 if merge succeeds, zero
+ * otherwise.
+ */
+static int ocfs2_try_to_merge_extent_map(struct ocfs2_extent_map_item *emi,
+ struct ocfs2_extent_map_item *ins)
+{
+ /*
+ * Handle contiguousness
+ */
+ if (ins->ei_phys == (emi->ei_phys + emi->ei_clusters) &&
+ ins->ei_cpos == (emi->ei_cpos + emi->ei_clusters) &&
+ ins->ei_flags == emi->ei_flags) {
+ emi->ei_clusters += ins->ei_clusters;
+ return 1;
+ } else if ((ins->ei_phys + ins->ei_clusters) == emi->ei_phys &&
+ (ins->ei_cpos + ins->ei_clusters) == emi->ei_phys &&
+ ins->ei_flags == emi->ei_flags) {
+ emi->ei_phys = ins->ei_phys;
+ emi->ei_cpos = ins->ei_cpos;
+ emi->ei_clusters += ins->ei_clusters;
+ return 1;
+ }
+
+ /*
+ * Overlapping extents - this shouldn't happen unless we've
+ * split an extent to change it's flags. That is exceedingly
+ * rare, so there's no sense in trying to optimize it yet.
+ */
+ if (ocfs2_ei_is_contained(emi, ins) ||
+ ocfs2_ei_is_contained(ins, emi)) {
+ ocfs2_copy_emi_fields(emi, ins);
+ return 1;
+ }
+
+ /* No merge was possible. */
+ return 0;
+}
+
+/*
+ * In order to reduce complexity on the caller, this insert function
+ * is intentionally liberal in what it will accept.
+ *
+ * The only rule is that the truncate call *must* be used whenever
+ * records have been deleted. This avoids inserting overlapping
+ * records with different physical mappings.
+ */
+void ocfs2_extent_map_insert_rec(struct inode *inode,
+ struct ocfs2_extent_rec *rec)
+{
+ struct ocfs2_inode_info *oi = OCFS2_I(inode);
+ struct ocfs2_extent_map *em = &oi->ip_extent_map;
+ struct ocfs2_extent_map_item *emi, *new_emi = NULL;
+ struct ocfs2_extent_map_item ins;
+
+ ins.ei_cpos = le32_to_cpu(rec->e_cpos);
+ ins.ei_phys = ocfs2_blocks_to_clusters(inode->i_sb,
+ le64_to_cpu(rec->e_blkno));
+ ins.ei_clusters = le16_to_cpu(rec->e_leaf_clusters);
+ ins.ei_flags = rec->e_flags;
+
+search:
+ spin_lock(&oi->ip_lock);
+
+ list_for_each_entry(emi, &em->em_list, ei_list) {
+ if (ocfs2_try_to_merge_extent_map(emi, &ins)) {
+ list_move(&emi->ei_list, &em->em_list);
+ spin_unlock(&oi->ip_lock);
+ goto out;
+ }
+ }
+
+ /*
+ * No item could be merged.
+ *
+ * Either allocate and add a new item, or overwrite the last recently
+ * inserted.
+ */
+
+ if (em->em_num_items < OCFS2_MAX_EXTENT_MAP_ITEMS) {
+ if (new_emi == NULL) {
+ spin_unlock(&oi->ip_lock);
+
+ new_emi = kmalloc(sizeof(*new_emi), GFP_NOFS);
+ if (new_emi == NULL)
+ goto out;
+
+ goto search;
+ }
+
+ ocfs2_copy_emi_fields(new_emi, &ins);
+ list_add(&new_emi->ei_list, &em->em_list);
+ em->em_num_items++;
+ new_emi = NULL;
+ } else {
+ BUG_ON(list_empty(&em->em_list) || em->em_num_items == 0);
+ emi = list_entry(em->em_list.prev,
+ struct ocfs2_extent_map_item, ei_list);
+ list_move(&emi->ei_list, &em->em_list);
+ ocfs2_copy_emi_fields(emi, &ins);
+ }
+
+ spin_unlock(&oi->ip_lock);
+
+out:
+ if (new_emi)
+ kfree(new_emi);
+}
+
/*
* Return the 1st index within el which contains an extent start
* larger than v_cluster.
return ret;
}
-/*
- * Return the index of the extent record which contains cluster #v_cluster.
- * -1 is returned if it was not found.
- *
- * Should work fine on interior and exterior nodes.
- */
-static int ocfs2_search_extent_list(struct ocfs2_extent_list *el,
- u32 v_cluster)
-{
- int ret = -1;
- int i;
- struct ocfs2_extent_rec *rec;
- u32 rec_end, rec_start, clusters;
-
- for(i = 0; i < le16_to_cpu(el->l_next_free_rec); i++) {
- rec = &el->l_recs[i];
-
- rec_start = le32_to_cpu(rec->e_cpos);
- clusters = ocfs2_rec_clusters(el, rec);
-
- rec_end = rec_start + clusters;
-
- if (v_cluster >= rec_start && v_cluster < rec_end) {
- ret = i;
- break;
- }
- }
-
- return ret;
-}
-
int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
u32 *p_cluster, u32 *num_clusters,
unsigned int *extent_flags)
struct ocfs2_extent_rec *rec;
u32 coff;
+ if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
+ ret = -ERANGE;
+ mlog_errno(ret);
+ goto out;
+ }
+
+ ret = ocfs2_extent_map_lookup(inode, v_cluster, p_cluster,
+ num_clusters, extent_flags);
+ if (ret == 0)
+ goto out;
+
ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), OCFS2_I(inode)->ip_blkno,
&di_bh, OCFS2_BH_CACHED, inode);
if (ret) {
*num_clusters = ocfs2_rec_clusters(el, rec) - coff;
flags = rec->e_flags;
+
+ ocfs2_extent_map_insert_rec(inode, rec);
}
if (extent_flags)
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