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-rw-r--r--fs/xfs/libxfs/xfs_iext_tree.c1050
1 files changed, 1050 insertions, 0 deletions
diff --git a/fs/xfs/libxfs/xfs_iext_tree.c b/fs/xfs/libxfs/xfs_iext_tree.c
new file mode 100644
index 000000000..773cf4349
--- /dev/null
+++ b/fs/xfs/libxfs/xfs_iext_tree.c
@@ -0,0 +1,1050 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2017 Christoph Hellwig.
+ */
+
+#include "xfs.h"
+#include "xfs_shared.h"
+#include "xfs_format.h"
+#include "xfs_bit.h"
+#include "xfs_log_format.h"
+#include "xfs_trans_resv.h"
+#include "xfs_mount.h"
+#include "xfs_inode.h"
+#include "xfs_trace.h"
+
+/*
+ * In-core extent record layout:
+ *
+ * +-------+----------------------------+
+ * | 00:53 | all 54 bits of startoff |
+ * | 54:63 | low 10 bits of startblock |
+ * +-------+----------------------------+
+ * | 00:20 | all 21 bits of length |
+ * | 21 | unwritten extent bit |
+ * | 22:63 | high 42 bits of startblock |
+ * +-------+----------------------------+
+ */
+#define XFS_IEXT_STARTOFF_MASK xfs_mask64lo(BMBT_STARTOFF_BITLEN)
+#define XFS_IEXT_LENGTH_MASK xfs_mask64lo(BMBT_BLOCKCOUNT_BITLEN)
+#define XFS_IEXT_STARTBLOCK_MASK xfs_mask64lo(BMBT_STARTBLOCK_BITLEN)
+
+struct xfs_iext_rec {
+ uint64_t lo;
+ uint64_t hi;
+};
+
+/*
+ * Given that the length can't be a zero, only an empty hi value indicates an
+ * unused record.
+ */
+static bool xfs_iext_rec_is_empty(struct xfs_iext_rec *rec)
+{
+ return rec->hi == 0;
+}
+
+static inline void xfs_iext_rec_clear(struct xfs_iext_rec *rec)
+{
+ rec->lo = 0;
+ rec->hi = 0;
+}
+
+static void
+xfs_iext_set(
+ struct xfs_iext_rec *rec,
+ struct xfs_bmbt_irec *irec)
+{
+ ASSERT((irec->br_startoff & ~XFS_IEXT_STARTOFF_MASK) == 0);
+ ASSERT((irec->br_blockcount & ~XFS_IEXT_LENGTH_MASK) == 0);
+ ASSERT((irec->br_startblock & ~XFS_IEXT_STARTBLOCK_MASK) == 0);
+
+ rec->lo = irec->br_startoff & XFS_IEXT_STARTOFF_MASK;
+ rec->hi = irec->br_blockcount & XFS_IEXT_LENGTH_MASK;
+
+ rec->lo |= (irec->br_startblock << 54);
+ rec->hi |= ((irec->br_startblock & ~xfs_mask64lo(10)) << (22 - 10));
+
+ if (irec->br_state == XFS_EXT_UNWRITTEN)
+ rec->hi |= (1 << 21);
+}
+
+static void
+xfs_iext_get(
+ struct xfs_bmbt_irec *irec,
+ struct xfs_iext_rec *rec)
+{
+ irec->br_startoff = rec->lo & XFS_IEXT_STARTOFF_MASK;
+ irec->br_blockcount = rec->hi & XFS_IEXT_LENGTH_MASK;
+
+ irec->br_startblock = rec->lo >> 54;
+ irec->br_startblock |= (rec->hi & xfs_mask64hi(42)) >> (22 - 10);
+
+ if (rec->hi & (1 << 21))
+ irec->br_state = XFS_EXT_UNWRITTEN;
+ else
+ irec->br_state = XFS_EXT_NORM;
+}
+
+enum {
+ NODE_SIZE = 256,
+ KEYS_PER_NODE = NODE_SIZE / (sizeof(uint64_t) + sizeof(void *)),
+ RECS_PER_LEAF = (NODE_SIZE - (2 * sizeof(struct xfs_iext_leaf *))) /
+ sizeof(struct xfs_iext_rec),
+};
+
+/*
+ * In-core extent btree block layout:
+ *
+ * There are two types of blocks in the btree: leaf and inner (non-leaf) blocks.
+ *
+ * The leaf blocks are made up by %KEYS_PER_NODE extent records, which each
+ * contain the startoffset, blockcount, startblock and unwritten extent flag.
+ * See above for the exact format, followed by pointers to the previous and next
+ * leaf blocks (if there are any).
+ *
+ * The inner (non-leaf) blocks first contain KEYS_PER_NODE lookup keys, followed
+ * by an equal number of pointers to the btree blocks at the next lower level.
+ *
+ * +-------+-------+-------+-------+-------+----------+----------+
+ * Leaf: | rec 1 | rec 2 | rec 3 | rec 4 | rec N | prev-ptr | next-ptr |
+ * +-------+-------+-------+-------+-------+----------+----------+
+ *
+ * +-------+-------+-------+-------+-------+-------+------+-------+
+ * Inner: | key 1 | key 2 | key 3 | key N | ptr 1 | ptr 2 | ptr3 | ptr N |
+ * +-------+-------+-------+-------+-------+-------+------+-------+
+ */
+struct xfs_iext_node {
+ uint64_t keys[KEYS_PER_NODE];
+#define XFS_IEXT_KEY_INVALID (1ULL << 63)
+ void *ptrs[KEYS_PER_NODE];
+};
+
+struct xfs_iext_leaf {
+ struct xfs_iext_rec recs[RECS_PER_LEAF];
+ struct xfs_iext_leaf *prev;
+ struct xfs_iext_leaf *next;
+};
+
+inline xfs_extnum_t xfs_iext_count(struct xfs_ifork *ifp)
+{
+ return ifp->if_bytes / sizeof(struct xfs_iext_rec);
+}
+
+static inline int xfs_iext_max_recs(struct xfs_ifork *ifp)
+{
+ if (ifp->if_height == 1)
+ return xfs_iext_count(ifp);
+ return RECS_PER_LEAF;
+}
+
+static inline struct xfs_iext_rec *cur_rec(struct xfs_iext_cursor *cur)
+{
+ return &cur->leaf->recs[cur->pos];
+}
+
+static inline bool xfs_iext_valid(struct xfs_ifork *ifp,
+ struct xfs_iext_cursor *cur)
+{
+ if (!cur->leaf)
+ return false;
+ if (cur->pos < 0 || cur->pos >= xfs_iext_max_recs(ifp))
+ return false;
+ if (xfs_iext_rec_is_empty(cur_rec(cur)))
+ return false;
+ return true;
+}
+
+static void *
+xfs_iext_find_first_leaf(
+ struct xfs_ifork *ifp)
+{
+ struct xfs_iext_node *node = ifp->if_u1.if_root;
+ int height;
+
+ if (!ifp->if_height)
+ return NULL;
+
+ for (height = ifp->if_height; height > 1; height--) {
+ node = node->ptrs[0];
+ ASSERT(node);
+ }
+
+ return node;
+}
+
+static void *
+xfs_iext_find_last_leaf(
+ struct xfs_ifork *ifp)
+{
+ struct xfs_iext_node *node = ifp->if_u1.if_root;
+ int height, i;
+
+ if (!ifp->if_height)
+ return NULL;
+
+ for (height = ifp->if_height; height > 1; height--) {
+ for (i = 1; i < KEYS_PER_NODE; i++)
+ if (!node->ptrs[i])
+ break;
+ node = node->ptrs[i - 1];
+ ASSERT(node);
+ }
+
+ return node;
+}
+
+void
+xfs_iext_first(
+ struct xfs_ifork *ifp,
+ struct xfs_iext_cursor *cur)
+{
+ cur->pos = 0;
+ cur->leaf = xfs_iext_find_first_leaf(ifp);
+}
+
+void
+xfs_iext_last(
+ struct xfs_ifork *ifp,
+ struct xfs_iext_cursor *cur)
+{
+ int i;
+
+ cur->leaf = xfs_iext_find_last_leaf(ifp);
+ if (!cur->leaf) {
+ cur->pos = 0;
+ return;
+ }
+
+ for (i = 1; i < xfs_iext_max_recs(ifp); i++) {
+ if (xfs_iext_rec_is_empty(&cur->leaf->recs[i]))
+ break;
+ }
+ cur->pos = i - 1;
+}
+
+void
+xfs_iext_next(
+ struct xfs_ifork *ifp,
+ struct xfs_iext_cursor *cur)
+{
+ if (!cur->leaf) {
+ ASSERT(cur->pos <= 0 || cur->pos >= RECS_PER_LEAF);
+ xfs_iext_first(ifp, cur);
+ return;
+ }
+
+ ASSERT(cur->pos >= 0);
+ ASSERT(cur->pos < xfs_iext_max_recs(ifp));
+
+ cur->pos++;
+ if (ifp->if_height > 1 && !xfs_iext_valid(ifp, cur) &&
+ cur->leaf->next) {
+ cur->leaf = cur->leaf->next;
+ cur->pos = 0;
+ }
+}
+
+void
+xfs_iext_prev(
+ struct xfs_ifork *ifp,
+ struct xfs_iext_cursor *cur)
+{
+ if (!cur->leaf) {
+ ASSERT(cur->pos <= 0 || cur->pos >= RECS_PER_LEAF);
+ xfs_iext_last(ifp, cur);
+ return;
+ }
+
+ ASSERT(cur->pos >= 0);
+ ASSERT(cur->pos <= RECS_PER_LEAF);
+
+recurse:
+ do {
+ cur->pos--;
+ if (xfs_iext_valid(ifp, cur))
+ return;
+ } while (cur->pos > 0);
+
+ if (ifp->if_height > 1 && cur->leaf->prev) {
+ cur->leaf = cur->leaf->prev;
+ cur->pos = RECS_PER_LEAF;
+ goto recurse;
+ }
+}
+
+static inline int
+xfs_iext_key_cmp(
+ struct xfs_iext_node *node,
+ int n,
+ xfs_fileoff_t offset)
+{
+ if (node->keys[n] > offset)
+ return 1;
+ if (node->keys[n] < offset)
+ return -1;
+ return 0;
+}
+
+static inline int
+xfs_iext_rec_cmp(
+ struct xfs_iext_rec *rec,
+ xfs_fileoff_t offset)
+{
+ uint64_t rec_offset = rec->lo & XFS_IEXT_STARTOFF_MASK;
+ uint32_t rec_len = rec->hi & XFS_IEXT_LENGTH_MASK;
+
+ if (rec_offset > offset)
+ return 1;
+ if (rec_offset + rec_len <= offset)
+ return -1;
+ return 0;
+}
+
+static void *
+xfs_iext_find_level(
+ struct xfs_ifork *ifp,
+ xfs_fileoff_t offset,
+ int level)
+{
+ struct xfs_iext_node *node = ifp->if_u1.if_root;
+ int height, i;
+
+ if (!ifp->if_height)
+ return NULL;
+
+ for (height = ifp->if_height; height > level; height--) {
+ for (i = 1; i < KEYS_PER_NODE; i++)
+ if (xfs_iext_key_cmp(node, i, offset) > 0)
+ break;
+
+ node = node->ptrs[i - 1];
+ if (!node)
+ break;
+ }
+
+ return node;
+}
+
+static int
+xfs_iext_node_pos(
+ struct xfs_iext_node *node,
+ xfs_fileoff_t offset)
+{
+ int i;
+
+ for (i = 1; i < KEYS_PER_NODE; i++) {
+ if (xfs_iext_key_cmp(node, i, offset) > 0)
+ break;
+ }
+
+ return i - 1;
+}
+
+static int
+xfs_iext_node_insert_pos(
+ struct xfs_iext_node *node,
+ xfs_fileoff_t offset)
+{
+ int i;
+
+ for (i = 0; i < KEYS_PER_NODE; i++) {
+ if (xfs_iext_key_cmp(node, i, offset) > 0)
+ return i;
+ }
+
+ return KEYS_PER_NODE;
+}
+
+static int
+xfs_iext_node_nr_entries(
+ struct xfs_iext_node *node,
+ int start)
+{
+ int i;
+
+ for (i = start; i < KEYS_PER_NODE; i++) {
+ if (node->keys[i] == XFS_IEXT_KEY_INVALID)
+ break;
+ }
+
+ return i;
+}
+
+static int
+xfs_iext_leaf_nr_entries(
+ struct xfs_ifork *ifp,
+ struct xfs_iext_leaf *leaf,
+ int start)
+{
+ int i;
+
+ for (i = start; i < xfs_iext_max_recs(ifp); i++) {
+ if (xfs_iext_rec_is_empty(&leaf->recs[i]))
+ break;
+ }
+
+ return i;
+}
+
+static inline uint64_t
+xfs_iext_leaf_key(
+ struct xfs_iext_leaf *leaf,
+ int n)
+{
+ return leaf->recs[n].lo & XFS_IEXT_STARTOFF_MASK;
+}
+
+static void
+xfs_iext_grow(
+ struct xfs_ifork *ifp)
+{
+ struct xfs_iext_node *node = kmem_zalloc(NODE_SIZE, KM_NOFS);
+ int i;
+
+ if (ifp->if_height == 1) {
+ struct xfs_iext_leaf *prev = ifp->if_u1.if_root;
+
+ node->keys[0] = xfs_iext_leaf_key(prev, 0);
+ node->ptrs[0] = prev;
+ } else {
+ struct xfs_iext_node *prev = ifp->if_u1.if_root;
+
+ ASSERT(ifp->if_height > 1);
+
+ node->keys[0] = prev->keys[0];
+ node->ptrs[0] = prev;
+ }
+
+ for (i = 1; i < KEYS_PER_NODE; i++)
+ node->keys[i] = XFS_IEXT_KEY_INVALID;
+
+ ifp->if_u1.if_root = node;
+ ifp->if_height++;
+}
+
+static void
+xfs_iext_update_node(
+ struct xfs_ifork *ifp,
+ xfs_fileoff_t old_offset,
+ xfs_fileoff_t new_offset,
+ int level,
+ void *ptr)
+{
+ struct xfs_iext_node *node = ifp->if_u1.if_root;
+ int height, i;
+
+ for (height = ifp->if_height; height > level; height--) {
+ for (i = 0; i < KEYS_PER_NODE; i++) {
+ if (i > 0 && xfs_iext_key_cmp(node, i, old_offset) > 0)
+ break;
+ if (node->keys[i] == old_offset)
+ node->keys[i] = new_offset;
+ }
+ node = node->ptrs[i - 1];
+ ASSERT(node);
+ }
+
+ ASSERT(node == ptr);
+}
+
+static struct xfs_iext_node *
+xfs_iext_split_node(
+ struct xfs_iext_node **nodep,
+ int *pos,
+ int *nr_entries)
+{
+ struct xfs_iext_node *node = *nodep;
+ struct xfs_iext_node *new = kmem_zalloc(NODE_SIZE, KM_NOFS);
+ const int nr_move = KEYS_PER_NODE / 2;
+ int nr_keep = nr_move + (KEYS_PER_NODE & 1);
+ int i = 0;
+
+ /* for sequential append operations just spill over into the new node */
+ if (*pos == KEYS_PER_NODE) {
+ *nodep = new;
+ *pos = 0;
+ *nr_entries = 0;
+ goto done;
+ }
+
+
+ for (i = 0; i < nr_move; i++) {
+ new->keys[i] = node->keys[nr_keep + i];
+ new->ptrs[i] = node->ptrs[nr_keep + i];
+
+ node->keys[nr_keep + i] = XFS_IEXT_KEY_INVALID;
+ node->ptrs[nr_keep + i] = NULL;
+ }
+
+ if (*pos >= nr_keep) {
+ *nodep = new;
+ *pos -= nr_keep;
+ *nr_entries = nr_move;
+ } else {
+ *nr_entries = nr_keep;
+ }
+done:
+ for (; i < KEYS_PER_NODE; i++)
+ new->keys[i] = XFS_IEXT_KEY_INVALID;
+ return new;
+}
+
+static void
+xfs_iext_insert_node(
+ struct xfs_ifork *ifp,
+ uint64_t offset,
+ void *ptr,
+ int level)
+{
+ struct xfs_iext_node *node, *new;
+ int i, pos, nr_entries;
+
+again:
+ if (ifp->if_height < level)
+ xfs_iext_grow(ifp);
+
+ new = NULL;
+ node = xfs_iext_find_level(ifp, offset, level);
+ pos = xfs_iext_node_insert_pos(node, offset);
+ nr_entries = xfs_iext_node_nr_entries(node, pos);
+
+ ASSERT(pos >= nr_entries || xfs_iext_key_cmp(node, pos, offset) != 0);
+ ASSERT(nr_entries <= KEYS_PER_NODE);
+
+ if (nr_entries == KEYS_PER_NODE)
+ new = xfs_iext_split_node(&node, &pos, &nr_entries);
+
+ /*
+ * Update the pointers in higher levels if the first entry changes
+ * in an existing node.
+ */
+ if (node != new && pos == 0 && nr_entries > 0)
+ xfs_iext_update_node(ifp, node->keys[0], offset, level, node);
+
+ for (i = nr_entries; i > pos; i--) {
+ node->keys[i] = node->keys[i - 1];
+ node->ptrs[i] = node->ptrs[i - 1];
+ }
+ node->keys[pos] = offset;
+ node->ptrs[pos] = ptr;
+
+ if (new) {
+ offset = new->keys[0];
+ ptr = new;
+ level++;
+ goto again;
+ }
+}
+
+static struct xfs_iext_leaf *
+xfs_iext_split_leaf(
+ struct xfs_iext_cursor *cur,
+ int *nr_entries)
+{
+ struct xfs_iext_leaf *leaf = cur->leaf;
+ struct xfs_iext_leaf *new = kmem_zalloc(NODE_SIZE, KM_NOFS);
+ const int nr_move = RECS_PER_LEAF / 2;
+ int nr_keep = nr_move + (RECS_PER_LEAF & 1);
+ int i;
+
+ /* for sequential append operations just spill over into the new node */
+ if (cur->pos == RECS_PER_LEAF) {
+ cur->leaf = new;
+ cur->pos = 0;
+ *nr_entries = 0;
+ goto done;
+ }
+
+ for (i = 0; i < nr_move; i++) {
+ new->recs[i] = leaf->recs[nr_keep + i];
+ xfs_iext_rec_clear(&leaf->recs[nr_keep + i]);
+ }
+
+ if (cur->pos >= nr_keep) {
+ cur->leaf = new;
+ cur->pos -= nr_keep;
+ *nr_entries = nr_move;
+ } else {
+ *nr_entries = nr_keep;
+ }
+done:
+ if (leaf->next)
+ leaf->next->prev = new;
+ new->next = leaf->next;
+ new->prev = leaf;
+ leaf->next = new;
+ return new;
+}
+
+static void
+xfs_iext_alloc_root(
+ struct xfs_ifork *ifp,
+ struct xfs_iext_cursor *cur)
+{
+ ASSERT(ifp->if_bytes == 0);
+
+ ifp->if_u1.if_root = kmem_zalloc(sizeof(struct xfs_iext_rec), KM_NOFS);
+ ifp->if_height = 1;
+
+ /* now that we have a node step into it */
+ cur->leaf = ifp->if_u1.if_root;
+ cur->pos = 0;
+}
+
+static void
+xfs_iext_realloc_root(
+ struct xfs_ifork *ifp,
+ struct xfs_iext_cursor *cur)
+{
+ int64_t new_size = ifp->if_bytes + sizeof(struct xfs_iext_rec);
+ void *new;
+
+ /* account for the prev/next pointers */
+ if (new_size / sizeof(struct xfs_iext_rec) == RECS_PER_LEAF)
+ new_size = NODE_SIZE;
+
+ new = krealloc(ifp->if_u1.if_root, new_size, GFP_NOFS | __GFP_NOFAIL);
+ memset(new + ifp->if_bytes, 0, new_size - ifp->if_bytes);
+ ifp->if_u1.if_root = new;
+ cur->leaf = new;
+}
+
+/*
+ * Increment the sequence counter on extent tree changes. If we are on a COW
+ * fork, this allows the writeback code to skip looking for a COW extent if the
+ * COW fork hasn't changed. We use WRITE_ONCE here to ensure the update to the
+ * sequence counter is seen before the modifications to the extent tree itself
+ * take effect.
+ */
+static inline void xfs_iext_inc_seq(struct xfs_ifork *ifp)
+{
+ WRITE_ONCE(ifp->if_seq, READ_ONCE(ifp->if_seq) + 1);
+}
+
+void
+xfs_iext_insert(
+ struct xfs_inode *ip,
+ struct xfs_iext_cursor *cur,
+ struct xfs_bmbt_irec *irec,
+ int state)
+{
+ struct xfs_ifork *ifp = xfs_iext_state_to_fork(ip, state);
+ xfs_fileoff_t offset = irec->br_startoff;
+ struct xfs_iext_leaf *new = NULL;
+ int nr_entries, i;
+
+ xfs_iext_inc_seq(ifp);
+
+ if (ifp->if_height == 0)
+ xfs_iext_alloc_root(ifp, cur);
+ else if (ifp->if_height == 1)
+ xfs_iext_realloc_root(ifp, cur);
+
+ nr_entries = xfs_iext_leaf_nr_entries(ifp, cur->leaf, cur->pos);
+ ASSERT(nr_entries <= RECS_PER_LEAF);
+ ASSERT(cur->pos >= nr_entries ||
+ xfs_iext_rec_cmp(cur_rec(cur), irec->br_startoff) != 0);
+
+ if (nr_entries == RECS_PER_LEAF)
+ new = xfs_iext_split_leaf(cur, &nr_entries);
+
+ /*
+ * Update the pointers in higher levels if the first entry changes
+ * in an existing node.
+ */
+ if (cur->leaf != new && cur->pos == 0 && nr_entries > 0) {
+ xfs_iext_update_node(ifp, xfs_iext_leaf_key(cur->leaf, 0),
+ offset, 1, cur->leaf);
+ }
+
+ for (i = nr_entries; i > cur->pos; i--)
+ cur->leaf->recs[i] = cur->leaf->recs[i - 1];
+ xfs_iext_set(cur_rec(cur), irec);
+ ifp->if_bytes += sizeof(struct xfs_iext_rec);
+
+ trace_xfs_iext_insert(ip, cur, state, _RET_IP_);
+
+ if (new)
+ xfs_iext_insert_node(ifp, xfs_iext_leaf_key(new, 0), new, 2);
+}
+
+static struct xfs_iext_node *
+xfs_iext_rebalance_node(
+ struct xfs_iext_node *parent,
+ int *pos,
+ struct xfs_iext_node *node,
+ int nr_entries)
+{
+ /*
+ * If the neighbouring nodes are completely full, or have different
+ * parents, we might never be able to merge our node, and will only
+ * delete it once the number of entries hits zero.
+ */
+ if (nr_entries == 0)
+ return node;
+
+ if (*pos > 0) {
+ struct xfs_iext_node *prev = parent->ptrs[*pos - 1];
+ int nr_prev = xfs_iext_node_nr_entries(prev, 0), i;
+
+ if (nr_prev + nr_entries <= KEYS_PER_NODE) {
+ for (i = 0; i < nr_entries; i++) {
+ prev->keys[nr_prev + i] = node->keys[i];
+ prev->ptrs[nr_prev + i] = node->ptrs[i];
+ }
+ return node;
+ }
+ }
+
+ if (*pos + 1 < xfs_iext_node_nr_entries(parent, *pos)) {
+ struct xfs_iext_node *next = parent->ptrs[*pos + 1];
+ int nr_next = xfs_iext_node_nr_entries(next, 0), i;
+
+ if (nr_entries + nr_next <= KEYS_PER_NODE) {
+ /*
+ * Merge the next node into this node so that we don't
+ * have to do an additional update of the keys in the
+ * higher levels.
+ */
+ for (i = 0; i < nr_next; i++) {
+ node->keys[nr_entries + i] = next->keys[i];
+ node->ptrs[nr_entries + i] = next->ptrs[i];
+ }
+
+ ++*pos;
+ return next;
+ }
+ }
+
+ return NULL;
+}
+
+static void
+xfs_iext_remove_node(
+ struct xfs_ifork *ifp,
+ xfs_fileoff_t offset,
+ void *victim)
+{
+ struct xfs_iext_node *node, *parent;
+ int level = 2, pos, nr_entries, i;
+
+ ASSERT(level <= ifp->if_height);
+ node = xfs_iext_find_level(ifp, offset, level);
+ pos = xfs_iext_node_pos(node, offset);
+again:
+ ASSERT(node->ptrs[pos]);
+ ASSERT(node->ptrs[pos] == victim);
+ kmem_free(victim);
+
+ nr_entries = xfs_iext_node_nr_entries(node, pos) - 1;
+ offset = node->keys[0];
+ for (i = pos; i < nr_entries; i++) {
+ node->keys[i] = node->keys[i + 1];
+ node->ptrs[i] = node->ptrs[i + 1];
+ }
+ node->keys[nr_entries] = XFS_IEXT_KEY_INVALID;
+ node->ptrs[nr_entries] = NULL;
+
+ if (pos == 0 && nr_entries > 0) {
+ xfs_iext_update_node(ifp, offset, node->keys[0], level, node);
+ offset = node->keys[0];
+ }
+
+ if (nr_entries >= KEYS_PER_NODE / 2)
+ return;
+
+ if (level < ifp->if_height) {
+ /*
+ * If we aren't at the root yet try to find a neighbour node to
+ * merge with (or delete the node if it is empty), and then
+ * recurse up to the next level.
+ */
+ level++;
+ parent = xfs_iext_find_level(ifp, offset, level);
+ pos = xfs_iext_node_pos(parent, offset);
+
+ ASSERT(pos != KEYS_PER_NODE);
+ ASSERT(parent->ptrs[pos] == node);
+
+ node = xfs_iext_rebalance_node(parent, &pos, node, nr_entries);
+ if (node) {
+ victim = node;
+ node = parent;
+ goto again;
+ }
+ } else if (nr_entries == 1) {
+ /*
+ * If we are at the root and only one entry is left we can just
+ * free this node and update the root pointer.
+ */
+ ASSERT(node == ifp->if_u1.if_root);
+ ifp->if_u1.if_root = node->ptrs[0];
+ ifp->if_height--;
+ kmem_free(node);
+ }
+}
+
+static void
+xfs_iext_rebalance_leaf(
+ struct xfs_ifork *ifp,
+ struct xfs_iext_cursor *cur,
+ struct xfs_iext_leaf *leaf,
+ xfs_fileoff_t offset,
+ int nr_entries)
+{
+ /*
+ * If the neighbouring nodes are completely full we might never be able
+ * to merge our node, and will only delete it once the number of
+ * entries hits zero.
+ */
+ if (nr_entries == 0)
+ goto remove_node;
+
+ if (leaf->prev) {
+ int nr_prev = xfs_iext_leaf_nr_entries(ifp, leaf->prev, 0), i;
+
+ if (nr_prev + nr_entries <= RECS_PER_LEAF) {
+ for (i = 0; i < nr_entries; i++)
+ leaf->prev->recs[nr_prev + i] = leaf->recs[i];
+
+ if (cur->leaf == leaf) {
+ cur->leaf = leaf->prev;
+ cur->pos += nr_prev;
+ }
+ goto remove_node;
+ }
+ }
+
+ if (leaf->next) {
+ int nr_next = xfs_iext_leaf_nr_entries(ifp, leaf->next, 0), i;
+
+ if (nr_entries + nr_next <= RECS_PER_LEAF) {
+ /*
+ * Merge the next node into this node so that we don't
+ * have to do an additional update of the keys in the
+ * higher levels.
+ */
+ for (i = 0; i < nr_next; i++) {
+ leaf->recs[nr_entries + i] =
+ leaf->next->recs[i];
+ }
+
+ if (cur->leaf == leaf->next) {
+ cur->leaf = leaf;
+ cur->pos += nr_entries;
+ }
+
+ offset = xfs_iext_leaf_key(leaf->next, 0);
+ leaf = leaf->next;
+ goto remove_node;
+ }
+ }
+
+ return;
+remove_node:
+ if (leaf->prev)
+ leaf->prev->next = leaf->next;
+ if (leaf->next)
+ leaf->next->prev = leaf->prev;
+ xfs_iext_remove_node(ifp, offset, leaf);
+}
+
+static void
+xfs_iext_free_last_leaf(
+ struct xfs_ifork *ifp)
+{
+ ifp->if_height--;
+ kmem_free(ifp->if_u1.if_root);
+ ifp->if_u1.if_root = NULL;
+}
+
+void
+xfs_iext_remove(
+ struct xfs_inode *ip,
+ struct xfs_iext_cursor *cur,
+ int state)
+{
+ struct xfs_ifork *ifp = xfs_iext_state_to_fork(ip, state);
+ struct xfs_iext_leaf *leaf = cur->leaf;
+ xfs_fileoff_t offset = xfs_iext_leaf_key(leaf, 0);
+ int i, nr_entries;
+
+ trace_xfs_iext_remove(ip, cur, state, _RET_IP_);
+
+ ASSERT(ifp->if_height > 0);
+ ASSERT(ifp->if_u1.if_root != NULL);
+ ASSERT(xfs_iext_valid(ifp, cur));
+
+ xfs_iext_inc_seq(ifp);
+
+ nr_entries = xfs_iext_leaf_nr_entries(ifp, leaf, cur->pos) - 1;
+ for (i = cur->pos; i < nr_entries; i++)
+ leaf->recs[i] = leaf->recs[i + 1];
+ xfs_iext_rec_clear(&leaf->recs[nr_entries]);
+ ifp->if_bytes -= sizeof(struct xfs_iext_rec);
+
+ if (cur->pos == 0 && nr_entries > 0) {
+ xfs_iext_update_node(ifp, offset, xfs_iext_leaf_key(leaf, 0), 1,
+ leaf);
+ offset = xfs_iext_leaf_key(leaf, 0);
+ } else if (cur->pos == nr_entries) {
+ if (ifp->if_height > 1 && leaf->next)
+ cur->leaf = leaf->next;
+ else
+ cur->leaf = NULL;
+ cur->pos = 0;
+ }
+
+ if (nr_entries >= RECS_PER_LEAF / 2)
+ return;
+
+ if (ifp->if_height > 1)
+ xfs_iext_rebalance_leaf(ifp, cur, leaf, offset, nr_entries);
+ else if (nr_entries == 0)
+ xfs_iext_free_last_leaf(ifp);
+}
+
+/*
+ * Lookup the extent covering bno.
+ *
+ * If there is an extent covering bno return the extent index, and store the
+ * expanded extent structure in *gotp, and the extent cursor in *cur.
+ * If there is no extent covering bno, but there is an extent after it (e.g.
+ * it lies in a hole) return that extent in *gotp and its cursor in *cur
+ * instead.
+ * If bno is beyond the last extent return false, and return an invalid
+ * cursor value.
+ */
+bool
+xfs_iext_lookup_extent(
+ struct xfs_inode *ip,
+ struct xfs_ifork *ifp,
+ xfs_fileoff_t offset,
+ struct xfs_iext_cursor *cur,
+ struct xfs_bmbt_irec *gotp)
+{
+ XFS_STATS_INC(ip->i_mount, xs_look_exlist);
+
+ cur->leaf = xfs_iext_find_level(ifp, offset, 1);
+ if (!cur->leaf) {
+ cur->pos = 0;
+ return false;
+ }
+
+ for (cur->pos = 0; cur->pos < xfs_iext_max_recs(ifp); cur->pos++) {
+ struct xfs_iext_rec *rec = cur_rec(cur);
+
+ if (xfs_iext_rec_is_empty(rec))
+ break;
+ if (xfs_iext_rec_cmp(rec, offset) >= 0)
+ goto found;
+ }
+
+ /* Try looking in the next node for an entry > offset */
+ if (ifp->if_height == 1 || !cur->leaf->next)
+ return false;
+ cur->leaf = cur->leaf->next;
+ cur->pos = 0;
+ if (!xfs_iext_valid(ifp, cur))
+ return false;
+found:
+ xfs_iext_get(gotp, cur_rec(cur));
+ return true;
+}
+
+/*
+ * Returns the last extent before end, and if this extent doesn't cover
+ * end, update end to the end of the extent.
+ */
+bool
+xfs_iext_lookup_extent_before(
+ struct xfs_inode *ip,
+ struct xfs_ifork *ifp,
+ xfs_fileoff_t *end,
+ struct xfs_iext_cursor *cur,
+ struct xfs_bmbt_irec *gotp)
+{
+ /* could be optimized to not even look up the next on a match.. */
+ if (xfs_iext_lookup_extent(ip, ifp, *end - 1, cur, gotp) &&
+ gotp->br_startoff <= *end - 1)
+ return true;
+ if (!xfs_iext_prev_extent(ifp, cur, gotp))
+ return false;
+ *end = gotp->br_startoff + gotp->br_blockcount;
+ return true;
+}
+
+void
+xfs_iext_update_extent(
+ struct xfs_inode *ip,
+ int state,
+ struct xfs_iext_cursor *cur,
+ struct xfs_bmbt_irec *new)
+{
+ struct xfs_ifork *ifp = xfs_iext_state_to_fork(ip, state);
+
+ xfs_iext_inc_seq(ifp);
+
+ if (cur->pos == 0) {
+ struct xfs_bmbt_irec old;
+
+ xfs_iext_get(&old, cur_rec(cur));
+ if (new->br_startoff != old.br_startoff) {
+ xfs_iext_update_node(ifp, old.br_startoff,
+ new->br_startoff, 1, cur->leaf);
+ }
+ }
+
+ trace_xfs_bmap_pre_update(ip, cur, state, _RET_IP_);
+ xfs_iext_set(cur_rec(cur), new);
+ trace_xfs_bmap_post_update(ip, cur, state, _RET_IP_);
+}
+
+/*
+ * Return true if the cursor points at an extent and return the extent structure
+ * in gotp. Else return false.
+ */
+bool
+xfs_iext_get_extent(
+ struct xfs_ifork *ifp,
+ struct xfs_iext_cursor *cur,
+ struct xfs_bmbt_irec *gotp)
+{
+ if (!xfs_iext_valid(ifp, cur))
+ return false;
+ xfs_iext_get(gotp, cur_rec(cur));
+ return true;
+}
+
+/*
+ * This is a recursive function, because of that we need to be extremely
+ * careful with stack usage.
+ */
+static void
+xfs_iext_destroy_node(
+ struct xfs_iext_node *node,
+ int level)
+{
+ int i;
+
+ if (level > 1) {
+ for (i = 0; i < KEYS_PER_NODE; i++) {
+ if (node->keys[i] == XFS_IEXT_KEY_INVALID)
+ break;
+ xfs_iext_destroy_node(node->ptrs[i], level - 1);
+ }
+ }
+
+ kmem_free(node);
+}
+
+void
+xfs_iext_destroy(
+ struct xfs_ifork *ifp)
+{
+ xfs_iext_destroy_node(ifp->if_u1.if_root, ifp->if_height);
+
+ ifp->if_bytes = 0;
+ ifp->if_height = 0;
+ ifp->if_u1.if_root = NULL;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-30 23:19:57 +0000