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xfs_da_btree.c
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/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* 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 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_mount.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_alloc.h"
#include "xfs_bmap.h"
#include "xfs_attr.h"
#include "xfs_attr_leaf.h"
#include "xfs_dir2_data.h"
#include "xfs_dir2_leaf.h"
#include "xfs_dir2_block.h"
#include "xfs_dir2_node.h"
#include "xfs_error.h"
#include "xfs_trace.h"
/*
* xfs_da_btree.c
*
* Routines to implement directories as Btrees of hashed names.
*/
/*========================================================================
* Function prototypes for the kernel.
*========================================================================*/
/*
* Routines used for growing the Btree.
*/
STATIC int xfs_da_root_split(xfs_da_state_t *state,
xfs_da_state_blk_t *existing_root,
xfs_da_state_blk_t *new_child);
STATIC int xfs_da_node_split(xfs_da_state_t *state,
xfs_da_state_blk_t *existing_blk,
xfs_da_state_blk_t *split_blk,
xfs_da_state_blk_t *blk_to_add,
int treelevel,
int *result);
STATIC void xfs_da_node_rebalance(xfs_da_state_t *state,
xfs_da_state_blk_t *node_blk_1,
xfs_da_state_blk_t *node_blk_2);
STATIC void xfs_da_node_add(xfs_da_state_t *state,
xfs_da_state_blk_t *old_node_blk,
xfs_da_state_blk_t *new_node_blk);
/*
* Routines used for shrinking the Btree.
*/
STATIC int xfs_da_root_join(xfs_da_state_t *state,
xfs_da_state_blk_t *root_blk);
STATIC int xfs_da_node_toosmall(xfs_da_state_t *state, int *retval);
STATIC void xfs_da_node_remove(xfs_da_state_t *state,
xfs_da_state_blk_t *drop_blk);
STATIC void xfs_da_node_unbalance(xfs_da_state_t *state,
xfs_da_state_blk_t *src_node_blk,
xfs_da_state_blk_t *dst_node_blk);
/*
* Utility routines.
*/
STATIC uint xfs_da_node_lasthash(xfs_dabuf_t *bp, int *count);
STATIC int xfs_da_node_order(xfs_dabuf_t *node1_bp, xfs_dabuf_t *node2_bp);
STATIC xfs_dabuf_t *xfs_da_buf_make(int nbuf, xfs_buf_t **bps, inst_t *ra);
STATIC int xfs_da_blk_unlink(xfs_da_state_t *state,
xfs_da_state_blk_t *drop_blk,
xfs_da_state_blk_t *save_blk);
STATIC void xfs_da_state_kill_altpath(xfs_da_state_t *state);
/*========================================================================
* Routines used for growing the Btree.
*========================================================================*/
/*
* Create the initial contents of an intermediate node.
*/
int
xfs_da_node_create(xfs_da_args_t *args, xfs_dablk_t blkno, int level,
xfs_dabuf_t **bpp, int whichfork)
{
xfs_da_intnode_t *node;
xfs_dabuf_t *bp;
int error;
xfs_trans_t *tp;
tp = args->trans;
error = xfs_da_get_buf(tp, args->dp, blkno, -1, &bp, whichfork);
if (error)
return(error);
ASSERT(bp != NULL);
node = bp->data;
node->hdr.info.forw = 0;
node->hdr.info.back = 0;
node->hdr.info.magic = cpu_to_be16(XFS_DA_NODE_MAGIC);
node->hdr.info.pad = 0;
node->hdr.count = 0;
node->hdr.level = cpu_to_be16(level);
xfs_da_log_buf(tp, bp,
XFS_DA_LOGRANGE(node, &node->hdr, sizeof(node->hdr)));
*bpp = bp;
return(0);
}
/*
* Split a leaf node, rebalance, then possibly split
* intermediate nodes, rebalance, etc.
*/
int /* error */
xfs_da_split(xfs_da_state_t *state)
{
xfs_da_state_blk_t *oldblk, *newblk, *addblk;
xfs_da_intnode_t *node;
xfs_dabuf_t *bp;
int max, action, error, i;
/*
* Walk back up the tree splitting/inserting/adjusting as necessary.
* If we need to insert and there isn't room, split the node, then
* decide which fragment to insert the new block from below into.
* Note that we may split the root this way, but we need more fixup.
*/
max = state->path.active - 1;
ASSERT((max >= 0) && (max < XFS_DA_NODE_MAXDEPTH));
ASSERT(state->path.blk[max].magic == XFS_ATTR_LEAF_MAGIC ||
state->path.blk[max].magic == XFS_DIR2_LEAFN_MAGIC);
addblk = &state->path.blk[max]; /* initial dummy value */
for (i = max; (i >= 0) && addblk; state->path.active--, i--) {
oldblk = &state->path.blk[i];
newblk = &state->altpath.blk[i];
/*
* If a leaf node then
* Allocate a new leaf node, then rebalance across them.
* else if an intermediate node then
* We split on the last layer, must we split the node?
*/
switch (oldblk->magic) {
case XFS_ATTR_LEAF_MAGIC:
error = xfs_attr_leaf_split(state, oldblk, newblk);
if ((error != 0) && (error != ENOSPC)) {
return(error); /* GROT: attr is inconsistent */
}
if (!error) {
addblk = newblk;
break;
}
/*
* Entry wouldn't fit, split the leaf again.
*/
state->extravalid = 1;
if (state->inleaf) {
state->extraafter = 0; /* before newblk */
error = xfs_attr_leaf_split(state, oldblk,
&state->extrablk);
} else {
state->extraafter = 1; /* after newblk */
error = xfs_attr_leaf_split(state, newblk,
&state->extrablk);
}
if (error)
return(error); /* GROT: attr inconsistent */
addblk = newblk;
break;
case XFS_DIR2_LEAFN_MAGIC:
error = xfs_dir2_leafn_split(state, oldblk, newblk);
if (error)
return error;
addblk = newblk;
break;
case XFS_DA_NODE_MAGIC:
error = xfs_da_node_split(state, oldblk, newblk, addblk,
max - i, &action);
xfs_da_buf_done(addblk->bp);
addblk->bp = NULL;
if (error)
return(error); /* GROT: dir is inconsistent */
/*
* Record the newly split block for the next time thru?
*/
if (action)
addblk = newblk;
else
addblk = NULL;
break;
}
/*
* Update the btree to show the new hashval for this child.
*/
xfs_da_fixhashpath(state, &state->path);
/*
* If we won't need this block again, it's getting dropped
* from the active path by the loop control, so we need
* to mark it done now.
*/
if (i > 0 || !addblk)
xfs_da_buf_done(oldblk->bp);
}
if (!addblk)
return(0);
/*
* Split the root node.
*/
ASSERT(state->path.active == 0);
oldblk = &state->path.blk[0];
error = xfs_da_root_split(state, oldblk, addblk);
if (error) {
xfs_da_buf_done(oldblk->bp);
xfs_da_buf_done(addblk->bp);
addblk->bp = NULL;
return(error); /* GROT: dir is inconsistent */
}
/*
* Update pointers to the node which used to be block 0 and
* just got bumped because of the addition of a new root node.
* There might be three blocks involved if a double split occurred,
* and the original block 0 could be at any position in the list.
*/
node = oldblk->bp->data;
if (node->hdr.info.forw) {
if (be32_to_cpu(node->hdr.info.forw) == addblk->blkno) {
bp = addblk->bp;
} else {
ASSERT(state->extravalid);
bp = state->extrablk.bp;
}
node = bp->data;
node->hdr.info.back = cpu_to_be32(oldblk->blkno);
xfs_da_log_buf(state->args->trans, bp,
XFS_DA_LOGRANGE(node, &node->hdr.info,
sizeof(node->hdr.info)));
}
node = oldblk->bp->data;
if (node->hdr.info.back) {
if (be32_to_cpu(node->hdr.info.back) == addblk->blkno) {
bp = addblk->bp;
} else {
ASSERT(state->extravalid);
bp = state->extrablk.bp;
}
node = bp->data;
node->hdr.info.forw = cpu_to_be32(oldblk->blkno);
xfs_da_log_buf(state->args->trans, bp,
XFS_DA_LOGRANGE(node, &node->hdr.info,
sizeof(node->hdr.info)));
}
xfs_da_buf_done(oldblk->bp);
xfs_da_buf_done(addblk->bp);
addblk->bp = NULL;
return(0);
}
/*
* Split the root. We have to create a new root and point to the two
* parts (the split old root) that we just created. Copy block zero to
* the EOF, extending the inode in process.
*/
STATIC int /* error */
xfs_da_root_split(xfs_da_state_t *state, xfs_da_state_blk_t *blk1,
xfs_da_state_blk_t *blk2)
{
xfs_da_intnode_t *node, *oldroot;
xfs_da_args_t *args;
xfs_dablk_t blkno;
xfs_dabuf_t *bp;
int error, size;
xfs_inode_t *dp;
xfs_trans_t *tp;
xfs_mount_t *mp;
xfs_dir2_leaf_t *leaf;
/*
* Copy the existing (incorrect) block from the root node position
* to a free space somewhere.
*/
args = state->args;
ASSERT(args != NULL);
error = xfs_da_grow_inode(args, &blkno);
if (error)
return(error);
dp = args->dp;
tp = args->trans;
mp = state->mp;
error = xfs_da_get_buf(tp, dp, blkno, -1, &bp, args->whichfork);
if (error)
return(error);
ASSERT(bp != NULL);
node = bp->data;
oldroot = blk1->bp->data;
if (be16_to_cpu(oldroot->hdr.info.magic) == XFS_DA_NODE_MAGIC) {
size = (int)((char *)&oldroot->btree[be16_to_cpu(oldroot->hdr.count)] -
(char *)oldroot);
} else {
ASSERT(be16_to_cpu(oldroot->hdr.info.magic) == XFS_DIR2_LEAFN_MAGIC);
leaf = (xfs_dir2_leaf_t *)oldroot;
size = (int)((char *)&leaf->ents[be16_to_cpu(leaf->hdr.count)] -
(char *)leaf);
}
memcpy(node, oldroot, size);
xfs_da_log_buf(tp, bp, 0, size - 1);
xfs_da_buf_done(blk1->bp);
blk1->bp = bp;
blk1->blkno = blkno;
/*
* Set up the new root node.
*/
error = xfs_da_node_create(args,
(args->whichfork == XFS_DATA_FORK) ? mp->m_dirleafblk : 0,
be16_to_cpu(node->hdr.level) + 1, &bp, args->whichfork);
if (error)
return(error);
node = bp->data;
node->btree[0].hashval = cpu_to_be32(blk1->hashval);
node->btree[0].before = cpu_to_be32(blk1->blkno);
node->btree[1].hashval = cpu_to_be32(blk2->hashval);
node->btree[1].before = cpu_to_be32(blk2->blkno);
node->hdr.count = cpu_to_be16(2);
#ifdef DEBUG
if (be16_to_cpu(oldroot->hdr.info.magic) == XFS_DIR2_LEAFN_MAGIC) {
ASSERT(blk1->blkno >= mp->m_dirleafblk &&
blk1->blkno < mp->m_dirfreeblk);
ASSERT(blk2->blkno >= mp->m_dirleafblk &&
blk2->blkno < mp->m_dirfreeblk);
}
#endif
/* Header is already logged by xfs_da_node_create */
xfs_da_log_buf(tp, bp,
XFS_DA_LOGRANGE(node, node->btree,
sizeof(xfs_da_node_entry_t) * 2));
xfs_da_buf_done(bp);
return(0);
}
/*
* Split the node, rebalance, then add the new entry.
*/
STATIC int /* error */
xfs_da_node_split(xfs_da_state_t *state, xfs_da_state_blk_t *oldblk,
xfs_da_state_blk_t *newblk,
xfs_da_state_blk_t *addblk,
int treelevel, int *result)
{
xfs_da_intnode_t *node;
xfs_dablk_t blkno;
int newcount, error;
int useextra;
node = oldblk->bp->data;
ASSERT(be16_to_cpu(node->hdr.info.magic) == XFS_DA_NODE_MAGIC);
/*
* With V2 dirs the extra block is data or freespace.
*/
useextra = state->extravalid && state->args->whichfork == XFS_ATTR_FORK;
newcount = 1 + useextra;
/*
* Do we have to split the node?
*/
if ((be16_to_cpu(node->hdr.count) + newcount) > state->node_ents) {
/*
* Allocate a new node, add to the doubly linked chain of
* nodes, then move some of our excess entries into it.
*/
error = xfs_da_grow_inode(state->args, &blkno);
if (error)
return(error); /* GROT: dir is inconsistent */
error = xfs_da_node_create(state->args, blkno, treelevel,
&newblk->bp, state->args->whichfork);
if (error)
return(error); /* GROT: dir is inconsistent */
newblk->blkno = blkno;
newblk->magic = XFS_DA_NODE_MAGIC;
xfs_da_node_rebalance(state, oldblk, newblk);
error = xfs_da_blk_link(state, oldblk, newblk);
if (error)
return(error);
*result = 1;
} else {
*result = 0;
}
/*
* Insert the new entry(s) into the correct block
* (updating last hashval in the process).
*
* xfs_da_node_add() inserts BEFORE the given index,
* and as a result of using node_lookup_int() we always
* point to a valid entry (not after one), but a split
* operation always results in a new block whose hashvals
* FOLLOW the current block.
*
* If we had double-split op below us, then add the extra block too.
*/
node = oldblk->bp->data;
if (oldblk->index <= be16_to_cpu(node->hdr.count)) {
oldblk->index++;
xfs_da_node_add(state, oldblk, addblk);
if (useextra) {
if (state->extraafter)
oldblk->index++;
xfs_da_node_add(state, oldblk, &state->extrablk);
state->extravalid = 0;
}
} else {
newblk->index++;
xfs_da_node_add(state, newblk, addblk);
if (useextra) {
if (state->extraafter)
newblk->index++;
xfs_da_node_add(state, newblk, &state->extrablk);
state->extravalid = 0;
}
}
return(0);
}
/*
* Balance the btree elements between two intermediate nodes,
* usually one full and one empty.
*
* NOTE: if blk2 is empty, then it will get the upper half of blk1.
*/
STATIC void
xfs_da_node_rebalance(xfs_da_state_t *state, xfs_da_state_blk_t *blk1,
xfs_da_state_blk_t *blk2)
{
xfs_da_intnode_t *node1, *node2, *tmpnode;
xfs_da_node_entry_t *btree_s, *btree_d;
int count, tmp;
xfs_trans_t *tp;
node1 = blk1->bp->data;
node2 = blk2->bp->data;
/*
* Figure out how many entries need to move, and in which direction.
* Swap the nodes around if that makes it simpler.
*/
if ((be16_to_cpu(node1->hdr.count) > 0) && (be16_to_cpu(node2->hdr.count) > 0) &&
((be32_to_cpu(node2->btree[0].hashval) < be32_to_cpu(node1->btree[0].hashval)) ||
(be32_to_cpu(node2->btree[be16_to_cpu(node2->hdr.count)-1].hashval) <
be32_to_cpu(node1->btree[be16_to_cpu(node1->hdr.count)-1].hashval)))) {
tmpnode = node1;
node1 = node2;
node2 = tmpnode;
}
ASSERT(be16_to_cpu(node1->hdr.info.magic) == XFS_DA_NODE_MAGIC);
ASSERT(be16_to_cpu(node2->hdr.info.magic) == XFS_DA_NODE_MAGIC);
count = (be16_to_cpu(node1->hdr.count) - be16_to_cpu(node2->hdr.count)) / 2;
if (count == 0)
return;
tp = state->args->trans;
/*
* Two cases: high-to-low and low-to-high.
*/
if (count > 0) {
/*
* Move elements in node2 up to make a hole.
*/
if ((tmp = be16_to_cpu(node2->hdr.count)) > 0) {
tmp *= (uint)sizeof(xfs_da_node_entry_t);
btree_s = &node2->btree[0];
btree_d = &node2->btree[count];
memmove(btree_d, btree_s, tmp);
}
/*
* Move the req'd B-tree elements from high in node1 to
* low in node2.
*/
be16_add_cpu(&node2->hdr.count, count);
tmp = count * (uint)sizeof(xfs_da_node_entry_t);
btree_s = &node1->btree[be16_to_cpu(node1->hdr.count) - count];
btree_d = &node2->btree[0];
memcpy(btree_d, btree_s, tmp);
be16_add_cpu(&node1->hdr.count, -count);
} else {
/*
* Move the req'd B-tree elements from low in node2 to
* high in node1.
*/
count = -count;
tmp = count * (uint)sizeof(xfs_da_node_entry_t);
btree_s = &node2->btree[0];
btree_d = &node1->btree[be16_to_cpu(node1->hdr.count)];
memcpy(btree_d, btree_s, tmp);
be16_add_cpu(&node1->hdr.count, count);
xfs_da_log_buf(tp, blk1->bp,
XFS_DA_LOGRANGE(node1, btree_d, tmp));
/*
* Move elements in node2 down to fill the hole.
*/
tmp = be16_to_cpu(node2->hdr.count) - count;
tmp *= (uint)sizeof(xfs_da_node_entry_t);
btree_s = &node2->btree[count];
btree_d = &node2->btree[0];
memmove(btree_d, btree_s, tmp);
be16_add_cpu(&node2->hdr.count, -count);
}
/*
* Log header of node 1 and all current bits of node 2.
*/
xfs_da_log_buf(tp, blk1->bp,
XFS_DA_LOGRANGE(node1, &node1->hdr, sizeof(node1->hdr)));
xfs_da_log_buf(tp, blk2->bp,
XFS_DA_LOGRANGE(node2, &node2->hdr,
sizeof(node2->hdr) +
sizeof(node2->btree[0]) * be16_to_cpu(node2->hdr.count)));
/*
* Record the last hashval from each block for upward propagation.
* (note: don't use the swapped node pointers)
*/
node1 = blk1->bp->data;
node2 = blk2->bp->data;
blk1->hashval = be32_to_cpu(node1->btree[be16_to_cpu(node1->hdr.count)-1].hashval);
blk2->hashval = be32_to_cpu(node2->btree[be16_to_cpu(node2->hdr.count)-1].hashval);
/*
* Adjust the expected index for insertion.
*/
if (blk1->index >= be16_to_cpu(node1->hdr.count)) {
blk2->index = blk1->index - be16_to_cpu(node1->hdr.count);
blk1->index = be16_to_cpu(node1->hdr.count) + 1; /* make it invalid */
}
}
/*
* Add a new entry to an intermediate node.
*/
STATIC void
xfs_da_node_add(xfs_da_state_t *state, xfs_da_state_blk_t *oldblk,
xfs_da_state_blk_t *newblk)
{
xfs_da_intnode_t *node;
xfs_da_node_entry_t *btree;
int tmp;
node = oldblk->bp->data;
ASSERT(be16_to_cpu(node->hdr.info.magic) == XFS_DA_NODE_MAGIC);
ASSERT((oldblk->index >= 0) && (oldblk->index <= be16_to_cpu(node->hdr.count)));
ASSERT(newblk->blkno != 0);
if (state->args->whichfork == XFS_DATA_FORK)
ASSERT(newblk->blkno >= state->mp->m_dirleafblk &&
newblk->blkno < state->mp->m_dirfreeblk);
/*
* We may need to make some room before we insert the new node.
*/
tmp = 0;
btree = &node->btree[ oldblk->index ];
if (oldblk->index < be16_to_cpu(node->hdr.count)) {
tmp = (be16_to_cpu(node->hdr.count) - oldblk->index) * (uint)sizeof(*btree);
memmove(btree + 1, btree, tmp);
}
btree->hashval = cpu_to_be32(newblk->hashval);
btree->before = cpu_to_be32(newblk->blkno);
xfs_da_log_buf(state->args->trans, oldblk->bp,
XFS_DA_LOGRANGE(node, btree, tmp + sizeof(*btree)));
be16_add_cpu(&node->hdr.count, 1);
xfs_da_log_buf(state->args->trans, oldblk->bp,
XFS_DA_LOGRANGE(node, &node->hdr, sizeof(node->hdr)));
/*
* Copy the last hash value from the oldblk to propagate upwards.
*/
oldblk->hashval = be32_to_cpu(node->btree[be16_to_cpu(node->hdr.count)-1 ].hashval);
}
/*========================================================================
* Routines used for shrinking the Btree.
*========================================================================*/
/*
* Deallocate an empty leaf node, remove it from its parent,
* possibly deallocating that block, etc...
*/
int
xfs_da_join(xfs_da_state_t *state)
{
xfs_da_state_blk_t *drop_blk, *save_blk;
int action, error;
action = 0;
drop_blk = &state->path.blk[ state->path.active-1 ];
save_blk = &state->altpath.blk[ state->path.active-1 ];
ASSERT(state->path.blk[0].magic == XFS_DA_NODE_MAGIC);
ASSERT(drop_blk->magic == XFS_ATTR_LEAF_MAGIC ||
drop_blk->magic == XFS_DIR2_LEAFN_MAGIC);
/*
* Walk back up the tree joining/deallocating as necessary.
* When we stop dropping blocks, break out.
*/
for ( ; state->path.active >= 2; drop_blk--, save_blk--,
state->path.active--) {
/*
* See if we can combine the block with a neighbor.
* (action == 0) => no options, just leave
* (action == 1) => coalesce, then unlink
* (action == 2) => block empty, unlink it
*/
switch (drop_blk->magic) {
case XFS_ATTR_LEAF_MAGIC:
error = xfs_attr_leaf_toosmall(state, &action);
if (error)
return(error);
if (action == 0)
return(0);
xfs_attr_leaf_unbalance(state, drop_blk, save_blk);
break;
case XFS_DIR2_LEAFN_MAGIC:
error = xfs_dir2_leafn_toosmall(state, &action);
if (error)
return error;
if (action == 0)
return 0;
xfs_dir2_leafn_unbalance(state, drop_blk, save_blk);
break;
case XFS_DA_NODE_MAGIC:
/*
* Remove the offending node, fixup hashvals,
* check for a toosmall neighbor.
*/
xfs_da_node_remove(state, drop_blk);
xfs_da_fixhashpath(state, &state->path);
error = xfs_da_node_toosmall(state, &action);
if (error)
return(error);
if (action == 0)
return 0;
xfs_da_node_unbalance(state, drop_blk, save_blk);
break;
}
xfs_da_fixhashpath(state, &state->altpath);
error = xfs_da_blk_unlink(state, drop_blk, save_blk);
xfs_da_state_kill_altpath(state);
if (error)
return(error);
error = xfs_da_shrink_inode(state->args, drop_blk->blkno,
drop_blk->bp);
drop_blk->bp = NULL;
if (error)
return(error);
}
/*
* We joined all the way to the top. If it turns out that
* we only have one entry in the root, make the child block
* the new root.
*/
xfs_da_node_remove(state, drop_blk);
xfs_da_fixhashpath(state, &state->path);
error = xfs_da_root_join(state, &state->path.blk[0]);
return(error);
}
/*
* We have only one entry in the root. Copy the only remaining child of
* the old root to block 0 as the new root node.
*/
STATIC int
xfs_da_root_join(xfs_da_state_t *state, xfs_da_state_blk_t *root_blk)
{
xfs_da_intnode_t *oldroot;
/* REFERENCED */
xfs_da_blkinfo_t *blkinfo;
xfs_da_args_t *args;
xfs_dablk_t child;
xfs_dabuf_t *bp;
int error;
args = state->args;
ASSERT(args != NULL);
ASSERT(root_blk->magic == XFS_DA_NODE_MAGIC);
oldroot = root_blk->bp->data;
ASSERT(be16_to_cpu(oldroot->hdr.info.magic) == XFS_DA_NODE_MAGIC);
ASSERT(!oldroot->hdr.info.forw);
ASSERT(!oldroot->hdr.info.back);
/*
* If the root has more than one child, then don't do anything.
*/
if (be16_to_cpu(oldroot->hdr.count) > 1)
return(0);
/*
* Read in the (only) child block, then copy those bytes into
* the root block's buffer and free the original child block.
*/
child = be32_to_cpu(oldroot->btree[0].before);
ASSERT(child != 0);
error = xfs_da_read_buf(args->trans, args->dp, child, -1, &bp,
args->whichfork);
if (error)
return(error);
ASSERT(bp != NULL);
blkinfo = bp->data;
if (be16_to_cpu(oldroot->hdr.level) == 1) {
ASSERT(be16_to_cpu(blkinfo->magic) == XFS_DIR2_LEAFN_MAGIC ||
be16_to_cpu(blkinfo->magic) == XFS_ATTR_LEAF_MAGIC);
} else {
ASSERT(be16_to_cpu(blkinfo->magic) == XFS_DA_NODE_MAGIC);
}
ASSERT(!blkinfo->forw);
ASSERT(!blkinfo->back);
memcpy(root_blk->bp->data, bp->data, state->blocksize);
xfs_da_log_buf(args->trans, root_blk->bp, 0, state->blocksize - 1);
error = xfs_da_shrink_inode(args, child, bp);
return(error);
}
/*
* Check a node block and its neighbors to see if the block should be
* collapsed into one or the other neighbor. Always keep the block
* with the smaller block number.
* If the current block is over 50% full, don't try to join it, return 0.
* If the block is empty, fill in the state structure and return 2.
* If it can be collapsed, fill in the state structure and return 1.
* If nothing can be done, return 0.
*/
STATIC int
xfs_da_node_toosmall(xfs_da_state_t *state, int *action)
{
xfs_da_intnode_t *node;
xfs_da_state_blk_t *blk;
xfs_da_blkinfo_t *info;
int count, forward, error, retval, i;
xfs_dablk_t blkno;
xfs_dabuf_t *bp;
/*
* Check for the degenerate case of the block being over 50% full.
* If so, it's not worth even looking to see if we might be able
* to coalesce with a sibling.
*/
blk = &state->path.blk[ state->path.active-1 ];
info = blk->bp->data;
ASSERT(be16_to_cpu(info->magic) == XFS_DA_NODE_MAGIC);
node = (xfs_da_intnode_t *)info;
count = be16_to_cpu(node->hdr.count);
if (count > (state->node_ents >> 1)) {
*action = 0; /* blk over 50%, don't try to join */
return(0); /* blk over 50%, don't try to join */
}
/*
* Check for the degenerate case of the block being empty.
* If the block is empty, we'll simply delete it, no need to
* coalesce it with a sibling block. We choose (arbitrarily)
* to merge with the forward block unless it is NULL.
*/
if (count == 0) {
/*
* Make altpath point to the block we want to keep and
* path point to the block we want to drop (this one).
*/
forward = (info->forw != 0);
memcpy(&state->altpath, &state->path, sizeof(state->path));
error = xfs_da_path_shift(state, &state->altpath, forward,
0, &retval);
if (error)
return(error);
if (retval) {
*action = 0;
} else {
*action = 2;
}
return(0);
}
/*
* Examine each sibling block to see if we can coalesce with
* at least 25% free space to spare. We need to figure out
* whether to merge with the forward or the backward block.
* We prefer coalescing with the lower numbered sibling so as
* to shrink a directory over time.
*/
/* start with smaller blk num */
forward = (be32_to_cpu(info->forw) < be32_to_cpu(info->back));
for (i = 0; i < 2; forward = !forward, i++) {
if (forward)
blkno = be32_to_cpu(info->forw);
else
blkno = be32_to_cpu(info->back);
if (blkno == 0)
continue;
error = xfs_da_read_buf(state->args->trans, state->args->dp,
blkno, -1, &bp, state->args->whichfork);
if (error)
return(error);
ASSERT(bp != NULL);
node = (xfs_da_intnode_t *)info;
count = state->node_ents;
count -= state->node_ents >> 2;
count -= be16_to_cpu(node->hdr.count);
node = bp->data;
ASSERT(be16_to_cpu(node->hdr.info.magic) == XFS_DA_NODE_MAGIC);
count -= be16_to_cpu(node->hdr.count);
xfs_da_brelse(state->args->trans, bp);
if (count >= 0)
break; /* fits with at least 25% to spare */
}
if (i >= 2) {
*action = 0;
return(0);
}
/*
* Make altpath point to the block we want to keep (the lower
* numbered block) and path point to the block we want to drop.
*/
memcpy(&state->altpath, &state->path, sizeof(state->path));
if (blkno < blk->blkno) {
error = xfs_da_path_shift(state, &state->altpath, forward,
0, &retval);
if (error) {
return(error);
}
if (retval) {
*action = 0;
return(0);
}
} else {
error = xfs_da_path_shift(state, &state->path, forward,
0, &retval);
if (error) {
return(error);
}
if (retval) {
*action = 0;
return(0);
}
}
*action = 1;
return(0);
}
/*
* Walk back up the tree adjusting hash values as necessary,
* when we stop making changes, return.
*/
void
xfs_da_fixhashpath(xfs_da_state_t *state, xfs_da_state_path_t *path)
{
xfs_da_state_blk_t *blk;
xfs_da_intnode_t *node;
xfs_da_node_entry_t *btree;
xfs_dahash_t lasthash=0;
int level, count;
level = path->active-1;
blk = &path->blk[ level ];
switch (blk->magic) {
case XFS_ATTR_LEAF_MAGIC:
lasthash = xfs_attr_leaf_lasthash(blk->bp, &count);
if (count == 0)
return;
break;
case XFS_DIR2_LEAFN_MAGIC:
lasthash = xfs_dir2_leafn_lasthash(blk->bp, &count);
if (count == 0)
return;
break;
case XFS_DA_NODE_MAGIC:
lasthash = xfs_da_node_lasthash(blk->bp, &count);
if (count == 0)
return;
break;
}
for (blk--, level--; level >= 0; blk--, level--) {
node = blk->bp->data;
ASSERT(be16_to_cpu(node->hdr.info.magic) == XFS_DA_NODE_MAGIC);
btree = &node->btree[ blk->index ];
if (be32_to_cpu(btree->hashval) == lasthash)
break;
blk->hashval = lasthash;
btree->hashval = cpu_to_be32(lasthash);
xfs_da_log_buf(state->args->trans, blk->bp,
XFS_DA_LOGRANGE(node, btree, sizeof(*btree)));
lasthash = be32_to_cpu(node->btree[be16_to_cpu(node->hdr.count)-1].hashval);
}
}
/*
* Remove an entry from an intermediate node.
*/
STATIC void
xfs_da_node_remove(xfs_da_state_t *state, xfs_da_state_blk_t *drop_blk)
{
xfs_da_intnode_t *node;
xfs_da_node_entry_t *btree;
int tmp;
node = drop_blk->bp->data;
ASSERT(drop_blk->index < be16_to_cpu(node->hdr.count));
ASSERT(drop_blk->index >= 0);
/*
* Copy over the offending entry, or just zero it out.
*/
btree = &node->btree[drop_blk->index];
if (drop_blk->index < (be16_to_cpu(node->hdr.count)-1)) {
tmp = be16_to_cpu(node->hdr.count) - drop_blk->index - 1;
tmp *= (uint)sizeof(xfs_da_node_entry_t);
memmove(btree, btree + 1, tmp);
xfs_da_log_buf(state->args->trans, drop_blk->bp,
XFS_DA_LOGRANGE(node, btree, tmp));
btree = &node->btree[be16_to_cpu(node->hdr.count)-1];
}
memset((char *)btree, 0, sizeof(xfs_da_node_entry_t));
xfs_da_log_buf(state->args->trans, drop_blk->bp,
XFS_DA_LOGRANGE(node, btree, sizeof(*btree)));
be16_add_cpu(&node->hdr.count, -1);
xfs_da_log_buf(state->args->trans, drop_blk->bp,
XFS_DA_LOGRANGE(node, &node->hdr, sizeof(node->hdr)));
/*
* Copy the last hash value from the block to propagate upwards.
*/
btree--;
drop_blk->hashval = be32_to_cpu(btree->hashval);
}
/*
* Unbalance the btree elements between two intermediate nodes,
* move all Btree elements from one node into another.
*/
STATIC void
xfs_da_node_unbalance(xfs_da_state_t *state, xfs_da_state_blk_t *drop_blk,
xfs_da_state_blk_t *save_blk)
{
xfs_da_intnode_t *drop_node, *save_node;
xfs_da_node_entry_t *btree;
int tmp;
xfs_trans_t *tp;
drop_node = drop_blk->bp->data;
save_node = save_blk->bp->data;
ASSERT(be16_to_cpu(drop_node->hdr.info.magic) == XFS_DA_NODE_MAGIC);
ASSERT(be16_to_cpu(save_node->hdr.info.magic) == XFS_DA_NODE_MAGIC);
tp = state->args->trans;
/*
* If the dying block has lower hashvals, then move all the
* elements in the remaining block up to make a hole.
*/
if ((be32_to_cpu(drop_node->btree[0].hashval) < be32_to_cpu(save_node->btree[ 0 ].hashval)) ||
(be32_to_cpu(drop_node->btree[be16_to_cpu(drop_node->hdr.count)-1].hashval) <
be32_to_cpu(save_node->btree[be16_to_cpu(save_node->hdr.count)-1].hashval)))
{
btree = &save_node->btree[be16_to_cpu(drop_node->hdr.count)];
tmp = be16_to_cpu(save_node->hdr.count) * (uint)sizeof(xfs_da_node_entry_t);
memmove(btree, &save_node->btree[0], tmp);
btree = &save_node->btree[0];
xfs_da_log_buf(tp, save_blk->bp,
XFS_DA_LOGRANGE(save_node, btree,
(be16_to_cpu(save_node->hdr.count) + be16_to_cpu(drop_node->hdr.count)) *