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jfs_xtree.c
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jfs_xtree.c
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/*
* Copyright (C) International Business Machines Corp., 2000-2005
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* jfs_xtree.c: extent allocation descriptor B+-tree manager
*/
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/quotaops.h>
#include <linux/seq_file.h>
#include "jfs_incore.h"
#include "jfs_filsys.h"
#include "jfs_metapage.h"
#include "jfs_dmap.h"
#include "jfs_dinode.h"
#include "jfs_superblock.h"
#include "jfs_debug.h"
/*
* xtree local flag
*/
#define XT_INSERT 0x00000001
/*
* xtree key/entry comparison: extent offset
*
* return:
* -1: k < start of extent
* 0: start_of_extent <= k <= end_of_extent
* 1: k > end_of_extent
*/
#define XT_CMP(CMP, K, X, OFFSET64)\
{\
OFFSET64 = offsetXAD(X);\
(CMP) = ((K) >= OFFSET64 + lengthXAD(X)) ? 1 :\
((K) < OFFSET64) ? -1 : 0;\
}
/* write a xad entry */
#define XT_PUTENTRY(XAD, FLAG, OFF, LEN, ADDR)\
{\
(XAD)->flag = (FLAG);\
XADoffset((XAD), (OFF));\
XADlength((XAD), (LEN));\
XADaddress((XAD), (ADDR));\
}
#define XT_PAGE(IP, MP) BT_PAGE(IP, MP, xtpage_t, i_xtroot)
/* get page buffer for specified block address */
/* ToDo: Replace this ugly macro with a function */
#define XT_GETPAGE(IP, BN, MP, SIZE, P, RC)\
{\
BT_GETPAGE(IP, BN, MP, xtpage_t, SIZE, P, RC, i_xtroot)\
if (!(RC))\
{\
if ((le16_to_cpu((P)->header.nextindex) < XTENTRYSTART) ||\
(le16_to_cpu((P)->header.nextindex) > le16_to_cpu((P)->header.maxentry)) ||\
(le16_to_cpu((P)->header.maxentry) > (((BN)==0)?XTROOTMAXSLOT:PSIZE>>L2XTSLOTSIZE)))\
{\
jfs_error((IP)->i_sb, "XT_GETPAGE: xtree page corrupt");\
BT_PUTPAGE(MP);\
MP = NULL;\
RC = -EIO;\
}\
}\
}
/* for consistency */
#define XT_PUTPAGE(MP) BT_PUTPAGE(MP)
#define XT_GETSEARCH(IP, LEAF, BN, MP, P, INDEX) \
BT_GETSEARCH(IP, LEAF, BN, MP, xtpage_t, P, INDEX, i_xtroot)
/* xtree entry parameter descriptor */
struct xtsplit {
struct metapage *mp;
s16 index;
u8 flag;
s64 off;
s64 addr;
int len;
struct pxdlist *pxdlist;
};
/*
* statistics
*/
#ifdef CONFIG_JFS_STATISTICS
static struct {
uint search;
uint fastSearch;
uint split;
} xtStat;
#endif
/*
* forward references
*/
static int xtSearch(struct inode *ip, s64 xoff, s64 *next, int *cmpp,
struct btstack * btstack, int flag);
static int xtSplitUp(tid_t tid,
struct inode *ip,
struct xtsplit * split, struct btstack * btstack);
static int xtSplitPage(tid_t tid, struct inode *ip, struct xtsplit * split,
struct metapage ** rmpp, s64 * rbnp);
static int xtSplitRoot(tid_t tid, struct inode *ip,
struct xtsplit * split, struct metapage ** rmpp);
#ifdef _STILL_TO_PORT
static int xtDeleteUp(tid_t tid, struct inode *ip, struct metapage * fmp,
xtpage_t * fp, struct btstack * btstack);
static int xtSearchNode(struct inode *ip,
xad_t * xad,
int *cmpp, struct btstack * btstack, int flag);
static int xtRelink(tid_t tid, struct inode *ip, xtpage_t * fp);
#endif /* _STILL_TO_PORT */
/*
* xtLookup()
*
* function: map a single page into a physical extent;
*/
int xtLookup(struct inode *ip, s64 lstart,
s64 llen, int *pflag, s64 * paddr, s32 * plen, int no_check)
{
int rc = 0;
struct btstack btstack;
int cmp;
s64 bn;
struct metapage *mp;
xtpage_t *p;
int index;
xad_t *xad;
s64 next, size, xoff, xend;
int xlen;
s64 xaddr;
*paddr = 0;
*plen = llen;
if (!no_check) {
/* is lookup offset beyond eof ? */
size = ((u64) ip->i_size + (JFS_SBI(ip->i_sb)->bsize - 1)) >>
JFS_SBI(ip->i_sb)->l2bsize;
if (lstart >= size)
return 0;
}
/*
* search for the xad entry covering the logical extent
*/
//search:
if ((rc = xtSearch(ip, lstart, &next, &cmp, &btstack, 0))) {
jfs_err("xtLookup: xtSearch returned %d", rc);
return rc;
}
/*
* compute the physical extent covering logical extent
*
* N.B. search may have failed (e.g., hole in sparse file),
* and returned the index of the next entry.
*/
/* retrieve search result */
XT_GETSEARCH(ip, btstack.top, bn, mp, p, index);
/* is xad found covering start of logical extent ?
* lstart is a page start address,
* i.e., lstart cannot start in a hole;
*/
if (cmp) {
if (next)
*plen = min(next - lstart, llen);
goto out;
}
/*
* lxd covered by xad
*/
xad = &p->xad[index];
xoff = offsetXAD(xad);
xlen = lengthXAD(xad);
xend = xoff + xlen;
xaddr = addressXAD(xad);
/* initialize new pxd */
*pflag = xad->flag;
*paddr = xaddr + (lstart - xoff);
/* a page must be fully covered by an xad */
*plen = min(xend - lstart, llen);
out:
XT_PUTPAGE(mp);
return rc;
}
/*
* xtSearch()
*
* function: search for the xad entry covering specified offset.
*
* parameters:
* ip - file object;
* xoff - extent offset;
* nextp - address of next extent (if any) for search miss
* cmpp - comparison result:
* btstack - traverse stack;
* flag - search process flag (XT_INSERT);
*
* returns:
* btstack contains (bn, index) of search path traversed to the entry.
* *cmpp is set to result of comparison with the entry returned.
* the page containing the entry is pinned at exit.
*/
static int xtSearch(struct inode *ip, s64 xoff, s64 *nextp,
int *cmpp, struct btstack * btstack, int flag)
{
struct jfs_inode_info *jfs_ip = JFS_IP(ip);
int rc = 0;
int cmp = 1; /* init for empty page */
s64 bn; /* block number */
struct metapage *mp; /* page buffer */
xtpage_t *p; /* page */
xad_t *xad;
int base, index, lim, btindex;
struct btframe *btsp;
int nsplit = 0; /* number of pages to split */
s64 t64;
s64 next = 0;
INCREMENT(xtStat.search);
BT_CLR(btstack);
btstack->nsplit = 0;
/*
* search down tree from root:
*
* between two consecutive entries of <Ki, Pi> and <Kj, Pj> of
* internal page, child page Pi contains entry with k, Ki <= K < Kj.
*
* if entry with search key K is not found
* internal page search find the entry with largest key Ki
* less than K which point to the child page to search;
* leaf page search find the entry with smallest key Kj
* greater than K so that the returned index is the position of
* the entry to be shifted right for insertion of new entry.
* for empty tree, search key is greater than any key of the tree.
*
* by convention, root bn = 0.
*/
for (bn = 0;;) {
/* get/pin the page to search */
XT_GETPAGE(ip, bn, mp, PSIZE, p, rc);
if (rc)
return rc;
/* try sequential access heuristics with the previous
* access entry in target leaf page:
* once search narrowed down into the target leaf,
* key must either match an entry in the leaf or
* key entry does not exist in the tree;
*/
//fastSearch:
if ((jfs_ip->btorder & BT_SEQUENTIAL) &&
(p->header.flag & BT_LEAF) &&
(index = jfs_ip->btindex) <
le16_to_cpu(p->header.nextindex)) {
xad = &p->xad[index];
t64 = offsetXAD(xad);
if (xoff < t64 + lengthXAD(xad)) {
if (xoff >= t64) {
*cmpp = 0;
goto out;
}
/* stop sequential access heuristics */
goto binarySearch;
} else { /* (t64 + lengthXAD(xad)) <= xoff */
/* try next sequential entry */
index++;
if (index <
le16_to_cpu(p->header.nextindex)) {
xad++;
t64 = offsetXAD(xad);
if (xoff < t64 + lengthXAD(xad)) {
if (xoff >= t64) {
*cmpp = 0;
goto out;
}
/* miss: key falls between
* previous and this entry
*/
*cmpp = 1;
next = t64;
goto out;
}
/* (xoff >= t64 + lengthXAD(xad));
* matching entry may be further out:
* stop heuristic search
*/
/* stop sequential access heuristics */
goto binarySearch;
}
/* (index == p->header.nextindex);
* miss: key entry does not exist in
* the target leaf/tree
*/
*cmpp = 1;
goto out;
}
/*
* if hit, return index of the entry found, and
* if miss, where new entry with search key is
* to be inserted;
*/
out:
/* compute number of pages to split */
if (flag & XT_INSERT) {
if (p->header.nextindex == /* little-endian */
p->header.maxentry)
nsplit++;
else
nsplit = 0;
btstack->nsplit = nsplit;
}
/* save search result */
btsp = btstack->top;
btsp->bn = bn;
btsp->index = index;
btsp->mp = mp;
/* update sequential access heuristics */
jfs_ip->btindex = index;
if (nextp)
*nextp = next;
INCREMENT(xtStat.fastSearch);
return 0;
}
/* well, ... full search now */
binarySearch:
lim = le16_to_cpu(p->header.nextindex) - XTENTRYSTART;
/*
* binary search with search key K on the current page
*/
for (base = XTENTRYSTART; lim; lim >>= 1) {
index = base + (lim >> 1);
XT_CMP(cmp, xoff, &p->xad[index], t64);
if (cmp == 0) {
/*
* search hit
*/
/* search hit - leaf page:
* return the entry found
*/
if (p->header.flag & BT_LEAF) {
*cmpp = cmp;
/* compute number of pages to split */
if (flag & XT_INSERT) {
if (p->header.nextindex ==
p->header.maxentry)
nsplit++;
else
nsplit = 0;
btstack->nsplit = nsplit;
}
/* save search result */
btsp = btstack->top;
btsp->bn = bn;
btsp->index = index;
btsp->mp = mp;
/* init sequential access heuristics */
btindex = jfs_ip->btindex;
if (index == btindex ||
index == btindex + 1)
jfs_ip->btorder = BT_SEQUENTIAL;
else
jfs_ip->btorder = BT_RANDOM;
jfs_ip->btindex = index;
return 0;
}
/* search hit - internal page:
* descend/search its child page
*/
if (index < le16_to_cpu(p->header.nextindex)-1)
next = offsetXAD(&p->xad[index + 1]);
goto next;
}
if (cmp > 0) {
base = index + 1;
--lim;
}
}
/*
* search miss
*
* base is the smallest index with key (Kj) greater than
* search key (K) and may be zero or maxentry index.
*/
if (base < le16_to_cpu(p->header.nextindex))
next = offsetXAD(&p->xad[base]);
/*
* search miss - leaf page:
*
* return location of entry (base) where new entry with
* search key K is to be inserted.
*/
if (p->header.flag & BT_LEAF) {
*cmpp = cmp;
/* compute number of pages to split */
if (flag & XT_INSERT) {
if (p->header.nextindex ==
p->header.maxentry)
nsplit++;
else
nsplit = 0;
btstack->nsplit = nsplit;
}
/* save search result */
btsp = btstack->top;
btsp->bn = bn;
btsp->index = base;
btsp->mp = mp;
/* init sequential access heuristics */
btindex = jfs_ip->btindex;
if (base == btindex || base == btindex + 1)
jfs_ip->btorder = BT_SEQUENTIAL;
else
jfs_ip->btorder = BT_RANDOM;
jfs_ip->btindex = base;
if (nextp)
*nextp = next;
return 0;
}
/*
* search miss - non-leaf page:
*
* if base is non-zero, decrement base by one to get the parent
* entry of the child page to search.
*/
index = base ? base - 1 : base;
/*
* go down to child page
*/
next:
/* update number of pages to split */
if (p->header.nextindex == p->header.maxentry)
nsplit++;
else
nsplit = 0;
/* push (bn, index) of the parent page/entry */
if (BT_STACK_FULL(btstack)) {
jfs_error(ip->i_sb, "stack overrun in xtSearch!");
XT_PUTPAGE(mp);
return -EIO;
}
BT_PUSH(btstack, bn, index);
/* get the child page block number */
bn = addressXAD(&p->xad[index]);
/* unpin the parent page */
XT_PUTPAGE(mp);
}
}
/*
* xtInsert()
*
* function:
*
* parameter:
* tid - transaction id;
* ip - file object;
* xflag - extent flag (XAD_NOTRECORDED):
* xoff - extent offset;
* xlen - extent length;
* xaddrp - extent address pointer (in/out):
* if (*xaddrp)
* caller allocated data extent at *xaddrp;
* else
* allocate data extent and return its xaddr;
* flag -
*
* return:
*/
int xtInsert(tid_t tid, /* transaction id */
struct inode *ip, int xflag, s64 xoff, s32 xlen, s64 * xaddrp,
int flag)
{
int rc = 0;
s64 xaddr, hint;
struct metapage *mp; /* meta-page buffer */
xtpage_t *p; /* base B+-tree index page */
s64 bn;
int index, nextindex;
struct btstack btstack; /* traverse stack */
struct xtsplit split; /* split information */
xad_t *xad;
int cmp;
s64 next;
struct tlock *tlck;
struct xtlock *xtlck;
jfs_info("xtInsert: nxoff:0x%lx nxlen:0x%x", (ulong) xoff, xlen);
/*
* search for the entry location at which to insert:
*
* xtFastSearch() and xtSearch() both returns (leaf page
* pinned, index at which to insert).
* n.b. xtSearch() may return index of maxentry of
* the full page.
*/
if ((rc = xtSearch(ip, xoff, &next, &cmp, &btstack, XT_INSERT)))
return rc;
/* retrieve search result */
XT_GETSEARCH(ip, btstack.top, bn, mp, p, index);
/* This test must follow XT_GETSEARCH since mp must be valid if
* we branch to out: */
if ((cmp == 0) || (next && (xlen > next - xoff))) {
rc = -EEXIST;
goto out;
}
/*
* allocate data extent requested
*
* allocation hint: last xad
*/
if ((xaddr = *xaddrp) == 0) {
if (index > XTENTRYSTART) {
xad = &p->xad[index - 1];
hint = addressXAD(xad) + lengthXAD(xad) - 1;
} else
hint = 0;
if ((rc = dquot_alloc_block(ip, xlen)))
goto out;
if ((rc = dbAlloc(ip, hint, (s64) xlen, &xaddr))) {
dquot_free_block(ip, xlen);
goto out;
}
}
/*
* insert entry for new extent
*/
xflag |= XAD_NEW;
/*
* if the leaf page is full, split the page and
* propagate up the router entry for the new page from split
*
* The xtSplitUp() will insert the entry and unpin the leaf page.
*/
nextindex = le16_to_cpu(p->header.nextindex);
if (nextindex == le16_to_cpu(p->header.maxentry)) {
split.mp = mp;
split.index = index;
split.flag = xflag;
split.off = xoff;
split.len = xlen;
split.addr = xaddr;
split.pxdlist = NULL;
if ((rc = xtSplitUp(tid, ip, &split, &btstack))) {
/* undo data extent allocation */
if (*xaddrp == 0) {
dbFree(ip, xaddr, (s64) xlen);
dquot_free_block(ip, xlen);
}
return rc;
}
*xaddrp = xaddr;
return 0;
}
/*
* insert the new entry into the leaf page
*/
/*
* acquire a transaction lock on the leaf page;
*
* action: xad insertion/extension;
*/
BT_MARK_DIRTY(mp, ip);
/* if insert into middle, shift right remaining entries. */
if (index < nextindex)
memmove(&p->xad[index + 1], &p->xad[index],
(nextindex - index) * sizeof(xad_t));
/* insert the new entry: mark the entry NEW */
xad = &p->xad[index];
XT_PUTENTRY(xad, xflag, xoff, xlen, xaddr);
/* advance next available entry index */
le16_add_cpu(&p->header.nextindex, 1);
/* Don't log it if there are no links to the file */
if (!test_cflag(COMMIT_Nolink, ip)) {
tlck = txLock(tid, ip, mp, tlckXTREE | tlckGROW);
xtlck = (struct xtlock *) & tlck->lock;
xtlck->lwm.offset =
(xtlck->lwm.offset) ? min(index,
(int)xtlck->lwm.offset) : index;
xtlck->lwm.length =
le16_to_cpu(p->header.nextindex) - xtlck->lwm.offset;
}
*xaddrp = xaddr;
out:
/* unpin the leaf page */
XT_PUTPAGE(mp);
return rc;
}
/*
* xtSplitUp()
*
* function:
* split full pages as propagating insertion up the tree
*
* parameter:
* tid - transaction id;
* ip - file object;
* split - entry parameter descriptor;
* btstack - traverse stack from xtSearch()
*
* return:
*/
static int
xtSplitUp(tid_t tid,
struct inode *ip, struct xtsplit * split, struct btstack * btstack)
{
int rc = 0;
struct metapage *smp;
xtpage_t *sp; /* split page */
struct metapage *rmp;
s64 rbn; /* new right page block number */
struct metapage *rcmp;
xtpage_t *rcp; /* right child page */
s64 rcbn; /* right child page block number */
int skip; /* index of entry of insertion */
int nextindex; /* next available entry index of p */
struct btframe *parent; /* parent page entry on traverse stack */
xad_t *xad;
s64 xaddr;
int xlen;
int nsplit; /* number of pages split */
struct pxdlist pxdlist;
pxd_t *pxd;
struct tlock *tlck;
struct xtlock *xtlck;
smp = split->mp;
sp = XT_PAGE(ip, smp);
/* is inode xtree root extension/inline EA area free ? */
if ((sp->header.flag & BT_ROOT) && (!S_ISDIR(ip->i_mode)) &&
(le16_to_cpu(sp->header.maxentry) < XTROOTMAXSLOT) &&
(JFS_IP(ip)->mode2 & INLINEEA)) {
sp->header.maxentry = cpu_to_le16(XTROOTMAXSLOT);
JFS_IP(ip)->mode2 &= ~INLINEEA;
BT_MARK_DIRTY(smp, ip);
/*
* acquire a transaction lock on the leaf page;
*
* action: xad insertion/extension;
*/
/* if insert into middle, shift right remaining entries. */
skip = split->index;
nextindex = le16_to_cpu(sp->header.nextindex);
if (skip < nextindex)
memmove(&sp->xad[skip + 1], &sp->xad[skip],
(nextindex - skip) * sizeof(xad_t));
/* insert the new entry: mark the entry NEW */
xad = &sp->xad[skip];
XT_PUTENTRY(xad, split->flag, split->off, split->len,
split->addr);
/* advance next available entry index */
le16_add_cpu(&sp->header.nextindex, 1);
/* Don't log it if there are no links to the file */
if (!test_cflag(COMMIT_Nolink, ip)) {
tlck = txLock(tid, ip, smp, tlckXTREE | tlckGROW);
xtlck = (struct xtlock *) & tlck->lock;
xtlck->lwm.offset = (xtlck->lwm.offset) ?
min(skip, (int)xtlck->lwm.offset) : skip;
xtlck->lwm.length =
le16_to_cpu(sp->header.nextindex) -
xtlck->lwm.offset;
}
return 0;
}
/*
* allocate new index blocks to cover index page split(s)
*
* allocation hint: ?
*/
if (split->pxdlist == NULL) {
nsplit = btstack->nsplit;
split->pxdlist = &pxdlist;
pxdlist.maxnpxd = pxdlist.npxd = 0;
pxd = &pxdlist.pxd[0];
xlen = JFS_SBI(ip->i_sb)->nbperpage;
for (; nsplit > 0; nsplit--, pxd++) {
if ((rc = dbAlloc(ip, (s64) 0, (s64) xlen, &xaddr))
== 0) {
PXDaddress(pxd, xaddr);
PXDlength(pxd, xlen);
pxdlist.maxnpxd++;
continue;
}
/* undo allocation */
XT_PUTPAGE(smp);
return rc;
}
}
/*
* Split leaf page <sp> into <sp> and a new right page <rp>.
*
* The split routines insert the new entry into the leaf page,
* and acquire txLock as appropriate.
* return <rp> pinned and its block number <rpbn>.
*/
rc = (sp->header.flag & BT_ROOT) ?
xtSplitRoot(tid, ip, split, &rmp) :
xtSplitPage(tid, ip, split, &rmp, &rbn);
XT_PUTPAGE(smp);
if (rc)
return -EIO;
/*
* propagate up the router entry for the leaf page just split
*
* insert a router entry for the new page into the parent page,
* propagate the insert/split up the tree by walking back the stack
* of (bn of parent page, index of child page entry in parent page)
* that were traversed during the search for the page that split.
*
* the propagation of insert/split up the tree stops if the root
* splits or the page inserted into doesn't have to split to hold
* the new entry.
*
* the parent entry for the split page remains the same, and
* a new entry is inserted at its right with the first key and
* block number of the new right page.
*
* There are a maximum of 3 pages pinned at any time:
* right child, left parent and right parent (when the parent splits)
* to keep the child page pinned while working on the parent.
* make sure that all pins are released at exit.
*/
while ((parent = BT_POP(btstack)) != NULL) {
/* parent page specified by stack frame <parent> */
/* keep current child pages <rcp> pinned */
rcmp = rmp;
rcbn = rbn;
rcp = XT_PAGE(ip, rcmp);
/*
* insert router entry in parent for new right child page <rp>
*/
/* get/pin the parent page <sp> */
XT_GETPAGE(ip, parent->bn, smp, PSIZE, sp, rc);
if (rc) {
XT_PUTPAGE(rcmp);
return rc;
}
/*
* The new key entry goes ONE AFTER the index of parent entry,
* because the split was to the right.
*/
skip = parent->index + 1;
/*
* split or shift right remaining entries of the parent page
*/
nextindex = le16_to_cpu(sp->header.nextindex);
/*
* parent page is full - split the parent page
*/
if (nextindex == le16_to_cpu(sp->header.maxentry)) {
/* init for parent page split */
split->mp = smp;
split->index = skip; /* index at insert */
split->flag = XAD_NEW;
split->off = offsetXAD(&rcp->xad[XTENTRYSTART]);
split->len = JFS_SBI(ip->i_sb)->nbperpage;
split->addr = rcbn;
/* unpin previous right child page */
XT_PUTPAGE(rcmp);
/* The split routines insert the new entry,
* and acquire txLock as appropriate.
* return <rp> pinned and its block number <rpbn>.
*/
rc = (sp->header.flag & BT_ROOT) ?
xtSplitRoot(tid, ip, split, &rmp) :
xtSplitPage(tid, ip, split, &rmp, &rbn);
if (rc) {
XT_PUTPAGE(smp);
return rc;
}
XT_PUTPAGE(smp);
/* keep new child page <rp> pinned */
}
/*
* parent page is not full - insert in parent page
*/
else {
/*
* insert router entry in parent for the right child
* page from the first entry of the right child page:
*/
/*
* acquire a transaction lock on the parent page;
*
* action: router xad insertion;
*/
BT_MARK_DIRTY(smp, ip);
/*
* if insert into middle, shift right remaining entries
*/
if (skip < nextindex)
memmove(&sp->xad[skip + 1], &sp->xad[skip],
(nextindex -
skip) << L2XTSLOTSIZE);
/* insert the router entry */
xad = &sp->xad[skip];
XT_PUTENTRY(xad, XAD_NEW,
offsetXAD(&rcp->xad[XTENTRYSTART]),
JFS_SBI(ip->i_sb)->nbperpage, rcbn);
/* advance next available entry index. */
le16_add_cpu(&sp->header.nextindex, 1);
/* Don't log it if there are no links to the file */
if (!test_cflag(COMMIT_Nolink, ip)) {
tlck = txLock(tid, ip, smp,
tlckXTREE | tlckGROW);
xtlck = (struct xtlock *) & tlck->lock;
xtlck->lwm.offset = (xtlck->lwm.offset) ?
min(skip, (int)xtlck->lwm.offset) : skip;
xtlck->lwm.length =
le16_to_cpu(sp->header.nextindex) -
xtlck->lwm.offset;
}
/* unpin parent page */
XT_PUTPAGE(smp);
/* exit propagate up */
break;
}
}
/* unpin current right page */
XT_PUTPAGE(rmp);
return 0;
}
/*
* xtSplitPage()
*
* function:
* split a full non-root page into
* original/split/left page and new right page
* i.e., the original/split page remains as left page.
*
* parameter:
* int tid,
* struct inode *ip,
* struct xtsplit *split,
* struct metapage **rmpp,
* u64 *rbnp,
*
* return:
* Pointer to page in which to insert or NULL on error.
*/
static int
xtSplitPage(tid_t tid, struct inode *ip,
struct xtsplit * split, struct metapage ** rmpp, s64 * rbnp)
{
int rc = 0;
struct metapage *smp;
xtpage_t *sp;
struct metapage *rmp;
xtpage_t *rp; /* new right page allocated */
s64 rbn; /* new right page block number */
struct metapage *mp;
xtpage_t *p;
s64 nextbn;
int skip, maxentry, middle, righthalf, n;
xad_t *xad;
struct pxdlist *pxdlist;
pxd_t *pxd;
struct tlock *tlck;
struct xtlock *sxtlck = NULL, *rxtlck = NULL;
int quota_allocation = 0;
smp = split->mp;
sp = XT_PAGE(ip, smp);
INCREMENT(xtStat.split);
pxdlist = split->pxdlist;
pxd = &pxdlist->pxd[pxdlist->npxd];
pxdlist->npxd++;
rbn = addressPXD(pxd);
/* Allocate blocks to quota. */
rc = dquot_alloc_block(ip, lengthPXD(pxd));
if (rc)
goto clean_up;
quota_allocation += lengthPXD(pxd);
/*
* allocate the new right page for the split
*/
rmp = get_metapage(ip, rbn, PSIZE, 1);
if (rmp == NULL) {
rc = -EIO;
goto clean_up;