cregit-Linux how code gets into the kernel

Release 4.10 fs/jfs/jfs_xtree.c

Directory: fs/jfs
/*
 *   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)				\
do {                                                                    \
        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\n");  \
                        BT_PUTPAGE(MP);                                 \
                        MP = NULL;                                      \
                        RC = -EIO;                                      \
                }                                                       \
        }                                                               \
} while (0)

/* 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; }

Contributors

PersonTokensPropCommitsCommitProp
dave kleikampdave kleikamp300100.00%5100.00%
Total300100.00%5100.00%

/* * 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!\n"); 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); } }

Contributors

PersonTokensPropCommitsCommitProp
dave kleikampdave kleikamp91199.89%685.71%
joe perchesjoe perches10.11%114.29%
Total912100.00%7100.00%

/* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
dave kleikampdave kleikamp60199.01%777.78%
christoph hellwigchristoph hellwig30.49%111.11%
marcin slusarzmarcin slusarz30.49%111.11%
Total607100.00%9100.00%

/* * 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