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| Current File : //sys/fs/ext2fs/ext2_alloc.c |
/*-
* modified for Lites 1.1
*
* Aug 1995, Godmar Back (gback@cs.utah.edu)
* University of Utah, Department of Computer Science
*/
/*-
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)ffs_alloc.c 8.8 (Berkeley) 2/21/94
* $FreeBSD: release/9.1.0/sys/fs/ext2fs/ext2_alloc.c 233322 2012-03-22 20:31:52Z pfg $
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/vnode.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/buf.h>
#include <fs/ext2fs/inode.h>
#include <fs/ext2fs/ext2_mount.h>
#include <fs/ext2fs/ext2fs.h>
#include <fs/ext2fs/fs.h>
#include <fs/ext2fs/ext2_extern.h>
static daddr_t ext2_alloccg(struct inode *, int, daddr_t, int);
static daddr_t ext2_clusteralloc(struct inode *, int, daddr_t, int);
static u_long ext2_dirpref(struct inode *);
static void ext2_fserr(struct m_ext2fs *, uid_t, char *);
static u_long ext2_hashalloc(struct inode *, int, long, int,
daddr_t (*)(struct inode *, int, daddr_t,
int));
static daddr_t ext2_nodealloccg(struct inode *, int, daddr_t, int);
static daddr_t ext2_mapsearch(struct m_ext2fs *, char *, daddr_t);
/*
* Allocate a block in the file system.
*
* A preference may be optionally specified. If a preference is given
* the following hierarchy is used to allocate a block:
* 1) allocate the requested block.
* 2) allocate a rotationally optimal block in the same cylinder.
* 3) allocate a block in the same cylinder group.
* 4) quadradically rehash into other cylinder groups, until an
* available block is located.
* If no block preference is given the following hierarchy is used
* to allocate a block:
* 1) allocate a block in the cylinder group that contains the
* inode for the file.
* 2) quadradically rehash into other cylinder groups, until an
* available block is located.
*/
int
ext2_alloc(ip, lbn, bpref, size, cred, bnp)
struct inode *ip;
int32_t lbn, bpref;
int size;
struct ucred *cred;
int32_t *bnp;
{
struct m_ext2fs *fs;
struct ext2mount *ump;
int32_t bno;
int cg;
*bnp = 0;
fs = ip->i_e2fs;
ump = ip->i_ump;
mtx_assert(EXT2_MTX(ump), MA_OWNED);
#ifdef DIAGNOSTIC
if ((u_int)size > fs->e2fs_bsize || blkoff(fs, size) != 0) {
vn_printf(ip->i_devvp, "bsize = %lu, size = %d, fs = %s\n",
(long unsigned int)fs->e2fs_bsize, size, fs->e2fs_fsmnt);
panic("ext2_alloc: bad size");
}
if (cred == NOCRED)
panic("ext2_alloc: missing credential");
#endif /* DIAGNOSTIC */
if (size == fs->e2fs_bsize && fs->e2fs->e2fs_fbcount == 0)
goto nospace;
if (cred->cr_uid != 0 &&
fs->e2fs->e2fs_fbcount < fs->e2fs->e2fs_rbcount)
goto nospace;
if (bpref >= fs->e2fs->e2fs_bcount)
bpref = 0;
if (bpref == 0)
cg = ino_to_cg(fs, ip->i_number);
else
cg = dtog(fs, bpref);
bno = (daddr_t)ext2_hashalloc(ip, cg, bpref, fs->e2fs_bsize,
ext2_alloccg);
if (bno > 0) {
/* set next_alloc fields as done in block_getblk */
ip->i_next_alloc_block = lbn;
ip->i_next_alloc_goal = bno;
ip->i_blocks += btodb(fs->e2fs_bsize);
ip->i_flag |= IN_CHANGE | IN_UPDATE;
*bnp = bno;
return (0);
}
nospace:
EXT2_UNLOCK(ump);
ext2_fserr(fs, cred->cr_uid, "file system full");
uprintf("\n%s: write failed, file system is full\n", fs->e2fs_fsmnt);
return (ENOSPC);
}
/*
* Reallocate a sequence of blocks into a contiguous sequence of blocks.
*
* The vnode and an array of buffer pointers for a range of sequential
* logical blocks to be made contiguous is given. The allocator attempts
* to find a range of sequential blocks starting as close as possible to
* an fs_rotdelay offset from the end of the allocation for the logical
* block immediately preceding the current range. If successful, the
* physical block numbers in the buffer pointers and in the inode are
* changed to reflect the new allocation. If unsuccessful, the allocation
* is left unchanged. The success in doing the reallocation is returned.
* Note that the error return is not reflected back to the user. Rather
* the previous block allocation will be used.
*/
SYSCTL_NODE(_vfs, OID_AUTO, ext2fs, CTLFLAG_RW, 0, "EXT2FS filesystem");
static int doasyncfree = 1;
SYSCTL_INT(_vfs_ext2fs, OID_AUTO, doasyncfree, CTLFLAG_RW, &doasyncfree, 0,
"Use asychronous writes to update block pointers when freeing blocks");
static int doreallocblks = 1;
SYSCTL_INT(_vfs_ext2fs, OID_AUTO, doreallocblks, CTLFLAG_RW, &doreallocblks, 0, "");
int
ext2_reallocblks(ap)
struct vop_reallocblks_args /* {
struct vnode *a_vp;
struct cluster_save *a_buflist;
} */ *ap;
{
struct m_ext2fs *fs;
struct inode *ip;
struct vnode *vp;
struct buf *sbp, *ebp;
int32_t *bap, *sbap, *ebap = 0;
struct ext2mount *ump;
struct cluster_save *buflist;
struct indir start_ap[NIADDR + 1], end_ap[NIADDR + 1], *idp;
int32_t start_lbn, end_lbn, soff, newblk, blkno;
int i, len, start_lvl, end_lvl, pref, ssize;
if (doreallocblks == 0)
return (ENOSPC);
vp = ap->a_vp;
ip = VTOI(vp);
fs = ip->i_e2fs;
ump = ip->i_ump;
if (fs->e2fs_contigsumsize <= 0)
return (ENOSPC);
buflist = ap->a_buflist;
len = buflist->bs_nchildren;
start_lbn = buflist->bs_children[0]->b_lblkno;
end_lbn = start_lbn + len - 1;
#ifdef DIAGNOSTIC
for (i = 1; i < len; i++)
if (buflist->bs_children[i]->b_lblkno != start_lbn + i)
panic("ext2_reallocblks: non-cluster");
#endif
/*
* If the latest allocation is in a new cylinder group, assume that
* the filesystem has decided to move and do not force it back to
* the previous cylinder group.
*/
if (dtog(fs, dbtofsb(fs, buflist->bs_children[0]->b_blkno)) !=
dtog(fs, dbtofsb(fs, buflist->bs_children[len - 1]->b_blkno)))
return (ENOSPC);
if (ext2_getlbns(vp, start_lbn, start_ap, &start_lvl) ||
ext2_getlbns(vp, end_lbn, end_ap, &end_lvl))
return (ENOSPC);
/*
* Get the starting offset and block map for the first block.
*/
if (start_lvl == 0) {
sbap = &ip->i_db[0];
soff = start_lbn;
} else {
idp = &start_ap[start_lvl - 1];
if (bread(vp, idp->in_lbn, (int)fs->e2fs_bsize, NOCRED, &sbp)) {
brelse(sbp);
return (ENOSPC);
}
sbap = (int32_t *)sbp->b_data;
soff = idp->in_off;
}
/*
* If the block range spans two block maps, get the second map.
*/
if (end_lvl == 0 || (idp = &end_ap[end_lvl - 1])->in_off + 1 >= len) {
ssize = len;
} else {
#ifdef DIAGNOSTIC
if (start_ap[start_lvl-1].in_lbn == idp->in_lbn)
panic("ext2_reallocblk: start == end");
#endif
ssize = len - (idp->in_off + 1);
if (bread(vp, idp->in_lbn, (int)fs->e2fs_bsize, NOCRED, &ebp))
goto fail;
ebap = (int32_t *)ebp->b_data;
}
/*
* Find the preferred location for the cluster.
*/
EXT2_LOCK(ump);
pref = ext2_blkpref(ip, start_lbn, soff, sbap, 0);
/*
* Search the block map looking for an allocation of the desired size.
*/
if ((newblk = (int32_t)ext2_hashalloc(ip, dtog(fs, pref), pref,
len, ext2_clusteralloc)) == 0){
EXT2_UNLOCK(ump);
goto fail;
}
/*
* We have found a new contiguous block.
*
* First we have to replace the old block pointers with the new
* block pointers in the inode and indirect blocks associated
* with the file.
*/
#ifdef DEBUG
printf("realloc: ino %d, lbns %jd-%jd\n\told:", ip->i_number,
(intmax_t)start_lbn, (intmax_t)end_lbn);
#endif /* DEBUG */
blkno = newblk;
for (bap = &sbap[soff], i = 0; i < len; i++, blkno += fs->e2fs_fpb) {
if (i == ssize) {
bap = ebap;
soff = -i;
}
#ifdef DIAGNOSTIC
if (buflist->bs_children[i]->b_blkno != fsbtodb(fs, *bap))
panic("ext2_reallocblks: alloc mismatch");
#endif
#ifdef DEBUG
printf(" %d,", *bap);
#endif /* DEBUG */
*bap++ = blkno;
}
/*
* Next we must write out the modified inode and indirect blocks.
* For strict correctness, the writes should be synchronous since
* the old block values may have been written to disk. In practise
* they are almost never written, but if we are concerned about
* strict correctness, the `doasyncfree' flag should be set to zero.
*
* The test on `doasyncfree' should be changed to test a flag
* that shows whether the associated buffers and inodes have
* been written. The flag should be set when the cluster is
* started and cleared whenever the buffer or inode is flushed.
* We can then check below to see if it is set, and do the
* synchronous write only when it has been cleared.
*/
if (sbap != &ip->i_db[0]) {
if (doasyncfree)
bdwrite(sbp);
else
bwrite(sbp);
} else {
ip->i_flag |= IN_CHANGE | IN_UPDATE;
if (!doasyncfree)
ext2_update(vp, 1);
}
if (ssize < len) {
if (doasyncfree)
bdwrite(ebp);
else
bwrite(ebp);
}
/*
* Last, free the old blocks and assign the new blocks to the buffers.
*/
#ifdef DEBUG
printf("\n\tnew:");
#endif /* DEBUG */
for (blkno = newblk, i = 0; i < len; i++, blkno += fs->e2fs_fpb) {
ext2_blkfree(ip, dbtofsb(fs, buflist->bs_children[i]->b_blkno),
fs->e2fs_bsize);
buflist->bs_children[i]->b_blkno = fsbtodb(fs, blkno);
#ifdef DEBUG
printf(" %d,", blkno);
#endif /* DEBUG */
}
#ifdef DEBUG
printf("\n");
#endif /* DEBUG */
return (0);
fail:
if (ssize < len)
brelse(ebp);
if (sbap != &ip->i_db[0])
brelse(sbp);
return (ENOSPC);
}
/*
* Allocate an inode in the file system.
*
*/
int
ext2_valloc(pvp, mode, cred, vpp)
struct vnode *pvp;
int mode;
struct ucred *cred;
struct vnode **vpp;
{
struct timespec ts;
struct inode *pip;
struct m_ext2fs *fs;
struct inode *ip;
struct ext2mount *ump;
ino_t ino, ipref;
int i, error, cg;
*vpp = NULL;
pip = VTOI(pvp);
fs = pip->i_e2fs;
ump = pip->i_ump;
EXT2_LOCK(ump);
if (fs->e2fs->e2fs_ficount == 0)
goto noinodes;
/*
* If it is a directory then obtain a cylinder group based on
* ext2_dirpref else obtain it using ino_to_cg. The preferred inode is
* always the next inode.
*/
if ((mode & IFMT) == IFDIR) {
cg = ext2_dirpref(pip);
if (fs->e2fs_contigdirs[cg] < 255)
fs->e2fs_contigdirs[cg]++;
} else {
cg = ino_to_cg(fs, pip->i_number);
if (fs->e2fs_contigdirs[cg] > 0)
fs->e2fs_contigdirs[cg]--;
}
ipref = cg * fs->e2fs->e2fs_ipg + 1;
ino = (ino_t)ext2_hashalloc(pip, cg, (long)ipref, mode, ext2_nodealloccg);
if (ino == 0)
goto noinodes;
error = VFS_VGET(pvp->v_mount, ino, LK_EXCLUSIVE, vpp);
if (error) {
ext2_vfree(pvp, ino, mode);
return (error);
}
ip = VTOI(*vpp);
/*
* The question is whether using VGET was such good idea at all:
* Linux doesn't read the old inode in when it is allocating a
* new one. I will set at least i_size and i_blocks to zero.
*/
ip->i_size = 0;
ip->i_blocks = 0;
ip->i_mode = 0;
ip->i_flags = 0;
/* now we want to make sure that the block pointers are zeroed out */
for (i = 0; i < NDADDR; i++)
ip->i_db[i] = 0;
for (i = 0; i < NIADDR; i++)
ip->i_ib[i] = 0;
/*
* Set up a new generation number for this inode.
* XXX check if this makes sense in ext2
*/
if (ip->i_gen == 0 || ++ip->i_gen == 0)
ip->i_gen = random() / 2 + 1;
vfs_timestamp(&ts);
ip->i_birthtime = ts.tv_sec;
ip->i_birthnsec = ts.tv_nsec;
/*
printf("ext2_valloc: allocated inode %d\n", ino);
*/
return (0);
noinodes:
EXT2_UNLOCK(ump);
ext2_fserr(fs, cred->cr_uid, "out of inodes");
uprintf("\n%s: create/symlink failed, no inodes free\n", fs->e2fs_fsmnt);
return (ENOSPC);
}
/*
* Find a cylinder to place a directory.
*
* The policy implemented by this algorithm is to allocate a
* directory inode in the same cylinder group as its parent
* directory, but also to reserve space for its files inodes
* and data. Restrict the number of directories which may be
* allocated one after another in the same cylinder group
* without intervening allocation of files.
*
* If we allocate a first level directory then force allocation
* in another cylinder group.
*
*/
static u_long
ext2_dirpref(struct inode *pip)
{
struct m_ext2fs *fs;
int cg, prefcg, dirsize, cgsize;
int avgifree, avgbfree, avgndir, curdirsize;
int minifree, minbfree, maxndir;
int mincg, minndir;
int maxcontigdirs;
mtx_assert(EXT2_MTX(pip->i_ump), MA_OWNED);
fs = pip->i_e2fs;
avgifree = fs->e2fs->e2fs_ficount / fs->e2fs_gcount;
avgbfree = fs->e2fs->e2fs_fbcount / fs->e2fs_gcount;
avgndir = fs->e2fs_total_dir / fs->e2fs_gcount;
/*
* Force allocation in another cg if creating a first level dir.
*/
ASSERT_VOP_LOCKED(ITOV(pip), "ext2fs_dirpref");
if (ITOV(pip)->v_vflag & VV_ROOT) {
prefcg = arc4random() % fs->e2fs_gcount;
mincg = prefcg;
minndir = fs->e2fs_ipg;
for (cg = prefcg; cg < fs->e2fs_gcount; cg++)
if (fs->e2fs_gd[cg].ext2bgd_ndirs < minndir &&
fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree &&
fs->e2fs_gd[cg].ext2bgd_nbfree >= avgbfree) {
mincg = cg;
minndir = fs->e2fs_gd[cg].ext2bgd_ndirs;
}
for (cg = 0; cg < prefcg; cg++)
if (fs->e2fs_gd[cg].ext2bgd_ndirs < minndir &&
fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree &&
fs->e2fs_gd[cg].ext2bgd_nbfree >= avgbfree) {
mincg = cg;
minndir = fs->e2fs_gd[cg].ext2bgd_ndirs;
}
return (mincg);
}
/*
* Count various limits which used for
* optimal allocation of a directory inode.
*/
maxndir = min(avgndir + fs->e2fs_ipg / 16, fs->e2fs_ipg);
minifree = avgifree - avgifree / 4;
if (minifree < 1)
minifree = 1;
minbfree = avgbfree - avgbfree / 4;
if (minbfree < 1)
minbfree = 1;
cgsize = fs->e2fs_fsize * fs->e2fs_fpg;
dirsize = AVGDIRSIZE;
curdirsize = avgndir ? (cgsize - avgbfree * fs->e2fs_bsize) / avgndir : 0;
if (dirsize < curdirsize)
dirsize = curdirsize;
if (dirsize <= 0)
maxcontigdirs = 0; /* dirsize overflowed */
else
maxcontigdirs = min((avgbfree * fs->e2fs_bsize) / dirsize, 255);
maxcontigdirs = min(maxcontigdirs, fs->e2fs_ipg / AFPDIR);
if (maxcontigdirs == 0)
maxcontigdirs = 1;
/*
* Limit number of dirs in one cg and reserve space for
* regular files, but only if we have no deficit in
* inodes or space.
*/
prefcg = ino_to_cg(fs, pip->i_number);
for (cg = prefcg; cg < fs->e2fs_gcount; cg++)
if (fs->e2fs_gd[cg].ext2bgd_ndirs < maxndir &&
fs->e2fs_gd[cg].ext2bgd_nifree >= minifree &&
fs->e2fs_gd[cg].ext2bgd_nbfree >= minbfree) {
if (fs->e2fs_contigdirs[cg] < maxcontigdirs)
return (cg);
}
for (cg = 0; cg < prefcg; cg++)
if (fs->e2fs_gd[cg].ext2bgd_ndirs < maxndir &&
fs->e2fs_gd[cg].ext2bgd_nifree >= minifree &&
fs->e2fs_gd[cg].ext2bgd_nbfree >= minbfree) {
if (fs->e2fs_contigdirs[cg] < maxcontigdirs)
return (cg);
}
/*
* This is a backstop when we have deficit in space.
*/
for (cg = prefcg; cg < fs->e2fs_gcount; cg++)
if (fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree)
return (cg);
for (cg = 0; cg < prefcg; cg++)
if (fs->e2fs_gd[cg].ext2bgd_nifree >= avgifree)
break;
return (cg);
}
/*
* Select the desired position for the next block in a file.
*
* we try to mimic what Remy does in inode_getblk/block_getblk
*
* we note: blocknr == 0 means that we're about to allocate either
* a direct block or a pointer block at the first level of indirection
* (In other words, stuff that will go in i_db[] or i_ib[])
*
* blocknr != 0 means that we're allocating a block that is none
* of the above. Then, blocknr tells us the number of the block
* that will hold the pointer
*/
int32_t
ext2_blkpref(ip, lbn, indx, bap, blocknr)
struct inode *ip;
int32_t lbn;
int indx;
int32_t *bap;
int32_t blocknr;
{
int tmp;
mtx_assert(EXT2_MTX(ip->i_ump), MA_OWNED);
/* if the next block is actually what we thought it is,
then set the goal to what we thought it should be
*/
if (ip->i_next_alloc_block == lbn && ip->i_next_alloc_goal != 0)
return ip->i_next_alloc_goal;
/* now check whether we were provided with an array that basically
tells us previous blocks to which we want to stay closeby
*/
if (bap)
for (tmp = indx - 1; tmp >= 0; tmp--)
if (bap[tmp])
return bap[tmp];
/* else let's fall back to the blocknr, or, if there is none,
follow the rule that a block should be allocated near its inode
*/
return blocknr ? blocknr :
(int32_t)(ip->i_block_group *
EXT2_BLOCKS_PER_GROUP(ip->i_e2fs)) +
ip->i_e2fs->e2fs->e2fs_first_dblock;
}
/*
* Implement the cylinder overflow algorithm.
*
* The policy implemented by this algorithm is:
* 1) allocate the block in its requested cylinder group.
* 2) quadradically rehash on the cylinder group number.
* 3) brute force search for a free block.
*/
static u_long
ext2_hashalloc(struct inode *ip, int cg, long pref, int size,
daddr_t (*allocator)(struct inode *, int, daddr_t, int))
{
struct m_ext2fs *fs;
ino_t result;
int i, icg = cg;
mtx_assert(EXT2_MTX(ip->i_ump), MA_OWNED);
fs = ip->i_e2fs;
/*
* 1: preferred cylinder group
*/
result = (*allocator)(ip, cg, pref, size);
if (result)
return (result);
/*
* 2: quadratic rehash
*/
for (i = 1; i < fs->e2fs_gcount; i *= 2) {
cg += i;
if (cg >= fs->e2fs_gcount)
cg -= fs->e2fs_gcount;
result = (*allocator)(ip, cg, 0, size);
if (result)
return (result);
}
/*
* 3: brute force search
* Note that we start at i == 2, since 0 was checked initially,
* and 1 is always checked in the quadratic rehash.
*/
cg = (icg + 2) % fs->e2fs_gcount;
for (i = 2; i < fs->e2fs_gcount; i++) {
result = (*allocator)(ip, cg, 0, size);
if (result)
return (result);
cg++;
if (cg == fs->e2fs_gcount)
cg = 0;
}
return (0);
}
/*
* Determine whether a block can be allocated.
*
* Check to see if a block of the appropriate size is available,
* and if it is, allocate it.
*/
static daddr_t
ext2_alloccg(struct inode *ip, int cg, daddr_t bpref, int size)
{
struct m_ext2fs *fs;
struct buf *bp;
struct ext2mount *ump;
daddr_t bno, runstart, runlen;
int bit, loc, end, error, start;
char *bbp;
/* XXX ondisk32 */
fs = ip->i_e2fs;
ump = ip->i_ump;
if (fs->e2fs_gd[cg].ext2bgd_nbfree == 0)
return (0);
EXT2_UNLOCK(ump);
error = bread(ip->i_devvp, fsbtodb(fs,
fs->e2fs_gd[cg].ext2bgd_b_bitmap),
(int)fs->e2fs_bsize, NOCRED, &bp);
if (error) {
brelse(bp);
EXT2_LOCK(ump);
return (0);
}
if (fs->e2fs_gd[cg].ext2bgd_nbfree == 0) {
/*
* Another thread allocated the last block in this
* group while we were waiting for the buffer.
*/
brelse(bp);
EXT2_LOCK(ump);
return (0);
}
bbp = (char *)bp->b_data;
if (dtog(fs, bpref) != cg)
bpref = 0;
if (bpref != 0) {
bpref = dtogd(fs, bpref);
/*
* if the requested block is available, use it
*/
if (isclr(bbp, bpref)) {
bno = bpref;
goto gotit;
}
}
/*
* no blocks in the requested cylinder, so take next
* available one in this cylinder group.
* first try to get 8 contigous blocks, then fall back to a single
* block.
*/
if (bpref)
start = dtogd(fs, bpref) / NBBY;
else
start = 0;
end = howmany(fs->e2fs->e2fs_fpg, NBBY) - start;
retry:
runlen = 0;
runstart = 0;
for (loc = start; loc < end; loc++) {
if (bbp[loc] == (char)0xff) {
runlen = 0;
continue;
}
/* Start of a run, find the number of high clear bits. */
if (runlen == 0) {
bit = fls(bbp[loc]);
runlen = NBBY - bit;
runstart = loc * NBBY + bit;
} else if (bbp[loc] == 0) {
/* Continue a run. */
runlen += NBBY;
} else {
/*
* Finish the current run. If it isn't long
* enough, start a new one.
*/
bit = ffs(bbp[loc]) - 1;
runlen += bit;
if (runlen >= 8) {
bno = runstart;
goto gotit;
}
/* Run was too short, start a new one. */
bit = fls(bbp[loc]);
runlen = NBBY - bit;
runstart = loc * NBBY + bit;
}
/* If the current run is long enough, use it. */
if (runlen >= 8) {
bno = runstart;
goto gotit;
}
}
if (start != 0) {
end = start;
start = 0;
goto retry;
}
bno = ext2_mapsearch(fs, bbp, bpref);
if (bno < 0){
brelse(bp);
EXT2_LOCK(ump);
return (0);
}
gotit:
#ifdef DIAGNOSTIC
if (isset(bbp, bno)) {
printf("ext2fs_alloccgblk: cg=%d bno=%jd fs=%s\n",
cg, (intmax_t)bno, fs->e2fs_fsmnt);
panic("ext2fs_alloccg: dup alloc");
}
#endif
setbit(bbp, bno);
EXT2_LOCK(ump);
ext2_clusteracct(fs, bbp, cg, bno, -1);
fs->e2fs->e2fs_fbcount--;
fs->e2fs_gd[cg].ext2bgd_nbfree--;
fs->e2fs_fmod = 1;
EXT2_UNLOCK(ump);
bdwrite(bp);
return (cg * fs->e2fs->e2fs_fpg + fs->e2fs->e2fs_first_dblock + bno);
}
/*
* Determine whether a cluster can be allocated.
*/
static daddr_t
ext2_clusteralloc(struct inode *ip, int cg, daddr_t bpref, int len)
{
struct m_ext2fs *fs;
struct ext2mount *ump;
struct buf *bp;
char *bbp;
int bit, error, got, i, loc, run;
int32_t *lp;
daddr_t bno;
fs = ip->i_e2fs;
ump = ip->i_ump;
if (fs->e2fs_maxcluster[cg] < len)
return (0);
EXT2_UNLOCK(ump);
error = bread(ip->i_devvp,
fsbtodb(fs, fs->e2fs_gd[cg].ext2bgd_b_bitmap),
(int)fs->e2fs_bsize, NOCRED, &bp);
if (error)
goto fail_lock;
bbp = (char *)bp->b_data;
bp->b_xflags |= BX_BKGRDWRITE;
EXT2_LOCK(ump);
/*
* Check to see if a cluster of the needed size (or bigger) is
* available in this cylinder group.
*/
lp = &fs->e2fs_clustersum[cg].cs_sum[len];
for (i = len; i <= fs->e2fs_contigsumsize; i++)
if (*lp++ > 0)
break;
if (i > fs->e2fs_contigsumsize) {
/*
* Update the cluster summary information to reflect
* the true maximum-sized cluster so that future cluster
* allocation requests can avoid reading the bitmap only
* to find no cluster.
*/
lp = &fs->e2fs_clustersum[cg].cs_sum[len - 1];
for (i = len - 1; i > 0; i--)
if (*lp-- > 0)
break;
fs->e2fs_maxcluster[cg] = i;
goto fail;
}
EXT2_UNLOCK(ump);
/* Search the bitmap to find a big enough cluster like in FFS. */
if (dtog(fs, bpref) != cg)
bpref = 0;
if (bpref != 0)
bpref = dtogd(fs, bpref);
loc = bpref / NBBY;
bit = 1 << (bpref % NBBY);
for (run = 0, got = bpref; got < fs->e2fs->e2fs_fpg; got++) {
if ((bbp[loc] & bit) != 0)
run = 0;
else {
run++;
if (run == len)
break;
}
if ((got & (NBBY - 1)) != (NBBY - 1))
bit <<= 1;
else {
loc++;
bit = 1;
}
}
if (got >= fs->e2fs->e2fs_fpg)
goto fail_lock;
/* Allocate the cluster that we found. */
for (i = 1; i < len; i++)
if (!isclr(bbp, got - run + i))
panic("ext2_clusteralloc: map mismatch");
bno = got - run + 1;
if (bno >= fs->e2fs->e2fs_fpg)
panic("ext2_clusteralloc: allocated out of group");
EXT2_LOCK(ump);
for (i = 0; i < len; i += fs->e2fs_fpb) {
setbit(bbp, bno + i);
ext2_clusteracct(fs, bbp, cg, bno + i, -1);
fs->e2fs->e2fs_fbcount--;
fs->e2fs_gd[cg].ext2bgd_nbfree--;
}
fs->e2fs_fmod = 1;
EXT2_UNLOCK(ump);
bdwrite(bp);
return (cg * fs->e2fs->e2fs_fpg + fs->e2fs->e2fs_first_dblock + bno);
fail_lock:
EXT2_LOCK(ump);
fail:
brelse(bp);
return (0);
}
/*
* Determine whether an inode can be allocated.
*
* Check to see if an inode is available, and if it is,
* allocate it using tode in the specified cylinder group.
*/
static daddr_t
ext2_nodealloccg(struct inode *ip, int cg, daddr_t ipref, int mode)
{
struct m_ext2fs *fs;
struct buf *bp;
struct ext2mount *ump;
int error, start, len, loc, map, i;
char *ibp;
ipref--; /* to avoid a lot of (ipref -1) */
if (ipref == -1)
ipref = 0;
fs = ip->i_e2fs;
ump = ip->i_ump;
if (fs->e2fs_gd[cg].ext2bgd_nifree == 0)
return (0);
EXT2_UNLOCK(ump);
error = bread(ip->i_devvp, fsbtodb(fs,
fs->e2fs_gd[cg].ext2bgd_i_bitmap),
(int)fs->e2fs_bsize, NOCRED, &bp);
if (error) {
brelse(bp);
EXT2_LOCK(ump);
return (0);
}
if (fs->e2fs_gd[cg].ext2bgd_nifree == 0) {
/*
* Another thread allocated the last i-node in this
* group while we were waiting for the buffer.
*/
brelse(bp);
EXT2_LOCK(ump);
return (0);
}
ibp = (char *)bp->b_data;
if (ipref) {
ipref %= fs->e2fs->e2fs_ipg;
if (isclr(ibp, ipref))
goto gotit;
}
start = ipref / NBBY;
len = howmany(fs->e2fs->e2fs_ipg - ipref, NBBY);
loc = skpc(0xff, len, &ibp[start]);
if (loc == 0) {
len = start + 1;
start = 0;
loc = skpc(0xff, len, &ibp[0]);
if (loc == 0) {
printf("cg = %d, ipref = %lld, fs = %s\n",
cg, (long long)ipref, fs->e2fs_fsmnt);
panic("ext2fs_nodealloccg: map corrupted");
/* NOTREACHED */
}
}
i = start + len - loc;
map = ibp[i] ^ 0xff;
if (map == 0) {
printf("fs = %s\n", fs->e2fs_fsmnt);
panic("ext2fs_nodealloccg: block not in map");
}
ipref = i * NBBY + ffs(map) - 1;
gotit:
setbit(ibp, ipref);
EXT2_LOCK(ump);
fs->e2fs_gd[cg].ext2bgd_nifree--;
fs->e2fs->e2fs_ficount--;
fs->e2fs_fmod = 1;
if ((mode & IFMT) == IFDIR) {
fs->e2fs_gd[cg].ext2bgd_ndirs++;
fs->e2fs_total_dir++;
}
EXT2_UNLOCK(ump);
bdwrite(bp);
return (cg * fs->e2fs->e2fs_ipg + ipref +1);
}
/*
* Free a block or fragment.
*
*/
void
ext2_blkfree(ip, bno, size)
struct inode *ip;
int32_t bno;
long size;
{
struct m_ext2fs *fs;
struct buf *bp;
struct ext2mount *ump;
int cg, error;
char *bbp;
fs = ip->i_e2fs;
ump = ip->i_ump;
cg = dtog(fs, bno);
if ((u_int)bno >= fs->e2fs->e2fs_bcount) {
printf("bad block %lld, ino %llu\n", (long long)bno,
(unsigned long long)ip->i_number);
ext2_fserr(fs, ip->i_uid, "bad block");
return;
}
error = bread(ip->i_devvp,
fsbtodb(fs, fs->e2fs_gd[cg].ext2bgd_b_bitmap),
(int)fs->e2fs_bsize, NOCRED, &bp);
if (error) {
brelse(bp);
return;
}
bbp = (char *)bp->b_data;
bno = dtogd(fs, bno);
if (isclr(bbp, bno)) {
printf("block = %lld, fs = %s\n",
(long long)bno, fs->e2fs_fsmnt);
panic("blkfree: freeing free block");
}
clrbit(bbp, bno);
EXT2_LOCK(ump);
ext2_clusteracct(fs, bbp, cg, bno, 1);
fs->e2fs->e2fs_fbcount++;
fs->e2fs_gd[cg].ext2bgd_nbfree++;
fs->e2fs_fmod = 1;
EXT2_UNLOCK(ump);
bdwrite(bp);
}
/*
* Free an inode.
*
*/
int
ext2_vfree(pvp, ino, mode)
struct vnode *pvp;
ino_t ino;
int mode;
{
struct m_ext2fs *fs;
struct inode *pip;
struct buf *bp;
struct ext2mount *ump;
int error, cg;
char * ibp;
/* mode_t save_i_mode; */
pip = VTOI(pvp);
fs = pip->i_e2fs;
ump = pip->i_ump;
if ((u_int)ino > fs->e2fs_ipg * fs->e2fs_gcount)
panic("ext2_vfree: range: devvp = %p, ino = %d, fs = %s",
pip->i_devvp, ino, fs->e2fs_fsmnt);
cg = ino_to_cg(fs, ino);
error = bread(pip->i_devvp,
fsbtodb(fs, fs->e2fs_gd[cg].ext2bgd_i_bitmap),
(int)fs->e2fs_bsize, NOCRED, &bp);
if (error) {
brelse(bp);
return (0);
}
ibp = (char *)bp->b_data;
ino = (ino - 1) % fs->e2fs->e2fs_ipg;
if (isclr(ibp, ino)) {
printf("ino = %llu, fs = %s\n",
(unsigned long long)ino, fs->e2fs_fsmnt);
if (fs->e2fs_ronly == 0)
panic("ifree: freeing free inode");
}
clrbit(ibp, ino);
EXT2_LOCK(ump);
fs->e2fs->e2fs_ficount++;
fs->e2fs_gd[cg].ext2bgd_nifree++;
if ((mode & IFMT) == IFDIR) {
fs->e2fs_gd[cg].ext2bgd_ndirs--;
fs->e2fs_total_dir--;
}
fs->e2fs_fmod = 1;
EXT2_UNLOCK(ump);
bdwrite(bp);
return (0);
}
/*
* Find a block in the specified cylinder group.
*
* It is a panic if a request is made to find a block if none are
* available.
*/
static daddr_t
ext2_mapsearch(struct m_ext2fs *fs, char *bbp, daddr_t bpref)
{
int start, len, loc, i, map;
/*
* find the fragment by searching through the free block
* map for an appropriate bit pattern
*/
if (bpref)
start = dtogd(fs, bpref) / NBBY;
else
start = 0;
len = howmany(fs->e2fs->e2fs_fpg, NBBY) - start;
loc = skpc(0xff, len, &bbp[start]);
if (loc == 0) {
len = start + 1;
start = 0;
loc = skpc(0xff, len, &bbp[start]);
if (loc == 0) {
printf("start = %d, len = %d, fs = %s\n",
start, len, fs->e2fs_fsmnt);
panic("ext2fs_alloccg: map corrupted");
/* NOTREACHED */
}
}
i = start + len - loc;
map = bbp[i] ^ 0xff;
if (map == 0) {
printf("fs = %s\n", fs->e2fs_fsmnt);
panic("ext2fs_mapsearch: block not in map");
}
return (i * NBBY + ffs(map) - 1);
}
/*
* Fserr prints the name of a file system with an error diagnostic.
*
* The form of the error message is:
* fs: error message
*/
static void
ext2_fserr(fs, uid, cp)
struct m_ext2fs *fs;
uid_t uid;
char *cp;
{
log(LOG_ERR, "uid %u on %s: %s\n", uid, fs->e2fs_fsmnt, cp);
}
int
cg_has_sb(int i)
{
int a3, a5, a7;
if (i == 0 || i == 1)
return 1;
for (a3 = 3, a5 = 5, a7 = 7;
a3 <= i || a5 <= i || a7 <= i;
a3 *= 3, a5 *= 5, a7 *= 7)
if (i == a3 || i == a5 || i == a7)
return 1;
return 0;
}