/
ffs_alloc.c
1556 lines (1432 loc) · 42.7 KB
/
ffs_alloc.c
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/* $OpenBSD: ffs_alloc.c,v 1.115 2024/02/03 18:51:58 beck Exp $ */
/* $NetBSD: ffs_alloc.c,v 1.11 1996/05/11 18:27:09 mycroft Exp $ */
/*
* Copyright (c) 2002 Networks Associates Technology, Inc.
* All rights reserved.
*
* This software was developed for the FreeBSD Project by Marshall
* Kirk McKusick and Network Associates Laboratories, the Security
* Research Division of Network Associates, Inc. under DARPA/SPAWAR
* contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS
* research program.
*
* 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.
* 3. 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 8.11 (Berkeley) 10/27/94
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/syslog.h>
#include <sys/stdint.h>
#include <sys/time.h>
#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/ufsmount.h>
#include <ufs/ufs/ufs_extern.h>
#include <ufs/ffs/fs.h>
#include <ufs/ffs/ffs_extern.h>
#define ffs_fserr(fs, uid, cp) do { \
log(LOG_ERR, "uid %u on %s: %s\n", (uid), \
(fs)->fs_fsmnt, (cp)); \
} while (0)
daddr_t ffs_alloccg(struct inode *, u_int, daddr_t, int);
struct buf * ffs_cgread(struct fs *, struct inode *, u_int);
daddr_t ffs_alloccgblk(struct inode *, struct buf *, daddr_t);
ufsino_t ffs_dirpref(struct inode *);
daddr_t ffs_fragextend(struct inode *, u_int, daddr_t, int, int);
daddr_t ffs_hashalloc(struct inode *, u_int, daddr_t, int,
daddr_t (*)(struct inode *, u_int, daddr_t, int));
daddr_t ffs_nodealloccg(struct inode *, u_int, daddr_t, int);
daddr_t ffs_mapsearch(struct fs *, struct cg *, daddr_t, int);
static const struct timeval fserr_interval = { 2, 0 };
/*
* Allocate a block in the file system.
*
* The size of the requested block is given, which must be some
* multiple of fs_fsize and <= fs_bsize.
* 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) quadratically 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) quadratically rehash into other cylinder groups, until an
* available block is located.
*/
int
ffs_alloc(struct inode *ip, daddr_t lbn, daddr_t bpref, int size,
struct ucred *cred, daddr_t *bnp)
{
static struct timeval fsfull_last;
struct fs *fs;
daddr_t bno;
u_int cg;
int error;
*bnp = 0;
fs = ip->i_fs;
#ifdef DIAGNOSTIC
if ((u_int)size > fs->fs_bsize || fragoff(fs, size) != 0) {
printf("dev = 0x%x, bsize = %d, size = %d, fs = %s\n",
ip->i_dev, fs->fs_bsize, size, fs->fs_fsmnt);
panic("ffs_alloc: bad size");
}
if (cred == NOCRED)
panic("ffs_alloc: missing credential");
#endif /* DIAGNOSTIC */
if (size == fs->fs_bsize && fs->fs_cstotal.cs_nbfree == 0)
goto nospace;
if (cred->cr_uid != 0 && freespace(fs, fs->fs_minfree) <= 0)
goto nospace;
if ((error = ufs_quota_alloc_blocks(ip, btodb(size), cred)) != 0)
return (error);
/*
* Start allocation in the preferred block's cylinder group or
* the file's inode's cylinder group if no preferred block was
* specified.
*/
if (bpref >= fs->fs_size)
bpref = 0;
if (bpref == 0)
cg = ino_to_cg(fs, ip->i_number);
else
cg = dtog(fs, bpref);
/* Try allocating a block. */
bno = ffs_hashalloc(ip, cg, bpref, size, ffs_alloccg);
if (bno > 0) {
/* allocation successful, update inode data */
DIP_ADD(ip, blocks, btodb(size));
ip->i_flag |= IN_CHANGE | IN_UPDATE;
*bnp = bno;
return (0);
}
/* Restore user's disk quota because allocation failed. */
(void) ufs_quota_free_blocks(ip, btodb(size), cred);
nospace:
if (ratecheck(&fsfull_last, &fserr_interval)) {
ffs_fserr(fs, cred->cr_uid, "file system full");
uprintf("\n%s: write failed, file system is full\n",
fs->fs_fsmnt);
}
return (ENOSPC);
}
/*
* Reallocate a fragment to a bigger size
*
* The number and size of the old block is given, and a preference
* and new size is also specified. The allocator attempts to extend
* the original block. Failing that, the regular block allocator is
* invoked to get an appropriate block.
*/
int
ffs_realloccg(struct inode *ip, daddr_t lbprev, daddr_t bpref, int osize,
int nsize, struct ucred *cred, struct buf **bpp, daddr_t *blknop)
{
static struct timeval fsfull_last;
struct fs *fs;
struct buf *bp = NULL;
daddr_t quota_updated = 0;
int request, error;
u_int cg;
daddr_t bprev, bno;
if (bpp != NULL)
*bpp = NULL;
fs = ip->i_fs;
#ifdef DIAGNOSTIC
if ((u_int)osize > fs->fs_bsize || fragoff(fs, osize) != 0 ||
(u_int)nsize > fs->fs_bsize || fragoff(fs, nsize) != 0) {
printf(
"dev = 0x%x, bsize = %d, osize = %d, nsize = %d, fs = %s\n",
ip->i_dev, fs->fs_bsize, osize, nsize, fs->fs_fsmnt);
panic("ffs_realloccg: bad size");
}
if (cred == NOCRED)
panic("ffs_realloccg: missing credential");
#endif /* DIAGNOSTIC */
if (cred->cr_uid != 0 && freespace(fs, fs->fs_minfree) <= 0)
goto nospace;
bprev = DIP(ip, db[lbprev]);
if (bprev == 0) {
printf("dev = 0x%x, bsize = %d, bprev = %lld, fs = %s\n",
ip->i_dev, fs->fs_bsize, (long long)bprev, fs->fs_fsmnt);
panic("ffs_realloccg: bad bprev");
}
/*
* Allocate the extra space in the buffer.
*/
if (bpp != NULL) {
if ((error = bread(ITOV(ip), lbprev, fs->fs_bsize, &bp)) != 0)
goto error;
buf_adjcnt(bp, osize);
}
if ((error = ufs_quota_alloc_blocks(ip, btodb(nsize - osize), cred))
!= 0)
goto error;
quota_updated = btodb(nsize - osize);
/*
* Check for extension in the existing location.
*/
cg = dtog(fs, bprev);
if ((bno = ffs_fragextend(ip, cg, bprev, osize, nsize)) != 0) {
DIP_ADD(ip, blocks, btodb(nsize - osize));
ip->i_flag |= IN_CHANGE | IN_UPDATE;
if (bpp != NULL) {
if (bp->b_blkno != fsbtodb(fs, bno))
panic("ffs_realloccg: bad blockno");
#ifdef DIAGNOSTIC
if (nsize > bp->b_bufsize)
panic("ffs_realloccg: small buf");
#endif
buf_adjcnt(bp, nsize);
bp->b_flags |= B_DONE;
memset(bp->b_data + osize, 0, nsize - osize);
*bpp = bp;
}
if (blknop != NULL) {
*blknop = bno;
}
return (0);
}
/*
* Allocate a new disk location.
*/
if (bpref >= fs->fs_size)
bpref = 0;
switch (fs->fs_optim) {
case FS_OPTSPACE:
/*
* Allocate an exact sized fragment. Although this makes
* best use of space, we will waste time relocating it if
* the file continues to grow. If the fragmentation is
* less than half of the minimum free reserve, we choose
* to begin optimizing for time.
*/
request = nsize;
if (fs->fs_minfree < 5 ||
fs->fs_cstotal.cs_nffree >
fs->fs_dsize * fs->fs_minfree / (2 * 100))
break;
fs->fs_optim = FS_OPTTIME;
break;
case FS_OPTTIME:
/*
* At this point we have discovered a file that is trying to
* grow a small fragment to a larger fragment. To save time,
* we allocate a full sized block, then free the unused portion.
* If the file continues to grow, the `ffs_fragextend' call
* above will be able to grow it in place without further
* copying. If aberrant programs cause disk fragmentation to
* grow within 2% of the free reserve, we choose to begin
* optimizing for space.
*/
request = fs->fs_bsize;
if (fs->fs_cstotal.cs_nffree <
fs->fs_dsize * (fs->fs_minfree - 2) / 100)
break;
fs->fs_optim = FS_OPTSPACE;
break;
default:
printf("dev = 0x%x, optim = %d, fs = %s\n",
ip->i_dev, fs->fs_optim, fs->fs_fsmnt);
panic("ffs_realloccg: bad optim");
/* NOTREACHED */
}
bno = ffs_hashalloc(ip, cg, bpref, request, ffs_alloccg);
if (bno <= 0)
goto nospace;
(void) uvm_vnp_uncache(ITOV(ip));
ffs_blkfree(ip, bprev, (long)osize);
if (nsize < request)
ffs_blkfree(ip, bno + numfrags(fs, nsize),
(long)(request - nsize));
DIP_ADD(ip, blocks, btodb(nsize - osize));
ip->i_flag |= IN_CHANGE | IN_UPDATE;
if (bpp != NULL) {
bp->b_blkno = fsbtodb(fs, bno);
#ifdef DIAGNOSTIC
if (nsize > bp->b_bufsize)
panic("ffs_realloccg: small buf 2");
#endif
buf_adjcnt(bp, nsize);
bp->b_flags |= B_DONE;
memset(bp->b_data + osize, 0, nsize - osize);
*bpp = bp;
}
if (blknop != NULL) {
*blknop = bno;
}
return (0);
nospace:
if (ratecheck(&fsfull_last, &fserr_interval)) {
ffs_fserr(fs, cred->cr_uid, "file system full");
uprintf("\n%s: write failed, file system is full\n",
fs->fs_fsmnt);
}
error = ENOSPC;
error:
if (bp != NULL) {
brelse(bp);
bp = NULL;
}
/*
* Restore user's disk quota because allocation failed.
*/
if (quota_updated != 0)
(void)ufs_quota_free_blocks(ip, quota_updated, cred);
return error;
}
/*
* Allocate an inode in the file system.
*
* If allocating a directory, use ffs_dirpref to select the inode.
* If allocating in a directory, the following hierarchy is followed:
* 1) allocate the preferred inode.
* 2) allocate an inode in the same cylinder group.
* 3) quadratically rehash into other cylinder groups, until an
* available inode is located.
* If no inode preference is given the following hierarchy is used
* to allocate an inode:
* 1) allocate an inode in cylinder group 0.
* 2) quadratically rehash into other cylinder groups, until an
* available inode is located.
*/
int
ffs_inode_alloc(struct inode *pip, mode_t mode, struct ucred *cred,
struct vnode **vpp)
{
static struct timeval fsnoinodes_last;
struct vnode *pvp = ITOV(pip);
struct fs *fs;
struct inode *ip;
ufsino_t ino, ipref;
u_int cg;
int error;
*vpp = NULL;
fs = pip->i_fs;
if (fs->fs_cstotal.cs_nifree == 0)
goto noinodes;
if ((mode & IFMT) == IFDIR)
ipref = ffs_dirpref(pip);
else
ipref = pip->i_number;
if (ipref >= fs->fs_ncg * fs->fs_ipg)
ipref = 0;
cg = ino_to_cg(fs, ipref);
/*
* Track number of dirs created one after another
* in a same cg without intervening by files.
*/
if ((mode & IFMT) == IFDIR) {
if (fs->fs_contigdirs[cg] < 255)
fs->fs_contigdirs[cg]++;
} else {
if (fs->fs_contigdirs[cg] > 0)
fs->fs_contigdirs[cg]--;
}
ino = (ufsino_t)ffs_hashalloc(pip, cg, ipref, mode, ffs_nodealloccg);
if (ino == 0)
goto noinodes;
error = VFS_VGET(pvp->v_mount, ino, vpp);
if (error) {
ffs_inode_free(pip, ino, mode);
return (error);
}
ip = VTOI(*vpp);
if (DIP(ip, mode)) {
printf("mode = 0%o, inum = %u, fs = %s\n",
DIP(ip, mode), ip->i_number, fs->fs_fsmnt);
panic("ffs_valloc: dup alloc");
}
if (DIP(ip, blocks)) {
printf("free inode %s/%d had %lld blocks\n",
fs->fs_fsmnt, ino, (long long)DIP(ip, blocks));
DIP_ASSIGN(ip, blocks, 0);
}
DIP_ASSIGN(ip, flags, 0);
/*
* Set up a new generation number for this inode.
* On wrap, we make sure to assign a number != 0 and != UINT_MAX
* (the original value).
*/
if (DIP(ip, gen) != 0)
DIP_ADD(ip, gen, 1);
while (DIP(ip, gen) == 0)
DIP_ASSIGN(ip, gen, arc4random_uniform(UINT_MAX));
return (0);
noinodes:
if (ratecheck(&fsnoinodes_last, &fserr_interval)) {
ffs_fserr(fs, cred->cr_uid, "out of inodes");
uprintf("\n%s: create/symlink failed, no inodes free\n",
fs->fs_fsmnt);
}
return (ENOSPC);
}
/*
* Find a cylinder group 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.
*/
ufsino_t
ffs_dirpref(struct inode *pip)
{
struct fs *fs;
u_int cg, prefcg;
u_int dirsize, cgsize;
u_int avgifree, avgbfree, avgndir, curdirsize;
u_int minifree, minbfree, maxndir;
u_int mincg, minndir;
u_int maxcontigdirs;
fs = pip->i_fs;
avgifree = fs->fs_cstotal.cs_nifree / fs->fs_ncg;
avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg;
avgndir = fs->fs_cstotal.cs_ndir / fs->fs_ncg;
/*
* Force allocation in another cg if creating a first level dir.
*/
if (ITOV(pip)->v_flag & VROOT) {
prefcg = arc4random_uniform(fs->fs_ncg);
mincg = prefcg;
minndir = fs->fs_ipg;
for (cg = prefcg; cg < fs->fs_ncg; cg++)
if (fs->fs_cs(fs, cg).cs_ndir < minndir &&
fs->fs_cs(fs, cg).cs_nifree >= avgifree &&
fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {
mincg = cg;
minndir = fs->fs_cs(fs, cg).cs_ndir;
}
for (cg = 0; cg < prefcg; cg++)
if (fs->fs_cs(fs, cg).cs_ndir < minndir &&
fs->fs_cs(fs, cg).cs_nifree >= avgifree &&
fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {
mincg = cg;
minndir = fs->fs_cs(fs, cg).cs_ndir;
}
cg = mincg;
goto end;
} else
prefcg = ino_to_cg(fs, pip->i_number);
/*
* Count various limits which used for
* optimal allocation of a directory inode.
*/
maxndir = min(avgndir + fs->fs_ipg / 16, fs->fs_ipg);
minifree = avgifree - (avgifree / 4);
if (minifree < 1)
minifree = 1;
minbfree = avgbfree - (avgbfree / 4);
if (minbfree < 1)
minbfree = 1;
cgsize = fs->fs_fsize * fs->fs_fpg;
dirsize = fs->fs_avgfilesize * fs->fs_avgfpdir;
curdirsize = avgndir ? (cgsize - avgbfree * fs->fs_bsize) / avgndir : 0;
if (dirsize < curdirsize)
dirsize = curdirsize;
if (dirsize <= 0)
maxcontigdirs = 0; /* dirsize overflowed */
else
maxcontigdirs = min(avgbfree * fs->fs_bsize / dirsize, 255);
if (fs->fs_avgfpdir > 0)
maxcontigdirs = min(maxcontigdirs,
fs->fs_ipg / fs->fs_avgfpdir);
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.
*
* We are trying to find a suitable cylinder group nearby
* our preferred cylinder group to place a new directory.
* We scan from our preferred cylinder group forward looking
* for a cylinder group that meets our criterion. If we get
* to the final cylinder group and do not find anything,
* we start scanning forwards from the beginning of the
* filesystem. While it might seem sensible to start scanning
* backwards or even to alternate looking forward and backward,
* this approach fails badly when the filesystem is nearly full.
* Specifically, we first search all the areas that have no space
* and finally try the one preceding that. We repeat this on
* every request and in the case of the final block end up
* searching the entire filesystem. By jumping to the front
* of the filesystem, our future forward searches always look
* in new cylinder groups so finds every possible block after
* one pass over the filesystem.
*/
for (cg = prefcg; cg < fs->fs_ncg; cg++)
if (fs->fs_cs(fs, cg).cs_ndir < maxndir &&
fs->fs_cs(fs, cg).cs_nifree >= minifree &&
fs->fs_cs(fs, cg).cs_nbfree >= minbfree) {
if (fs->fs_contigdirs[cg] < maxcontigdirs)
goto end;
}
for (cg = 0; cg < prefcg; cg++)
if (fs->fs_cs(fs, cg).cs_ndir < maxndir &&
fs->fs_cs(fs, cg).cs_nifree >= minifree &&
fs->fs_cs(fs, cg).cs_nbfree >= minbfree) {
if (fs->fs_contigdirs[cg] < maxcontigdirs)
goto end;
}
/*
* This is a backstop when we have deficit in space.
*/
for (cg = prefcg; cg < fs->fs_ncg; cg++)
if (fs->fs_cs(fs, cg).cs_nifree >= avgifree)
goto end;
for (cg = 0; cg < prefcg; cg++)
if (fs->fs_cs(fs, cg).cs_nifree >= avgifree)
goto end;
end:
return ((ufsino_t)(fs->fs_ipg * cg));
}
/*
* Select the desired position for the next block in a file. The file is
* logically divided into sections. The first section is composed of the
* direct blocks. Each additional section contains fs_maxbpg blocks.
*
* If no blocks have been allocated in the first section, the policy is to
* request a block in the same cylinder group as the inode that describes
* the file. The first indirect is allocated immediately following the last
* direct block and the data blocks for the first indirect immediately
* follow it.
*
* If no blocks have been allocated in any other section, the indirect
* block(s) are allocated in the same cylinder group as its inode in an
* area reserved immediately following the inode blocks. The policy for
* the data blocks is to place them in a cylinder group with a greater than
* average number of free blocks. An appropriate cylinder group is found
* by using a rotor that sweeps the cylinder groups. When a new group of
* blocks is needed, the sweep begins in the cylinder group following the
* cylinder group from which the previous allocation was made. The sweep
* continues until a cylinder group with greater than the average number
* of free blocks is found. If the allocation is for the first block in an
* indirect block, the information on the previous allocation is unavailable;
* here a best guess is made based upon the logical block number being
* allocated.
*/
int32_t
ffs1_blkpref(struct inode *ip, daddr_t lbn, int indx, int32_t *bap)
{
struct fs *fs;
u_int cg, inocg;
u_int avgbfree, startcg;
uint32_t pref;
KASSERT(indx <= 0 || bap != NULL);
fs = ip->i_fs;
/*
* Allocation of indirect blocks is indicated by passing negative
* values in indx: -1 for single indirect, -2 for double indirect,
* -3 for triple indirect. As noted below, we attempt to allocate
* the first indirect inline with the file data. For all later
* indirect blocks, the data is often allocated in other cylinder
* groups. However to speed random file access and to speed up
* fsck, the filesystem reserves the first fs_metaspace blocks
* (typically half of fs_minfree) of the data area of each cylinder
* group to hold these later indirect blocks.
*/
inocg = ino_to_cg(fs, ip->i_number);
if (indx < 0) {
/*
* Our preference for indirect blocks is the zone at the
* beginning of the inode's cylinder group data area that
* we try to reserve for indirect blocks.
*/
pref = cgmeta(fs, inocg);
/*
* If we are allocating the first indirect block, try to
* place it immediately following the last direct block.
*/
if (indx == -1 && lbn < NDADDR + NINDIR(fs) &&
ip->i_din1->di_db[NDADDR - 1] != 0)
pref = ip->i_din1->di_db[NDADDR - 1] + fs->fs_frag;
return (pref);
}
/*
* If we are allocating the first data block in the first indirect
* block and the indirect has been allocated in the data block area,
* try to place it immediately following the indirect block.
*/
if (lbn == NDADDR) {
pref = ip->i_din1->di_ib[0];
if (pref != 0 && pref >= cgdata(fs, inocg) &&
pref < cgbase(fs, inocg + 1))
return (pref + fs->fs_frag);
}
/*
* If we are the beginning of a file, or we have already allocated
* the maximum number of blocks per cylinder group, or we do not
* have a block allocated immediately preceding us, then we need
* to decide where to start allocating new blocks.
*/
if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) {
/*
* If we are allocating a directory data block, we want
* to place it in the metadata area.
*/
if ((DIP(ip, mode) & IFMT) == IFDIR)
return (cgmeta(fs, inocg));
/*
* Until we fill all the direct and all the first indirect's
* blocks, we try to allocate in the data area of the inode's
* cylinder group.
*/
if (lbn < NDADDR + NINDIR(fs))
return (cgdata(fs, inocg));
/*
* Find a cylinder with greater than average number of
* unused data blocks.
*/
if (indx == 0 || bap[indx - 1] == 0)
startcg = inocg + lbn / fs->fs_maxbpg;
else
startcg = dtog(fs, bap[indx - 1]) + 1;
startcg %= fs->fs_ncg;
avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg;
for (cg = startcg; cg < fs->fs_ncg; cg++)
if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {
fs->fs_cgrotor = cg;
return (cgdata(fs, cg));
}
for (cg = 0; cg <= startcg; cg++)
if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree) {
fs->fs_cgrotor = cg;
return (cgdata(fs, cg));
}
return (0);
}
/*
* Otherwise, we just always try to lay things out contiguously.
*/
return (bap[indx - 1] + fs->fs_frag);
}
/*
* Same as above, for UFS2.
*/
#ifdef FFS2
int64_t
ffs2_blkpref(struct inode *ip, daddr_t lbn, int indx, int64_t *bap)
{
struct fs *fs;
u_int cg, inocg;
u_int avgbfree, startcg;
uint64_t pref;
KASSERT(indx <= 0 || bap != NULL);
fs = ip->i_fs;
/*
* Allocation of indirect blocks is indicated by passing negative
* values in indx: -1 for single indirect, -2 for double indirect,
* -3 for triple indirect. As noted below, we attempt to allocate
* the first indirect inline with the file data. For all later
* indirect blocks, the data is often allocated in other cylinder
* groups. However to speed random file access and to speed up
* fsck, the filesystem reserves the first fs_metaspace blocks
* (typically half of fs_minfree) of the data area of each cylinder
* group to hold these later indirect blocks.
*/
inocg = ino_to_cg(fs, ip->i_number);
if (indx < 0) {
/*
* Our preference for indirect blocks is the zone at the
* beginning of the inode's cylinder group data area that
* we try to reserve for indirect blocks.
*/
pref = cgmeta(fs, inocg);
/*
* If we are allocating the first indirect block, try to
* place it immediately following the last direct block.
*/
if (indx == -1 && lbn < NDADDR + NINDIR(fs) &&
ip->i_din2->di_db[NDADDR - 1] != 0)
pref = ip->i_din2->di_db[NDADDR - 1] + fs->fs_frag;
return (pref);
}
/*
* If we are allocating the first data block in the first indirect
* block and the indirect has been allocated in the data block area,
* try to place it immediately following the indirect block.
*/
if (lbn == NDADDR) {
pref = ip->i_din2->di_ib[0];
if (pref != 0 && pref >= cgdata(fs, inocg) &&
pref < cgbase(fs, inocg + 1))
return (pref + fs->fs_frag);
}
/*
* If we are the beginning of a file, or we have already allocated
* the maximum number of blocks per cylinder group, or we do not
* have a block allocated immediately preceding us, then we need
* to decide where to start allocating new blocks.
*/
if (indx % fs->fs_maxbpg == 0 || bap[indx - 1] == 0) {
/*
* If we are allocating a directory data block, we want
* to place it in the metadata area.
*/
if ((DIP(ip, mode) & IFMT) == IFDIR)
return (cgmeta(fs, inocg));
/*
* Until we fill all the direct and all the first indirect's
* blocks, we try to allocate in the data area of the inode's
* cylinder group.
*/
if (lbn < NDADDR + NINDIR(fs))
return (cgdata(fs, inocg));
/*
* Find a cylinder with greater than average number of
* unused data blocks.
*/
if (indx == 0 || bap[indx - 1] == 0)
startcg = inocg + lbn / fs->fs_maxbpg;
else
startcg = dtog(fs, bap[indx - 1] + 1);
startcg %= fs->fs_ncg;
avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg;
for (cg = startcg; cg < fs->fs_ncg; cg++)
if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree)
return (cgbase(fs, cg) + fs->fs_frag);
for (cg = 0; cg < startcg; cg++)
if (fs->fs_cs(fs, cg).cs_nbfree >= avgbfree)
return (cgbase(fs, cg) + fs->fs_frag);
return (0);
}
/*
* Otherwise, we just always try to lay things out contiguously.
*/
return (bap[indx - 1] + fs->fs_frag);
}
#endif /* FFS2 */
/*
* Implement the cylinder overflow algorithm.
*
* The policy implemented by this algorithm is:
* 1) allocate the block in its requested cylinder group.
* 2) quadratically rehash on the cylinder group number.
* 3) brute force search for a free block.
*/
daddr_t
ffs_hashalloc(struct inode *ip, u_int cg, daddr_t pref, int size,
daddr_t (*allocator)(struct inode *, u_int, daddr_t, int))
{
struct fs *fs;
daddr_t result;
u_int i, icg = cg;
fs = ip->i_fs;
/*
* 1: preferred cylinder group
*/
result = (*allocator)(ip, cg, pref, size);
if (result)
return (result);
/*
* 2: quadratic rehash
*/
for (i = 1; i < fs->fs_ncg; i *= 2) {
cg += i;
if (cg >= fs->fs_ncg)
cg -= fs->fs_ncg;
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->fs_ncg;
for (i = 2; i < fs->fs_ncg; i++) {
result = (*allocator)(ip, cg, 0, size);
if (result)
return (result);
cg++;
if (cg == fs->fs_ncg)
cg = 0;
}
return (0);
}
struct buf *
ffs_cgread(struct fs *fs, struct inode *ip, u_int cg)
{
struct buf *bp;
if (bread(ip->i_devvp, fsbtodb(fs, cgtod(fs, cg)),
(int)fs->fs_cgsize, &bp)) {
brelse(bp);
return (NULL);
}
if (!cg_chkmagic((struct cg *)bp->b_data)) {
brelse(bp);
return (NULL);
}
return bp;
}
/*
* Determine whether a fragment can be extended.
*
* Check to see if the necessary fragments are available, and
* if they are, allocate them.
*/
daddr_t
ffs_fragextend(struct inode *ip, u_int cg, daddr_t bprev, int osize, int nsize)
{
struct fs *fs;
struct cg *cgp;
struct buf *bp;
struct timespec now;
daddr_t bno;
int i, frags, bbase;
fs = ip->i_fs;
if (fs->fs_cs(fs, cg).cs_nffree < numfrags(fs, nsize - osize))
return (0);
frags = numfrags(fs, nsize);
bbase = fragnum(fs, bprev);
if (bbase > fragnum(fs, (bprev + frags - 1))) {
/* cannot extend across a block boundary */
return (0);
}
if (!(bp = ffs_cgread(fs, ip, cg)))
return (0);
cgp = (struct cg *)bp->b_data;
nanotime(&now);
cgp->cg_ffs2_time = now.tv_sec;
cgp->cg_time = now.tv_sec;
bno = dtogd(fs, bprev);
for (i = numfrags(fs, osize); i < frags; i++)
if (isclr(cg_blksfree(cgp), bno + i)) {
brelse(bp);
return (0);
}
/*
* the current fragment can be extended
* deduct the count on fragment being extended into
* increase the count on the remaining fragment (if any)
* allocate the extended piece
*/
for (i = frags; i < fs->fs_frag - bbase; i++)
if (isclr(cg_blksfree(cgp), bno + i))
break;
cgp->cg_frsum[i - numfrags(fs, osize)]--;
if (i != frags)
cgp->cg_frsum[i - frags]++;
for (i = numfrags(fs, osize); i < frags; i++) {
clrbit(cg_blksfree(cgp), bno + i);
cgp->cg_cs.cs_nffree--;
fs->fs_cstotal.cs_nffree--;
fs->fs_cs(fs, cg).cs_nffree--;
}
fs->fs_fmod = 1;
bdwrite(bp);
return (bprev);
}
/*
* 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.
*/
daddr_t
ffs_alloccg(struct inode *ip, u_int cg, daddr_t bpref, int size)
{
struct fs *fs;
struct cg *cgp;
struct buf *bp;
struct timespec now;
daddr_t bno, blkno;
int i, frags, allocsiz;
fs = ip->i_fs;
if (fs->fs_cs(fs, cg).cs_nbfree == 0 && size == fs->fs_bsize)
return (0);
if (!(bp = ffs_cgread(fs, ip, cg)))
return (0);
cgp = (struct cg *)bp->b_data;
if (cgp->cg_cs.cs_nbfree == 0 && size == fs->fs_bsize) {
brelse(bp);
return (0);
}
nanotime(&now);
cgp->cg_ffs2_time = now.tv_sec;
cgp->cg_time = now.tv_sec;
if (size == fs->fs_bsize) {
/* allocate and return a complete data block */
bno = ffs_alloccgblk(ip, bp, bpref);
bdwrite(bp);
return (bno);
}
/*
* check to see if any fragments are already available
* allocsiz is the size which will be allocated, hacking
* it down to a smaller size if necessary
*/
frags = numfrags(fs, size);
for (allocsiz = frags; allocsiz < fs->fs_frag; allocsiz++)
if (cgp->cg_frsum[allocsiz] != 0)
break;
if (allocsiz == fs->fs_frag) {
/*
* no fragments were available, so a block will be
* allocated, and hacked up
*/
if (cgp->cg_cs.cs_nbfree == 0) {
brelse(bp);
return (0);
}
bno = ffs_alloccgblk(ip, bp, bpref);
bpref = dtogd(fs, bno);
for (i = frags; i < fs->fs_frag; i++)
setbit(cg_blksfree(cgp), bpref + i);
i = fs->fs_frag - frags;
cgp->cg_cs.cs_nffree += i;
fs->fs_cstotal.cs_nffree += i;
fs->fs_cs(fs, cg).cs_nffree += i;
fs->fs_fmod = 1;
cgp->cg_frsum[i]++;
bdwrite(bp);
return (bno);
}
bno = ffs_mapsearch(fs, cgp, bpref, allocsiz);
if (bno < 0) {
brelse(bp);