a3d0c189ea
the gating of system calls that cause modifications to the underlying filesystem. The gating can be enabled by any filesystem that needs to consistently suspend operations by adding the vop_stdgetwritemount to their set of vnops. Once gating is enabled, the function vfs_write_suspend stops all new write operations to a filesystem, allows any filesystem modifying system calls already in progress to complete, then sync's the filesystem to disk and returns. The function vfs_write_resume allows the suspended write operations to begin again. Gating is not added by default for all filesystems as for SMP systems it adds two extra locks to such critical kernel paths as the write system call. Thus, gating should only be added as needed. Details on the use and current status of snapshots in FFS can be found in /sys/ufs/ffs/README.snapshot so for brevity and timelyness is not included here. Unless and until you create a snapshot file, these changes should have no effect on your system (famous last words).
400 lines
11 KiB
C
400 lines
11 KiB
C
/*
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)ffs_balloc.c 8.8 (Berkeley) 6/16/95
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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/bio.h>
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#include <sys/buf.h>
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#include <sys/lock.h>
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#include <sys/mount.h>
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#include <sys/vnode.h>
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#include <ufs/ufs/quota.h>
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#include <ufs/ufs/inode.h>
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#include <ufs/ufs/ufs_extern.h>
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#include <ufs/ffs/fs.h>
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#include <ufs/ffs/ffs_extern.h>
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/*
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* Balloc defines the structure of file system storage
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* by allocating the physical blocks on a device given
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* the inode and the logical block number in a file.
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*/
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int
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ffs_balloc(ap)
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struct vop_balloc_args /* {
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struct vnode *a_vp;
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ufs_daddr_t a_lbn;
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int a_size;
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struct ucred *a_cred;
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int a_flags;
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struct buf *a_bpp;
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} */ *ap;
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{
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struct inode *ip;
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ufs_daddr_t lbn;
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int size;
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struct ucred *cred;
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int flags;
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struct fs *fs;
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ufs_daddr_t nb;
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struct buf *bp, *nbp;
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struct vnode *vp;
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struct indir indirs[NIADDR + 2];
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ufs_daddr_t newb, *bap, pref;
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int deallocated, osize, nsize, num, i, error;
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ufs_daddr_t *allocib, *blkp, *allocblk, allociblk[NIADDR + 1];
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int unwindidx = -1;
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struct proc *p = curproc; /* XXX */
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vp = ap->a_vp;
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ip = VTOI(vp);
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fs = ip->i_fs;
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lbn = lblkno(fs, ap->a_startoffset);
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size = blkoff(fs, ap->a_startoffset) + ap->a_size;
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if (size > fs->fs_bsize)
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panic("ffs_balloc: blk too big");
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*ap->a_bpp = NULL;
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if (lbn < 0)
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return (EFBIG);
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cred = ap->a_cred;
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flags = ap->a_flags;
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/*
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* If the next write will extend the file into a new block,
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* and the file is currently composed of a fragment
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* this fragment has to be extended to be a full block.
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*/
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nb = lblkno(fs, ip->i_size);
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if (nb < NDADDR && nb < lbn) {
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osize = blksize(fs, ip, nb);
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if (osize < fs->fs_bsize && osize > 0) {
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error = ffs_realloccg(ip, nb,
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ffs_blkpref(ip, nb, (int)nb, &ip->i_db[0]),
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osize, (int)fs->fs_bsize, cred, &bp);
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if (error)
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return (error);
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if (DOINGSOFTDEP(vp))
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softdep_setup_allocdirect(ip, nb,
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dbtofsb(fs, bp->b_blkno), ip->i_db[nb],
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fs->fs_bsize, osize, bp);
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ip->i_size = smalllblktosize(fs, nb + 1);
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ip->i_db[nb] = dbtofsb(fs, bp->b_blkno);
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ip->i_flag |= IN_CHANGE | IN_UPDATE;
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if (flags & B_SYNC)
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bwrite(bp);
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else
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bawrite(bp);
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}
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}
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/*
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* The first NDADDR blocks are direct blocks
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*/
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if (lbn < NDADDR) {
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if (flags & B_METAONLY)
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panic("ffs_balloc: B_METAONLY for direct block");
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nb = ip->i_db[lbn];
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if (nb != 0 && ip->i_size >= smalllblktosize(fs, lbn + 1)) {
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error = bread(vp, lbn, fs->fs_bsize, NOCRED, &bp);
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if (error) {
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brelse(bp);
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return (error);
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}
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bp->b_blkno = fsbtodb(fs, nb);
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*ap->a_bpp = bp;
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return (0);
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}
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if (nb != 0) {
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/*
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* Consider need to reallocate a fragment.
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*/
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osize = fragroundup(fs, blkoff(fs, ip->i_size));
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nsize = fragroundup(fs, size);
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if (nsize <= osize) {
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error = bread(vp, lbn, osize, NOCRED, &bp);
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if (error) {
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brelse(bp);
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return (error);
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}
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bp->b_blkno = fsbtodb(fs, nb);
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} else {
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error = ffs_realloccg(ip, lbn,
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ffs_blkpref(ip, lbn, (int)lbn,
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&ip->i_db[0]), osize, nsize, cred, &bp);
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if (error)
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return (error);
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if (DOINGSOFTDEP(vp))
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softdep_setup_allocdirect(ip, lbn,
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dbtofsb(fs, bp->b_blkno), nb,
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nsize, osize, bp);
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}
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} else {
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if (ip->i_size < smalllblktosize(fs, lbn + 1))
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nsize = fragroundup(fs, size);
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else
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nsize = fs->fs_bsize;
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error = ffs_alloc(ip, lbn,
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ffs_blkpref(ip, lbn, (int)lbn, &ip->i_db[0]),
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nsize, cred, &newb);
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if (error)
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return (error);
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bp = getblk(vp, lbn, nsize, 0, 0);
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bp->b_blkno = fsbtodb(fs, newb);
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if (flags & B_CLRBUF)
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vfs_bio_clrbuf(bp);
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if (DOINGSOFTDEP(vp))
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softdep_setup_allocdirect(ip, lbn, newb, 0,
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nsize, 0, bp);
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}
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ip->i_db[lbn] = dbtofsb(fs, bp->b_blkno);
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ip->i_flag |= IN_CHANGE | IN_UPDATE;
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*ap->a_bpp = bp;
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return (0);
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}
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/*
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* Determine the number of levels of indirection.
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*/
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pref = 0;
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if ((error = ufs_getlbns(vp, lbn, indirs, &num)) != 0)
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return(error);
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#ifdef DIAGNOSTIC
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if (num < 1)
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panic ("ffs_balloc: ufs_bmaparray returned indirect block");
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#endif
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/*
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* Fetch the first indirect block allocating if necessary.
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*/
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--num;
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nb = ip->i_ib[indirs[0].in_off];
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allocib = NULL;
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allocblk = allociblk;
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if (nb == 0) {
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pref = ffs_blkpref(ip, lbn, 0, (ufs_daddr_t *)0);
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if ((error = ffs_alloc(ip, lbn, pref, (int)fs->fs_bsize,
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cred, &newb)) != 0)
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return (error);
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nb = newb;
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*allocblk++ = nb;
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bp = getblk(vp, indirs[1].in_lbn, fs->fs_bsize, 0, 0);
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bp->b_blkno = fsbtodb(fs, nb);
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vfs_bio_clrbuf(bp);
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if (DOINGSOFTDEP(vp)) {
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softdep_setup_allocdirect(ip, NDADDR + indirs[0].in_off,
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newb, 0, fs->fs_bsize, 0, bp);
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bdwrite(bp);
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} else {
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/*
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* Write synchronously so that indirect blocks
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* never point at garbage.
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*/
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if (DOINGASYNC(vp))
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bdwrite(bp);
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else if ((error = bwrite(bp)) != 0)
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goto fail;
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}
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allocib = &ip->i_ib[indirs[0].in_off];
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*allocib = nb;
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ip->i_flag |= IN_CHANGE | IN_UPDATE;
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}
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/*
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* Fetch through the indirect blocks, allocating as necessary.
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*/
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for (i = 1;;) {
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error = bread(vp,
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indirs[i].in_lbn, (int)fs->fs_bsize, NOCRED, &bp);
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if (error) {
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brelse(bp);
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goto fail;
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}
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bap = (ufs_daddr_t *)bp->b_data;
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nb = bap[indirs[i].in_off];
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if (i == num)
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break;
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i += 1;
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if (nb != 0) {
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bqrelse(bp);
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continue;
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}
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if (pref == 0)
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pref = ffs_blkpref(ip, lbn, 0, (ufs_daddr_t *)0);
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if ((error =
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ffs_alloc(ip, lbn, pref, (int)fs->fs_bsize, cred, &newb)) != 0) {
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brelse(bp);
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goto fail;
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}
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nb = newb;
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*allocblk++ = nb;
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nbp = getblk(vp, indirs[i].in_lbn, fs->fs_bsize, 0, 0);
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nbp->b_blkno = fsbtodb(fs, nb);
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vfs_bio_clrbuf(nbp);
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if (DOINGSOFTDEP(vp)) {
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softdep_setup_allocindir_meta(nbp, ip, bp,
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indirs[i - 1].in_off, nb);
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bdwrite(nbp);
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} else {
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/*
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* Write synchronously so that indirect blocks
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* never point at garbage.
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*/
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if ((error = bwrite(nbp)) != 0) {
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brelse(bp);
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goto fail;
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}
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}
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bap[indirs[i - 1].in_off] = nb;
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if (allocib == NULL && unwindidx < 0)
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unwindidx = i - 1;
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/*
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* If required, write synchronously, otherwise use
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* delayed write.
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*/
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if (flags & B_SYNC) {
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bwrite(bp);
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} else {
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if (bp->b_bufsize == fs->fs_bsize)
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bp->b_flags |= B_CLUSTEROK;
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bdwrite(bp);
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}
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}
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/*
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* If asked only for the indirect block, then return it.
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*/
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if (flags & B_METAONLY) {
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*ap->a_bpp = bp;
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return (0);
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}
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/*
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* Get the data block, allocating if necessary.
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*/
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if (nb == 0) {
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pref = ffs_blkpref(ip, lbn, indirs[i].in_off, &bap[0]);
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error = ffs_alloc(ip,
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lbn, pref, (int)fs->fs_bsize, cred, &newb);
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if (error) {
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brelse(bp);
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goto fail;
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}
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nb = newb;
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*allocblk++ = nb;
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nbp = getblk(vp, lbn, fs->fs_bsize, 0, 0);
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nbp->b_blkno = fsbtodb(fs, nb);
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if (flags & B_CLRBUF)
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vfs_bio_clrbuf(nbp);
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if (DOINGSOFTDEP(vp))
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softdep_setup_allocindir_page(ip, lbn, bp,
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indirs[i].in_off, nb, 0, nbp);
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bap[indirs[i].in_off] = nb;
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/*
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* If required, write synchronously, otherwise use
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* delayed write.
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*/
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if (flags & B_SYNC) {
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bwrite(bp);
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} else {
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if (bp->b_bufsize == fs->fs_bsize)
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bp->b_flags |= B_CLUSTEROK;
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bdwrite(bp);
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}
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*ap->a_bpp = nbp;
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return (0);
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}
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brelse(bp);
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if (flags & B_CLRBUF) {
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error = bread(vp, lbn, (int)fs->fs_bsize, NOCRED, &nbp);
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if (error) {
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brelse(nbp);
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goto fail;
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}
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} else {
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nbp = getblk(vp, lbn, fs->fs_bsize, 0, 0);
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nbp->b_blkno = fsbtodb(fs, nb);
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}
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*ap->a_bpp = nbp;
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return (0);
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fail:
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/*
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* If we have failed part way through block allocation, we
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* have to deallocate any indirect blocks that we have allocated.
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* We have to fsync the file before we start to get rid of all
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* of its dependencies so that we do not leave them dangling.
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* We have to sync it at the end so that the soft updates code
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* does not find any untracked changes. Although this is really
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* slow, running out of disk space is not expected to be a common
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* occurence. The error return from fsync is ignored as we already
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* have an error to return to the user.
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*/
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(void) VOP_FSYNC(vp, cred, MNT_WAIT, p);
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for (deallocated = 0, blkp = allociblk; blkp < allocblk; blkp++) {
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ffs_blkfree(ip, *blkp, fs->fs_bsize);
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deallocated += fs->fs_bsize;
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}
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if (allocib != NULL) {
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*allocib = 0;
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} else if (unwindidx >= 0) {
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int r;
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r = bread(vp, indirs[unwindidx].in_lbn,
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(int)fs->fs_bsize, NOCRED, &bp);
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if (r) {
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panic("Could not unwind indirect block, error %d", r);
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brelse(bp);
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} else {
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bap = (ufs_daddr_t *)bp->b_data;
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bap[indirs[unwindidx].in_off] = 0;
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if (flags & B_SYNC) {
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bwrite(bp);
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} else {
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if (bp->b_bufsize == fs->fs_bsize)
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bp->b_flags |= B_CLUSTEROK;
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bdwrite(bp);
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}
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}
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}
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if (deallocated) {
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#ifdef QUOTA
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/*
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* Restore user's disk quota because allocation failed.
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*/
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(void) chkdq(ip, (long)-btodb(deallocated), cred, FORCE);
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#endif
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ip->i_blocks -= btodb(deallocated);
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ip->i_flag |= IN_CHANGE | IN_UPDATE;
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}
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(void) VOP_FSYNC(vp, cred, MNT_WAIT, p);
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return (error);
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}
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