FreeBSD-5.3/sys/gnu/ext2fs/ext2_readwrite.c
/*
* modified for Lites 1.1
*
* Aug 1995, Godmar Back (gback@cs.utah.edu)
* University of Utah, Department of Computer Science
*/
/*
* Copyright (c) 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.
*
* @(#)ufs_readwrite.c 8.7 (Berkeley) 1/21/94
* $FreeBSD: src/sys/gnu/ext2fs/ext2_readwrite.c,v 1.29 2004/04/07 20:46:03 imp Exp $
*/
#define BLKSIZE(a, b, c) blksize(a, b, c)
#define FS struct ext2_sb_info
#define I_FS i_e2fs
#define READ ext2_read
#define READ_S "ext2_read"
#define WRITE ext2_write
#define WRITE_S "ext2_write"
/*
* Vnode op for reading.
*/
/* ARGSUSED */
static int
READ(ap)
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
struct vnode *vp;
struct inode *ip;
struct uio *uio;
FS *fs;
struct buf *bp;
daddr_t lbn, nextlbn;
off_t bytesinfile;
long size, xfersize, blkoffset;
int error, orig_resid;
int seqcount = ap->a_ioflag >> IO_SEQSHIFT;
u_short mode;
vp = ap->a_vp;
ip = VTOI(vp);
mode = ip->i_mode;
uio = ap->a_uio;
#ifdef DIAGNOSTIC
if (uio->uio_rw != UIO_READ)
panic("%s: mode", READ_S);
if (vp->v_type == VLNK) {
if ((int)ip->i_size < vp->v_mount->mnt_maxsymlinklen)
panic("%s: short symlink", READ_S);
} else if (vp->v_type != VREG && vp->v_type != VDIR)
panic("%s: type %d", READ_S, vp->v_type);
#endif
fs = ip->I_FS;
if ((uoff_t)uio->uio_offset > fs->fs_maxfilesize)
return (EFBIG);
orig_resid = uio->uio_resid;
for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) {
if ((bytesinfile = ip->i_size - uio->uio_offset) <= 0)
break;
lbn = lblkno(fs, uio->uio_offset);
nextlbn = lbn + 1;
size = BLKSIZE(fs, ip, lbn);
blkoffset = blkoff(fs, uio->uio_offset);
xfersize = fs->s_frag_size - blkoffset;
if (uio->uio_resid < xfersize)
xfersize = uio->uio_resid;
if (bytesinfile < xfersize)
xfersize = bytesinfile;
if (lblktosize(fs, nextlbn) >= ip->i_size)
error = bread(vp, lbn, size, NOCRED, &bp);
else if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0)
error = cluster_read(vp,
ip->i_size, lbn, size, NOCRED,
uio->uio_resid, (ap->a_ioflag >> IO_SEQSHIFT), &bp);
else if (seqcount > 1) {
int nextsize = BLKSIZE(fs, ip, nextlbn);
error = breadn(vp, lbn,
size, &nextlbn, &nextsize, 1, NOCRED, &bp);
} else
error = bread(vp, lbn, size, NOCRED, &bp);
if (error) {
brelse(bp);
bp = NULL;
break;
}
/*
* We should only get non-zero b_resid when an I/O error
* has occurred, which should cause us to break above.
* However, if the short read did not cause an error,
* then we want to ensure that we do not uiomove bad
* or uninitialized data.
*/
size -= bp->b_resid;
if (size < xfersize) {
if (size == 0)
break;
xfersize = size;
}
error =
uiomove((char *)bp->b_data + blkoffset, (int)xfersize, uio);
if (error)
break;
bqrelse(bp);
}
if (bp != NULL)
bqrelse(bp);
if (orig_resid > 0 && (error == 0 || uio->uio_resid != orig_resid) &&
(vp->v_mount->mnt_flag & MNT_NOATIME) == 0)
ip->i_flag |= IN_ACCESS;
return (error);
}
/*
* Vnode op for writing.
*/
static int
WRITE(ap)
struct vop_write_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
struct vnode *vp;
struct uio *uio;
struct inode *ip;
FS *fs;
struct buf *bp;
struct thread *td;
daddr_t lbn;
off_t osize;
int seqcount;
int blkoffset, error, flags, ioflag, resid, size, xfersize;
ioflag = ap->a_ioflag;
seqcount = ap->a_ioflag >> IO_SEQSHIFT;
uio = ap->a_uio;
vp = ap->a_vp;
ip = VTOI(vp);
#ifdef DIAGNOSTIC
if (uio->uio_rw != UIO_WRITE)
panic("%s: mode", WRITE_S);
#endif
switch (vp->v_type) {
case VREG:
if (ioflag & IO_APPEND)
uio->uio_offset = ip->i_size;
if ((ip->i_flags & APPEND) && uio->uio_offset != ip->i_size)
return (EPERM);
/* FALLTHROUGH */
case VLNK:
break;
case VDIR:
if ((ioflag & IO_SYNC) == 0)
panic("%s: nonsync dir write", WRITE_S);
break;
default:
panic("%s: type", WRITE_S);
}
fs = ip->I_FS;
if (uio->uio_offset < 0 ||
(uoff_t)uio->uio_offset + uio->uio_resid > fs->fs_maxfilesize)
return (EFBIG);
/*
* Maybe this should be above the vnode op call, but so long as
* file servers have no limits, I don't think it matters.
*/
td = uio->uio_td;
if (vp->v_type == VREG && td != NULL) {
PROC_LOCK(td->td_proc);
if (uio->uio_offset + uio->uio_resid >
lim_cur(td->td_proc, RLIMIT_FSIZE)) {
psignal(td->td_proc, SIGXFSZ);
PROC_UNLOCK(td->td_proc);
return (EFBIG);
}
PROC_UNLOCK(td->td_proc);
}
resid = uio->uio_resid;
osize = ip->i_size;
flags = ioflag & IO_SYNC ? B_SYNC : 0;
for (error = 0; uio->uio_resid > 0;) {
lbn = lblkno(fs, uio->uio_offset);
blkoffset = blkoff(fs, uio->uio_offset);
xfersize = fs->s_frag_size - blkoffset;
if (uio->uio_resid < xfersize)
xfersize = uio->uio_resid;
if (uio->uio_offset + xfersize > ip->i_size)
vnode_pager_setsize(vp, uio->uio_offset + xfersize);
/*
* Avoid a data-consistency race between write() and mmap()
* by ensuring that newly allocated blocks are zerod. The
* race can occur even in the case where the write covers
* the entire block.
*/
flags |= B_CLRBUF;
#if 0
if (fs->s_frag_size > xfersize)
flags |= B_CLRBUF;
else
flags &= ~B_CLRBUF;
#endif
error = ext2_balloc(ip,
lbn, blkoffset + xfersize, ap->a_cred, &bp, flags);
if (error)
break;
if (uio->uio_offset + xfersize > ip->i_size) {
ip->i_size = uio->uio_offset + xfersize;
}
size = BLKSIZE(fs, ip, lbn) - bp->b_resid;
if (size < xfersize)
xfersize = size;
error =
uiomove((char *)bp->b_data + blkoffset, (int)xfersize, uio);
if ((ioflag & IO_VMIO) &&
(LIST_FIRST(&bp->b_dep) == NULL)) /* in ext2fs? */
bp->b_flags |= B_RELBUF;
if (ioflag & IO_SYNC) {
(void)bwrite(bp);
} else if (xfersize + blkoffset == fs->s_frag_size) {
if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERW) == 0) {
bp->b_flags |= B_CLUSTEROK;
cluster_write(bp, ip->i_size, seqcount);
} else {
bawrite(bp);
}
} else {
bp->b_flags |= B_CLUSTEROK;
bdwrite(bp);
}
if (error || xfersize == 0)
break;
ip->i_flag |= IN_CHANGE | IN_UPDATE;
}
/*
* If we successfully wrote any data, and we are not the superuser
* we clear the setuid and setgid bits as a precaution against
* tampering.
*/
if (resid > uio->uio_resid && ap->a_cred && ap->a_cred->cr_uid != 0)
ip->i_mode &= ~(ISUID | ISGID);
if (error) {
if (ioflag & IO_UNIT) {
(void)ext2_truncate(vp, osize,
ioflag & IO_SYNC, ap->a_cred, uio->uio_td);
uio->uio_offset -= resid - uio->uio_resid;
uio->uio_resid = resid;
}
} else if (resid > uio->uio_resid && (ioflag & IO_SYNC))
error = ext2_update(vp, 1);
return (error);
}