minix/sys/ufs/lfs/ulfs_readwrite.c

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/* $NetBSD: ulfs_readwrite.c,v 1.7 2013/10/17 21:01:08 christos Exp $ */
/* from NetBSD: ufs_readwrite.c,v 1.105 2013/01/22 09:39:18 dholland Exp */
/*-
* 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.
* 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.
*
* @(#)ufs_readwrite.c 8.11 (Berkeley) 5/8/95
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(1, "$NetBSD: ulfs_readwrite.c,v 1.7 2013/10/17 21:01:08 christos Exp $");
#ifdef LFS_READWRITE
#define FS struct lfs
#define I_FS i_lfs
#define READ lfs_read
#define READ_S "lfs_read"
#define WRITE lfs_write
#define WRITE_S "lfs_write"
#define fs_bsize lfs_bsize
#define fs_bmask lfs_bmask
#else
#define FS struct fs
#define I_FS i_fs
#define READ ffs_read
#define READ_S "ffs_read"
#define WRITE ffs_write
#define WRITE_S "ffs_write"
#endif
/*
* Vnode op for reading.
*/
/* ARGSUSED */
int
READ(void *v)
{
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
kauth_cred_t a_cred;
} */ *ap = v;
struct vnode *vp;
struct inode *ip;
struct uio *uio;
struct buf *bp;
FS *fs;
vsize_t bytelen;
daddr_t lbn, nextlbn;
off_t bytesinfile;
long size, xfersize, blkoffset;
int error, ioflag;
bool usepc = false;
vp = ap->a_vp;
ip = VTOI(vp);
fs = ip->I_FS;
uio = ap->a_uio;
ioflag = ap->a_ioflag;
error = 0;
#ifdef DIAGNOSTIC
if (uio->uio_rw != UIO_READ)
panic("%s: mode", READ_S);
if (vp->v_type == VLNK) {
if (ip->i_size < fs->um_maxsymlinklen ||
(fs->um_maxsymlinklen == 0 && DIP(ip, blocks) == 0))
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
if ((u_int64_t)uio->uio_offset > fs->um_maxfilesize)
return (EFBIG);
if (uio->uio_resid == 0)
return (0);
#ifndef LFS_READWRITE
if ((ip->i_flags & (SF_SNAPSHOT | SF_SNAPINVAL)) == SF_SNAPSHOT)
return ffs_snapshot_read(vp, uio, ioflag);
#endif /* !LFS_READWRITE */
fstrans_start(vp->v_mount, FSTRANS_SHARED);
if (uio->uio_offset >= ip->i_size)
goto out;
#ifdef LFS_READWRITE
usepc = (vp->v_type == VREG && ip->i_number != LFS_IFILE_INUM);
#else /* !LFS_READWRITE */
usepc = vp->v_type == VREG;
#endif /* !LFS_READWRITE */
if (usepc) {
const int advice = IO_ADV_DECODE(ap->a_ioflag);
while (uio->uio_resid > 0) {
if (ioflag & IO_DIRECT) {
genfs_directio(vp, uio, ioflag);
}
bytelen = MIN(ip->i_size - uio->uio_offset,
uio->uio_resid);
if (bytelen == 0)
break;
error = ubc_uiomove(&vp->v_uobj, uio, bytelen, advice,
UBC_READ | UBC_PARTIALOK | UBC_UNMAP_FLAG(vp));
if (error)
break;
}
goto out;
}
for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) {
bytesinfile = ip->i_size - uio->uio_offset;
if (bytesinfile <= 0)
break;
lbn = lfs_lblkno(fs, uio->uio_offset);
nextlbn = lbn + 1;
size = lfs_blksize(fs, ip, lbn);
blkoffset = lfs_blkoff(fs, uio->uio_offset);
xfersize = MIN(MIN(fs->fs_bsize - blkoffset, uio->uio_resid),
bytesinfile);
if (lfs_lblktosize(fs, nextlbn) >= ip->i_size)
error = bread(vp, lbn, size, NOCRED, 0, &bp);
else {
int nextsize = lfs_blksize(fs, ip, nextlbn);
error = breadn(vp, lbn,
size, &nextlbn, &nextsize, 1, NOCRED, 0, &bp);
}
if (error)
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, xfersize, uio);
if (error)
break;
brelse(bp, 0);
}
if (bp != NULL)
brelse(bp, 0);
out:
if (!(vp->v_mount->mnt_flag & MNT_NOATIME)) {
ip->i_flag |= IN_ACCESS;
if ((ap->a_ioflag & IO_SYNC) == IO_SYNC) {
error = lfs_update(vp, NULL, NULL, UPDATE_WAIT);
}
}
fstrans_done(vp->v_mount);
return (error);
}
/*
* Vnode op for writing.
*/
int
WRITE(void *v)
{
struct vop_write_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
kauth_cred_t a_cred;
} */ *ap = v;
struct vnode *vp;
struct uio *uio;
struct inode *ip;
FS *fs;
struct buf *bp;
kauth_cred_t cred;
daddr_t lbn;
off_t osize, origoff, oldoff, preallocoff, endallocoff, nsize;
int blkoffset, error, flags, ioflag, resid, size, xfersize;
int aflag;
int extended=0;
vsize_t bytelen;
bool async;
bool usepc = false;
#ifdef LFS_READWRITE
bool need_unreserve = false;
#endif
cred = ap->a_cred;
ioflag = ap->a_ioflag;
uio = ap->a_uio;
vp = ap->a_vp;
ip = VTOI(vp);
KASSERT(vp->v_size == ip->i_size);
#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 ||
(u_int64_t)uio->uio_offset + uio->uio_resid > fs->um_maxfilesize)
return (EFBIG);
#ifdef LFS_READWRITE
/* Disallow writes to the Ifile, even if noschg flag is removed */
/* XXX can this go away when the Ifile is no longer in the namespace? */
if (vp == fs->lfs_ivnode)
return (EPERM);
#endif
if (uio->uio_resid == 0)
return (0);
fstrans_start(vp->v_mount, FSTRANS_SHARED);
flags = ioflag & IO_SYNC ? B_SYNC : 0;
async = vp->v_mount->mnt_flag & MNT_ASYNC;
origoff = uio->uio_offset;
resid = uio->uio_resid;
osize = ip->i_size;
error = 0;
usepc = vp->v_type == VREG;
#ifdef LFS_READWRITE
async = true;
lfs_availwait(fs, lfs_btofsb(fs, uio->uio_resid));
lfs_check(vp, LFS_UNUSED_LBN, 0);
#endif /* !LFS_READWRITE */
if (!usepc)
goto bcache;
preallocoff = round_page(lfs_blkroundup(fs, MAX(osize, uio->uio_offset)));
aflag = ioflag & IO_SYNC ? B_SYNC : 0;
nsize = MAX(osize, uio->uio_offset + uio->uio_resid);
endallocoff = nsize - lfs_blkoff(fs, nsize);
/*
* if we're increasing the file size, deal with expanding
* the fragment if there is one.
*/
if (nsize > osize && lfs_lblkno(fs, osize) < ULFS_NDADDR &&
lfs_lblkno(fs, osize) != lfs_lblkno(fs, nsize) &&
lfs_blkroundup(fs, osize) != osize) {
off_t eob;
eob = lfs_blkroundup(fs, osize);
uvm_vnp_setwritesize(vp, eob);
error = ulfs_balloc_range(vp, osize, eob - osize, cred, aflag);
if (error)
goto out;
if (flags & B_SYNC) {
mutex_enter(vp->v_interlock);
VOP_PUTPAGES(vp, trunc_page(osize & fs->fs_bmask),
round_page(eob),
PGO_CLEANIT | PGO_SYNCIO | PGO_JOURNALLOCKED);
}
}
while (uio->uio_resid > 0) {
int ubc_flags = UBC_WRITE;
bool overwrite; /* if we're overwrite a whole block */
off_t newoff;
if (ioflag & IO_DIRECT) {
genfs_directio(vp, uio, ioflag | IO_JOURNALLOCKED);
}
oldoff = uio->uio_offset;
blkoffset = lfs_blkoff(fs, uio->uio_offset);
bytelen = MIN(fs->fs_bsize - blkoffset, uio->uio_resid);
if (bytelen == 0) {
break;
}
/*
* if we're filling in a hole, allocate the blocks now and
* initialize the pages first. if we're extending the file,
* we can safely allocate blocks without initializing pages
* since the new blocks will be inaccessible until the write
* is complete.
*/
overwrite = uio->uio_offset >= preallocoff &&
uio->uio_offset < endallocoff;
if (!overwrite && (vp->v_vflag & VV_MAPPED) == 0 &&
lfs_blkoff(fs, uio->uio_offset) == 0 &&
(uio->uio_offset & PAGE_MASK) == 0) {
vsize_t len;
len = trunc_page(bytelen);
len -= lfs_blkoff(fs, len);
if (len > 0) {
overwrite = true;
bytelen = len;
}
}
newoff = oldoff + bytelen;
if (vp->v_size < newoff) {
uvm_vnp_setwritesize(vp, newoff);
}
if (!overwrite) {
error = ulfs_balloc_range(vp, uio->uio_offset, bytelen,
cred, aflag);
if (error)
break;
} else {
genfs_node_wrlock(vp);
error = GOP_ALLOC(vp, uio->uio_offset, bytelen,
aflag, cred);
genfs_node_unlock(vp);
if (error)
break;
ubc_flags |= UBC_FAULTBUSY;
}
/*
* copy the data.
*/
error = ubc_uiomove(&vp->v_uobj, uio, bytelen,
IO_ADV_DECODE(ioflag), ubc_flags | UBC_UNMAP_FLAG(vp));
/*
* update UVM's notion of the size now that we've
* copied the data into the vnode's pages.
*
* we should update the size even when uiomove failed.
*/
if (vp->v_size < newoff) {
uvm_vnp_setsize(vp, newoff);
extended = 1;
}
if (error)
break;
/*
* flush what we just wrote if necessary.
* XXXUBC simplistic async flushing.
*/
#ifndef LFS_READWRITE
if (!async && oldoff >> 16 != uio->uio_offset >> 16) {
mutex_enter(vp->v_interlock);
error = VOP_PUTPAGES(vp, (oldoff >> 16) << 16,
(uio->uio_offset >> 16) << 16,
PGO_CLEANIT | PGO_JOURNALLOCKED | PGO_LAZY);
if (error)
break;
}
#else
__USE(async);
#endif
}
if (error == 0 && ioflag & IO_SYNC) {
mutex_enter(vp->v_interlock);
error = VOP_PUTPAGES(vp, trunc_page(origoff & fs->fs_bmask),
round_page(lfs_blkroundup(fs, uio->uio_offset)),
PGO_CLEANIT | PGO_SYNCIO | PGO_JOURNALLOCKED);
}
goto out;
bcache:
mutex_enter(vp->v_interlock);
VOP_PUTPAGES(vp, trunc_page(origoff), round_page(origoff + resid),
PGO_CLEANIT | PGO_FREE | PGO_SYNCIO | PGO_JOURNALLOCKED);
while (uio->uio_resid > 0) {
lbn = lfs_lblkno(fs, uio->uio_offset);
blkoffset = lfs_blkoff(fs, uio->uio_offset);
xfersize = MIN(fs->fs_bsize - blkoffset, uio->uio_resid);
if (fs->fs_bsize > xfersize)
flags |= B_CLRBUF;
else
flags &= ~B_CLRBUF;
#ifdef LFS_READWRITE
error = lfs_reserve(fs, vp, NULL,
lfs_btofsb(fs, (ULFS_NIADDR + 1) << fs->lfs_bshift));
if (error)
break;
need_unreserve = true;
#endif
error = lfs_balloc(vp, uio->uio_offset, xfersize,
ap->a_cred, flags, &bp);
if (error)
break;
if (uio->uio_offset + xfersize > ip->i_size) {
ip->i_size = uio->uio_offset + xfersize;
DIP_ASSIGN(ip, size, ip->i_size);
uvm_vnp_setsize(vp, ip->i_size);
extended = 1;
}
size = lfs_blksize(fs, ip, lbn) - bp->b_resid;
if (xfersize > size)
xfersize = size;
error = uiomove((char *)bp->b_data + blkoffset, xfersize, uio);
/*
* if we didn't clear the block and the uiomove failed,
* the buf will now contain part of some other file,
* so we need to invalidate it.
*/
if (error && (flags & B_CLRBUF) == 0) {
brelse(bp, BC_INVAL);
break;
}
#ifdef LFS_READWRITE
(void)VOP_BWRITE(bp->b_vp, bp);
lfs_reserve(fs, vp, NULL,
-lfs_btofsb(fs, (ULFS_NIADDR + 1) << fs->lfs_bshift));
need_unreserve = false;
#else
if (ioflag & IO_SYNC)
(void)bwrite(bp);
else if (xfersize + blkoffset == fs->fs_bsize)
bawrite(bp);
else
bdwrite(bp);
#endif
if (error || xfersize == 0)
break;
}
#ifdef LFS_READWRITE
if (need_unreserve) {
lfs_reserve(fs, vp, NULL,
-lfs_btofsb(fs, (ULFS_NIADDR + 1) << fs->lfs_bshift));
}
#endif
/*
* If we successfully wrote any data, and we are not the superuser
* we clear the setuid and setgid bits as a precaution against
* tampering.
*/
out:
ip->i_flag |= IN_CHANGE | IN_UPDATE;
if (vp->v_mount->mnt_flag & MNT_RELATIME)
ip->i_flag |= IN_ACCESS;
if (resid > uio->uio_resid && ap->a_cred) {
if (ip->i_mode & ISUID) {
if (kauth_authorize_vnode(ap->a_cred,
KAUTH_VNODE_RETAIN_SUID, vp, NULL, EPERM) != 0) {
ip->i_mode &= ~ISUID;
DIP_ASSIGN(ip, mode, ip->i_mode);
}
}
if (ip->i_mode & ISGID) {
if (kauth_authorize_vnode(ap->a_cred,
KAUTH_VNODE_RETAIN_SGID, vp, NULL, EPERM) != 0) {
ip->i_mode &= ~ISGID;
DIP_ASSIGN(ip, mode, ip->i_mode);
}
}
}
if (resid > uio->uio_resid)
VN_KNOTE(vp, NOTE_WRITE | (extended ? NOTE_EXTEND : 0));
if (error) {
(void) lfs_truncate(vp, osize, ioflag & IO_SYNC, ap->a_cred);
uio->uio_offset -= resid - uio->uio_resid;
uio->uio_resid = resid;
} else if (resid > uio->uio_resid && (ioflag & IO_SYNC) == IO_SYNC) {
error = lfs_update(vp, NULL, NULL, UPDATE_WAIT);
} else {
/* nothing */
}
KASSERT(vp->v_size == ip->i_size);
fstrans_done(vp->v_mount);
return (error);
}