FreeBSD-4.3-UFS/ufs_readwrite.c
/*-
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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 8.11 (Berkeley) 5/8/95
* $FreeBSD: src/sys/ufs/ufs/ufs_readwrite.c,v 1.65.2.6 2000/12/30 01:51:11 dillon Exp $
*/
#define BLKSIZE(a, b, c) blksize(a, b, c)
#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"
#include <vm/vm.h>
#include <vm/vm_object.h>
#include <vm/vm_pager.h>
#include <vm/vm_map.h>
#include <vm/vnode_pager.h>
#include <sys/event.h>
#include <sys/vmmeter.h>
#define VN_KNOTE(vp, b) \
KNOTE((struct klist *)&vp->v_pollinfo.vpi_selinfo.si_note, (b))
/*
* Vnode op for reading.
*/
/* ARGSUSED */
int
READ(ap)
struct vop_read_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
register struct vnode *vp;
register struct inode *ip;
register struct uio *uio;
register FS *fs;
struct buf *bp;
ufs_daddr_t lbn, nextlbn;
off_t bytesinfile;
long size, xfersize, blkoffset;
int error, orig_resid;
u_short mode;
int seqcount;
int ioflag;
vm_object_t object;
vp = ap->a_vp;
seqcount = ap->a_ioflag >> 16;
ip = VTOI(vp);
mode = ip->i_mode;
uio = ap->a_uio;
ioflag = ap->a_ioflag;
#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 ((u_int64_t)uio->uio_offset > fs->fs_maxfilesize)
return (EFBIG);
orig_resid = uio->uio_resid;
if (orig_resid <= 0)
return (0);
object = vp->v_object;
bytesinfile = ip->i_size - uio->uio_offset;
if (bytesinfile <= 0) {
if ((vp->v_mount->mnt_flag & MNT_NOATIME) == 0)
ip->i_flag |= IN_ACCESS;
return 0;
}
if (object)
vm_object_reference(object);
#ifdef ENABLE_VFS_IOOPT
/*
* If IO optimisation is turned on,
* and we are NOT a VM based IO request,
* (i.e. not headed for the buffer cache)
* but there IS a vm object associated with it.
*/
if ((ioflag & IO_VMIO) == 0 && (vfs_ioopt > 1) && object) {
int nread, toread;
toread = uio->uio_resid;
if (toread > bytesinfile)
toread = bytesinfile;
if (toread >= PAGE_SIZE) {
/*
* Then if it's at least a page in size, try
* get the data from the object using vm tricks
*/
error = uioread(toread, uio, object, &nread);
if ((uio->uio_resid == 0) || (error != 0)) {
/*
* If we finished or there was an error
* then finish up (the reference previously
* obtained on object must be released).
*/
if ((error == 0 ||
uio->uio_resid != orig_resid) &&
(vp->v_mount->mnt_flag & MNT_NOATIME) == 0)
ip->i_flag |= IN_ACCESS;
if (object)
vm_object_vndeallocate(object);
return error;
}
}
}
#endif
/*
* Ok so we couldn't do it all in one vm trick...
* so cycle around trying smaller bites..
*/
for (error = 0, bp = NULL; uio->uio_resid > 0; bp = NULL) {
if ((bytesinfile = ip->i_size - uio->uio_offset) <= 0)
break;
#ifdef ENABLE_VFS_IOOPT
if ((ioflag & IO_VMIO) == 0 && (vfs_ioopt > 1) && object) {
/*
* Obviously we didn't finish above, but we
* didn't get an error either. Try the same trick again.
* but this time we are looping.
*/
int nread, toread;
toread = uio->uio_resid;
if (toread > bytesinfile)
toread = bytesinfile;
/*
* Once again, if there isn't enough for a
* whole page, don't try optimising.
*/
if (toread >= PAGE_SIZE) {
error = uioread(toread, uio, object, &nread);
if ((uio->uio_resid == 0) || (error != 0)) {
/*
* If we finished or there was an
* error then finish up (the reference
* previously obtained on object must
* be released).
*/
if ((error == 0 ||
uio->uio_resid != orig_resid) &&
(vp->v_mount->mnt_flag &
MNT_NOATIME) == 0)
ip->i_flag |= IN_ACCESS;
if (object)
vm_object_vndeallocate(object);
return error;
}
/*
* To get here we didnt't finish or err.
* If we did get some data,
* loop to try another bite.
*/
if (nread > 0) {
continue;
}
}
}
#endif
lbn = lblkno(fs, uio->uio_offset);
nextlbn = lbn + 1;
/*
* size of buffer. The buffer representing the
* end of the file is rounded up to the size of
* the block type ( fragment or full block,
* depending ).
*/
size = BLKSIZE(fs, ip, lbn);
blkoffset = blkoff(fs, uio->uio_offset);
/*
* The amount we want to transfer in this iteration is
* one FS block less the amount of the data before
* our startpoint (duh!)
*/
xfersize = fs->fs_bsize - blkoffset;
/*
* But if we actually want less than the block,
* or the file doesn't have a whole block more of data,
* then use the lesser number.
*/
if (uio->uio_resid < xfersize)
xfersize = uio->uio_resid;
if (bytesinfile < xfersize)
xfersize = bytesinfile;
if (lblktosize(fs, nextlbn) >= ip->i_size)
/*
* Don't do readahead if this is the end of the file.
*/
error = bread(vp, lbn, size, NOCRED, &bp);
else if ((vp->v_mount->mnt_flag & MNT_NOCLUSTERR) == 0)
/*
* Otherwise if we are allowed to cluster,
* grab as much as we can.
*
* XXX This may not be a win if we are not
* doing sequential access.
*/
error = cluster_read(vp, ip->i_size, lbn,
size, NOCRED, uio->uio_resid, seqcount, &bp);
else if (seqcount > 1) {
/*
* If we are NOT allowed to cluster, then
* if we appear to be acting sequentially,
* fire off a request for a readahead
* as well as a read. Note that the 4th and 5th
* arguments point to arrays of the size specified in
* the 6th argument.
*/
int nextsize = BLKSIZE(fs, ip, nextlbn);
error = breadn(vp, lbn,
size, &nextlbn, &nextsize, 1, NOCRED, &bp);
} else
/*
* Failing all of the above, just read what the
* user asked for. Interestingly, the same as
* the first option above.
*/
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;
}
#ifdef ENABLE_VFS_IOOPT
if (vfs_ioopt && object &&
(bp->b_flags & B_VMIO) &&
((blkoffset & PAGE_MASK) == 0) &&
((xfersize & PAGE_MASK) == 0)) {
/*
* If VFS IO optimisation is turned on,
* and it's an exact page multiple
* And a normal VM based op,
* then use uiomiveco()
*/
error =
uiomoveco((char *)bp->b_data + blkoffset,
(int)xfersize, uio, object);
} else
#endif
{
/*
* otherwise use the general form
*/
error =
uiomove((char *)bp->b_data + blkoffset,
(int)xfersize, uio);
}
if (error)
break;
if ((ioflag & IO_VMIO) &&
(LIST_FIRST(&bp->b_dep) == NULL)) {
/*
* If there are no dependencies, and
* it's VMIO, then we don't need the buf,
* mark it available for freeing. The VM has the data.
*/
bp->b_flags |= B_RELBUF;
brelse(bp);
} else {
/*
* Otherwise let whoever
* made the request take care of
* freeing it. We just queue
* it onto another list.
*/
bqrelse(bp);
}
}
/*
* This can only happen in the case of an error
* because the loop above resets bp to NULL on each iteration
* and on normal completion has not set a new value into it.
* so it must have come from a 'break' statement
*/
if (bp != NULL) {
if ((ioflag & IO_VMIO) &&
(LIST_FIRST(&bp->b_dep) == NULL)) {
bp->b_flags |= B_RELBUF;
brelse(bp);
} else {
bqrelse(bp);
}
}
if (object)
vm_object_vndeallocate(object);
if ((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.
*/
int
WRITE(ap)
struct vop_write_args /* {
struct vnode *a_vp;
struct uio *a_uio;
int a_ioflag;
struct ucred *a_cred;
} */ *ap;
{
register struct vnode *vp;
register struct uio *uio;
register struct inode *ip;
register FS *fs;
struct buf *bp;
struct proc *p;
ufs_daddr_t lbn;
off_t osize;
int seqcount;
int blkoffset, error, extended, flags, ioflag, resid, size, xfersize;
vm_object_t object;
extended = 0;
seqcount = ap->a_ioflag >> 16;
ioflag = ap->a_ioflag;
uio = ap->a_uio;
vp = ap->a_vp;
ip = VTOI(vp);
object = vp->v_object;
if (object)
vm_object_reference(object);
#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) {
if (object)
vm_object_vndeallocate(object);
return (EPERM);
}
/* FALLTHROUGH */
case VLNK:
break;
case VDIR:
panic("%s: dir write", WRITE_S);
break;
default:
panic("%s: type %p %d (%d,%d)", WRITE_S, vp, (int)vp->v_type,
(int)uio->uio_offset,
(int)uio->uio_resid
);
}
fs = ip->I_FS;
if (uio->uio_offset < 0 ||
(u_int64_t)uio->uio_offset + uio->uio_resid > fs->fs_maxfilesize) {
if (object)
vm_object_vndeallocate(object);
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.
*/
p = uio->uio_procp;
if (vp->v_type == VREG && p &&
uio->uio_offset + uio->uio_resid >
p->p_rlimit[RLIMIT_FSIZE].rlim_cur) {
psignal(p, SIGXFSZ);
if (object)
vm_object_vndeallocate(object);
return (EFBIG);
}
resid = uio->uio_resid;
osize = ip->i_size;
flags = 0;
if ((ioflag & IO_SYNC) && !DOINGASYNC(vp))
flags = B_SYNC;
if (object && (object->flags & OBJ_OPT)) {
vm_freeze_copyopts(object,
OFF_TO_IDX(uio->uio_offset),
OFF_TO_IDX(uio->uio_offset + uio->uio_resid + PAGE_MASK));
}
for (error = 0; uio->uio_resid > 0;) {
lbn = lblkno(fs, uio->uio_offset);
blkoffset = blkoff(fs, uio->uio_offset);
xfersize = fs->fs_bsize - 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->fs_bsize > xfersize)
flags |= B_CLRBUF;
else
flags &= ~B_CLRBUF;
#endif
/* XXX is uio->uio_offset the right thing here? */
error = VOP_BALLOC(vp, uio->uio_offset, xfersize,
ap->a_cred, flags, &bp);
if (error != 0)
break;
if (uio->uio_offset + xfersize > ip->i_size) {
ip->i_size = uio->uio_offset + xfersize;
extended = 1;
}
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))
bp->b_flags |= B_RELBUF;
if (ioflag & IO_SYNC) {
(void)bwrite(bp);
} else if (vm_page_count_severe() ||
buf_dirty_count_severe() ||
(ioflag & IO_ASYNC)) {
bp->b_flags |= B_CLUSTEROK;
bawrite(bp);
} else if (xfersize + blkoffset == fs->fs_bsize) {
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 (resid > uio->uio_resid)
VN_KNOTE(vp, NOTE_WRITE | (extended ? NOTE_EXTEND : 0));
if (error) {
if (ioflag & IO_UNIT) {
(void)UFS_TRUNCATE(vp, osize,
ioflag & IO_SYNC, ap->a_cred, uio->uio_procp);
uio->uio_offset -= resid - uio->uio_resid;
uio->uio_resid = resid;
}
} else if (resid > uio->uio_resid && (ioflag & IO_SYNC))
error = UFS_UPDATE(vp, 1);
if (object)
vm_object_vndeallocate(object);
return (error);
}
/*
* get page routine
*/
int
ffs_getpages(ap)
struct vop_getpages_args *ap;
{
off_t foff, physoffset;
int i, size, bsize;
struct vnode *dp, *vp;
vm_object_t obj;
vm_pindex_t pindex, firstindex;
vm_page_t mreq;
int bbackwards, bforwards;
int pbackwards, pforwards;
int firstpage;
int reqlblkno;
daddr_t reqblkno;
int poff;
int pcount;
int rtval;
int pagesperblock;
pcount = round_page(ap->a_count) / PAGE_SIZE;
mreq = ap->a_m[ap->a_reqpage];
firstindex = ap->a_m[0]->pindex;
/*
* if ANY DEV_BSIZE blocks are valid on a large filesystem block,
* then the entire page is valid. Since the page may be mapped,
* user programs might reference data beyond the actual end of file
* occuring within the page. We have to zero that data.
*/
if (mreq->valid) {
if (mreq->valid != VM_PAGE_BITS_ALL)
vm_page_zero_invalid(mreq, TRUE);
for (i = 0; i < pcount; i++) {
if (i != ap->a_reqpage) {
vm_page_free(ap->a_m[i]);
}
}
return VM_PAGER_OK;
}
vp = ap->a_vp;
obj = vp->v_object;
bsize = vp->v_mount->mnt_stat.f_iosize;
pindex = mreq->pindex;
foff = IDX_TO_OFF(pindex) /* + ap->a_offset should be zero */;
if (bsize < PAGE_SIZE)
return vnode_pager_generic_getpages(ap->a_vp, ap->a_m,
ap->a_count,
ap->a_reqpage);
/*
* foff is the file offset of the required page
* reqlblkno is the logical block that contains the page
* poff is the index of the page into the logical block
*/
reqlblkno = foff / bsize;
poff = (foff % bsize) / PAGE_SIZE;
if ( VOP_BMAP( vp, reqlblkno, &dp, &reqblkno,
&bforwards, &bbackwards) || (reqblkno == -1)) {
for(i = 0; i < pcount; i++) {
if (i != ap->a_reqpage)
vm_page_free(ap->a_m[i]);
}
if (reqblkno == -1) {
if ((mreq->flags & PG_ZERO) == 0)
vm_page_zero_fill(mreq);
vm_page_undirty(mreq);
mreq->valid = VM_PAGE_BITS_ALL;
return VM_PAGER_OK;
} else {
return VM_PAGER_ERROR;
}
}
physoffset = (off_t)reqblkno * DEV_BSIZE + poff * PAGE_SIZE;
pagesperblock = bsize / PAGE_SIZE;
/*
* find the first page that is contiguous...
* note that pbackwards is the number of pages that are contiguous
* backwards.
*/
firstpage = 0;
if (ap->a_count) {
pbackwards = poff + bbackwards * pagesperblock;
if (ap->a_reqpage > pbackwards) {
firstpage = ap->a_reqpage - pbackwards;
for(i=0;i<firstpage;i++)
vm_page_free(ap->a_m[i]);
}
/*
* pforwards is the number of pages that are contiguous
* after the current page.
*/
pforwards = (pagesperblock - (poff + 1)) +
bforwards * pagesperblock;
if (pforwards < (pcount - (ap->a_reqpage + 1))) {
for( i = ap->a_reqpage + pforwards + 1; i < pcount; i++)
vm_page_free(ap->a_m[i]);
pcount = ap->a_reqpage + pforwards + 1;
}
/*
* number of pages for I/O corrected for the non-contig pages at
* the beginning of the array.
*/
pcount -= firstpage;
}
/*
* calculate the size of the transfer
*/
size = pcount * PAGE_SIZE;
if ((IDX_TO_OFF(ap->a_m[firstpage]->pindex) + size) >
obj->un_pager.vnp.vnp_size)
size = obj->un_pager.vnp.vnp_size -
IDX_TO_OFF(ap->a_m[firstpage]->pindex);
physoffset -= foff;
rtval = VOP_GETPAGES(dp, &ap->a_m[firstpage], size,
(ap->a_reqpage - firstpage), physoffset);
return (rtval);
}
/*
* put page routine
*
* XXX By default, wimp out... note that a_offset is ignored (and always
* XXX has been).
*/
int
ffs_putpages(ap)
struct vop_putpages_args *ap;
{
return vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count,
ap->a_sync, ap->a_rtvals);
}