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freebsd-dev/sys/ufs/ffs/ffs_rawread.c
Pedro F. Giffuni fe267a5590 sys: general adoption of SPDX licensing ID tags. 
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.
2017-11-27 15:23:17 +00:00

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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2000-2003 Tor Egge
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/fcntl.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/proc.h>
#include <sys/limits.h>
#include <sys/mount.h>
#include <sys/namei.h>
#include <sys/vnode.h>
#include <sys/conf.h>
#include <sys/filio.h>
#include <sys/ttycom.h>
#include <sys/bio.h>
#include <sys/buf.h>
#include <sys/rwlock.h>
#include <ufs/ufs/extattr.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>
#include <vm/vm.h>
#include <vm/vm_extern.h>
#include <vm/vm_object.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
static int ffs_rawread_readahead(struct vnode *vp,
caddr_t udata,
off_t offset,
size_t len,
struct thread *td,
struct buf *bp);
static int ffs_rawread_main(struct vnode *vp,
struct uio *uio);
static int ffs_rawread_sync(struct vnode *vp);
int ffs_rawread(struct vnode *vp, struct uio *uio, int *workdone);
SYSCTL_DECL(_vfs_ffs);
static int ffsrawbufcnt = 4;
SYSCTL_INT(_vfs_ffs, OID_AUTO, ffsrawbufcnt, CTLFLAG_RD, &ffsrawbufcnt, 0,
"Buffers available for raw reads");
static int allowrawread = 1;
SYSCTL_INT(_vfs_ffs, OID_AUTO, allowrawread, CTLFLAG_RW, &allowrawread, 0,
"Flag to enable raw reads");
static int rawreadahead = 1;
SYSCTL_INT(_vfs_ffs, OID_AUTO, rawreadahead, CTLFLAG_RW, &rawreadahead, 0,
"Flag to enable readahead for long raw reads");
static void
ffs_rawread_setup(void *arg __unused)
{
ffsrawbufcnt = (nswbuf > 100 ) ? (nswbuf - (nswbuf >> 4)) : nswbuf - 8;
}
SYSINIT(ffs_raw, SI_SUB_VM_CONF, SI_ORDER_ANY, ffs_rawread_setup, NULL);
static int
ffs_rawread_sync(struct vnode *vp)
{
int error;
int upgraded;
struct bufobj *bo;
struct mount *mp;
vm_object_t obj;
/* Check for dirty mmap, pending writes and dirty buffers */
bo = &vp->v_bufobj;
BO_LOCK(bo);
VI_LOCK(vp);
if (bo->bo_numoutput > 0 ||
bo->bo_dirty.bv_cnt > 0 ||
((obj = vp->v_object) != NULL &&
(obj->flags & OBJ_MIGHTBEDIRTY) != 0)) {
VI_UNLOCK(vp);
BO_UNLOCK(bo);
if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
upgraded = 1;
else
upgraded = 0;
VOP_UNLOCK(vp, 0);
(void) vn_start_write(vp, &mp, V_WAIT);
VOP_LOCK(vp, LK_EXCLUSIVE);
} else if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
upgraded = 1;
/* Upgrade to exclusive lock, this might block */
VOP_LOCK(vp, LK_UPGRADE);
} else
upgraded = 0;
VI_LOCK(vp);
/* Check if vnode was reclaimed while unlocked. */
if ((vp->v_iflag & VI_DOOMED) != 0) {
VI_UNLOCK(vp);
if (upgraded != 0)
VOP_LOCK(vp, LK_DOWNGRADE);
vn_finished_write(mp);
return (EIO);
}
/* Attempt to msync mmap() regions to clean dirty mmap */
if ((obj = vp->v_object) != NULL &&
(obj->flags & OBJ_MIGHTBEDIRTY) != 0) {
VI_UNLOCK(vp);
VM_OBJECT_WLOCK(obj);
vm_object_page_clean(obj, 0, 0, OBJPC_SYNC);
VM_OBJECT_WUNLOCK(obj);
} else
VI_UNLOCK(vp);
/* Wait for pending writes to complete */
BO_LOCK(bo);
error = bufobj_wwait(&vp->v_bufobj, 0, 0);
if (error != 0) {
/* XXX: can't happen with a zero timeout ??? */
BO_UNLOCK(bo);
if (upgraded != 0)
VOP_LOCK(vp, LK_DOWNGRADE);
vn_finished_write(mp);
return (error);
}
/* Flush dirty buffers */
if (bo->bo_dirty.bv_cnt > 0) {
BO_UNLOCK(bo);
if ((error = ffs_syncvnode(vp, MNT_WAIT, 0)) != 0) {
if (upgraded != 0)
VOP_LOCK(vp, LK_DOWNGRADE);
vn_finished_write(mp);
return (error);
}
BO_LOCK(bo);
if (bo->bo_numoutput > 0 || bo->bo_dirty.bv_cnt > 0)
panic("ffs_rawread_sync: dirty bufs");
}
BO_UNLOCK(bo);
if (upgraded != 0)
VOP_LOCK(vp, LK_DOWNGRADE);
vn_finished_write(mp);
} else {
VI_UNLOCK(vp);
BO_UNLOCK(bo);
}
return 0;
}
static int
ffs_rawread_readahead(struct vnode *vp,
caddr_t udata,
off_t offset,
size_t len,
struct thread *td,
struct buf *bp)
{
int error;
u_int iolen;
off_t blockno;
int blockoff;
int bsize;
struct vnode *dp;
int bforwards;
struct inode *ip;
ufs2_daddr_t blkno;
bsize = vp->v_mount->mnt_stat.f_iosize;
ip = VTOI(vp);
dp = ITODEVVP(ip);
iolen = ((vm_offset_t) udata) & PAGE_MASK;
bp->b_bcount = len;
if (bp->b_bcount + iolen > bp->b_kvasize) {
bp->b_bcount = bp->b_kvasize;
if (iolen != 0)
bp->b_bcount -= PAGE_SIZE;
}
bp->b_flags = 0; /* XXX necessary ? */
bp->b_iocmd = BIO_READ;
bp->b_iodone = bdone;
bp->b_data = udata;
blockno = offset / bsize;
blockoff = (offset % bsize) / DEV_BSIZE;
if ((daddr_t) blockno != blockno) {
return EINVAL; /* blockno overflow */
}
bp->b_lblkno = bp->b_blkno = blockno;
error = ufs_bmaparray(vp, bp->b_lblkno, &blkno, NULL, &bforwards, NULL);
if (error != 0)
return error;
if (blkno == -1) {
/* Fill holes with NULs to preserve semantics */
if (bp->b_bcount + blockoff * DEV_BSIZE > bsize)
bp->b_bcount = bsize - blockoff * DEV_BSIZE;
bp->b_bufsize = bp->b_bcount;
if (vmapbuf(bp, 1) < 0)
return EFAULT;
maybe_yield();
bzero(bp->b_data, bp->b_bufsize);
/* Mark operation completed (similar to bufdone()) */
bp->b_resid = 0;
bp->b_flags |= B_DONE;
return 0;
}
bp->b_blkno = blkno + blockoff;
bp->b_offset = bp->b_iooffset = (blkno + blockoff) * DEV_BSIZE;
if (bp->b_bcount + blockoff * DEV_BSIZE > bsize * (1 + bforwards))
bp->b_bcount = bsize * (1 + bforwards) - blockoff * DEV_BSIZE;
bp->b_bufsize = bp->b_bcount;
if (vmapbuf(bp, 1) < 0)
return EFAULT;
BO_STRATEGY(&dp->v_bufobj, bp);
return 0;
}
static int
ffs_rawread_main(struct vnode *vp,
struct uio *uio)
{
int error, nerror;
struct buf *bp, *nbp, *tbp;
u_int iolen;
caddr_t udata;
long resid;
off_t offset;
struct thread *td;
td = uio->uio_td ? uio->uio_td : curthread;
udata = uio->uio_iov->iov_base;
resid = uio->uio_resid;
offset = uio->uio_offset;
/*
* keep the process from being swapped
*/
PHOLD(td->td_proc);
error = 0;
nerror = 0;
bp = NULL;
nbp = NULL;
while (resid > 0) {
if (bp == NULL) { /* Setup first read */
/* XXX: Leave some bufs for swap */
bp = getpbuf(&ffsrawbufcnt);
pbgetvp(vp, bp);
error = ffs_rawread_readahead(vp, udata, offset,
resid, td, bp);
if (error != 0)
break;
if (resid > bp->b_bufsize) { /* Setup fist readahead */
/* XXX: Leave bufs for swap */
if (rawreadahead != 0)
nbp = trypbuf(&ffsrawbufcnt);
else
nbp = NULL;
if (nbp != NULL) {
pbgetvp(vp, nbp);
nerror = ffs_rawread_readahead(vp,
udata +
bp->b_bufsize,
offset +
bp->b_bufsize,
resid -
bp->b_bufsize,
td,
nbp);
if (nerror) {
pbrelvp(nbp);
relpbuf(nbp, &ffsrawbufcnt);
nbp = NULL;
}
}
}
}
bwait(bp, PRIBIO, "rawrd");
vunmapbuf(bp);
iolen = bp->b_bcount - bp->b_resid;
if (iolen == 0 && (bp->b_ioflags & BIO_ERROR) == 0) {
nerror = 0; /* Ignore possible beyond EOF error */
break; /* EOF */
}
if ((bp->b_ioflags & BIO_ERROR) != 0) {
error = bp->b_error;
break;
}
resid -= iolen;
udata += iolen;
offset += iolen;
if (iolen < bp->b_bufsize) {
/* Incomplete read. Try to read remaining part */
error = ffs_rawread_readahead(vp,
udata,
offset,
bp->b_bufsize - iolen,
td,
bp);
if (error != 0)
break;
} else if (nbp != NULL) { /* Complete read with readahead */
tbp = bp;
bp = nbp;
nbp = tbp;
if (resid <= bp->b_bufsize) { /* No more readaheads */
pbrelvp(nbp);
relpbuf(nbp, &ffsrawbufcnt);
nbp = NULL;
} else { /* Setup next readahead */
nerror = ffs_rawread_readahead(vp,
udata +
bp->b_bufsize,
offset +
bp->b_bufsize,
resid -
bp->b_bufsize,
td,
nbp);
if (nerror != 0) {
pbrelvp(nbp);
relpbuf(nbp, &ffsrawbufcnt);
nbp = NULL;
}
}
} else if (nerror != 0) {/* Deferred Readahead error */
break;
} else if (resid > 0) { /* More to read, no readahead */
error = ffs_rawread_readahead(vp, udata, offset,
resid, td, bp);
if (error != 0)
break;
}
}
if (bp != NULL) {
pbrelvp(bp);
relpbuf(bp, &ffsrawbufcnt);
}
if (nbp != NULL) { /* Run down readahead buffer */
bwait(nbp, PRIBIO, "rawrd");
vunmapbuf(nbp);
pbrelvp(nbp);
relpbuf(nbp, &ffsrawbufcnt);
}
if (error == 0)
error = nerror;
PRELE(td->td_proc);
uio->uio_iov->iov_base = udata;
uio->uio_resid = resid;
uio->uio_offset = offset;
return error;
}
int
ffs_rawread(struct vnode *vp,
struct uio *uio,
int *workdone)
{
if (allowrawread != 0 &&
uio->uio_iovcnt == 1 &&
uio->uio_segflg == UIO_USERSPACE &&
uio->uio_resid == uio->uio_iov->iov_len &&
(((uio->uio_td != NULL) ? uio->uio_td : curthread)->td_pflags &
TDP_DEADLKTREAT) == 0) {
int secsize; /* Media sector size */
off_t filebytes; /* Bytes left of file */
int blockbytes; /* Bytes left of file in full blocks */
int partialbytes; /* Bytes in last partial block */
int skipbytes; /* Bytes not to read in ffs_rawread */
struct inode *ip;
int error;
/* Only handle sector aligned reads */
ip = VTOI(vp);
secsize = ITODEVVP(ip)->v_bufobj.bo_bsize;
if ((uio->uio_offset & (secsize - 1)) == 0 &&
(uio->uio_resid & (secsize - 1)) == 0) {
/* Sync dirty pages and buffers if needed */
error = ffs_rawread_sync(vp);
if (error != 0)
return error;
/* Check for end of file */
if (ip->i_size > uio->uio_offset) {
filebytes = ip->i_size - uio->uio_offset;
/* No special eof handling needed ? */
if (uio->uio_resid <= filebytes) {
*workdone = 1;
return ffs_rawread_main(vp, uio);
}
partialbytes = ((unsigned int) ip->i_size) %
ITOFS(ip)->fs_bsize;
blockbytes = (int) filebytes - partialbytes;
if (blockbytes > 0) {
skipbytes = uio->uio_resid -
blockbytes;
uio->uio_resid = blockbytes;
error = ffs_rawread_main(vp, uio);
uio->uio_resid += skipbytes;
if (error != 0)
return error;
/* Read remaining part using buffer */
}
}
}
}
*workdone = 0;
return 0;
}
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