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Address several problems in vn_read and vn_write:

Browse Source 
1. Make read-ahead work for pread and aio_read.

2. Fix one place where a comparison of uio_offset with -1
   wasn't updated to use FOF_OFFSET.

3. Honor O_APPEND in the FOF_OFFSET case.

In addition, use the variable name "ioflag" in both vn_read and
vn_write to avoid possible confusion between the variable "flag"
and the parameter "flags".

Submitted by:	Bruce Evans <bde@zeta.org.au> and me
This commit is contained in:
Alan Cox 1999-04-21 05:56:45 +00:00
parent 3923532907
commit f78fd73fa6
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=45893
1 changed files with 21 additions and 35 deletions
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56
sys/kern/vfs_vnops.c
View File

@ -36,7 +36,7 @@
* SUCH DAMAGE.
*
* @(#)vfs_vnops.c 8.2 (Berkeley) 1/21/94
* $Id: vfs_vnops.c,v 1.64 1999/03/26 20:25:21 alc Exp $
* $Id: vfs_vnops.c,v 1.65 1999/04/04 21:41:17 dt Exp $
*/
#include <sys/param.h>
@ -280,22 +280,15 @@ vn_read(fp, uio, cred, flags)
{
struct vnode *vp = (struct vnode *)fp->f_data;
struct proc *p = uio->uio_procp;
int count, error;
int flag;
int error, ioflag;
ioflag = 0;
if (fp->f_flag & FNONBLOCK)
ioflag |= IO_NDELAY;
VOP_LEASE(vp, p, cred, LEASE_READ);
vn_lock(vp, LK_SHARED | LK_NOPAUSE | LK_RETRY, p);
flag = 0;
if (fp->f_flag & FNONBLOCK)
flag |= IO_NDELAY;
if (flags & FOF_OFFSET) {
error = VOP_READ(vp, uio, flag, cred);
goto out;
}
uio->uio_offset = fp->f_offset;
count = uio->uio_resid;
if ((flags & FOF_OFFSET) == 0)
uio->uio_offset = fp->f_offset;
/*
* Sequential read heuristic.
@ -303,8 +296,8 @@ vn_read(fp, uio, cred, flags)
* a rewind operation doesn't turn off
* sequential input mode.
*/
if (((fp->f_offset == 0) && (fp->f_seqcount > 0)) ||
(fp->f_offset == fp->f_nextread)) {
if ((uio->uio_offset == 0 && fp->f_seqcount > 0) ||
uio->uio_offset == fp->f_nextread) {
int tmpseq = fp->f_seqcount;
/*
* XXX we assume that the filesystem block size is
@ -312,22 +305,21 @@ vn_read(fp, uio, cred, flags)
* good indicator of how sequential the read operations
* are.
*/
tmpseq += ((count + BKVASIZE - 1) / BKVASIZE);
tmpseq += (uio->uio_resid + BKVASIZE - 1) / BKVASIZE;
if (tmpseq >= 127)
tmpseq = 127;
fp->f_seqcount = tmpseq;
flag |= (fp->f_seqcount << 16);
ioflag |= fp->f_seqcount << 16;
} else {
if (fp->f_seqcount > 1)
fp->f_seqcount = 1;
else
fp->f_seqcount = 0;
}
error = VOP_READ(vp, uio, flag, cred);
fp->f_offset += count - uio->uio_resid;
fp->f_nextread = fp->f_offset;
out:
error = VOP_READ(vp, uio, ioflag, cred);
if ((flags & FOF_OFFSET) == 0)
fp->f_offset = uio->uio_offset;
fp->f_nextread = uio->uio_offset;
VOP_UNLOCK(vp, 0, p);
return (error);
}
@ -344,9 +336,10 @@ vn_write(fp, uio, cred, flags)
{
struct vnode *vp = (struct vnode *)fp->f_data;
struct proc *p = uio->uio_procp;
int count, error, ioflag = IO_UNIT;
int error, ioflag;
if (uio->uio_offset == -1 && vp->v_type == VREG && (fp->f_flag & O_APPEND))
ioflag = IO_UNIT;
if (vp->v_type == VREG && (fp->f_flag & O_APPEND))
ioflag |= IO_APPEND;
if (fp->f_flag & FNONBLOCK)
ioflag |= IO_NDELAY;
@ -355,18 +348,11 @@ vn_write(fp, uio, cred, flags)
ioflag |= IO_SYNC;
VOP_LEASE(vp, p, cred, LEASE_WRITE);
vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, p);
if (flags & FOF_OFFSET) {
error = VOP_WRITE(vp, uio, ioflag, cred);
goto out;
}
uio->uio_offset = fp->f_offset;
count = uio->uio_resid;
if ((flags & FOF_OFFSET) == 0)
uio->uio_offset = fp->f_offset;
error = VOP_WRITE(vp, uio, ioflag, cred);
if (ioflag & IO_APPEND)
if ((flags & FOF_OFFSET) == 0)
fp->f_offset = uio->uio_offset;
else
fp->f_offset += count - uio->uio_resid;
out:
VOP_UNLOCK(vp, 0, p);
return (error);
}