d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Add a special workaround to handle UIO_NOCOPY case. This fixes data

Browse Source 
corruption observed when sendfile() is being used.

PR:		kern/127213
Submitted by:	gk
MFC after:	2 weeks
This commit is contained in:
Xin LI 2009-10-07 23:17:15 +00:00
parent c27838c722
commit 3fa0694aaa
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=197850
1 changed files with 87 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

118
sys/fs/tmpfs/tmpfs_vnops.c
View File

@ -43,6 +43,8 @@ __FBSDID("$FreeBSD$");
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/sf_buf.h>
#include <sys/stat.h>
#include <sys/systm.h>
#include <sys/unistd.h>
@ -428,42 +430,13 @@ tmpfs_setattr(struct vop_setattr_args *v)
}
/* --------------------------------------------------------------------- */
static int
tmpfs_mappedread(vm_object_t vobj, vm_object_t tobj, size_t len, struct uio *uio)
tmpfs_nocacheread(vm_object_t tobj, vm_pindex_t idx,
vm_offset_t offset, size_t tlen, struct uio *uio)
{
vm_pindex_t idx;
vm_page_t m;
vm_offset_t offset;
off_t addr;
size_t tlen;
int error;
addr = uio->uio_offset;
idx = OFF_TO_IDX(addr);
offset = addr & PAGE_MASK;
tlen = MIN(PAGE_SIZE - offset, len);
if ((vobj == NULL) ||
(vobj->resident_page_count == 0 && vobj->cache == NULL))
goto nocache;
VM_OBJECT_LOCK(vobj);
lookupvpg:
if (((m = vm_page_lookup(vobj, idx)) != NULL) &&
vm_page_is_valid(m, offset, tlen)) {
if (vm_page_sleep_if_busy(m, FALSE, "tmfsmr"))
goto lookupvpg;
vm_page_busy(m);
VM_OBJECT_UNLOCK(vobj);
error = uiomove_fromphys(&m, offset, tlen, uio);
VM_OBJECT_LOCK(vobj);
vm_page_wakeup(m);
VM_OBJECT_UNLOCK(vobj);
return (error);
}
VM_OBJECT_UNLOCK(vobj);
nocache:
VM_OBJECT_LOCK(tobj);
vm_object_pip_add(tobj, 1);
m = vm_page_grab(tobj, idx, VM_ALLOC_WIRED |
@ -489,6 +462,89 @@ tmpfs_mappedread(vm_object_t vobj, vm_object_t tobj, size_t len, struct uio *uio
vm_object_pip_subtract(tobj, 1);
VM_OBJECT_UNLOCK(tobj);
return (error);
}
static __inline int
tmpfs_nocacheread_buf(vm_object_t tobj, vm_pindex_t idx,
vm_offset_t offset, size_t tlen, void *buf)
{
struct uio uio;
struct iovec iov;
uio.uio_iovcnt = 1;
uio.uio_iov = &iov;
iov.iov_base = buf;
iov.iov_len = tlen;
uio.uio_offset = 0;
uio.uio_resid = tlen;
uio.uio_rw = UIO_READ;
uio.uio_segflg = UIO_SYSSPACE;
uio.uio_td = curthread;
return (tmpfs_nocacheread(tobj, idx, offset, tlen, &uio));
}
static int
tmpfs_mappedread(vm_object_t vobj, vm_object_t tobj, size_t len, struct uio *uio)
{
struct sf_buf *sf;
vm_pindex_t idx;
vm_page_t m;
vm_offset_t offset;
off_t addr;
size_t tlen;
char *ma;
int error;
addr = uio->uio_offset;
idx = OFF_TO_IDX(addr);
offset = addr & PAGE_MASK;
tlen = MIN(PAGE_SIZE - offset, len);
if ((vobj == NULL) ||
(vobj->resident_page_count == 0 && vobj->cache == NULL))
goto nocache;
VM_OBJECT_LOCK(vobj);
lookupvpg:
if (((m = vm_page_lookup(vobj, idx)) != NULL) &&
vm_page_is_valid(m, offset, tlen)) {
if (vm_page_sleep_if_busy(m, FALSE, "tmfsmr"))
goto lookupvpg;
vm_page_busy(m);
VM_OBJECT_UNLOCK(vobj);
error = uiomove_fromphys(&m, offset, tlen, uio);
VM_OBJECT_LOCK(vobj);
vm_page_wakeup(m);
VM_OBJECT_UNLOCK(vobj);
return (error);
} else if (m != NULL && uio->uio_segflg == UIO_NOCOPY) {
if (vm_page_sleep_if_busy(m, FALSE, "tmfsmr"))
goto lookupvpg;
vm_page_busy(m);
VM_OBJECT_UNLOCK(vobj);
sched_pin();
sf = sf_buf_alloc(m, SFB_CPUPRIVATE);
ma = (char *)sf_buf_kva(sf);
error = tmpfs_nocacheread_buf(tobj, idx, offset, tlen,
ma + offset);
if (error == 0) {
uio->uio_offset += tlen;
uio->uio_resid -= tlen;
}
sf_buf_free(sf);
sched_unpin();
VM_OBJECT_LOCK(vobj);
vm_page_wakeup(m);
VM_OBJECT_UNLOCK(vobj);
return (error);
}
VM_OBJECT_UNLOCK(vobj);
nocache:
error = tmpfs_nocacheread(tobj, idx, offset, tlen, uio);
return (error);
}