File: [Development] / xfs-linux / xfs_rw.c (download)
Revision 1.36, Sat Apr 23 00:57:13 1994 UTC (23 years, 5 months ago) by ajs
Branch: MAIN
Changes since 1.35: +32 -78
lines
Change the write path to not create buffers which extend
beyond the EOF. This eliminates some complications
involving dirty pages over holes in the file. Also
change the rest of the code which expected to deal with
such pages.
|
#include <sys/types.h>
#ifdef SIM
#define _KERNEL 1
#endif
#include <sys/buf.h>
#include <sys/uio.h>
#include <sys/vfs.h>
#include <sys/vnode.h>
#include <sys/cred.h>
#include <sys/sysmacros.h>
#include <sys/pfdat.h>
#include <sys/proc.h>
#include <sys/user.h>
#include <sys/uuid.h>
#include <sys/grio.h>
#ifdef SIM
#undef _KERNEL
#endif
#include <sys/cmn_err.h>
#include <sys/debug.h>
#include <sys/errno.h>
#include <sys/fcntl.h>
#include <sys/var.h>
#ifdef SIM
#include <bstring.h>
#include <stdio.h>
#else
#include <sys/conf.h>
#include <sys/systm.h>
#endif
#include <sys/kmem.h>
#include <sys/sema.h>
#include <sys/uuid.h>
#include <sys/param.h>
#include <sys/file.h>
#include <sys/region.h>
#include <sys/runq.h>
#include <sys/schedctl.h>
#include "xfs_types.h"
#include "xfs_inum.h"
#include "xfs_log.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_mount.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc.h"
#include "xfs_ag.h"
#include "xfs_bmap_btree.h"
#include "xfs_bmap.h"
#include "xfs_btree.h"
#include "xfs_dinode.h"
#include "xfs_inode_item.h"
#include "xfs_inode.h"
#ifdef SIM
#include "sim.h"
#endif
/*
* This lock is used by xfs_strat_write().
* The xfs_strat_lock is initialized in xfs_init().
*/
lock_t xfs_strat_lock;
/*
* Variables for coordination with the xfsd daemons.
* The xfsd_lock and xfsd_wait variables are initialized
* in xfs_init();
*/
static int xfsd_count;
static buf_t *xfsd_list;
static int xfsd_bufcount;
lock_t xfsd_lock;
sema_t xfsd_wait;
STATIC void
xfs_zero_bp(
buf_t *bp,
int data_offset,
int data_len);
STATIC int
xfs_retrieved(
int available,
off_t offset,
int count,
uint *total_retrieved,
xfs_fsize_t isize);
int
xfs_diordwr(
vnode_t *vp,
uio_t *uiop,
int ioflag,
cred_t *credp,
int rw);
extern int
xfs_grio_req(
xfs_inode_t *,
struct reservation_id *,
uio_t *,
int,
cred_t *,
int);
/*
* Round the given file offset down to the nearest read/write
* size boundary.
*/
#define XFS_READIO_ALIGN(mp,off) (((off) >> mp->m_readio_log) \
<< mp->m_readio_log)
#define XFS_WRITEIO_ALIGN(mp,off) (((off) >> mp->m_writeio_log) \
<< mp->m_writeio_log)
/*
* Fill in the bmap structure to indicate how the next bp
* should fit over the given extent.
*
* Everything here is in terms of file system blocks, not BBs.
*/
void
xfs_next_bmap(
xfs_mount_t *mp,
xfs_bmbt_irec_t *imapp,
struct bmapval *bmapp,
int iosize,
int last_iosize,
xfs_fileoff_t ioalign,
xfs_fileoff_t last_offset,
xfs_fileoff_t req_offset)
{
int extra_blocks;
xfs_fileoff_t size_diff;
xfs_fileoff_t ext_offset;
xfs_fsblock_t start_block;
/*
* Make sure that the request offset lies in the extent given.
*/
ASSERT(req_offset >= imapp->br_startoff);
ASSERT(req_offset < (imapp->br_startoff + imapp->br_blockcount));
if (last_offset == -1) {
ASSERT(ioalign != -1);
if (ioalign < imapp->br_startoff) {
/*
* The alignment we guessed at can't
* happen on this extent, so align
* to the beginning of this extent.
* Subtract whatever we drop from the
* iosize so that we stay aligned on
* our iosize boundaries.
*/
size_diff = imapp->br_startoff - ioalign;
iosize -= size_diff;
ASSERT(iosize > 0);
ext_offset = 0;
bmapp->offset = imapp->br_startoff;
ASSERT(bmapp->offset <= req_offset);
} else {
/*
* The alignment requested fits on this
* extent, so use it.
*/
ext_offset = ioalign - imapp->br_startoff;
bmapp->offset = ioalign;
ASSERT(bmapp->offset <= req_offset);
}
} else {
/*
* This is one of a series of sequential access to the
* file. Make sure to line up the buffer we specify
* so that it doesn't overlap the last one. It should
* either be the same as the last one (if we need data
* from it) or follow immediately after the last one.
*/
ASSERT(ioalign == -1);
if (last_offset >= imapp->br_startoff) {
/*
* The last I/O was from the same extent
* that this one will at least start on.
* This assumes that we're going sequentially.
*/
if (req_offset < (last_offset + last_iosize)) {
/*
* This request overlaps the buffer
* we used for the last request. Just
* get that buffer again.
*/
ext_offset = last_offset -
imapp->br_startoff;
bmapp->offset = last_offset;
iosize = last_iosize;
} else {
/*
* This request does not overlap the buffer
* used for the last one. Get it its own.
*/
ext_offset = req_offset - imapp->br_startoff;
bmapp->offset = req_offset;
}
} else {
/*
* The last I/O was on a different extent than
* this one. We start at the beginning of this one.
* This assumes that we're going sequentially.
*/
ext_offset = 0;
bmapp->offset = req_offset;
ASSERT(bmapp->offset == imapp->br_startoff);
}
}
start_block = imapp->br_startblock;
if (start_block == HOLESTARTBLOCK) {
bmapp->bn = -1;
bmapp->eof = BMAP_HOLE;
} else if (start_block == DELAYSTARTBLOCK) {
bmapp->bn = -1;
bmapp->eof = BMAP_DELAY;
} else {
bmapp->bn = start_block + ext_offset;
bmapp->eof = 0;
}
bmapp->length = iosize;
/*
* If the iosize from our offset extends beyond the
* end of the extent, then trim down the length
* to match that of the extent.
*/
extra_blocks = (bmapp->offset + bmapp->length) -
(imapp->br_startoff + imapp->br_blockcount);
if (extra_blocks > 0) {
bmapp->length -= extra_blocks;
ASSERT(bmapp->length > 0);
}
bmapp->bsize = XFS_FSB_TO_B(mp, bmapp->length);
}
/*
* xfs_retrieved() is a utility function used to calculate the
* value of bmap.pbsize.
*
* Available is the number of bytes mapped by the current bmap.
* Offset is the file offset of the current request by the user.
* Count is the size of the current request by the user.
* Total_retrieved is a running total of the number of bytes
* which have been setup for the user in this call so far.
* Isize is the current size of the file being read.
*/
STATIC int
xfs_retrieved(
int available,
off_t offset,
int count,
uint *total_retrieved,
xfs_fsize_t isize)
{
int retrieved;
xfs_fsize_t file_bytes_left;
if ((available + *total_retrieved) > count) {
/*
* This buffer will return more bytes
* than we asked for. Trim retrieved
* so we can set bmapp->pbsize correctly.
*/
retrieved = count - *total_retrieved;
} else {
retrieved = available;
}
file_bytes_left = isize - (offset + *total_retrieved);
if (file_bytes_left < retrieved) {
/*
* The user has requested more bytes
* than there are in the file. Trim
* down the number to those left in
* the file.
*/
retrieved = file_bytes_left;
}
*total_retrieved += retrieved;
return retrieved;
}
/*
* xfs_iomap_extra()
*
* This is called to fill in the bmapval for a page which overlaps
* the end of the file and the fs block size is less than the page
* size. We map the rest of the blocks up to the end of the page
* here. The first part of the page would have been handled in the
* normal path, and the rest of the page is passed off to here.
*/
STATIC void
xfs_iomap_extra(
xfs_inode_t *ip,
off_t offset,
size_t count,
struct bmapval *bmapp,
int *nbmaps)
{
xfs_fileoff_t offset_fsb;
xfs_fileoff_t count_fsb;
xfs_mount_t *mp;
ASSERT((offset == BTOBB(BBTOB(ip->i_d.di_size))) && (count < NBPP));
ASSERT(ip->i_mount->m_sb.sb_blocksize < NBPP);
mp = ip->i_mount;
offset_fsb = XFS_B_TO_FSBT(mp, offset);
count_fsb = XFS_B_TO_FSB(mp, count);
/*
* Don't set BMAP_HOLE here because we don't want to trap
* on writes to this page beyond the EOF.
*/
*nbmaps = 1;
bmapp->eof = BMAP_DELAY | BMAP_EOF;
bmapp->bn = -1;
bmapp->offset = XFS_FSB_TO_BB(mp, offset_fsb);
bmapp->length = XFS_FSB_TO_BB(mp, count_fsb);
bmapp->bsize = XFS_FSB_TO_B(mp, count_fsb);
bmapp->pboff = offset - XFS_FSB_TO_B(mp, offset_fsb);
bmapp->pbsize = count;
if (ip->i_d.di_flags & XFS_DIFLAG_REALTIME) {
bmapp->pbdev = mp->m_rtdev;
} else {
bmapp->pbdev = mp->m_dev;
}
}
void
xfs_iomap_read(
xfs_inode_t *ip,
off_t offset,
size_t count,
struct bmapval *bmapp,
int *nbmaps)
{
xfs_fileoff_t offset_fsb;
xfs_fileoff_t ioalign;
xfs_fileoff_t last_offset;
xfs_fileoff_t last_required_offset;
xfs_fileoff_t last_fsb;
xfs_fileoff_t next_offset;
xfs_fsize_t nisize;
off_t offset_page;
int nimaps;
unsigned int iosize;
unsigned int last_iosize;
unsigned int retrieved_bytes;
unsigned int total_retrieved_bytes;
short filled_bmaps;
short read_aheads;
int x;
xfs_mount_t *mp;
struct bmapval *curr_bmapp;
struct bmapval *next_bmapp;
struct bmapval *last_bmapp;
struct bmapval *first_read_ahead_bmapp;
struct bmapval *next_read_ahead_bmapp;
xfs_bmbt_irec_t *curr_imapp;
xfs_bmbt_irec_t *last_imapp;
#define XFS_READ_IMAPS XFS_BMAP_MAX_NMAP
xfs_bmbt_irec_t imap[XFS_READ_IMAPS];
mp = ip->i_mount;
nisize = ip->i_new_size;
if (nisize < ip->i_d.di_size) {
nisize = ip->i_d.di_size;
}
offset_fsb = XFS_B_TO_FSBT(mp, offset);
nimaps = XFS_READ_IMAPS;
last_fsb = XFS_B_TO_FSB(mp, nisize);
if (last_fsb <= offset_fsb) {
/*
* The VM/chunk code is trying to map a page to be
* pushed out which contains the last file block
* and byte. Since the file ended, we did not map
* the entire page, and now it is calling back to
* map the rest of it. Handle it here so that it
* does not interfere with the normal path code.
* This can only happen if the fs block size is
* less than the page size.
*/
xfs_iomap_extra(ip, offset, count, bmapp, nbmaps);
return;
}
(void)xfs_bmapi(NULL, ip, offset_fsb,
(xfs_extlen_t)(last_fsb - offset_fsb),
XFS_BMAPI_ENTIRE, NULLFSBLOCK, 0, imap,
&nimaps, NULL);
if ((offset == ip->i_next_offset) &&
(count <= ip->i_last_req_sz)) {
/*
* Sequential I/O of same size as last time.
*/
ASSERT(ip->i_io_size > 0);
iosize = ip->i_io_size;
last_offset = ip->i_io_offset;
ioalign = -1;
} else {
/*
* The I/O size for the file has not yet been
* determined, so figure it out.
*/
if (XFS_B_TO_FSB(mp, count) <= mp->m_readio_blocks) {
/*
* The request is smaller than our
* minimum I/O size, so default to
* the minimum. For these size requests
* we always want to align the requests
* to XFS_READ_SIZE boundaries as well.
*/
iosize = mp->m_readio_blocks;
ioalign = XFS_READIO_ALIGN(mp, offset);
ioalign = XFS_B_TO_FSBT(mp, ioalign);
} else {
/*
* The request is bigger than our
* minimum I/O size and it's the
* first one in this sequence, so
* set the I/O size for the file
* now.
*
* In calculating the offset rounded down
* to a page, make sure to round down the
* fs block offset rather than the byte
* offset for the case where our block size
* is greater than the page size. This way
* offset_page will always align to a fs block
* as well as a page.
*
* For the end of the I/O we need to round
* offset + count up to a page boundary and
* then round that up to a file system block
* boundary.
*/
offset_page = ctob(btoct(XFS_FSB_TO_B(mp, offset_fsb)));
last_fsb = XFS_B_TO_FSB(mp,
ctob(btoc(offset + count)));
iosize = last_fsb - XFS_B_TO_FSBT(mp, offset_page);
ioalign = XFS_B_TO_FSB(mp, offset_page);
}
last_offset = -1;
}
/*
* Now we've got the I/O size and the last offset,
* so start figuring out how to align our
* buffers.
*/
xfs_next_bmap(mp, imap, bmapp, iosize, iosize, ioalign,
last_offset, offset_fsb);
ASSERT((bmapp->length > 0) &&
(offset >= XFS_FSB_TO_B(mp, bmapp->offset)));
if ((nimaps == 1) &&
(XFS_FSB_TO_B(mp, bmapp->offset + bmapp->length) >= nisize)) {
bmapp->eof |= BMAP_EOF;
}
bmapp->pboff = offset - XFS_FSB_TO_B(mp, bmapp->offset);
retrieved_bytes = bmapp->bsize - bmapp->pboff;
total_retrieved_bytes = 0;
bmapp->pbsize = xfs_retrieved(retrieved_bytes, offset, count,
&total_retrieved_bytes, nisize);
/*
* Only map additional buffers if they've been asked for
* and the I/O being done is sequential and has reached the
* point where we need to initiate more read ahead or we didn't get
* the whole request in the first bmap.
*/
filled_bmaps = 1;
last_required_offset = bmapp[0].offset;
first_read_ahead_bmapp = NULL;
if ((*nbmaps > 1) &&
(((offset == ip->i_next_offset) &&
(offset_fsb >= ip->i_reada_blkno)) ||
(retrieved_bytes < count))) {
curr_bmapp = &bmapp[0];
next_bmapp = &bmapp[1];
last_bmapp = &bmapp[*nbmaps - 1];
curr_imapp = &imap[0];
last_imapp = &imap[nimaps - 1];
/*
* curr_bmap is always the last one we filled
* in, and next_bmapp is always the next one
* to be filled in.
*/
while (next_bmapp <= last_bmapp) {
next_offset = curr_bmapp->offset +
curr_bmapp->length;
last_iosize = curr_bmapp->length;
if (next_offset <
(curr_imapp->br_startoff +
curr_imapp->br_blockcount)) {
xfs_next_bmap(mp, curr_imapp,
next_bmapp, iosize, last_iosize, -1,
curr_bmapp->offset, next_offset);
} else {
curr_imapp++;
if (curr_imapp <= last_imapp) {
xfs_next_bmap(mp,
curr_imapp, next_bmapp,
iosize, last_iosize, -1,
curr_bmapp->offset, next_offset);
} else {
/*
* We're out of imaps. We
* either hit the end of
* file or just didn't give
* enough of them to bmapi.
* The caller will just come
* back if we haven't done
* enough yet.
*/
break;
}
}
filled_bmaps++;
curr_bmapp = next_bmapp;
next_bmapp++;
/*
* Make sure to fill in the pboff and pbsize
* fields as long as the bmaps are required for
* the request (as opposed to strictly read-ahead).
*/
if (total_retrieved_bytes < count) {
curr_bmapp->pboff = 0;
curr_bmapp->pbsize =
xfs_retrieved(curr_bmapp->bsize,
offset, count,
&total_retrieved_bytes,
nisize);
}
if ((curr_imapp == last_imapp) &&
(XFS_FSB_TO_B(mp, curr_bmapp->offset +
curr_bmapp->length) >= nisize)) {
curr_bmapp->eof |= BMAP_EOF;
}
/*
* Keep track of the offset of the last buffer
* needed to satisfy the I/O request. This will
* be used for i_io_offset later. Also record
* the first bmapp used to track a read ahead.
*/
if (XFS_FSB_TO_B(mp, curr_bmapp->offset) <
(offset + count)) {
last_required_offset = curr_bmapp->offset;
} else if (first_read_ahead_bmapp == NULL) {
first_read_ahead_bmapp = curr_bmapp;
}
}
/*
* If we're describing any read-ahead here, then move
* the read-ahead blkno up to the point where we've
* gone through half the read-ahead described here.
* This way we don't issue more read-ahead until we
* are half-way through the last read-ahead.
*
* If we're not describing any read-ahead because the
* request is just fragmented, then move up the
* read-ahead blkno to just past what we're returning
* so that we can maybe start it on the next request.
*/
if (first_read_ahead_bmapp != NULL) {
read_aheads = curr_bmapp - first_read_ahead_bmapp +1;
next_read_ahead_bmapp = first_read_ahead_bmapp +
(read_aheads / 2);
ip->i_reada_blkno = next_read_ahead_bmapp->offset;
} else {
ip->i_reada_blkno = curr_bmapp->offset +
curr_bmapp->length;
}
} else if ((*nbmaps > 1) && (offset != ip->i_io_offset)) {
/*
* In this case the caller is not yet accessing the
* file sequentially, but set the read-ahead blkno
* so that we can tell if they start doing so.
*/
ip->i_reada_blkno = bmapp[0].offset + bmapp[0].length;
}
ip->i_io_size = iosize;
ip->i_io_offset = last_required_offset;
if (count > ip->i_last_req_sz) {
/*
* Record the "last request size" for the file.
* We don't let it shrink so that big requests
* that are not satisfied in one call here still
* record the full request size (not the smaller
* one that comes in to finish mapping the request).
*/
ip->i_last_req_sz = count;
}
if (total_retrieved_bytes >= count) {
/*
* We've mapped all of the caller's request, so
* the next request in a sequential read will
* come in the block this one ended on or the
* next if we consumed up to the very end of
* a block.
*/
ip->i_next_offset = offset + count;
} else {
/*
* We didn't satisfy the entire request, so we
* can expect xfs_read_file() to come back with
* what is left of the request.
*/
ip->i_next_offset = offset + total_retrieved_bytes;
}
*nbmaps = filled_bmaps;
for (x = 0; x < filled_bmaps; x++) {
curr_bmapp = &bmapp[x];
if (ip->i_d.di_flags & XFS_DIFLAG_REALTIME) {
curr_bmapp->pbdev = mp->m_rtdev;
} else {
curr_bmapp->pbdev = mp->m_dev;
}
curr_bmapp->offset = XFS_FSB_TO_BB(mp, curr_bmapp->offset);
curr_bmapp->length = XFS_FSB_TO_BB(mp, curr_bmapp->length);
if (curr_bmapp->bn != -1) {
curr_bmapp->bn =
XFS_FSB_TO_DADDR(mp, curr_bmapp->bn);
}
}
return;
}
int
xfs_read_file(
vnode_t *vp,
uio_t *uiop,
int ioflag,
cred_t *credp)
{
#define XFS_READ_BMAPS 4
struct bmapval bmaps[XFS_READ_BMAPS];
struct bmapval *bmapp;
int nbmaps;
buf_t *bp;
int read_bmaps;
int buffer_bytes_ok;
xfs_inode_t *ip;
int error;
ip = XFS_VTOI(vp);
error = 0;
buffer_bytes_ok = 0;
/*
* Loop until uio->uio_resid, which is the number of bytes the
* caller has requested, goes to 0 or we get an error. Each
* call to xfs_iomap_read tries to map as much of the request
* plus read-ahead as it can.
*/
do {
xfs_ilock(ip, XFS_ILOCK_SHARED);
/*
* We've fallen off the end of the file, so
* just return with what we've done so far.
*/
if (uiop->uio_offset >= ip->i_d.di_size) {
xfs_iunlock(ip, XFS_ILOCK_SHARED);
break;
}
nbmaps = XFS_READ_BMAPS;
xfs_iomap_read(ip, uiop->uio_offset, uiop->uio_resid,
bmaps, &nbmaps);
xfs_iunlock(ip, XFS_ILOCK_SHARED);
if (error || (bmaps[0].pbsize == 0)) {
break;
}
bmapp = &bmaps[0];
read_bmaps = nbmaps;
/*
* The first time through this loop we kick off I/O on
* all the bmaps described by the iomap_read call.
* Subsequent passes just wait for each buffer needed
* to satisfy this request to complete. Buffers which
* are started in the first pass but are actually just
* read ahead buffers are never waited for, since uio_resid
* will go to 0 before we get to them.
*
* This works OK because iomap_read always tries to
* describe all the buffers we need to satisfy this
* read call plus the necessary read-ahead in the
* first call to it.
*/
while ((uiop->uio_resid != 0) && (nbmaps > 0)) {
bp = chunkread(vp, bmapp, read_bmaps, credp);
if (bp->b_flags & B_ERROR) {
error = geterror(bp);
break;
} else if (bp->b_resid != 0) {
buffer_bytes_ok = 0;
break;
} else {
buffer_bytes_ok = 1;
ASSERT((BBTOB(bmapp->offset) + bmapp->pboff)
== uiop->uio_offset);
error = biomove(bp, bmapp->pboff,
bmapp->pbsize, UIO_READ,
uiop);
if (error) {
break;
}
}
brelse(bp);
read_bmaps = 1;
nbmaps--;
bmapp++;
}
} while (!error && (uiop->uio_resid != 0) && buffer_bytes_ok);
return error;
}
/*
* xfs_read
*
* This is a stub.
*/
int
xfs_read(
vnode_t *vp,
uio_t *uiop,
int ioflag,
cred_t *credp)
{
struct reservation_id id;
xfs_inode_t *ip;
int type;
off_t offset;
size_t count;
int error;
ip = XFS_VTOI(vp);
ASSERT(ismrlocked(&ip->i_iolock, MR_ACCESS | MR_UPDATE) != 0);
type = ip->i_d.di_mode & IFMT;
ASSERT(type == IFREG || type == IFDIR ||
type == IFLNK || type == IFSOCK);
offset = uiop->uio_offset;
count = uiop->uio_resid;
#ifndef SIM
if (MANDLOCK(vp, ip->i_d.di_mode) &&
(error = chklock(vp, FREAD, offset, count, uiop->uio_fmode))) {
return error;
}
#endif
if (offset < 0)
return EINVAL;
if (count <= 0)
return 0;
switch (type) {
case IFREG:
/*
* Not ready for in-line files yet.
*/
ASSERT((ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS) ||
(ip->i_d.di_format == XFS_DINODE_FMT_BTREE));
#ifdef SIM
/*
* Need pid of client not of simulator process.
* This may not always be correct.
*/
id.pid = MAKE_REQ_PID(u.u_procp->p_pid - 1, 0);
#else
id.pid = MAKE_REQ_PID(u.u_procp->p_pid, 0);
#endif
id.ino = ip->i_ino;
error = xfs_grio_req(ip, &id, uiop, ioflag, credp, UIO_READ);
break;
case IFDIR:
case IFLNK:
error = EINVAL;
break;
case IFSOCK:
error = ENODEV;
break;
default:
ASSERT(0);
error = EINVAL;
}
return error;
}
/*
* Map the given I/O size and I/O alignment over the given extent.
* If we're at the end of the file and the underlying extent is
* delayed alloc, make sure we extend out to the
* next m_writeio_blocks boundary. Otherwise make sure that we
* are confined to the given extent.
*/
STATIC void
xfs_write_bmap(
xfs_mount_t *mp,
xfs_bmbt_irec_t *imapp,
struct bmapval *bmapp,
int iosize,
xfs_fileoff_t ioalign,
xfs_fsize_t isize)
{
int extra_blocks;
xfs_fileoff_t size_diff;
xfs_fileoff_t ext_offset;
xfs_fsblock_t start_block;
off_t last_imap_byte;
if (ioalign < imapp->br_startoff) {
/*
* The desired alignment doesn't end up on this
* extent. Move up to the beginning of the extent.
* Subtract whatever we drop from the iosize so that
* we stay aligned on iosize boundaries.
*/
size_diff = imapp->br_startoff - ioalign;
iosize -= (int)size_diff;
ASSERT(iosize > 0);
ext_offset = 0;
bmapp->offset = imapp->br_startoff;
} else {
/*
* The alignment requested fits on this extent,
* so use it.
*/
ext_offset = ioalign - imapp->br_startoff;
bmapp->offset = ioalign;
}
start_block = imapp->br_startblock;
ASSERT(start_block != HOLESTARTBLOCK);
if (start_block != DELAYSTARTBLOCK) {
bmapp->bn = start_block + ext_offset;
bmapp->eof = 0;
} else {
bmapp->bn = -1;
bmapp->eof = BMAP_DELAY;
}
bmapp->length = iosize;
/*
* If the iosize from our offset extends beyond the end of
* the extent, then trim down length to match that of the extent.
*/
extra_blocks = (int)((bmapp->offset + bmapp->length) -
(imapp->br_startoff + imapp->br_blockcount));
last_imap_byte = XFS_FSB_TO_B(mp, imapp->br_startoff +
imapp->br_blockcount);
if (extra_blocks > 0) {
bmapp->length -= extra_blocks;
ASSERT(bmapp->length > 0);
}
bmapp->bsize = XFS_FSB_TO_B(mp, bmapp->length);
}
/*
* This routine is called to handle zeroing any space in the last
* block of the file that is beyond the EOF. We do this since the
* size is being increased without writing anything to that block
* and we don't want anyone to read the garbage on the disk.
*/
void
xfs_zero_eof(
xfs_inode_t *ip,
off_t offset,
xfs_fsize_t isize,
cred_t *credp)
{
xfs_fileoff_t last_fsb;
xfs_mount_t *mp;
buf_t *bp;
int iosize;
vnode_t *vp;
int nimaps;
int zero_offset;
int zero_len;
int isize_fsb_offset;
xfs_bmbt_irec_t imap;
struct bmapval bmap;
ASSERT(ismrlocked(&ip->i_lock, MR_UPDATE) != 0);
ASSERT(offset > isize);
mp = ip->i_mount;
vp = XFS_ITOV(ip);
isize_fsb_offset = XFS_B_FSB_OFFSET(mp, isize);
if (isize_fsb_offset == 0) {
/*
* There are not extra bytes in the last block to
* zero, so return.
*/
return;
}
last_fsb = XFS_B_TO_FSBT(mp, isize);
nimaps = 1;
(void) xfs_bmapi(NULL, ip, last_fsb, 1, 0, NULLFSBLOCK, 0, &imap,
&nimaps, NULL);
ASSERT(nimaps > 0);
/*
* If the block underlying isize is just a hole, then there
* is nothing to zero.
*/
if (imap.br_startblock == HOLESTARTBLOCK) {
return;
}
/*
* Get a buffer for the last block, zero the part beyond the
* EOF, and write it out async. We need to drop the ilock
* while we do this so we don't deadlock when the buffer cache
* calls back to us.
*/
xfs_iunlock(ip, XFS_ILOCK_EXCL);
bmap.offset = XFS_FSB_TO_BB(mp, last_fsb);
bmap.length = XFS_FSB_TO_BB(mp, 1);
bmap.bsize = BBTOB(bmap.length);
bmap.pboff = 0;
bmap.pbsize = bmap.bsize;
if (ip->i_d.di_flags & XFS_DIFLAG_REALTIME) {
bmap.pbdev = mp->m_rtdev;
} else {
bmap.pbdev = mp->m_dev;
}
bmap.eof = BMAP_EOF;
if (imap.br_startblock != DELAYSTARTBLOCK) {
bmap.bn = XFS_FSB_TO_DADDR(mp, imap.br_startblock);
} else {
bmap.bn = -1;
bmap.eof |= BMAP_DELAY;
}
bp = chunkread(XFS_ITOV(ip), &bmap, 1, credp);
zero_offset = isize_fsb_offset;
zero_len = mp->m_sb.sb_blocksize - isize_fsb_offset;
xfs_zero_bp(bp, zero_offset, zero_len);
bawrite(bp);
xfs_ilock(ip, XFS_ILOCK_EXCL);
return;
}
STATIC void
xfs_iomap_write(
xfs_inode_t *ip,
off_t offset,
size_t count,
struct bmapval *bmapp,
int *nbmaps)
{
xfs_fileoff_t offset_fsb;
xfs_fileoff_t ioalign;
xfs_fileoff_t next_offset_fsb;
xfs_fileoff_t last_fsb;
xfs_fileoff_t bmap_end_fsb;
off_t next_offset;
xfs_fsize_t isize;
int nimaps;
unsigned int iosize;
unsigned int writing_bytes;
short filled_bmaps;
short x;
size_t count_remaining;
xfs_mount_t *mp;
struct bmapval *curr_bmapp;
struct bmapval *next_bmapp;
struct bmapval *last_bmapp;
xfs_bmbt_irec_t *curr_imapp;
xfs_bmbt_irec_t *last_imapp;
#define XFS_WRITE_IMAPS XFS_BMAP_MAX_NMAP
xfs_bmbt_irec_t imap[XFS_WRITE_IMAPS];
ASSERT(ismrlocked(&ip->i_lock, MR_UPDATE) != 0);
mp = ip->i_mount;
isize = ip->i_d.di_size;
offset_fsb = XFS_B_TO_FSBT(mp, offset);
nimaps = XFS_WRITE_IMAPS;
last_fsb = XFS_B_TO_FSB(mp, offset + count);
(void) xfs_bmapi(NULL, ip, offset_fsb,
(xfs_extlen_t)(last_fsb - offset_fsb),
XFS_BMAPI_DELAY | XFS_BMAPI_WRITE |
XFS_BMAPI_ENTIRE, NULLFSBLOCK, 1, imap,
&nimaps, NULL);
iosize = mp->m_writeio_blocks;
ioalign = XFS_WRITEIO_ALIGN(mp, offset);
ioalign = XFS_B_TO_FSBT(mp, ioalign);
/*
* Now map our desired I/O size and alignment over the
* extents returned by xfs_bmapi().
*/
xfs_write_bmap(mp, imap, bmapp, iosize, ioalign, isize);
ASSERT((bmapp->length > 0) &&
(offset >= XFS_FSB_TO_B(mp, bmapp->offset)));
/*
* A bmap is the EOF bmap when it reaches to or beyond the current
* inode size AND it encompasses the last block allocated to the
* file. Beyond the inode size is not good enough, because we
* could be writing more in this very request beyond what we
* are willing to describe in a single bmap.
*/
bmap_end_fsb = bmapp->offset + bmapp->length;
if ((nimaps == 1) &&
(bmap_end_fsb >= imap[0].br_startoff + imap[0].br_blockcount) &&
(XFS_FSB_TO_B(mp, bmap_end_fsb) >= isize)) {
bmapp->eof |= BMAP_EOF;
}
bmapp->pboff = offset - XFS_FSB_TO_B(mp, bmapp->offset);
writing_bytes = bmapp->bsize - bmapp->pboff;
if (writing_bytes > count) {
/*
* The mapping is for more bytes than we're actually
* going to write, so trim writing_bytes so we can
* get bmapp->pbsize right.
*/
writing_bytes = count;
}
bmapp->pbsize = writing_bytes;
/*
* Map more buffers if the first does not map the entire
* request. We do this until we run out of bmaps, imaps,
* or bytes to write.
*/
filled_bmaps = 1;
if ((*nbmaps > 1) &&
((nimaps > 1) || (bmapp->offset + bmapp->length <
imap[0].br_startoff + imap[0].br_blockcount)) &&
(writing_bytes < count)) {
curr_bmapp = &bmapp[0];
next_bmapp = &bmapp[1];
last_bmapp = &bmapp[*nbmaps - 1];
curr_imapp = &imap[0];
last_imapp = &imap[nimaps - 1];
count_remaining = count - writing_bytes;
/*
* curr_bmapp is always the last one we filled
* in, and next_bmapp is always the next one to
* be filled in.
*/
while (next_bmapp <= last_bmapp) {
next_offset_fsb = curr_bmapp->offset +
curr_bmapp->length;
if (next_offset_fsb <
(curr_imapp->br_startoff +
curr_imapp->br_blockcount)) {
/*
* I'm still on the same extent, so
* the last bmap must have ended on
* a writeio_blocks boundary. Thus,
* we just start where the last one
* left off.
*/
ASSERT((XFS_FSB_TO_B(mp, next_offset_fsb) &
((1 << mp->m_writeio_log) - 1))==0);
xfs_write_bmap(mp, curr_imapp, next_bmapp,
iosize, next_offset_fsb,
isize);
} else {
curr_imapp++;
if (curr_imapp <= last_imapp) {
/*
* We're moving on to the next
* extent. Since we try to end
* all buffers on writeio_blocks
* boundaries, round next_offset
* down to a writeio_blocks boundary
* before calling xfs_write_bmap().
*
* XXXajs
* Adding a macro to writeio align
* fsblocks would be good to reduce
* the bit shifting here.
*/
ioalign = XFS_FSB_TO_B(mp,
next_offset_fsb);
ioalign = XFS_WRITEIO_ALIGN(mp,
ioalign);
ioalign = XFS_B_TO_FSBT(mp, ioalign);
xfs_write_bmap(mp, curr_imapp,
next_bmapp, iosize,
ioalign, isize);
} else {
/*
* We're out of imaps. The caller
* will have to call again to map
* the rest of the write request.
*/
break;
}
}
/*
* The write must start at offset 0 in this bmap
* since we're just continuing from the last
* buffer. Thus the request offset in the buffer
* indicated by pboff must be 0.
*/
next_bmapp->pboff = 0;
/*
* The request size within this buffer is the
* entire buffer unless the count of bytes to
* write runs out.
*/
next_offset = XFS_FSB_TO_B(mp, next_offset_fsb);
writing_bytes = next_bmapp->bsize;
if (writing_bytes > count_remaining) {
writing_bytes = count_remaining;
}
next_bmapp->pbsize = writing_bytes;
count_remaining -= writing_bytes;
ASSERT(count_remaining >= 0);
filled_bmaps++;
curr_bmapp++;
next_bmapp++;
/*
* A bmap is the EOF bmap when it reaches to
* or beyond the current inode size AND it
* encompasses the last block allocated to the
* file. Beyond the inode size is not good
* enough, because we could be writing more
* in this very request beyond what we
* are willing to describe in a single bmap.
*/
bmap_end_fsb = curr_bmapp->offset +
curr_bmapp->length;
if ((curr_imapp == last_imapp) &&
(bmap_end_fsb >= curr_imapp->br_startoff +
curr_imapp->br_blockcount) &&
(XFS_FSB_TO_B(mp, bmap_end_fsb) >= isize)) {
curr_bmapp->eof |= BMAP_EOF;
}
}
}
*nbmaps = filled_bmaps;
for (x = 0; x < filled_bmaps; x++) {
curr_bmapp = &bmapp[x];
if (ip->i_d.di_flags & XFS_DIFLAG_REALTIME) {
curr_bmapp->pbdev = mp->m_rtdev;
} else {
curr_bmapp->pbdev = mp->m_dev;
}
curr_bmapp->offset = XFS_FSB_TO_BB(mp, curr_bmapp->offset);
curr_bmapp->length = XFS_FSB_TO_BB(mp, curr_bmapp->length);
if (curr_bmapp->bn != -1) {
curr_bmapp->bn =
XFS_FSB_TO_DADDR(mp, curr_bmapp->bn);
}
}
}
int
xfs_write_file(
vnode_t *vp,
uio_t *uiop,
int ioflag,
cred_t *credp)
{
#define XFS_WRITE_BMAPS 4
struct bmapval bmaps[XFS_WRITE_BMAPS];
struct bmapval *bmapp;
int nbmaps;
buf_t *bp;
int buffer_bytes_ok;
xfs_inode_t *ip;
int error;
int eof_zeroed;
xfs_fsize_t isize;
ip = XFS_VTOI(vp);
error = 0;
buffer_bytes_ok = 0;
eof_zeroed = 0;
/*
* i_new_size is used by xfs_iomap_read() when the chunk
* cache code calls back into the file system through
* xfs_bmap(). This way we can tell where the end of
* file is going to be even though we haven't yet updated
* ip->i_d.di_size. This is guarded by the iolock which
* is held exclusively through here.
*/
ip->i_new_size = uiop->uio_offset + uiop->uio_resid;
/*
* Loop until uiop->uio_resid, which is the number of bytes the
* caller has requested to write, goes to 0 or we get an error.
* Each call to xfs_iomap_write() tries to map as much of the
* request as it can in mp->m_writeio_blks sized chunks.
*/
do {
xfs_ilock(ip, XFS_ILOCK_EXCL);
isize = ip->i_d.di_size;
if (ip->i_new_size < isize) {
ip->i_new_size = isize;
}
/*
* If we've seeked passed the EOF to do this write,
* then we need to make sure that any buffer overlapping
* the EOF is zeroed beyond the EOF.
*/
if (!eof_zeroed &&
(uiop->uio_offset > isize) &&
(isize != 0)) {
xfs_zero_eof(ip, uiop->uio_offset, isize, credp);
eof_zeroed = 1;
}
nbmaps = XFS_WRITE_BMAPS;
xfs_iomap_write(ip, uiop->uio_offset, uiop->uio_resid,
bmaps, &nbmaps);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
if (error || (bmaps[0].pbsize == 0)) {
break;
}
bmapp = &bmaps[0];
/*
* Each pass through the loop writes another buffer
* to the file. For big requests, iomap_write will
* have given up multiple bmaps to use so we make fewer
* calls to it on big requests than if it only gave
* us one at a time.
*/
while ((uiop->uio_resid != 0) && (nbmaps > 0)) {
/*
* If the write doesn't completely overwrite
* the buffer and we're not writing from
* the beginning of the buffer to the end
* of the file then we need to read the
* buffer.
*
* Reading the buffer will send it to xfs_strategy
* which will take care of zeroing the holey
* parts of the buffer and coordinating with
* other, simultaneous writers.
*/
if ((bmapp->pbsize != bmapp->bsize) &&
!((bmapp->pboff == 0) &&
(uiop->uio_offset >= isize))) {
bp = chunkread(vp, bmapp, 1, credp);
} else {
bp = getchunk(vp, bmapp, credp);
}
/*
* XXXajs
* The error handling below needs more work.
*/
if (bp->b_flags & B_ERROR) {
error = geterror(bp);
brelse(bp);
break;
}
ASSERT((BBTOB(bmapp->offset) + bmapp->pboff) ==
uiop->uio_offset);
if (error = biomove(bp, bmapp->pboff, bmapp->pbsize,
UIO_WRITE, uiop)) {
if (!(bp->b_flags & B_DONE)) {
bp->b_flags |= B_STALE | B_DONE |
B_ERROR;
}
brelse(bp);
break;
}
/*
* If we've grown the file, get back the
* inode lock and move di_size up to the
* new size. It may be that someone else
* made it even bigger, so be careful not
* to shrink it.
*
* Noone could have shrunken the file, because
* we are holding the iolock shared.
*/
if (uiop->uio_offset > isize) {
xfs_ilock(ip, XFS_ILOCK_EXCL);
if (uiop->uio_offset > ip->i_d.di_size) {
ip->i_d.di_size = uiop->uio_offset;
ip->i_update_core = 1;
isize = uiop->uio_offset;
}
xfs_iunlock(ip, XFS_ILOCK_EXCL);
}
if (uiop->uio_fmode & FSYNC) {
bwrite(bp);
} else {
bdwrite(bp);
}
bmapp++;
nbmaps--;
}
} while ((uiop->uio_resid > 0) && !error);
ip->i_new_size = 0;
return error;
}
/*
* xfs_write
*
*/
int
xfs_write(
vnode_t *vp,
uio_t *uiop,
int ioflag,
cred_t *credp)
{
struct reservation_id id;
xfs_inode_t *ip;
int type;
off_t offset;
size_t count;
int error;
int n;
int resid;
timestruc_t tv;
ip = XFS_VTOI(vp);
ASSERT(ismrlocked(&ip->i_iolock, MR_UPDATE) != 0);
type = ip->i_d.di_mode & IFMT;
ASSERT(type == IFREG || type == IFDIR ||
type == IFLNK || type == IFSOCK);
if (ioflag & IO_APPEND) {
/*
* In append mode, start at the end of the file.
* Since I've got the iolock exclusive I can look
* at di_size.
*/
uiop->uio_offset = ip->i_d.di_size;
}
offset = uiop->uio_offset;
count = uiop->uio_resid;
#ifndef SIM
if (MANDLOCK(vp, ip->i_d.di_mode) &&
(error = chklock(vp, FWRITE, offset, count, uiop->uio_fmode))) {
return error;
}
#endif
if ((offset < 0) || ((offset + count) > XFS_MAX_FILE_OFFSET)) {
return EINVAL;
}
if (count <= 0) {
return 0;
}
switch (type) {
case IFREG:
n = uiop->uio_limit - uiop->uio_offset;
if (n <= 0) {
return EFBIG;
}
if (n < uiop->uio_resid) {
resid = uiop->uio_resid - n;
uiop->uio_resid = n;
} else {
resid = 0;
}
#ifdef SIM
/*
* Need pid of client not of simulator process.
* This may not always be correct.
*/
id.pid = MAKE_REQ_PID(u.u_procp->p_pid - 1, 0);
#else
id.pid = MAKE_REQ_PID(u.u_procp->p_pid, 0);
#endif
id.ino = ip->i_ino;
error = xfs_grio_req( ip, &id, uiop, ioflag, credp, UIO_WRITE);
/*
* Add back whatever we refused to do because of
* uio_limit.
*/
uiop->uio_resid += resid;
/*
* We've done at least a partial write, so don't
* return an error on this call. Also update the
* timestamps since we changed the file.
*
* XXXajs
* Are these the right timestamps?
*/
if (count != uiop->uio_resid) {
error = 0;
nanotime(&tv);
ip->i_d.di_mtime.t_sec = tv.tv_sec;
ip->i_d.di_ctime.t_sec = tv.tv_sec;
ip->i_update_core = 1;
}
break;
case IFDIR:
case IFLNK:
return EINVAL;
case IFSOCK:
return ENODEV;
default:
ASSERT(0);
return EINVAL;
}
return error;
}
/*
* This is the xFS entry point for VOP_BMAP().
* It simply switches based on the given flags
* to either xfs_iomap_read() or xfs_iomap_write().
* This cannot be used to grow a file or to read
* beyond the end of the file.
*
* The caller is required to be holding the inode's
* iolock in at least shared mode.
*/
int
xfs_bmap(
vnode_t *vp,
off_t offset,
ssize_t count,
int flags,
cred_t *credp,
struct bmapval *bmapp,
int *nbmaps)
{
xfs_inode_t *ip;
ip = XFS_VTOI(vp);
ASSERT((ip->i_d.di_mode & IFMT) == IFREG);
ASSERT(ismrlocked(&ip->i_iolock, MR_ACCESS | MR_UPDATE) != 0);
ASSERT((flags == B_READ) || (flags == B_WRITE));
if (flags == B_READ) {
xfs_ilock(ip, XFS_ILOCK_SHARED);
xfs_iomap_read(ip, offset, count, bmapp, nbmaps);
xfs_iunlock(ip, XFS_ILOCK_SHARED);
} else {
xfs_ilock(ip, XFS_ILOCK_EXCL);
ASSERT(ip->i_d.di_size >= (offset + count));
xfs_iomap_write(ip, offset, count, bmapp, nbmaps);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
}
return 0;
}
/*
* Set up rbp so that it points to the memory attached to bp
* from rbp_offset from the start of bp for rbp_len bytes.
*/
STATIC void
xfs_overlap_bp(
buf_t *bp,
buf_t *rbp,
uint rbp_offset,
uint rbp_len)
{
int pgbboff;
int bytes_off;
pfd_t *pfdp;
if (BP_ISMAPPED(bp)) {
/*
* The real buffer is already mapped, so just use
* its virtual memory for ourselves.
*/
rbp->b_un.b_addr = bp->b_un.b_addr + rbp_offset;
rbp->b_bcount = rbp_len;
rbp->b_bufsize = rbp_len;
} else {
/*
* The real buffer is not yet mapped to virtual memory.
* Just get the subordinate buffer's page pointers
* set up and make it a PAGEIO buffer like the real one.
*
* First find the first page of rbp. We do this by
* walking the list of pages in bp until we find the
* one containing the start of rbp. Note that neither
* bp nor rbp are required to start on page boundaries.
*/
bytes_off = rbp_offset + BBTOB(dpoff(bp->b_offset));
pfdp = NULL;
pfdp = getnextpg(bp, pfdp);
ASSERT(pfdp != NULL);
while (bytes_off >= NBPP) {
pfdp = getnextpg(bp, pfdp);
ASSERT(pfdp != NULL);
bytes_off -= NBPP;
}
rbp->b_pages = pfdp;
rbp->b_bcount = rbp_len;
rbp->b_offset = bp->b_offset + BTOBB(rbp_offset);
pgbboff = dpoff(rbp->b_offset);
rbp->b_bufsize = ctob(dtop(pgbboff + BTOBB(rbp_len)));
rbp->b_flags |= B_PAGEIO;
#ifndef SIM
if (pgbboff != 0) {
bp_mapin(rbp);
}
#endif
}
rbp->b_blkno = bp->b_blkno + BTOBB(rbp_offset);
rbp->b_remain = 0;
rbp->b_vp = bp->b_vp;
rbp->b_edev = bp->b_edev;
rbp->b_flags |= (bp->b_flags & (B_UNCACHED | B_ASYNC));
}
/*
* Zero the given bp from data_offset from the start of it for data_len
* bytes.
*/
STATIC void
xfs_zero_bp(
buf_t *bp,
int data_offset,
int data_len)
{
pfd_t *pfdp;
caddr_t page_addr;
int len;
data_offset += BBTOB(dpoff(bp->b_offset));
pfdp = NULL;
pfdp = getnextpg(bp, pfdp);
ASSERT(pfdp != NULL);
while (data_offset >= NBPP) {
pfdp = getnextpg(bp, pfdp);
ASSERT(pfdp != NULL);
data_offset -= NBPP;
}
ASSERT(data_offset >= 0);
while (data_len > 0) {
page_addr = page_mapin(pfdp, (bp->b_flags & B_UNCACHED ?
VM_UNCACHED : 0), 0);
len = MIN(data_len, NBPP - data_offset);
bzero(page_addr + data_offset, len);
data_len -= len;
data_offset = 0;
page_mapout(page_addr);
pfdp = getnextpg(bp, pfdp);
}
}
/*
* "Read" in a buffer whose b_blkno is -1. This means that
* at the time the buffer was created there was no underlying
* backing store for the range of the file covered by the bp.
* To figure out the current state of things, we lock the inode
* and call xfs_bmapi() to look at the current extents format.
* If we're over a hole or delayed allocation space we simply
* zero the corresponding portions of the buffer. For parts
* over real disk space we need to read in the stuff from disk.
*/
STATIC void
xfs_strat_read(
vnode_t *vp,
buf_t *bp)
{
xfs_fileoff_t offset_fsb;
xfs_fileoff_t map_start_fsb;
xfs_fileoff_t imap_offset;
xfs_extlen_t count_fsb;
xfs_extlen_t imap_blocks;
xfs_fsize_t isize;
off_t offset;
off_t end_offset;
int x;
caddr_t datap;
buf_t *rbp;
xfs_mount_t *mp;
xfs_inode_t *ip;
int data_bytes;
int data_offset;
int data_len;
int nimaps;
#define XFS_STRAT_READ_IMAPS 4
xfs_bmbt_irec_t imap[XFS_STRAT_READ_IMAPS];
ASSERT(bp->b_blkno == -1);
ip = XFS_VTOI(vp);
mp = XFS_VFSTOM(vp->v_vfsp);
offset_fsb = XFS_BB_TO_FSBT(mp, bp->b_offset);
/*
* Only read up to the EOF.
*/
isize = ip->i_d.di_size;
offset = BBTOB(bp->b_offset);
end_offset = offset + bp->b_bcount;
if ((offset < isize) && (end_offset > isize)) {
count_fsb = XFS_B_TO_FSB(mp, isize - offset);
} else {
count_fsb = XFS_B_TO_FSB(mp, bp->b_bcount);
}
map_start_fsb = offset_fsb;
xfs_ilock(ip, XFS_ILOCK_SHARED);
while (count_fsb != 0) {
nimaps = XFS_STRAT_READ_IMAPS;
(void) xfs_bmapi(NULL, ip, map_start_fsb, count_fsb, 0,
NULLFSBLOCK, 0, imap, &nimaps, NULL);
ASSERT(nimaps >= 1);
for (x = 0; x < nimaps; x++) {
imap_offset = imap[x].br_startoff;
ASSERT(imap_offset == map_start_fsb);
imap_blocks = imap[x].br_blockcount;
ASSERT(imap_blocks <= count_fsb);
if ((imap[x].br_startblock == DELAYSTARTBLOCK) ||
(imap[x].br_startblock == HOLESTARTBLOCK)) {
/*
* This is either a hole or a delayed
* alloc extent. Either way, just fill
* it with zeroes.
*/
#ifndef SIM
datap = bp_mapin(bp);
datap += XFS_FSB_TO_B(mp, imap_offset -
offset_fsb);
data_bytes = XFS_FSB_TO_B(mp, imap_blocks);
bzero(datap, data_bytes);
#else /* SIM */
ASSERT(bp->b_flags & B_PAGEIO);
data_offset = XFS_FSB_TO_B(mp, imap_offset -
offset_fsb);
data_len = XFS_FSB_TO_B(mp, imap_blocks);
xfs_zero_bp(bp, data_offset, data_len);
#endif /* SIM */
} else {
/*
* The extent really exists on disk, so
* read it in.
*/
rbp = getrbuf(KM_SLEEP);
data_offset = XFS_FSB_TO_B(mp, imap_offset -
offset_fsb);
data_len = XFS_FSB_TO_B(mp, imap_blocks);
xfs_overlap_bp(bp, rbp, data_offset,
data_len);
rbp->b_flags |= B_READ;
rbp->b_flags &= ~B_ASYNC;
bdstrat(bmajor(rbp->b_edev), rbp);
iowait(rbp);
if (rbp->b_flags & B_ERROR) {
bp->b_flags |= B_ERROR;
bp->b_error = rbp->b_error;
}
#ifndef SIM
if (BP_ISMAPPED(rbp)) {
bp_mapout(rbp);
}
#endif
freerbuf(rbp);
}
count_fsb -= imap_blocks;
map_start_fsb += imap_blocks;
}
}
xfs_iunlock(ip, XFS_ILOCK_SHARED);
iodone(bp);
}
/*
* xfs_strat_write_count
*
* Figure out the number of fs blocks underlying the given
* delayed allocation buffer. There may be a mix of allocated
* and delayed allocation extents beneath the buffer, but there
* should only be a hole (if any) at the end of the buffer.
* The hole would be the result of the aggressive buffer allocation
* we do (past the EOF) when writing a file. It may even be that
* the entire buffer sits over a hole. This is from the case where
* pdflush() turns one of our extra pages into a buffer.
*/
STATIC xfs_extlen_t
xfs_strat_write_count(
xfs_inode_t *ip,
xfs_fileoff_t offset_fsb,
xfs_extlen_t buf_fsb,
xfs_bmbt_irec_t *imap,
int imap_count)
{
xfs_fileoff_t off_fsb;
xfs_extlen_t count_fsb;
boolean_t done;
int nimaps;
int n;
ASSERT(ismrlocked(&(ip->i_lock), MR_ACCESS | MR_UPDATE) != 0);
off_fsb = offset_fsb;
count_fsb = 0;
done = B_FALSE;
while ((count_fsb < buf_fsb) && (!done)) {
nimaps = imap_count;
(void) xfs_bmapi(NULL, ip, (off_fsb + count_fsb),
(buf_fsb - count_fsb), 0, NULLFSBLOCK, 0,
imap, &nimaps, NULL);
ASSERT(nimaps > 0);
n = 0;
while (n < nimaps) {
if (imap[n].br_startblock == HOLESTARTBLOCK) {
/*
* We've hit the hole at the end of the
* buffer, so that's it. We assert
* that the hole we've found extends
* all the way to the end of the buffer.
*/
ASSERT(0);
ASSERT((imap[n].br_startoff +
imap[n].br_blockcount) ==
(offset_fsb + buf_fsb));
done = B_TRUE;
break;
}
count_fsb += imap[n].br_blockcount;
ASSERT(count_fsb <= buf_fsb);
n++;
}
}
return count_fsb;
}
/*
* This is the completion routine for the heap-allocated buffers
* used to write out a buffer which becomes fragmented during
* xfs_strat_write(). It must coordinate with xfs_strat_write()
* to properly mark the lead buffer as done when necessary and
* to free the subordinate buffer.
*/
STATIC void
xfs_strat_write_relse(
buf_t *rbp)
{
int s;
buf_t *leader;
buf_t *forw;
buf_t *back;
s = splockspl(xfs_strat_lock, splhi);
ASSERT(rbp->b_flags & B_DONE);
forw = (buf_t*)rbp->b_fsprivate2;
back = (buf_t*)rbp->b_fsprivate;
ASSERT(back != NULL);
ASSERT(back->b_fsprivate2 == rbp);
ASSERT((forw == NULL) || (forw->b_fsprivate == rbp));
/*
* Pull ourselves from the list.
*/
back->b_fsprivate2 = forw;
if (forw != NULL) {
forw->b_fsprivate = back;
}
if ((forw == NULL) &&
(back->b_flags & B_LEADER) &&
!(back->b_flags & B_PARTIAL)) {
/*
* We are the only buffer in the list and the lead buffer
* has cleared the B_PARTIAL bit to indicate that all
* subordinate buffers have been issued. That means it
* is time to finish off the lead buffer.
*/
leader = back;
if (rbp->b_flags & B_ERROR) {
leader->b_flags |= B_ERROR;
leader->b_error = rbp->b_error;
}
leader->b_flags &= ~B_LEADER;
spunlockspl(xfs_strat_lock, s);
iodone(leader);
} else {
/*
* Either there are still other buffers in the list or
* not all of the subordinate buffers have yet been issued.
* In this case just pass any errors on to the lead buffer.
*/
while (!(back->b_flags & B_LEADER)) {
back = (buf_t*)back->b_fsprivate;
}
ASSERT(back != NULL);
ASSERT(back->b_flags & B_LEADER);
leader = back;
if (rbp->b_flags & B_ERROR) {
leader->b_flags |= B_ERROR;
leader->b_error = rbp->b_error;
}
spunlockspl(xfs_strat_lock, s);
}
rbp->b_fsprivate = NULL;
rbp->b_fsprivate2 = NULL;
rbp->b_relse = NULL;
#ifndef SIM
if (BP_ISMAPPED(rbp)) {
bp_mapout(rbp);
}
#endif
freerbuf(rbp);
}
STATIC void
xfs_strat_write(
vnode_t *vp,
buf_t *bp)
{
xfs_fileoff_t offset_fsb;
xfs_fileoff_t map_start_fsb;
xfs_fileoff_t imap_offset;
xfs_fsblock_t first_block;
xfs_extlen_t count_fsb;
xfs_extlen_t imap_blocks;
int x;
caddr_t datap;
buf_t *rbp;
xfs_mount_t *mp;
xfs_inode_t *ip;
xfs_trans_t *tp;
int error;
xfs_bmap_free_t free_list;
xfs_bmbt_irec_t *imapp;
int rbp_offset;
int rbp_len;
int set_lead = 0;
int s;
int imap_index;
int nimaps;
#define XFS_STRAT_WRITE_IMAPS 4
xfs_bmbt_irec_t imap[XFS_STRAT_WRITE_IMAPS];
ip = XFS_VTOI(vp);
mp = ip->i_mount;
bp->b_flags |= B_STALE;
/*
* Figure out what the underlying mappings look like.
* We need to map out all the space underlying the
* buffer to figure out whether the buffer extends
* beyond the allocated (or at least reserved) space
* and not to write that part.
*/
ASSERT(bp->b_blkno == -1);
offset_fsb = XFS_BB_TO_FSBT(mp, bp->b_offset);
count_fsb = XFS_B_TO_FSB(mp, bp->b_bcount);
xfs_ilock(ip, XFS_ILOCK_SHARED);
count_fsb = xfs_strat_write_count(ip, offset_fsb, count_fsb, imap,
XFS_STRAT_WRITE_IMAPS);
xfs_iunlock(ip, XFS_ILOCK_SHARED);
if (count_fsb == 0) {
/*
* The buffer sits entirely over a hole. Just mark
* it done and return.
*/
iodone(bp);
return;
}
map_start_fsb = offset_fsb;
while (count_fsb != 0) {
/*
* Set up a transaction with which to allocate the
* backing store for the file.
*/
tp = xfs_trans_alloc(mp, XFS_TRANS_FILE_WRITE);
error = xfs_trans_reserve(tp, 0, XFS_DEFAULT_LOG_RES(mp),
0, 0);
ASSERT(error == 0);
xfs_ilock(ip, XFS_ILOCK_EXCL);
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
xfs_trans_ihold(tp, ip);
/*
* Allocate the backing store for the file.
*/
XFS_BMAP_INIT(&free_list, &first_block);
nimaps = XFS_STRAT_WRITE_IMAPS;
first_block = xfs_bmapi(tp, ip, map_start_fsb, count_fsb,
XFS_BMAPI_WRITE, first_block, 1,
imap, &nimaps, &free_list);
ASSERT(nimaps > 0);
(void) xfs_bmap_finish(&tp, &free_list, first_block, 0);
xfs_trans_commit(tp, 0);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
/*
* This is a quick check to see if the first time through
* was able to allocate a single extent over which to
* write
*/
if ((map_start_fsb == offset_fsb) &&
(imap[0].br_blockcount == count_fsb)) {
ASSERT(nimaps == 1);
bp->b_blkno = XFS_FSB_TO_DADDR(mp,
imap[0].br_startblock);
bp->b_bcount = XFS_FSB_TO_B(mp, count_fsb);
bdstrat(bmajor(bp->b_edev), bp);
return;
}
/*
* Bmap couldn't manage to lay the buffer out as
* one extent, so we need to do multiple writes
* to push the data to the multiple extents.
* Write out the subordinate bps asynchronously
* and have their completion functions coordinate
* with the code at the end of this function to
* deal with marking our bp as done when they have
* ALL completed.
*/
imap_index = 0;
if (!set_lead) {
bp->b_flags |= B_LEADER | B_PARTIAL;
set_lead = 1;
}
while (imap_index < nimaps) {
rbp = getrbuf(KM_SLEEP);
imapp = &imap[imap_index];
ASSERT((imapp->br_startblock != DELAYSTARTBLOCK) &&
(imapp->br_startblock != HOLESTARTBLOCK));
imap_offset = imapp->br_startoff;
rbp_offset = XFS_FSB_TO_B(mp, imap_offset - offset_fsb);
imap_blocks = imapp->br_blockcount;
rbp_len = XFS_FSB_TO_B(mp, imap_blocks);
xfs_overlap_bp(bp, rbp, rbp_offset, rbp_len);
rbp->b_blkno = XFS_FSB_TO_DADDR(mp,
imapp->br_startblock);
/*
* Link the buffer into the list of subordinate
* buffers started at bp->b_fsprivate2. The
* subordinate buffers use b_fsprivate and
* b_fsprivate2 for back and forw pointers, but
* the lead buffer cannot use b_fsprivate.
* A subordinate buffer can always find the lead
* buffer by searching back through the fsprivate
* fields until it finds the buffer marked with
* B_LEADER.
*/
s = splockspl(xfs_strat_lock, splhi);
rbp->b_fsprivate = bp;
rbp->b_fsprivate2 = bp->b_fsprivate2;
if (bp->b_fsprivate2 != NULL) {
((buf_t*)(bp->b_fsprivate2))->b_fsprivate =
rbp;
}
bp->b_fsprivate2 = rbp;
spunlockspl(xfs_strat_lock, s);
rbp->b_relse = xfs_strat_write_relse;
bdstrat(bmajor(rbp->b_edev), rbp);
map_start_fsb += imapp->br_blockcount;
count_fsb -= imapp->br_blockcount;
ASSERT(count_fsb >= 0);
imap_index++;
}
}
/*
* Now that we've issued all the partial I/Os, check to see
* if they've all completed. If they have then mark the buffer
* as done, otherwise clear the B_PARTIAL flag in the buffer to
* indicate that the last subordinate buffer to complete should
* mark the buffer done.
*/
s = splockspl(xfs_strat_lock, splhi);
ASSERT((bp->b_flags & (B_DONE | B_PARTIAL)) == B_PARTIAL);
ASSERT(bp->b_flags & B_LEADER);
if (bp->b_fsprivate2 == NULL) {
/*
* All of the subordinate buffers have completed.
* Call iodone() to note that the I/O has completed.
*/
bp->b_flags &= ~(B_PARTIAL | B_LEADER);
spunlockspl(xfs_strat_lock, s);
iodone(bp);
return;
}
bp->b_flags &= ~B_PARTIAL;
spunlockspl(xfs_strat_lock, s);
return;
}
/*
* xfs_strategy
*
* This is where all the I/O and all the REAL allocations take
* place. For buffers with -1 for their b_blkno field, we need
* to do a bmap to figure out what to do with them. If it's a
* write we may need to do an allocation, while if it's a read
* we may either need to read from disk or do some block zeroing.
* If b_blkno specifies a real block, then all we need to do
* is pass the buffer on to the underlying driver.
*/
void
xfs_strategy(
vnode_t *vp,
buf_t *bp)
{
xfs_mount_t *mp;
int s;
mp = XFS_VFSTOM(vp->v_vfsp);
/*
* If this is just a buffer whose underlying disk space
* is already allocated, then just do the requested I/O.
*/
if (bp->b_blkno >= 0) {
bdstrat(bmajor(bp->b_edev), bp);
return;
}
/*
* If we're reading, then we need to find out how the
* portion of the file required for this buffer is layed
* out and zero/read in the appropriate data.
*/
if (bp->b_flags & B_READ) {
xfs_strat_read(vp, bp);
return;
}
/*
* Here we're writing the file and probably need to allocate
* some underlying disk space. If the buffer is being written
* asynchronously by bdflush() then we queue if for the xfsds
* so that we won't put bdflush() to sleep.
*/
if ((bp->b_flags & (B_ASYNC | B_BDFLUSH)) == (B_ASYNC | B_BDFLUSH) &&
(xfsd_count > 0)) {
s = splock(xfsd_lock);
/*
* Queue the buffer at the end of the list.
*/
if (xfsd_list == NULL) {
bp->av_forw = bp;
bp->av_back = bp;
xfsd_list = bp;
} else {
bp->av_back = xfsd_list->av_back;
xfsd_list->av_back->av_forw = bp;
xfsd_list->av_back = bp;
bp->av_forw = xfsd_list;
}
xfsd_bufcount++;
cvsema(&xfsd_wait);
spunlock(xfsd_lock, s);
} else {
xfs_strat_write(vp, bp);
}
}
#ifndef SIM
/*
* This is the routine called by the xfs daemons as they enter the
* kernel. From here they wait in a loop for buffers which will
* require transactions to write out and process them as they come.
* This way we never force bdflush() to wait on one of our transactions,
* thereby keeping the system happier and preventing buffer deadlocks.
*/
int
xfsd(void)
{
int s;
buf_t *bp;
buf_t *forw;
buf_t *back;
/*
* Get rid of our address space, we're never returning to
* user space.
*/
vrelvm();
/*
* Make us a high non-degrading priority process like bdflush(),
* since that is who we're relieving of work.
*/
setinfoRunq(u.u_procp, RQRTPRI, NDPHIMIN);
/*
* We should never sleep at an interruptible priority, but
* just to make sure...
*/
if (setjmp(u.u_qsav)) {
cmn_err(CE_PANIC, "xfsd interrupted");
}
s = splock(xfsd_lock);
xfsd_count++;
while (1) {
while (xfsd_list == NULL) {
(void) spunlock_psema(xfsd_lock, s, &xfsd_wait,
PRIBIO);
s = splock(xfsd_lock);
}
/*
* Pull a buffer off of the list.
*/
bp = xfsd_list;
forw = bp->av_forw;
back = bp->av_back;
forw->av_back = back;
back->av_forw = forw;
if (forw == bp) {
xfsd_list = NULL;
} else {
xfsd_list = forw;
}
bp->av_forw = bp;
bp->av_back = bp;
xfsd_bufcount--;;
ASSERT(xfsd_bufcount >= 0);
spunlock(xfsd_lock, s);
ASSERT((bp->b_flags & (B_BUSY | B_ASYNC | B_READ)) ==
(B_BUSY | B_ASYNC));
xfs_strat_write(bp->b_vp, bp);
s = splock(xfsd_lock);
}
}
#endif /* !SIM */
struct dio_s {
struct vnode *vp;
struct cred *cr;
int ioflag;
};
/*
* xfs_diostrat()
* This routine issues the calls to the disk device strategy routine
* for file system reads and writes made using direct I/O from user
* space. In the case of a write request the I/Os are issued one
* extent at a time. In the case of a read request I/Os for each extent
* involved are issued at once.
*
* RETURNS:
* none
*/
int
xfs_diostrat( buf_t *bp)
{
struct dio_s *dp;
xfs_inode_t *ip;
xfs_trans_t *tp;
vnode_t *vp;
xfs_mount_t *mp;
xfs_bmbt_irec_t imaps[XFS_BMAP_MAX_NMAP], *imapp, *timapp;
buf_t *bps[XFS_BMAP_MAX_NMAP], *nbp;
xfs_fileoff_t offset_fsb, last_fsb;
xfs_fsblock_t firstfsb;
xfs_extlen_t blocks, count_fsb, total;
xfs_bmap_free_t free_list;
caddr_t base;
ssize_t bytes_this_req, resid, count, totxfer;
off_t offset, offset_this_req;
int i, j, error, writeflag, reccount;
int end_of_file, bufsissued, totresid, exist;
int ioflag, blk_algn, rt, numrtextents, rtextsize;
dp = (struct dio_s *)bp->b_private;
vp = dp->vp;
ip = XFS_VTOI(vp);
mp = XFS_VFSTOM(XFS_ITOV(ip)->v_vfsp);
base = bp->b_un.b_addr;
error = resid = totxfer = end_of_file = 0;
ioflag = dp->ioflag;
offset = BBTOB(bp->b_blkno);
blk_algn = 0;
totresid = count = bp->b_bcount;
/*
* Determine if this file is using the realtime volume.
*/
if ( ip->i_d.di_flags & XFS_DIFLAG_REALTIME ) {
rt = 1;
rtextsize = mp->m_sb.sb_rextsize;
} else {
numrtextents = 0;
rtextsize = 0;
rt = 0;
}
ASSERT(!(bp->b_flags & B_DONE));
ASSERT(ismrlocked(&ip->i_iolock, MR_UPDATE) != 0);
/*
* Alignment checks are done in xfs_diordwr().
* Determine if the operation is a read or a write.
*/
if (bp->b_flags & B_READ) {
writeflag = 0;
} else {
writeflag = XFS_BMAPI_WRITE;
}
/*
* Check if the request is on a file system block boundary.
*/
if ( (offset % mp->m_sb.sb_blocksize) != 0 ) {
/*
* The request is NOT on a file system block boundary.
*/
blk_algn = BTOBB(offset % mp->m_sb.sb_blocksize);
}
/*
* Process the request until:
* 1) an I/O error occurs
* 2) end of file is reached.
* 3) end of device (driver error) occurs
* 4) request is completed.
*/
while ( !error && !end_of_file && !resid && count ) {
offset_fsb = XFS_B_TO_FSBT( mp, offset );
last_fsb = XFS_B_TO_FSB( mp, offset + count);
count_fsb = XFS_B_TO_FSB( mp, count);
blocks = (xfs_extlen_t)(last_fsb - offset_fsb);
exist = 1;
XFS_BMAP_INIT(&free_list, &firstfsb);
if ( writeflag ) {
/*
* In the write case, need to call bmapi() with
* the read flag set first to determine the existing
* extents. This is done so that the correct amount
* of space can be reserved in the transaction
* structure.
*/
reccount = XFS_BMAP_MAX_NMAP;
xfs_ilock( ip, XFS_ILOCK_EXCL );
firstfsb = xfs_bmapi( tp, ip, offset_fsb,
count_fsb, 0, firstfsb, 0, imaps,
&reccount, 0);
/*
* Get a pointer to the current extent map.
* Writes will always be issued one at a time.
*/
reccount = 1;
imapp = &imaps[0];
count_fsb = imapp->br_blockcount;
if ((imapp->br_startblock == DELAYSTARTBLOCK) ||
(imapp->br_startblock == HOLESTARTBLOCK)) {
exist = 0;
}
/*
* If blocks are not yet allocated for this part of
* the file, allocate space for the transactions.
*/
if (!exist) {
if (rt) {
/*
* Round up to even number of extents.
*/
numrtextents = (count_fsb+rtextsize-1)/
rtextsize;
}
/*
* Setup transactions.
*/
tp = xfs_trans_alloc( mp, XFS_TRANS_FILE_WRITE);
error = xfs_trans_reserve( tp,
XFS_BM_MAXLEVELS(mp) + count_fsb,
XFS_DEFAULT_LOG_RES(mp),
numrtextents, 0 );
if (error) {
/*
* Ran out of file system space.
* Free the transaction structure.
*/
ASSERT( error == ENOSPC );
xfs_trans_cancel(tp, 0);
xfs_iunlock( ip, XFS_ILOCK_EXCL);
break;
} else {
xfs_trans_ijoin(tp,ip,XFS_ILOCK_EXCL);
xfs_trans_ihold( tp, ip);
}
} else {
tp = NULL;
}
} else {
/*
* Read case.
* Read requests will be issued
* up to XFS_BMAP_MAX_MAP at a time.
*/
reccount = XFS_BMAP_MAX_NMAP;
imapp = &imaps[0];
xfs_ilock( ip, XFS_ILOCK_SHARED);
}
/*
* Issue the bmapi() call to get the extent info.
* In the case of write requests this call does the
* actual file space allocation.
*/
firstfsb = xfs_bmapi( tp, ip, offset_fsb, count_fsb,
writeflag, firstfsb, 0, imapp, &reccount, &free_list);
if ( writeflag ) {
/*
* Complete the bmapi() transactions.
*/
if (!exist) {
xfs_bmap_finish( &tp, &free_list, firstfsb, 0 );
xfs_trans_commit(tp , 0 );
}
xfs_iunlock( ip, XFS_ILOCK_EXCL);
} else {
xfs_iunlock( ip, XFS_ILOCK_SHARED);
}
/*
* xfs_bmapi() was unable to allocate space
*/
if (reccount == 0) {
error = ENOSPC;
break;
}
/*
* Run through each extent.
*/
bufsissued = 0;
for (i = 0; (i < reccount) && (!end_of_file) && (count); i++){
imapp = &imaps[i];
bytes_this_req = XFS_FSB_TO_B(mp,
imapp->br_blockcount) - BBTOB(blk_algn);
offset_this_req = XFS_FSB_TO_B(mp,
imapp->br_startoff) + BBTOB(blk_algn);
/*
* Check if this is the end of the file.
*/
if (offset_this_req +bytes_this_req >ip->i_d.di_size){
if ( writeflag ) {
/*
* File is being extended on a
* write, update the file size.
*/
ASSERT((vp->v_flag & VISSWAP) == 0);
xfs_ilock(ip, XFS_ILOCK_EXCL);
ip->i_d.di_size = offset_this_req +
bytes_this_req;
ip->i_update_core = 1;
xfs_iunlock(ip, XFS_ILOCK_EXCL);
} else {
/*
* If trying to read past end of
* file, shorten the request size.
*/
bytes_this_req = ip->i_d.di_size -
offset_this_req;
end_of_file = 1;
}
}
/*
* Reduce request size, if it
* is longer than user buffer.
*/
if ( bytes_this_req > count ) {
bytes_this_req = count;
}
/*
* Do not do I/O if there is a hole in the file.
*/
if (imapp->br_startblock != HOLESTARTBLOCK) {
/*
* Setup I/O request for this extent.
*/
bps[bufsissued++]= nbp = getphysbuf();
nbp->b_flags = bp->b_flags;
nbp->b_flags2 = bp->b_flags2;
if (ioflag & IO_GRIO) {
nbp->b_flags2 |= B_GR_BUF;
} else {
nbp->b_flags2 &= ~B_GR_BUF;
}
nbp->b_error = 0;
nbp->b_proc = bp->b_proc;
nbp->b_edev = bp->b_edev;
if (rt) {
nbp->b_blkno = XFS_BTOD(mp,
imapp->br_startblock);
} else {
nbp->b_blkno = XFS_FSB_TO_DADDR(mp,
imapp->br_startblock) +
blk_algn;
}
nbp->b_bcount = bytes_this_req;
nbp->b_un.b_addr = base;
/*
* Issue I/O request.
*/
bdstrat( bmajor(nbp->b_edev), nbp );
if (error = geterror(nbp)) {
iowait( nbp );
nbp->b_flags = 0;
nbp->b_un.b_addr = 0;
putphysbuf( nbp );
bps[bufsissued--] = 0;
break;
}
} else {
/*
* Hole in file can only happen on read case.
*/
ASSERT(!writeflag);
/*
* Physio() has already mapped user address.
*/
bzero(base, bytes_this_req);
/*
* Bump the transfer count.
*/
totxfer += bytes_this_req;
}
/*
* update pointers for next round.
*/
base += bytes_this_req;
offset += bytes_this_req;
count -= bytes_this_req;
blk_algn= 0;
} /* end of for loop */
/*
* Wait for I/O completion and recover buffers.
*/
for ( j = 0; j < bufsissued ; j++) {
nbp = bps[j];
iowait( nbp );
if (!error)
error = geterror( nbp );
if (!error && !resid) {
resid = nbp->b_resid;
totxfer += (nbp->b_bcount - resid);
}
nbp->b_flags = 0;
nbp->b_un.b_addr = 0;
nbp->b_bcount = 0;
putphysbuf( nbp );
}
} /* end of while loop */
/*
* Fill in resid count for original buffer.
*/
bp->b_resid = totresid - totxfer;
/*
* Update the inode timestamp if file was written.
*/
if ( writeflag ) {
timestruc_t tv;
xfs_ilock(ip, XFS_ILOCK_EXCL);
if ((ip->i_d.di_mode & (ISUID|ISGID)) && dp->cr->cr_uid != 0){
ip->i_d.di_mode &= ~ISUID;
if (ip->i_d.di_mode & (IEXEC >> 3))
ip->i_d.di_mode &= ~ISGID;
}
nanotime( &tv );
ip->i_d.di_mtime.t_sec = ip->i_d.di_ctime.t_sec = tv.tv_sec;
ip->i_update_core = 1;
xfs_iunlock(ip, XFS_ILOCK_EXCL);
}
/*
* Issue completion on the original buffer.
*/
bioerror( bp, error);
iodone( bp );
return(0);
}
/*
* xfs_diordwr()
* This routine sets up a buf structure to be used to perform
* direct I/O operations to user space. The user specified
* paramters are checked for alignment and size limitations. A buf
* structure is allocated an biophysio() is called.
*
* RETURNS:
* 0 on success
* errno on error
*/
int
xfs_diordwr(vnode_t *vp,
uio_t *uiop,
int ioflag,
cred_t *credp,
int rw)
{
xfs_inode_t *ip;
struct dio_s dp;
xfs_mount_t *mp;
buf_t *bp;
int error;
ip = XFS_VTOI(vp);
/*
* Check that the user buffer address, file offset, and
* request size are all multiples of BBSIZE. This prevents
* the need for read/modify/write operations.
*/
if ((((int)(uiop->uio_iov->iov_base)) & BBMASK) ||
(uiop->uio_offset & BBMASK) ||
(uiop->uio_resid & BBMASK)) {
#ifndef SIM
return EINVAL;
#endif
}
/*
* Do maxio check.
*/
if (uiop->uio_resid > ctob(v.v_maxdmasz)) {
#ifndef SIM
return EINVAL;
#endif
}
/*
* Use dio_s structure to pass file/credential
* information to file system strategy routine.
*/
dp.vp = vp;
dp.cr = credp;
dp.ioflag = ioflag;
/*
* Allocate local buf structure.
*/
bp = getphysbuf();
bp->b_private = &dp;
mp = XFS_VFSTOM(vp->v_vfsp);
if (ip->i_d.di_flags & XFS_DIFLAG_REALTIME) {
bp->b_edev = mp->m_rtdev;
} else {
bp->b_edev = mp->m_dev;
}
/*
* Perform I/O operation.
*/
error = biophysio(xfs_diostrat, bp, bp->b_edev, rw,
(daddr_t)BTOBB(uiop->uio_offset), uiop);
/*
* Free local buf structure.
*/
bp->b_flags = 0;
#ifdef SIM
bp->b_un.b_addr = 0;
#endif
putphysbuf(bp);
return( error );
}
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