/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "xfs.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir.h"
#include "xfs_dir2.h"
#include "xfs_trans.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_dir_sf.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_alloc.h"
#include "xfs_btree.h"
#include "xfs_error.h"
#include "xfs_rw.h"
#include "xfs_iomap.h"
#include <linux/mpage.h>
#include <linux/writeback.h>
STATIC void xfs_count_page_state(struct page *, int *, int *, int *);
STATIC void xfs_convert_page(struct inode *, struct page *, xfs_iomap_t *,
struct writeback_control *wbc, void *, int, int);
#if defined(XFS_RW_TRACE)
void
xfs_page_trace(
int tag,
struct inode *inode,
struct page *page,
int mask)
{
xfs_inode_t *ip;
bhv_desc_t *bdp;
vnode_t *vp = LINVFS_GET_VP(inode);
loff_t isize = i_size_read(inode);
loff_t offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
int delalloc = -1, unmapped = -1, unwritten = -1;
if (page_has_buffers(page))
xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
bdp = vn_bhv_lookup(VN_BHV_HEAD(vp), &xfs_vnodeops);
ip = XFS_BHVTOI(bdp);
if (!ip->i_rwtrace)
return;
ktrace_enter(ip->i_rwtrace,
(void *)((unsigned long)tag),
(void *)ip,
(void *)inode,
(void *)page,
(void *)((unsigned long)mask),
(void *)((unsigned long)((ip->i_d.di_size >> 32) & 0xffffffff)),
(void *)((unsigned long)(ip->i_d.di_size & 0xffffffff)),
(void *)((unsigned long)((isize >> 32) & 0xffffffff)),
(void *)((unsigned long)(isize & 0xffffffff)),
(void *)((unsigned long)((offset >> 32) & 0xffffffff)),
(void *)((unsigned long)(offset & 0xffffffff)),
(void *)((unsigned long)delalloc),
(void *)((unsigned long)unmapped),
(void *)((unsigned long)unwritten),
(void *)NULL,
(void *)NULL);
}
#else
#define xfs_page_trace(tag, inode, page, mask)
#endif
/*
* Schedule IO completion handling on a xfsdatad if this was
* the final hold on this ioend.
*/
STATIC void
xfs_finish_ioend(
xfs_ioend_t *ioend)
{
if (atomic_dec_and_test(&ioend->io_remaining))
queue_work(xfsdatad_workqueue, &ioend->io_work);
}
STATIC void
xfs_destroy_ioend(
xfs_ioend_t *ioend)
{
vn_iowake(ioend->io_vnode);
mempool_free(ioend, xfs_ioend_pool);
}
/*
* Issue transactions to convert a buffer range from unwritten
* to written extents.
*/
STATIC void
xfs_end_bio_unwritten(
void *data)
{
xfs_ioend_t *ioend = data;
vnode_t *vp = ioend->io_vnode;
xfs_off_t offset = ioend->io_offset;
size_t size = ioend->io_size;
struct buffer_head *bh, *next;
int error;
if (ioend->io_uptodate)
VOP_BMAP(vp, offset, size, BMAPI_UNWRITTEN, NULL, NULL, error);
/* ioend->io_buffer_head is only non-NULL for buffered I/O */
for (bh = ioend->io_buffer_head; bh; bh = next) {
next = bh->b_private;
bh->b_end_io = NULL;
clear_buffer_unwritten(bh);
end_buffer_async_write(bh, ioend->io_uptodate);
}
xfs_destroy_ioend(ioend);
}
/*
* Allocate and initialise an IO completion structure.
* We need to track unwritten extent write completion here initially.
* We'll need to extend this for updating the ondisk inode size later
* (vs. incore size).
*/
STATIC xfs_ioend_t *
xfs_alloc_ioend(
struct inode *inode)
{
xfs_ioend_t *ioend;
ioend = mempool_alloc(xfs_ioend_pool, GFP_NOFS);
/*
* Set the count to 1 initially, which will prevent an I/O
* completion callback from happening before we have started
* all the I/O from calling the completion routine too early.
*/
atomic_set(&ioend->io_remaining, 1);
ioend->io_uptodate = 1; /* cleared if any I/O fails */
ioend->io_vnode = LINVFS_GET_VP(inode);
ioend->io_buffer_head = NULL;
atomic_inc(&ioend->io_vnode->v_iocount);
ioend->io_offset = 0;
ioend->io_size = 0;
INIT_WORK(&ioend->io_work, xfs_end_bio_unwritten, ioend);
return ioend;
}
void
linvfs_unwritten_done(
struct buffer_head *bh,
int uptodate)
{
xfs_ioend_t *ioend = bh->b_private;
static spinlock_t unwritten_done_lock = SPIN_LOCK_UNLOCKED;
unsigned long flags;
ASSERT(buffer_unwritten(bh));
bh->b_end_io = NULL;
if (!uptodate)
ioend->io_uptodate = 0;
/*
* Deep magic here. We reuse b_private in the buffer_heads to build
* a chain for completing the I/O from user context after we've issued
* a transaction to convert the unwritten extent.
*/
spin_lock_irqsave(&unwritten_done_lock, flags);
bh->b_private = ioend->io_buffer_head;
ioend->io_buffer_head = bh;
spin_unlock_irqrestore(&unwritten_done_lock, flags);
xfs_finish_ioend(ioend);
}
STATIC int
xfs_map_blocks(
struct inode *inode,
loff_t offset,
ssize_t count,
xfs_iomap_t *mapp,
int flags)
{
vnode_t *vp = LINVFS_GET_VP(inode);
int error, nmaps = 1;
VOP_BMAP(vp, offset, count, flags, mapp, &nmaps, error);
if (!error && (flags & (BMAPI_WRITE|BMAPI_ALLOCATE)))
VMODIFY(vp);
return -error;
}
/*
* Finds the corresponding mapping in block @map array of the
* given @offset within a @page.
*/
STATIC xfs_iomap_t *
xfs_offset_to_map(
struct page *page,
xfs_iomap_t *iomapp,
unsigned long offset)
{
loff_t full_offset; /* offset from start of file */
ASSERT(offset < PAGE_CACHE_SIZE);
full_offset = page->index; /* NB: using 64bit number */
full_offset <<= PAGE_CACHE_SHIFT; /* offset from file start */
full_offset += offset; /* offset from page start */
if (full_offset < iomapp->iomap_offset)
return NULL;
if (iomapp->iomap_offset + (iomapp->iomap_bsize -1) >= full_offset)
return iomapp;
return NULL;
}
STATIC void
xfs_map_at_offset(
struct page *page,
struct buffer_head *bh,
unsigned long offset,
int block_bits,
xfs_iomap_t *iomapp)
{
xfs_daddr_t bn;
loff_t delta;
int sector_shift;
ASSERT(!(iomapp->iomap_flags & IOMAP_HOLE));
ASSERT(!(iomapp->iomap_flags & IOMAP_DELAY));
ASSERT(iomapp->iomap_bn != IOMAP_DADDR_NULL);
delta = page->index;
delta <<= PAGE_CACHE_SHIFT;
delta += offset;
delta -= iomapp->iomap_offset;
delta >>= block_bits;
sector_shift = block_bits - BBSHIFT;
bn = iomapp->iomap_bn >> sector_shift;
bn += delta;
BUG_ON(!bn && !(iomapp->iomap_flags & IOMAP_REALTIME));
ASSERT((bn << sector_shift) >= iomapp->iomap_bn);
lock_buffer(bh);
bh->b_blocknr = bn;
bh->b_bdev = iomapp->iomap_target->pbr_bdev;
set_buffer_mapped(bh);
clear_buffer_delay(bh);
}
/*
* Look for a page at index which is unlocked and contains our
* unwritten extent flagged buffers at its head. Returns page
* locked and with an extra reference count, and length of the
* unwritten extent component on this page that we can write,
* in units of filesystem blocks.
*/
STATIC struct page *
xfs_probe_unwritten_page(
struct address_space *mapping,
pgoff_t index,
xfs_iomap_t *iomapp,
xfs_ioend_t *ioend,
unsigned long max_offset,
unsigned long *fsbs,
unsigned int bbits)
{
struct page *page;
page = find_trylock_page(mapping, index);
if (!page)
return NULL;
if (PageWriteback(page))
goto out;
if (page->mapping && page_has_buffers(page)) {
struct buffer_head *bh, *head;
unsigned long p_offset = 0;
*fsbs = 0;
bh = head = page_buffers(page);
do {
if (!buffer_unwritten(bh) || !buffer_uptodate(bh))
break;
if (!xfs_offset_to_map(page, iomapp, p_offset))
break;
if (p_offset >= max_offset)
break;
xfs_map_at_offset(page, bh, p_offset, bbits, iomapp);
set_buffer_unwritten_io(bh);
bh->b_private = ioend;
p_offset += bh->b_size;
(*fsbs)++;
} while ((bh = bh->b_this_page) != head);
if (p_offset)
return page;
}
out:
unlock_page(page);
return NULL;
}
/*
* Look for a page at index which is unlocked and not mapped
* yet - clustering for mmap write case.
*/
STATIC unsigned int
xfs_probe_unmapped_page(
struct address_space *mapping,
pgoff_t index,
unsigned int pg_offset)
{
struct page *page;
int ret = 0;
page = find_trylock_page(mapping, index);
if (!page)
return 0;
if (PageWriteback(page))
goto out;
if (page->mapping && PageDirty(page)) {
if (page_has_buffers(page)) {
struct buffer_head *bh, *head;
bh = head = page_buffers(page);
do {
if (buffer_mapped(bh) || !buffer_uptodate(bh))
break;
ret += bh->b_size;
if (ret >= pg_offset)
break;
} while ((bh = bh->b_this_page) != head);
} else
ret = PAGE_CACHE_SIZE;
}
out:
unlock_page(page);
return ret;
}
STATIC unsigned int
xfs_probe_unmapped_cluster(
struct inode *inode,
struct page *startpage,
struct buffer_head *bh,
struct buffer_head *head)
{
pgoff_t tindex, tlast, tloff;
unsigned int pg_offset, len, total = 0;
struct address_space *mapping = inode->i_mapping;
/* First sum forwards in this page */
do {
if (buffer_mapped(bh))
break;
total += bh->b_size;
} while ((bh = bh->b_this_page) != head);
/* If we reached the end of the page, sum forwards in
* following pages.
*/
if (bh == head) {
tlast = i_size_read(inode) >> PAGE_CACHE_SHIFT;
/* Prune this back to avoid pathological behavior */
tloff = min(tlast, startpage->index + 64);
for (tindex = startpage->index + 1; tindex < tloff; tindex++) {
len = xfs_probe_unmapped_page(mapping, tindex,
PAGE_CACHE_SIZE);
if (!len)
return total;
total += len;
}
if (tindex == tlast &&
(pg_offset = i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) {
total += xfs_probe_unmapped_page(mapping,
tindex, pg_offset);
}
}
return total;
}
/*
* Probe for a given page (index) in the inode and test if it is delayed
* and without unwritten buffers. Returns page locked and with an extra
* reference count.
*/
STATIC struct page *
xfs_probe_delalloc_page(
struct inode *inode,
pgoff_t index)
{
struct page *page;
page = find_trylock_page(inode->i_mapping, index);
if (!page)
return NULL;
if (PageWriteback(page))
goto out;
if (page->mapping && page_has_buffers(page)) {
struct buffer_head *bh, *head;
int acceptable = 0;
bh = head = page_buffers(page);
do {
if (buffer_unwritten(bh)) {
acceptable = 0;
break;
} else if (buffer_delay(bh)) {
acceptable = 1;
}
} while ((bh = bh->b_this_page) != head);
if (acceptable)
return page;
}
out:
unlock_page(page);
return NULL;
}
STATIC int
xfs_map_unwritten(
struct inode *inode,
struct page *start_page,
struct buffer_head *head,
struct buffer_head *curr,
unsigned long p_offset,
int block_bits,
xfs_iomap_t *iomapp,
struct writeback_control *wbc,
int startio,
int all_bh)
{
struct buffer_head *bh = curr;
xfs_iomap_t *tmp;
xfs_ioend_t *ioend;
loff_t offset;
unsigned long nblocks = 0;
offset = start_page->index;
offset <<= PAGE_CACHE_SHIFT;
offset += p_offset;
ioend = xfs_alloc_ioend(inode);
/* First map forwards in the page consecutive buffers
* covering this unwritten extent
*/
do {
if (!buffer_unwritten(bh))
break;
tmp = xfs_offset_to_map(start_page, iomapp, p_offset);
if (!tmp)
break;
xfs_map_at_offset(start_page, bh, p_offset, block_bits, iomapp);
set_buffer_unwritten_io(bh);
bh->b_private = ioend;
p_offset += bh->b_size;
nblocks++;
} while ((bh = bh->b_this_page) != head);
atomic_add(nblocks, &ioend->io_remaining);
/* If we reached the end of the page, map forwards in any
* following pages which are also covered by this extent.
*/
if (bh == head) {
struct address_space *mapping = inode->i_mapping;
pgoff_t tindex, tloff, tlast;
unsigned long bs;
unsigned int pg_offset, bbits = inode->i_blkbits;
struct page *page;
tlast = i_size_read(inode) >> PAGE_CACHE_SHIFT;
tloff = (iomapp->iomap_offset + iomapp->iomap_bsize) >> PAGE_CACHE_SHIFT;
tloff = min(tlast, tloff);
for (tindex = start_page->index + 1; tindex < tloff; tindex++) {
page = xfs_probe_unwritten_page(mapping,
tindex, iomapp, ioend,
PAGE_CACHE_SIZE, &bs, bbits);
if (!page)
break;
nblocks += bs;
atomic_add(bs, &ioend->io_remaining);
xfs_convert_page(inode, page, iomapp, wbc, ioend,
startio, all_bh);
/* stop if converting the next page might add
* enough blocks that the corresponding byte
* count won't fit in our ulong page buf length */
if (nblocks >= ((ULONG_MAX - PAGE_SIZE) >> block_bits))
goto enough;
}
if (tindex == tlast &&
(pg_offset = (i_size_read(inode) & (PAGE_CACHE_SIZE - 1)))) {
page = xfs_probe_unwritten_page(mapping,
tindex, iomapp, ioend,
pg_offset, &bs, bbits);
if (page) {
nblocks += bs;
atomic_add(bs, &ioend->io_remaining);
xfs_convert_page(inode, page, iomapp, wbc, ioend,
startio, all_bh);
if (nblocks >= ((ULONG_MAX - PAGE_SIZE) >> block_bits))
goto enough;
}
}
}
enough:
ioend->io_size = (xfs_off_t)nblocks << block_bits;
ioend->io_offset = offset;
xfs_finish_ioend(ioend);
return 0;
}
STATIC void
xfs_submit_page(
struct page *page,
struct writeback_control *wbc,
struct buffer_head *bh_arr[],
int bh_count,
int probed_page,
int clear_dirty)
{
struct buffer_head *bh;
int i;
BUG_ON(PageWriteback(page));
if (bh_count)
set_page_writeback(page);
if (clear_dirty)
clear_page_dirty(page);
unlock_page(page);
if (bh_count) {
for (i = 0; i < bh_count; i++) {
bh = bh_arr[i];
mark_buffer_async_write(bh);
if (buffer_unwritten(bh))
set_buffer_unwritten_io(bh);
set_buffer_uptodate(bh);
clear_buffer_dirty(bh);
}
for (i = 0; i < bh_count; i++)
submit_bh(WRITE, bh_arr[i]);
if (probed_page && clear_dirty)
wbc->nr_to_write--; /* Wrote an "extra" page */
}
}
/*
* Allocate & map buffers for page given the extent map. Write it out.
* except for the original page of a writepage, this is called on
* delalloc/unwritten pages only, for the original page it is possible
* that the page has no mapping at all.
*/
STATIC void
xfs_convert_page(
struct inode *inode,
struct page *page,
xfs_iomap_t *iomapp,
struct writeback_control *wbc,
void *private,
int startio,
int all_bh)
{
struct buffer_head *bh_arr[MAX_BUF_PER_PAGE], *bh, *head;
xfs_iomap_t *mp = iomapp, *tmp;
unsigned long offset, end_offset;
int index = 0;
int bbits = inode->i_blkbits;
int len, page_dirty;
end_offset = (i_size_read(inode) & (PAGE_CACHE_SIZE - 1));
/*
* page_dirty is initially a count of buffers on the page before
* EOF and is decrememted as we move each into a cleanable state.
*/
len = 1 << inode->i_blkbits;
end_offset = max(end_offset, PAGE_CACHE_SIZE);
end_offset = roundup(end_offset, len);
page_dirty = end_offset / len;
offset = 0;
bh = head = page_buffers(page);
do {
if (offset >= end_offset)
break;
if (!(PageUptodate(page) || buffer_uptodate(bh)))
continue;
if (buffer_mapped(bh) && all_bh &&
!(buffer_unwritten(bh) || buffer_delay(bh))) {
if (startio) {
lock_buffer(bh);
bh_arr[index++] = bh;
page_dirty--;
}
continue;
}
tmp = xfs_offset_to_map(page, mp, offset);
if (!tmp)
continue;
ASSERT(!(tmp->iomap_flags & IOMAP_HOLE));
ASSERT(!(tmp->iomap_flags & IOMAP_DELAY));
/* If this is a new unwritten extent buffer (i.e. one
* that we haven't passed in private data for, we must
* now map this buffer too.
*/
if (buffer_unwritten(bh) && !bh->b_end_io) {
ASSERT(tmp->iomap_flags & IOMAP_UNWRITTEN);
xfs_map_unwritten(inode, page, head, bh, offset,
bbits, tmp, wbc, startio, all_bh);
} else if (! (buffer_unwritten(bh) && buffer_locked(bh))) {
xfs_map_at_offset(page, bh, offset, bbits, tmp);
if (buffer_unwritten(bh)) {
set_buffer_unwritten_io(bh);
bh->b_private = private;
ASSERT(private);
}
}
if (startio) {
bh_arr[index++] = bh;
} else {
set_buffer_dirty(bh);
unlock_buffer(bh);
mark_buffer_dirty(bh);
}
page_dirty--;
} while (offset += len, (bh = bh->b_this_page) != head);
if (startio && index) {
xfs_submit_page(page, wbc, bh_arr, index, 1, !page_dirty);
} else {
unlock_page(page);
}
}
/*
* Convert & write out a cluster of pages in the same extent as defined
* by mp and following the start page.
*/
STATIC void
xfs_cluster_write(
struct inode *inode,
pgoff_t tindex,
xfs_iomap_t *iomapp,
struct writeback_control *wbc,
int startio,
int all_bh,
pgoff_t tlast)
{
struct page *page;
for (; tindex <= tlast; tindex++) {
page = xfs_probe_delalloc_page(inode, tindex);
if (!page)
break;
xfs_convert_page(inode, page, iomapp, wbc, NULL,
startio, all_bh);
}
}
/*
* Calling this without startio set means we are being asked to make a dirty
* page ready for freeing it's buffers. When called with startio set then
* we are coming from writepage.
*
* When called with startio set it is important that we write the WHOLE
* page if possible.
* The bh->b_state's cannot know if any of the blocks or which block for
* that matter are dirty due to mmap writes, and therefore bh uptodate is
* only vaild if the page itself isn't completely uptodate. Some layers
* may clear the page dirty flag prior to calling write page, under the
* assumption the entire page will be written out; by not writing out the
* whole page the page can be reused before all valid dirty data is
* written out. Note: in the case of a page that has been dirty'd by
* mapwrite and but partially setup by block_prepare_write the
* bh->b_states's will not agree and only ones setup by BPW/BCW will have
* valid state, thus the whole page must be written out thing.
*/
STATIC int
xfs_page_state_convert(
struct inode *inode,
struct page *page,
struct writeback_control *wbc,
int startio,
int unmapped) /* also implies page uptodate */
{
struct buffer_head *bh_arr[MAX_BUF_PER_PAGE], *bh, *head;
xfs_iomap_t *iomp, iomap;
loff_t offset;
unsigned long p_offset = 0;
__uint64_t end_offset;
pgoff_t end_index, last_index, tlast;
int len, err, i, cnt = 0, uptodate = 1;
int flags;
int page_dirty;
/* wait for other IO threads? */
flags = (startio && wbc->sync_mode != WB_SYNC_NONE) ? 0 : BMAPI_TRYLOCK;
/* Is this page beyond the end of the file? */
offset = i_size_read(inode);
end_index = offset >> PAGE_CACHE_SHIFT;
last_index = (offset - 1) >> PAGE_CACHE_SHIFT;
if (page->index >= end_index) {
if ((page->index >= end_index + 1) ||
!(i_size_read(inode) & (PAGE_CACHE_SIZE - 1))) {
if (startio)
unlock_page(page);
return 0;
}
}
end_offset = min_t(unsigned long long,
(loff_t)(page->index + 1) << PAGE_CACHE_SHIFT, offset);
offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
/*
* page_dirty is initially a count of buffers on the page before
* EOF and is decrememted as we move each into a cleanable state.
*/
len = 1 << inode->i_blkbits;
p_offset = max(p_offset, PAGE_CACHE_SIZE);
p_offset = roundup(p_offset, len);
page_dirty = p_offset / len;
iomp = NULL;
p_offset = 0;
bh = head = page_buffers(page);
do {
if (offset >= end_offset)
break;
if (!buffer_uptodate(bh))
uptodate = 0;
if (!(PageUptodate(page) || buffer_uptodate(bh)) && !startio)
continue;
if (iomp) {
iomp = xfs_offset_to_map(page, &iomap, p_offset);
}
/*
* First case, map an unwritten extent and prepare for
* extent state conversion transaction on completion.
*/
if (buffer_unwritten(bh)) {
if (!startio)
continue;
if (!iomp) {
err = xfs_map_blocks(inode, offset, len, &iomap,
BMAPI_WRITE|BMAPI_IGNSTATE);
if (err) {
goto error;
}
iomp = xfs_offset_to_map(page, &iomap,
p_offset);
}
if (iomp) {
if (!bh->b_end_io) {
err = xfs_map_unwritten(inode, page,
head, bh, p_offset,
inode->i_blkbits, iomp,
wbc, startio, unmapped);
if (err) {
goto error;
}
} else {
set_bit(BH_Lock, &bh->b_state);
}
BUG_ON(!buffer_locked(bh));
bh_arr[cnt++] = bh;
page_dirty--;
}
/*
* Second case, allocate space for a delalloc buffer.
* We can return EAGAIN here in the release page case.
*/
} else if (buffer_delay(bh)) {
if (!iomp) {
err = xfs_map_blocks(inode, offset, len, &iomap,
BMAPI_ALLOCATE | flags);
if (err) {
goto error;
}
iomp = xfs_offset_to_map(page, &iomap,
p_offset);
}
if (iomp) {
xfs_map_at_offset(page, bh, p_offset,
inode->i_blkbits, iomp);
if (startio) {
bh_arr[cnt++] = bh;
} else {
set_buffer_dirty(bh);
unlock_buffer(bh);
mark_buffer_dirty(bh);
}
page_dirty--;
}
} else if ((buffer_uptodate(bh) || PageUptodate(page)) &&
(unmapped || startio)) {
if (!buffer_mapped(bh)) {
int size;
/*
* Getting here implies an unmapped buffer
* was found, and we are in a path where we
* need to write the whole page out.
*/
if (!iomp) {
size = xfs_probe_unmapped_cluster(
inode, page, bh, head);
err = xfs_map_blocks(inode, offset,
size, &iomap,
BMAPI_WRITE|BMAPI_MMAP);
if (err) {
goto error;
}
iomp = xfs_offset_to_map(page, &iomap,
p_offset);
}
if (iomp) {
xfs_map_at_offset(page,
bh, p_offset,
inode->i_blkbits, iomp);
if (startio) {
bh_arr[cnt++] = bh;
} else {
set_buffer_dirty(bh);
unlock_buffer(bh);
mark_buffer_dirty(bh);
}
page_dirty--;
}
} else if (startio) {
if (buffer_uptodate(bh) &&
!test_and_set_bit(BH_Lock, &bh->b_state)) {
bh_arr[cnt++] = bh;
page_dirty--;
}
}
}
} while (offset += len, p_offset += len,
((bh = bh->b_this_page) != head));
if (uptodate && bh == head)
SetPageUptodate(page);
if (startio) {
xfs_submit_page(page, wbc, bh_arr, cnt, 0, !page_dirty);
}
if (iomp) {
offset = (iomp->iomap_offset + iomp->iomap_bsize - 1) >>
PAGE_CACHE_SHIFT;
tlast = min_t(pgoff_t, offset, last_index);
xfs_cluster_write(inode, page->index + 1, iomp, wbc,
startio, unmapped, tlast);
}
return page_dirty;
error:
for (i = 0; i < cnt; i++) {
unlock_buffer(bh_arr[i]);
}
/*
* If it's delalloc and we have nowhere to put it,
* throw it away, unless the lower layers told
* us to try again.
*/
if (err != -EAGAIN) {
if (!unmapped) {
block_invalidatepage(page, 0);
}
ClearPageUptodate(page);
}
return err;
}
STATIC int
__linvfs_get_block(
struct inode *inode,
sector_t iblock,
unsigned long blocks,
struct buffer_head *bh_result,
int create,
int direct,
bmapi_flags_t flags)
{
vnode_t *vp = LINVFS_GET_VP(inode);
xfs_iomap_t iomap;
xfs_off_t offset;
ssize_t size;
int retpbbm = 1;
int error;
offset = (xfs_off_t)iblock << inode->i_blkbits;
if (blocks)
size = (ssize_t) min_t(xfs_off_t, LONG_MAX,
(xfs_off_t)blocks << inode->i_blkbits);
else
size = 1 << inode->i_blkbits;
VOP_BMAP(vp, offset, size,
create ? flags : BMAPI_READ, &iomap, &retpbbm, error);
if (error)
return -error;
if (retpbbm == 0)
return 0;
if (iomap.iomap_bn != IOMAP_DADDR_NULL) {
xfs_daddr_t bn;
xfs_off_t delta;
/* For unwritten extents do not report a disk address on
* the read case (treat as if we're reading into a hole).
*/
if (create || !(iomap.iomap_flags & IOMAP_UNWRITTEN)) {
delta = offset - iomap.iomap_offset;
delta >>= inode->i_blkbits;
bn = iomap.iomap_bn >> (inode->i_blkbits - BBSHIFT);
bn += delta;
BUG_ON(!bn && !(iomap.iomap_flags & IOMAP_REALTIME));
bh_result->b_blocknr = bn;
set_buffer_mapped(bh_result);
}
if (create && (iomap.iomap_flags & IOMAP_UNWRITTEN)) {
if (direct)
bh_result->b_private = inode;
set_buffer_unwritten(bh_result);
set_buffer_delay(bh_result);
}
}
/* If this is a realtime file, data might be on a new device */
bh_result->b_bdev = iomap.iomap_target->pbr_bdev;
/* If we previously allocated a block out beyond eof and
* we are now coming back to use it then we will need to
* flag it as new even if it has a disk address.
*/
if (create &&
((!buffer_mapped(bh_result) && !buffer_uptodate(bh_result)) ||
(offset >= i_size_read(inode)) || (iomap.iomap_flags & IOMAP_NEW)))
set_buffer_new(bh_result);
if (iomap.iomap_flags & IOMAP_DELAY) {
BUG_ON(direct);
if (create) {
set_buffer_uptodate(bh_result);
set_buffer_mapped(bh_result);
set_buffer_delay(bh_result);
}
}
if (blocks) {
ASSERT(iomap.iomap_bsize - iomap.iomap_delta > 0);
offset = min_t(xfs_off_t,
iomap.iomap_bsize - iomap.iomap_delta,
(xfs_off_t)blocks << inode->i_blkbits);
bh_result->b_size = (u32) min_t(xfs_off_t, UINT_MAX, offset);
}
return 0;
}
int
linvfs_get_block(
struct inode *inode,
sector_t iblock,
struct buffer_head *bh_result,
int create)
{
return __linvfs_get_block(inode, iblock, 0, bh_result,
create, 0, BMAPI_WRITE);
}
STATIC int
linvfs_get_blocks_direct(
struct inode *inode,
sector_t iblock,
unsigned long max_blocks,
struct buffer_head *bh_result,
int create)
{
return __linvfs_get_block(inode, iblock, max_blocks, bh_result,
create, 1, BMAPI_WRITE|BMAPI_DIRECT);
}
STATIC void
linvfs_end_io_direct(
struct kiocb *iocb,
loff_t offset,
ssize_t size,
void *private)
{
xfs_ioend_t *ioend = iocb->private;
/*
* Non-NULL private data means we need to issue a transaction to
* convert a range from unwritten to written extents. This needs
* to happen from process contect but aio+dio I/O completion
* happens from irq context so we need to defer it to a workqueue.
* This is not nessecary for synchronous direct I/O, but we do
* it anyway to keep the code uniform and simpler.
*
* The core direct I/O code might be changed to always call the
* completion handler in the future, in which case all this can
* go away.
*/
if (private && size > 0) {
ioend->io_offset = offset;
ioend->io_size = size;
xfs_finish_ioend(ioend);
} else {
ASSERT(size >= 0);
xfs_destroy_ioend(ioend);
}
/*
* blockdev_direct_IO can return an error even afer the I/O
* completion handler was called. Thus we need to protect
* against double-freeing.
*/
iocb->private = NULL;
}
STATIC ssize_t
linvfs_direct_IO(
int rw,
struct kiocb *iocb,
const struct iovec *iov,
loff_t offset,
unsigned long nr_segs)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
vnode_t *vp = LINVFS_GET_VP(inode);
xfs_iomap_t iomap;
int maps = 1;
int error;
ssize_t ret;
VOP_BMAP(vp, offset, 0, BMAPI_DEVICE, &iomap, &maps, error);
if (error)
return -error;
iocb->private = xfs_alloc_ioend(inode);
ret = blockdev_direct_IO_own_locking(rw, iocb, inode,
iomap.iomap_target->pbr_bdev,
iov, offset, nr_segs,
linvfs_get_blocks_direct,
linvfs_end_io_direct);
if (unlikely(ret <= 0 && iocb->private))
xfs_destroy_ioend(iocb->private);
return ret;
}
STATIC sector_t
linvfs_bmap(
struct address_space *mapping,
sector_t block)
{
struct inode *inode = (struct inode *)mapping->host;
vnode_t *vp = LINVFS_GET_VP(inode);
int error;
vn_trace_entry(vp, "linvfs_bmap", (inst_t *)__return_address);
VOP_RWLOCK(vp, VRWLOCK_READ);
VOP_FLUSH_PAGES(vp, (xfs_off_t)0, -1, 0, FI_REMAPF, error);
VOP_RWUNLOCK(vp, VRWLOCK_READ);
return generic_block_bmap(mapping, block, linvfs_get_block);
}
STATIC int
linvfs_readpage(
struct file *unused,
struct page *page)
{
return mpage_readpage(page, linvfs_get_block);
}
STATIC int
linvfs_readpages(
struct file *unused,
struct address_space *mapping,
struct list_head *pages,
unsigned nr_pages)
{
return mpage_readpages(mapping, pages, nr_pages, linvfs_get_block);
}
STATIC void
xfs_count_page_state(
struct page *page,
int *delalloc,
int *unmapped,
int *unwritten)
{
struct buffer_head *bh, *head;
*delalloc = *unmapped = *unwritten = 0;
bh = head = page_buffers(page);
do {
if (buffer_uptodate(bh) && !buffer_mapped(bh))
(*unmapped) = 1;
else if (buffer_unwritten(bh) && !buffer_delay(bh))
clear_buffer_unwritten(bh);
else if (buffer_unwritten(bh))
(*unwritten) = 1;
else if (buffer_delay(bh))
(*delalloc) = 1;
} while ((bh = bh->b_this_page) != head);
}
/*
* writepage: Called from one of two places:
*
* 1. we are flushing a delalloc buffer head.
*
* 2. we are writing out a dirty page. Typically the page dirty
* state is cleared before we get here. In this case is it
* conceivable we have no buffer heads.
*
* For delalloc space on the page we need to allocate space and
* flush it. For unmapped buffer heads on the page we should
* allocate space if the page is uptodate. For any other dirty
* buffer heads on the page we should flush them.
*
* If we detect that a transaction would be required to flush
* the page, we have to check the process flags first, if we
* are already in a transaction or disk I/O during allocations
* is off, we need to fail the writepage and redirty the page.
*/
STATIC int
linvfs_writepage(
struct page *page,
struct writeback_control *wbc)
{
int error;
int need_trans;
int delalloc, unmapped, unwritten;
struct inode *inode = page->mapping->host;
xfs_page_trace(XFS_WRITEPAGE_ENTER, inode, page, 0);
/*
* We need a transaction if:
* 1. There are delalloc buffers on the page
* 2. The page is uptodate and we have unmapped buffers
* 3. The page is uptodate and we have no buffers
* 4. There are unwritten buffers on the page
*/
if (!page_has_buffers(page)) {
unmapped = 1;
need_trans = 1;
} else {
xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
if (!PageUptodate(page))
unmapped = 0;
need_trans = delalloc + unmapped + unwritten;
}
/*
* If we need a transaction and the process flags say
* we are already in a transaction, or no IO is allowed
* then mark the page dirty again and leave the page
* as is.
*/
if (PFLAGS_TEST_FSTRANS() && need_trans)
goto out_fail;
/*
* Delay hooking up buffer heads until we have
* made our go/no-go decision.
*/
if (!page_has_buffers(page))
create_empty_buffers(page, 1 << inode->i_blkbits, 0);
/*
* Convert delayed allocate, unwritten or unmapped space
* to real space and flush out to disk.
*/
error = xfs_page_state_convert(inode, page, wbc, 1, unmapped);
if (error == -EAGAIN)
goto out_fail;
if (unlikely(error < 0))
goto out_unlock;
return 0;
out_fail:
redirty_page_for_writepage(wbc, page);
unlock_page(page);
return 0;
out_unlock:
unlock_page(page);
return error;
}
STATIC int
linvfs_invalidate_page(
struct page *page,
unsigned long offset)
{
xfs_page_trace(XFS_INVALIDPAGE_ENTER,
page->mapping->host, page, offset);
return block_invalidatepage(page, offset);
}
/*
* Called to move a page into cleanable state - and from there
* to be released. Possibly the page is already clean. We always
* have buffer heads in this call.
*
* Returns 0 if the page is ok to release, 1 otherwise.
*
* Possible scenarios are:
*
* 1. We are being called to release a page which has been written
* to via regular I/O. buffer heads will be dirty and possibly
* delalloc. If no delalloc buffer heads in this case then we
* can just return zero.
*
* 2. We are called to release a page which has been written via
* mmap, all we need to do is ensure there is no delalloc
* state in the buffer heads, if not we can let the caller
* free them and we should come back later via writepage.
*/
STATIC int
linvfs_release_page(
struct page *page,
gfp_t gfp_mask)
{
struct inode *inode = page->mapping->host;
int dirty, delalloc, unmapped, unwritten;
struct writeback_control wbc = {
.sync_mode = WB_SYNC_ALL,
.nr_to_write = 1,
};
xfs_page_trace(XFS_RELEASEPAGE_ENTER, inode, page, gfp_mask);
xfs_count_page_state(page, &delalloc, &unmapped, &unwritten);
if (!delalloc && !unwritten)
goto free_buffers;
if (!(gfp_mask & __GFP_FS))
return 0;
/* If we are already inside a transaction or the thread cannot
* do I/O, we cannot release this page.
*/
if (PFLAGS_TEST_FSTRANS())
return 0;
/*
* Convert delalloc space to real space, do not flush the
* data out to disk, that will be done by the caller.
* Never need to allocate space here - we will always
* come back to writepage in that case.
*/
dirty = xfs_page_state_convert(inode, page, &wbc, 0, 0);
if (dirty == 0 && !unwritten)
goto free_buffers;
return 0;
free_buffers:
return try_to_free_buffers(page);
}
STATIC int
linvfs_prepare_write(
struct file *file,
struct page *page,
unsigned int from,
unsigned int to)
{
return block_prepare_write(page, from, to, linvfs_get_block);
}
struct address_space_operations linvfs_aops = {
.readpage = linvfs_readpage,
.readpages = linvfs_readpages,
.writepage = linvfs_writepage,
.sync_page = block_sync_page,
.releasepage = linvfs_release_page,
.invalidatepage = linvfs_invalidate_page,
.prepare_write = linvfs_prepare_write,
.commit_write = generic_commit_write,
.bmap = linvfs_bmap,
.direct_IO = linvfs_direct_IO,
};
