Linux-2.6.33.2/fs/xfs/linux-2.6/xfs_aops.c
/*
* 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_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_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 "xfs_vnodeops.h"
#include "xfs_trace.h"
#include <linux/mpage.h>
#include <linux/pagevec.h>
#include <linux/writeback.h>
/*
* Prime number of hash buckets since address is used as the key.
*/
#define NVSYNC 37
#define to_ioend_wq(v) (&xfs_ioend_wq[((unsigned long)v) % NVSYNC])
static wait_queue_head_t xfs_ioend_wq[NVSYNC];
void __init
xfs_ioend_init(void)
{
int i;
for (i = 0; i < NVSYNC; i++)
init_waitqueue_head(&xfs_ioend_wq[i]);
}
void
xfs_ioend_wait(
xfs_inode_t *ip)
{
wait_queue_head_t *wq = to_ioend_wq(ip);
wait_event(*wq, (atomic_read(&ip->i_iocount) == 0));
}
STATIC void
xfs_ioend_wake(
xfs_inode_t *ip)
{
if (atomic_dec_and_test(&ip->i_iocount))
wake_up(to_ioend_wq(ip));
}
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))
(*unwritten) = 1;
else if (buffer_delay(bh))
(*delalloc) = 1;
} while ((bh = bh->b_this_page) != head);
}
STATIC struct block_device *
xfs_find_bdev_for_inode(
struct xfs_inode *ip)
{
struct xfs_mount *mp = ip->i_mount;
if (XFS_IS_REALTIME_INODE(ip))
return mp->m_rtdev_targp->bt_bdev;
else
return mp->m_ddev_targp->bt_bdev;
}
/*
* We're now finished for good with this ioend structure.
* Update the page state via the associated buffer_heads,
* release holds on the inode and bio, and finally free
* up memory. Do not use the ioend after this.
*/
STATIC void
xfs_destroy_ioend(
xfs_ioend_t *ioend)
{
struct buffer_head *bh, *next;
struct xfs_inode *ip = XFS_I(ioend->io_inode);
for (bh = ioend->io_buffer_head; bh; bh = next) {
next = bh->b_private;
bh->b_end_io(bh, !ioend->io_error);
}
/*
* Volume managers supporting multiple paths can send back ENODEV
* when the final path disappears. In this case continuing to fill
* the page cache with dirty data which cannot be written out is
* evil, so prevent that.
*/
if (unlikely(ioend->io_error == -ENODEV)) {
xfs_do_force_shutdown(ip->i_mount, SHUTDOWN_DEVICE_REQ,
__FILE__, __LINE__);
}
xfs_ioend_wake(ip);
mempool_free(ioend, xfs_ioend_pool);
}
/*
* If the end of the current ioend is beyond the current EOF,
* return the new EOF value, otherwise zero.
*/
STATIC xfs_fsize_t
xfs_ioend_new_eof(
xfs_ioend_t *ioend)
{
xfs_inode_t *ip = XFS_I(ioend->io_inode);
xfs_fsize_t isize;
xfs_fsize_t bsize;
bsize = ioend->io_offset + ioend->io_size;
isize = MAX(ip->i_size, ip->i_new_size);
isize = MIN(isize, bsize);
return isize > ip->i_d.di_size ? isize : 0;
}
/*
* Update on-disk file size now that data has been written to disk.
* The current in-memory file size is i_size. If a write is beyond
* eof i_new_size will be the intended file size until i_size is
* updated. If this write does not extend all the way to the valid
* file size then restrict this update to the end of the write.
*/
STATIC void
xfs_setfilesize(
xfs_ioend_t *ioend)
{
xfs_inode_t *ip = XFS_I(ioend->io_inode);
xfs_fsize_t isize;
ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFREG);
ASSERT(ioend->io_type != IOMAP_READ);
if (unlikely(ioend->io_error))
return;
xfs_ilock(ip, XFS_ILOCK_EXCL);
isize = xfs_ioend_new_eof(ioend);
if (isize) {
ip->i_d.di_size = isize;
xfs_mark_inode_dirty_sync(ip);
}
xfs_iunlock(ip, XFS_ILOCK_EXCL);
}
/*
* IO write completion.
*/
STATIC void
xfs_end_io(
struct work_struct *work)
{
xfs_ioend_t *ioend =
container_of(work, xfs_ioend_t, io_work);
struct xfs_inode *ip = XFS_I(ioend->io_inode);
/*
* For unwritten extents we need to issue transactions to convert a
* range to normal written extens after the data I/O has finished.
*/
if (ioend->io_type == IOMAP_UNWRITTEN &&
likely(!ioend->io_error && !XFS_FORCED_SHUTDOWN(ip->i_mount))) {
int error;
error = xfs_iomap_write_unwritten(ip, ioend->io_offset,
ioend->io_size);
if (error)
ioend->io_error = error;
}
/*
* We might have to update the on-disk file size after extending
* writes.
*/
if (ioend->io_type != IOMAP_READ)
xfs_setfilesize(ioend);
xfs_destroy_ioend(ioend);
}
/*
* Schedule IO completion handling on a xfsdatad if this was
* the final hold on this ioend. If we are asked to wait,
* flush the workqueue.
*/
STATIC void
xfs_finish_ioend(
xfs_ioend_t *ioend,
int wait)
{
if (atomic_dec_and_test(&ioend->io_remaining)) {
struct workqueue_struct *wq;
wq = (ioend->io_type == IOMAP_UNWRITTEN) ?
xfsconvertd_workqueue : xfsdatad_workqueue;
queue_work(wq, &ioend->io_work);
if (wait)
flush_workqueue(wq);
}
}
/*
* 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,
unsigned int type)
{
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_error = 0;
ioend->io_list = NULL;
ioend->io_type = type;
ioend->io_inode = inode;
ioend->io_buffer_head = NULL;
ioend->io_buffer_tail = NULL;
atomic_inc(&XFS_I(ioend->io_inode)->i_iocount);
ioend->io_offset = 0;
ioend->io_size = 0;
INIT_WORK(&ioend->io_work, xfs_end_io);
return ioend;
}
STATIC int
xfs_map_blocks(
struct inode *inode,
loff_t offset,
ssize_t count,
xfs_iomap_t *mapp,
int flags)
{
int nmaps = 1;
return -xfs_iomap(XFS_I(inode), offset, count, flags, mapp, &nmaps);
}
STATIC int
xfs_iomap_valid(
xfs_iomap_t *iomapp,
loff_t offset)
{
return offset >= iomapp->iomap_offset &&
offset < iomapp->iomap_offset + iomapp->iomap_bsize;
}
/*
* BIO completion handler for buffered IO.
*/
STATIC void
xfs_end_bio(
struct bio *bio,
int error)
{
xfs_ioend_t *ioend = bio->bi_private;
ASSERT(atomic_read(&bio->bi_cnt) >= 1);
ioend->io_error = test_bit(BIO_UPTODATE, &bio->bi_flags) ? 0 : error;
/* Toss bio and pass work off to an xfsdatad thread */
bio->bi_private = NULL;
bio->bi_end_io = NULL;
bio_put(bio);
xfs_finish_ioend(ioend, 0);
}
STATIC void
xfs_submit_ioend_bio(
struct writeback_control *wbc,
xfs_ioend_t *ioend,
struct bio *bio)
{
atomic_inc(&ioend->io_remaining);
bio->bi_private = ioend;
bio->bi_end_io = xfs_end_bio;
/*
* If the I/O is beyond EOF we mark the inode dirty immediately
* but don't update the inode size until I/O completion.
*/
if (xfs_ioend_new_eof(ioend))
xfs_mark_inode_dirty_sync(XFS_I(ioend->io_inode));
submit_bio(wbc->sync_mode == WB_SYNC_ALL ?
WRITE_SYNC_PLUG : WRITE, bio);
ASSERT(!bio_flagged(bio, BIO_EOPNOTSUPP));
bio_put(bio);
}
STATIC struct bio *
xfs_alloc_ioend_bio(
struct buffer_head *bh)
{
struct bio *bio;
int nvecs = bio_get_nr_vecs(bh->b_bdev);
do {
bio = bio_alloc(GFP_NOIO, nvecs);
nvecs >>= 1;
} while (!bio);
ASSERT(bio->bi_private == NULL);
bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9);
bio->bi_bdev = bh->b_bdev;
bio_get(bio);
return bio;
}
STATIC void
xfs_start_buffer_writeback(
struct buffer_head *bh)
{
ASSERT(buffer_mapped(bh));
ASSERT(buffer_locked(bh));
ASSERT(!buffer_delay(bh));
ASSERT(!buffer_unwritten(bh));
mark_buffer_async_write(bh);
set_buffer_uptodate(bh);
clear_buffer_dirty(bh);
}
STATIC void
xfs_start_page_writeback(
struct page *page,
int clear_dirty,
int buffers)
{
ASSERT(PageLocked(page));
ASSERT(!PageWriteback(page));
if (clear_dirty)
clear_page_dirty_for_io(page);
set_page_writeback(page);
unlock_page(page);
/* If no buffers on the page are to be written, finish it here */
if (!buffers)
end_page_writeback(page);
}
static inline int bio_add_buffer(struct bio *bio, struct buffer_head *bh)
{
return bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
}
/*
* Submit all of the bios for all of the ioends we have saved up, covering the
* initial writepage page and also any probed pages.
*
* Because we may have multiple ioends spanning a page, we need to start
* writeback on all the buffers before we submit them for I/O. If we mark the
* buffers as we got, then we can end up with a page that only has buffers
* marked async write and I/O complete on can occur before we mark the other
* buffers async write.
*
* The end result of this is that we trip a bug in end_page_writeback() because
* we call it twice for the one page as the code in end_buffer_async_write()
* assumes that all buffers on the page are started at the same time.
*
* The fix is two passes across the ioend list - one to start writeback on the
* buffer_heads, and then submit them for I/O on the second pass.
*/
STATIC void
xfs_submit_ioend(
struct writeback_control *wbc,
xfs_ioend_t *ioend)
{
xfs_ioend_t *head = ioend;
xfs_ioend_t *next;
struct buffer_head *bh;
struct bio *bio;
sector_t lastblock = 0;
/* Pass 1 - start writeback */
do {
next = ioend->io_list;
for (bh = ioend->io_buffer_head; bh; bh = bh->b_private) {
xfs_start_buffer_writeback(bh);
}
} while ((ioend = next) != NULL);
/* Pass 2 - submit I/O */
ioend = head;
do {
next = ioend->io_list;
bio = NULL;
for (bh = ioend->io_buffer_head; bh; bh = bh->b_private) {
if (!bio) {
retry:
bio = xfs_alloc_ioend_bio(bh);
} else if (bh->b_blocknr != lastblock + 1) {
xfs_submit_ioend_bio(wbc, ioend, bio);
goto retry;
}
if (bio_add_buffer(bio, bh) != bh->b_size) {
xfs_submit_ioend_bio(wbc, ioend, bio);
goto retry;
}
lastblock = bh->b_blocknr;
}
if (bio)
xfs_submit_ioend_bio(wbc, ioend, bio);
xfs_finish_ioend(ioend, 0);
} while ((ioend = next) != NULL);
}
/*
* Cancel submission of all buffer_heads so far in this endio.
* Toss the endio too. Only ever called for the initial page
* in a writepage request, so only ever one page.
*/
STATIC void
xfs_cancel_ioend(
xfs_ioend_t *ioend)
{
xfs_ioend_t *next;
struct buffer_head *bh, *next_bh;
do {
next = ioend->io_list;
bh = ioend->io_buffer_head;
do {
next_bh = bh->b_private;
clear_buffer_async_write(bh);
unlock_buffer(bh);
} while ((bh = next_bh) != NULL);
xfs_ioend_wake(XFS_I(ioend->io_inode));
mempool_free(ioend, xfs_ioend_pool);
} while ((ioend = next) != NULL);
}
/*
* Test to see if we've been building up a completion structure for
* earlier buffers -- if so, we try to append to this ioend if we
* can, otherwise we finish off any current ioend and start another.
* Return true if we've finished the given ioend.
*/
STATIC void
xfs_add_to_ioend(
struct inode *inode,
struct buffer_head *bh,
xfs_off_t offset,
unsigned int type,
xfs_ioend_t **result,
int need_ioend)
{
xfs_ioend_t *ioend = *result;
if (!ioend || need_ioend || type != ioend->io_type) {
xfs_ioend_t *previous = *result;
ioend = xfs_alloc_ioend(inode, type);
ioend->io_offset = offset;
ioend->io_buffer_head = bh;
ioend->io_buffer_tail = bh;
if (previous)
previous->io_list = ioend;
*result = ioend;
} else {
ioend->io_buffer_tail->b_private = bh;
ioend->io_buffer_tail = bh;
}
bh->b_private = NULL;
ioend->io_size += bh->b_size;
}
STATIC void
xfs_map_buffer(
struct buffer_head *bh,
xfs_iomap_t *mp,
xfs_off_t offset,
uint block_bits)
{
sector_t bn;
ASSERT(mp->iomap_bn != IOMAP_DADDR_NULL);
bn = (mp->iomap_bn >> (block_bits - BBSHIFT)) +
((offset - mp->iomap_offset) >> block_bits);
ASSERT(bn || (mp->iomap_flags & IOMAP_REALTIME));
bh->b_blocknr = bn;
set_buffer_mapped(bh);
}
STATIC void
xfs_map_at_offset(
struct buffer_head *bh,
loff_t offset,
int block_bits,
xfs_iomap_t *iomapp)
{
ASSERT(!(iomapp->iomap_flags & IOMAP_HOLE));
ASSERT(!(iomapp->iomap_flags & IOMAP_DELAY));
lock_buffer(bh);
xfs_map_buffer(bh, iomapp, offset, block_bits);
bh->b_bdev = iomapp->iomap_target->bt_bdev;
set_buffer_mapped(bh);
clear_buffer_delay(bh);
clear_buffer_unwritten(bh);
}
/*
* Look for a page at index that is suitable for clustering.
*/
STATIC unsigned int
xfs_probe_page(
struct page *page,
unsigned int pg_offset,
int mapped)
{
int ret = 0;
if (PageWriteback(page))
return 0;
if (page->mapping && PageDirty(page)) {
if (page_has_buffers(page)) {
struct buffer_head *bh, *head;
bh = head = page_buffers(page);
do {
if (!buffer_uptodate(bh))
break;
if (mapped != buffer_mapped(bh))
break;
ret += bh->b_size;
if (ret >= pg_offset)
break;
} while ((bh = bh->b_this_page) != head);
} else
ret = mapped ? 0 : PAGE_CACHE_SIZE;
}
return ret;
}
STATIC size_t
xfs_probe_cluster(
struct inode *inode,
struct page *startpage,
struct buffer_head *bh,
struct buffer_head *head,
int mapped)
{
struct pagevec pvec;
pgoff_t tindex, tlast, tloff;
size_t total = 0;
int done = 0, i;
/* First sum forwards in this page */
do {
if (!buffer_uptodate(bh) || (mapped != buffer_mapped(bh)))
return total;
total += bh->b_size;
} while ((bh = bh->b_this_page) != head);
/* if we reached the end of the page, sum forwards in following pages */
tlast = i_size_read(inode) >> PAGE_CACHE_SHIFT;
tindex = startpage->index + 1;
/* Prune this back to avoid pathological behavior */
tloff = min(tlast, startpage->index + 64);
pagevec_init(&pvec, 0);
while (!done && tindex <= tloff) {
unsigned len = min_t(pgoff_t, PAGEVEC_SIZE, tlast - tindex + 1);
if (!pagevec_lookup(&pvec, inode->i_mapping, tindex, len))
break;
for (i = 0; i < pagevec_count(&pvec); i++) {
struct page *page = pvec.pages[i];
size_t pg_offset, pg_len = 0;
if (tindex == tlast) {
pg_offset =
i_size_read(inode) & (PAGE_CACHE_SIZE - 1);
if (!pg_offset) {
done = 1;
break;
}
} else
pg_offset = PAGE_CACHE_SIZE;
if (page->index == tindex && trylock_page(page)) {
pg_len = xfs_probe_page(page, pg_offset, mapped);
unlock_page(page);
}
if (!pg_len) {
done = 1;
break;
}
total += pg_len;
tindex++;
}
pagevec_release(&pvec);
cond_resched();
}
return total;
}
/*
* Test if a given page is suitable for writing as part of an unwritten
* or delayed allocate extent.
*/
STATIC int
xfs_is_delayed_page(
struct page *page,
unsigned int type)
{
if (PageWriteback(page))
return 0;
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 = (type == IOMAP_UNWRITTEN);
else if (buffer_delay(bh))
acceptable = (type == IOMAP_DELAY);
else if (buffer_dirty(bh) && buffer_mapped(bh))
acceptable = (type == IOMAP_NEW);
else
break;
} while ((bh = bh->b_this_page) != head);
if (acceptable)
return 1;
}
return 0;
}
/*
* 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 int
xfs_convert_page(
struct inode *inode,
struct page *page,
loff_t tindex,
xfs_iomap_t *mp,
xfs_ioend_t **ioendp,
struct writeback_control *wbc,
int startio,
int all_bh)
{
struct buffer_head *bh, *head;
xfs_off_t end_offset;
unsigned long p_offset;
unsigned int type;
int bbits = inode->i_blkbits;
int len, page_dirty;
int count = 0, done = 0, uptodate = 1;
xfs_off_t offset = page_offset(page);
if (page->index != tindex)
goto fail;
if (!trylock_page(page))
goto fail;
if (PageWriteback(page))
goto fail_unlock_page;
if (page->mapping != inode->i_mapping)
goto fail_unlock_page;
if (!xfs_is_delayed_page(page, (*ioendp)->io_type))
goto fail_unlock_page;
/*
* page_dirty is initially a count of buffers on the page before
* EOF and is decremented as we move each into a cleanable state.
*
* Derivation:
*
* End offset is the highest offset that this page should represent.
* If we are on the last page, (end_offset & (PAGE_CACHE_SIZE - 1))
* will evaluate non-zero and be less than PAGE_CACHE_SIZE and
* hence give us the correct page_dirty count. On any other page,
* it will be zero and in that case we need page_dirty to be the
* count of buffers on the page.
*/
end_offset = min_t(unsigned long long,
(xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT,
i_size_read(inode));
len = 1 << inode->i_blkbits;
p_offset = min_t(unsigned long, end_offset & (PAGE_CACHE_SIZE - 1),
PAGE_CACHE_SIZE);
p_offset = p_offset ? roundup(p_offset, len) : PAGE_CACHE_SIZE;
page_dirty = p_offset / len;
bh = head = page_buffers(page);
do {
if (offset >= end_offset)
break;
if (!buffer_uptodate(bh))
uptodate = 0;
if (!(PageUptodate(page) || buffer_uptodate(bh))) {
done = 1;
continue;
}
if (buffer_unwritten(bh) || buffer_delay(bh)) {
if (buffer_unwritten(bh))
type = IOMAP_UNWRITTEN;
else
type = IOMAP_DELAY;
if (!xfs_iomap_valid(mp, offset)) {
done = 1;
continue;
}
ASSERT(!(mp->iomap_flags & IOMAP_HOLE));
ASSERT(!(mp->iomap_flags & IOMAP_DELAY));
xfs_map_at_offset(bh, offset, bbits, mp);
if (startio) {
xfs_add_to_ioend(inode, bh, offset,
type, ioendp, done);
} else {
set_buffer_dirty(bh);
unlock_buffer(bh);
mark_buffer_dirty(bh);
}
page_dirty--;
count++;
} else {
type = IOMAP_NEW;
if (buffer_mapped(bh) && all_bh && startio) {
lock_buffer(bh);
xfs_add_to_ioend(inode, bh, offset,
type, ioendp, done);
count++;
page_dirty--;
} else {
done = 1;
}
}
} while (offset += len, (bh = bh->b_this_page) != head);
if (uptodate && bh == head)
SetPageUptodate(page);
if (startio) {
if (count) {
wbc->nr_to_write--;
if (wbc->nr_to_write <= 0)
done = 1;
}
xfs_start_page_writeback(page, !page_dirty, count);
}
return done;
fail_unlock_page:
unlock_page(page);
fail:
return 1;
}
/*
* 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,
xfs_ioend_t **ioendp,
struct writeback_control *wbc,
int startio,
int all_bh,
pgoff_t tlast)
{
struct pagevec pvec;
int done = 0, i;
pagevec_init(&pvec, 0);
while (!done && tindex <= tlast) {
unsigned len = min_t(pgoff_t, PAGEVEC_SIZE, tlast - tindex + 1);
if (!pagevec_lookup(&pvec, inode->i_mapping, tindex, len))
break;
for (i = 0; i < pagevec_count(&pvec); i++) {
done = xfs_convert_page(inode, pvec.pages[i], tindex++,
iomapp, ioendp, wbc, startio, all_bh);
if (done)
break;
}
pagevec_release(&pvec);
cond_resched();
}
}
/*
* 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 valid 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, *head;
xfs_iomap_t iomap;
xfs_ioend_t *ioend = NULL, *iohead = NULL;
loff_t offset;
unsigned long p_offset = 0;
unsigned int type;
__uint64_t end_offset;
pgoff_t end_index, last_index, tlast;
ssize_t size, len;
int flags, err, iomap_valid = 0, uptodate = 1;
int page_dirty, count = 0;
int trylock = 0;
int all_bh = unmapped;
if (startio) {
if (wbc->sync_mode == WB_SYNC_NONE && wbc->nonblocking)
trylock |= 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;
}
}
/*
* page_dirty is initially a count of buffers on the page before
* EOF and is decremented as we move each into a cleanable state.
*
* Derivation:
*
* End offset is the highest offset that this page should represent.
* If we are on the last page, (end_offset & (PAGE_CACHE_SIZE - 1))
* will evaluate non-zero and be less than PAGE_CACHE_SIZE and
* hence give us the correct page_dirty count. On any other page,
* it will be zero and in that case we need page_dirty to be the
* count of buffers on the page.
*/
end_offset = min_t(unsigned long long,
(xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT, offset);
len = 1 << inode->i_blkbits;
p_offset = min_t(unsigned long, end_offset & (PAGE_CACHE_SIZE - 1),
PAGE_CACHE_SIZE);
p_offset = p_offset ? roundup(p_offset, len) : PAGE_CACHE_SIZE;
page_dirty = p_offset / len;
bh = head = page_buffers(page);
offset = page_offset(page);
flags = BMAPI_READ;
type = IOMAP_NEW;
/* TODO: cleanup count and page_dirty */
do {
if (offset >= end_offset)
break;
if (!buffer_uptodate(bh))
uptodate = 0;
if (!(PageUptodate(page) || buffer_uptodate(bh)) && !startio) {
/*
* the iomap is actually still valid, but the ioend
* isn't. shouldn't happen too often.
*/
iomap_valid = 0;
continue;
}
if (iomap_valid)
iomap_valid = xfs_iomap_valid(&iomap, offset);
/*
* First case, map an unwritten extent and prepare for
* extent state conversion transaction on completion.
*
* Second case, allocate space for a delalloc buffer.
* We can return EAGAIN here in the release page case.
*
* Third case, an unmapped buffer was found, and we are
* in a path where we need to write the whole page out.
*/
if (buffer_unwritten(bh) || buffer_delay(bh) ||
((buffer_uptodate(bh) || PageUptodate(page)) &&
!buffer_mapped(bh) && (unmapped || startio))) {
int new_ioend = 0;
/*
* Make sure we don't use a read-only iomap
*/
if (flags == BMAPI_READ)
iomap_valid = 0;
if (buffer_unwritten(bh)) {
type = IOMAP_UNWRITTEN;
flags = BMAPI_WRITE | BMAPI_IGNSTATE;
} else if (buffer_delay(bh)) {
type = IOMAP_DELAY;
flags = BMAPI_ALLOCATE | trylock;
} else {
type = IOMAP_NEW;
flags = BMAPI_WRITE | BMAPI_MMAP;
}
if (!iomap_valid) {
/*
* if we didn't have a valid mapping then we
* need to ensure that we put the new mapping
* in a new ioend structure. This needs to be
* done to ensure that the ioends correctly
* reflect the block mappings at io completion
* for unwritten extent conversion.
*/
new_ioend = 1;
if (type == IOMAP_NEW) {
size = xfs_probe_cluster(inode,
page, bh, head, 0);
} else {
size = len;
}
err = xfs_map_blocks(inode, offset, size,
&iomap, flags);
if (err)
goto error;
iomap_valid = xfs_iomap_valid(&iomap, offset);
}
if (iomap_valid) {
xfs_map_at_offset(bh, offset,
inode->i_blkbits, &iomap);
if (startio) {
xfs_add_to_ioend(inode, bh, offset,
type, &ioend,
new_ioend);
} else {
set_buffer_dirty(bh);
unlock_buffer(bh);
mark_buffer_dirty(bh);
}
page_dirty--;
count++;
}
} else if (buffer_uptodate(bh) && startio) {
/*
* we got here because the buffer is already mapped.
* That means it must already have extents allocated
* underneath it. Map the extent by reading it.
*/
if (!iomap_valid || flags != BMAPI_READ) {
flags = BMAPI_READ;
size = xfs_probe_cluster(inode, page, bh,
head, 1);
err = xfs_map_blocks(inode, offset, size,
&iomap, flags);
if (err)
goto error;
iomap_valid = xfs_iomap_valid(&iomap, offset);
}
/*
* We set the type to IOMAP_NEW in case we are doing a
* small write at EOF that is extending the file but
* without needing an allocation. We need to update the
* file size on I/O completion in this case so it is
* the same case as having just allocated a new extent
* that we are writing into for the first time.
*/
type = IOMAP_NEW;
if (trylock_buffer(bh)) {
ASSERT(buffer_mapped(bh));
if (iomap_valid)
all_bh = 1;
xfs_add_to_ioend(inode, bh, offset, type,
&ioend, !iomap_valid);
page_dirty--;
count++;
} else {
iomap_valid = 0;
}
} else if ((buffer_uptodate(bh) || PageUptodate(page)) &&
(unmapped || startio)) {
iomap_valid = 0;
}
if (!iohead)
iohead = ioend;
} while (offset += len, ((bh = bh->b_this_page) != head));
if (uptodate && bh == head)
SetPageUptodate(page);
if (startio)
xfs_start_page_writeback(page, 1, count);
if (ioend && iomap_valid) {
offset = (iomap.iomap_offset + iomap.iomap_bsize - 1) >>
PAGE_CACHE_SHIFT;
tlast = min_t(pgoff_t, offset, last_index);
xfs_cluster_write(inode, page->index + 1, &iomap, &ioend,
wbc, startio, all_bh, tlast);
}
if (iohead)
xfs_submit_ioend(wbc, iohead);
return page_dirty;
error:
if (iohead)
xfs_cancel_ioend(iohead);
/*
* 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;
}
/*
* 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
xfs_vm_writepage(
struct page *page,
struct writeback_control *wbc)
{
int error;
int need_trans;
int delalloc, unmapped, unwritten;
struct inode *inode = page->mapping->host;
trace_xfs_writepage(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 (current_test_flags(PF_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);
/*
* VM calculation for nr_to_write seems off. Bump it way
* up, this gets simple streaming writes zippy again.
* To be reviewed again after Jens' writeback changes.
*/
wbc->nr_to_write *= 4;
/*
* 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
xfs_vm_writepages(
struct address_space *mapping,
struct writeback_control *wbc)
{
xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
return generic_writepages(mapping, wbc);
}
/*
* 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
xfs_vm_releasepage(
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,
};
trace_xfs_releasepage(inode, page, 0);
if (!page_has_buffers(page))
return 0;
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 (current_test_flags(PF_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
__xfs_get_blocks(
struct inode *inode,
sector_t iblock,
struct buffer_head *bh_result,
int create,
int direct,
bmapi_flags_t flags)
{
xfs_iomap_t iomap;
xfs_off_t offset;
ssize_t size;
int niomap = 1;
int error;
offset = (xfs_off_t)iblock << inode->i_blkbits;
ASSERT(bh_result->b_size >= (1 << inode->i_blkbits));
size = bh_result->b_size;
if (!create && direct && offset >= i_size_read(inode))
return 0;
error = xfs_iomap(XFS_I(inode), offset, size,
create ? flags : BMAPI_READ, &iomap, &niomap);
if (error)
return -error;
if (niomap == 0)
return 0;
if (iomap.iomap_bn != IOMAP_DADDR_NULL) {
/*
* 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)) {
xfs_map_buffer(bh_result, &iomap, offset,
inode->i_blkbits);
}
if (create && (iomap.iomap_flags & IOMAP_UNWRITTEN)) {
if (direct)
bh_result->b_private = inode;
set_buffer_unwritten(bh_result);
}
}
/*
* If this is a realtime file, data may be on a different device.
* to that pointed to from the buffer_head b_bdev currently.
*/
bh_result->b_bdev = iomap.iomap_target->bt_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.
*
* With sub-block writes into unwritten extents we also need to mark
* the buffer as new so that the unwritten parts of the buffer gets
* correctly zeroed.
*/
if (create &&
((!buffer_mapped(bh_result) && !buffer_uptodate(bh_result)) ||
(offset >= i_size_read(inode)) ||
(iomap.iomap_flags & (IOMAP_NEW|IOMAP_UNWRITTEN))))
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 (direct || size > (1 << inode->i_blkbits)) {
ASSERT(iomap.iomap_bsize - iomap.iomap_delta > 0);
offset = min_t(xfs_off_t,
iomap.iomap_bsize - iomap.iomap_delta, size);
bh_result->b_size = (ssize_t)min_t(xfs_off_t, LONG_MAX, offset);
}
return 0;
}
int
xfs_get_blocks(
struct inode *inode,
sector_t iblock,
struct buffer_head *bh_result,
int create)
{
return __xfs_get_blocks(inode, iblock,
bh_result, create, 0, BMAPI_WRITE);
}
STATIC int
xfs_get_blocks_direct(
struct inode *inode,
sector_t iblock,
struct buffer_head *bh_result,
int create)
{
return __xfs_get_blocks(inode, iblock,
bh_result, create, 1, BMAPI_WRITE|BMAPI_DIRECT);
}
STATIC void
xfs_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 context but aio+dio I/O completion
* happens from irq context so we need to defer it to a workqueue.
* This is not necessary for synchronous direct I/O, but we do
* it anyway to keep the code uniform and simpler.
*
* Well, if only it were that simple. Because synchronous direct I/O
* requires extent conversion to occur *before* we return to userspace,
* we have to wait for extent conversion to complete. Look at the
* iocb that has been passed to us to determine if this is AIO or
* not. If it is synchronous, tell xfs_finish_ioend() to kick the
* workqueue and wait for it to complete.
*
* 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.
*/
ioend->io_offset = offset;
ioend->io_size = size;
if (ioend->io_type == IOMAP_READ) {
xfs_finish_ioend(ioend, 0);
} else if (private && size > 0) {
xfs_finish_ioend(ioend, is_sync_kiocb(iocb));
} else {
/*
* A direct I/O write ioend starts it's life in unwritten
* state in case they map an unwritten extent. This write
* didn't map an unwritten extent so switch it's completion
* handler.
*/
ioend->io_type = IOMAP_NEW;
xfs_finish_ioend(ioend, 0);
}
/*
* blockdev_direct_IO can return an error even after the I/O
* completion handler was called. Thus we need to protect
* against double-freeing.
*/
iocb->private = NULL;
}
STATIC ssize_t
xfs_vm_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;
struct block_device *bdev;
ssize_t ret;
bdev = xfs_find_bdev_for_inode(XFS_I(inode));
iocb->private = xfs_alloc_ioend(inode, rw == WRITE ?
IOMAP_UNWRITTEN : IOMAP_READ);
ret = blockdev_direct_IO_no_locking(rw, iocb, inode, bdev, iov,
offset, nr_segs,
xfs_get_blocks_direct,
xfs_end_io_direct);
if (unlikely(ret != -EIOCBQUEUED && iocb->private))
xfs_destroy_ioend(iocb->private);
return ret;
}
STATIC int
xfs_vm_write_begin(
struct file *file,
struct address_space *mapping,
loff_t pos,
unsigned len,
unsigned flags,
struct page **pagep,
void **fsdata)
{
*pagep = NULL;
return block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
xfs_get_blocks);
}
STATIC sector_t
xfs_vm_bmap(
struct address_space *mapping,
sector_t block)
{
struct inode *inode = (struct inode *)mapping->host;
struct xfs_inode *ip = XFS_I(inode);
xfs_itrace_entry(XFS_I(inode));
xfs_ilock(ip, XFS_IOLOCK_SHARED);
xfs_flush_pages(ip, (xfs_off_t)0, -1, 0, FI_REMAPF);
xfs_iunlock(ip, XFS_IOLOCK_SHARED);
return generic_block_bmap(mapping, block, xfs_get_blocks);
}
STATIC int
xfs_vm_readpage(
struct file *unused,
struct page *page)
{
return mpage_readpage(page, xfs_get_blocks);
}
STATIC int
xfs_vm_readpages(
struct file *unused,
struct address_space *mapping,
struct list_head *pages,
unsigned nr_pages)
{
return mpage_readpages(mapping, pages, nr_pages, xfs_get_blocks);
}
STATIC void
xfs_vm_invalidatepage(
struct page *page,
unsigned long offset)
{
trace_xfs_invalidatepage(page->mapping->host, page, offset);
block_invalidatepage(page, offset);
}
const struct address_space_operations xfs_address_space_operations = {
.readpage = xfs_vm_readpage,
.readpages = xfs_vm_readpages,
.writepage = xfs_vm_writepage,
.writepages = xfs_vm_writepages,
.sync_page = block_sync_page,
.releasepage = xfs_vm_releasepage,
.invalidatepage = xfs_vm_invalidatepage,
.write_begin = xfs_vm_write_begin,
.write_end = generic_write_end,
.bmap = xfs_vm_bmap,
.direct_IO = xfs_vm_direct_IO,
.migratepage = buffer_migrate_page,
.is_partially_uptodate = block_is_partially_uptodate,
.error_remove_page = generic_error_remove_page,
};