linux/fs/xfs/linux-2.6/xfs_aops.c
Dave Chinner 3ed3a4343b xfs: truncate delalloc extents when IO fails in writeback
We currently use block_invalidatepage() to clean up pages where I/O
fails in ->writepage(). Unfortunately, if the page has delalloc
regions on it, we fail to remove the delalloc regions when we
invalidate the page.  This can result in tripping a BUG() in
xfs_get_blocks() later on if a direct IO read is done on that same
region - the delalloc extent is returned when none is supposed to be
there.

Fix this by truncating away the delalloc regions on the page before
invalidating it. Because they are delalloc, we can do this without
needing a transaction. Indeed - if we get ENOSPC errors, we have to
be able to do this truncation without a transaction as there is
no space left for block reservation (typically why we see a ENOSPC
in writeback).

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Alex Elder <aelder@sgi.com>
2010-03-05 11:01:53 -06:00

1685 lines
42 KiB
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 "xfs_bmap.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.
*
* This function does not block as blocking on the inode lock in IO completion
* can lead to IO completion order dependency deadlocks.. If it can't get the
* inode ilock it will return EAGAIN. Callers must handle this.
*/
STATIC int
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 0;
if (!xfs_ilock_nowait(ip, XFS_ILOCK_EXCL))
return EAGAIN;
isize = xfs_ioend_new_eof(ioend);
if (isize) {
ip->i_d.di_size = isize;
xfs_mark_inode_dirty(ip);
}
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return 0;
}
/*
* 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);
}
}
/*
* 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);
int error = 0;
/*
* 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))) {
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) {
error = xfs_setfilesize(ioend);
ASSERT(!error || error == EAGAIN);
}
/*
* If we didn't complete processing of the ioend, requeue it to the
* tail of the workqueue for another attempt later. Otherwise destroy
* it.
*/
if (error == EAGAIN) {
atomic_inc(&ioend->io_remaining);
xfs_finish_ioend(ioend, 0);
/* ensure we don't spin on blocked ioends */
delay(1);
} else
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,
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(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();
}
}
STATIC void
xfs_vm_invalidatepage(
struct page *page,
unsigned long offset)
{
trace_xfs_invalidatepage(page->mapping->host, page, offset);
block_invalidatepage(page, offset);
}
/*
* If the page has delalloc buffers on it, we need to punch them out before we
* invalidate the page. If we don't, we leave a stale delalloc mapping on the
* inode that can trip a BUG() in xfs_get_blocks() later on if a direct IO read
* is done on that same region - the delalloc extent is returned when none is
* supposed to be there.
*
* We prevent this by truncating away the delalloc regions on the page before
* invalidating it. Because they are delalloc, we can do this without needing a
* transaction. Indeed - if we get ENOSPC errors, we have to be able to do this
* truncation without a transaction as there is no space left for block
* reservation (typically why we see a ENOSPC in writeback).
*
* This is not a performance critical path, so for now just do the punching a
* buffer head at a time.
*/
STATIC void
xfs_aops_discard_page(
struct page *page)
{
struct inode *inode = page->mapping->host;
struct xfs_inode *ip = XFS_I(inode);
struct buffer_head *bh, *head;
loff_t offset = page_offset(page);
ssize_t len = 1 << inode->i_blkbits;
if (!xfs_is_delayed_page(page, IOMAP_DELAY))
goto out_invalidate;
xfs_fs_cmn_err(CE_ALERT, ip->i_mount,
"page discard on page %p, inode 0x%llx, offset %llu.",
page, ip->i_ino, offset);
xfs_ilock(ip, XFS_ILOCK_EXCL);
bh = head = page_buffers(page);
do {
int done;
xfs_fileoff_t offset_fsb;
xfs_bmbt_irec_t imap;
int nimaps = 1;
int error;
xfs_fsblock_t firstblock;
xfs_bmap_free_t flist;
if (!buffer_delay(bh))
goto next_buffer;
offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
/*
* Map the range first and check that it is a delalloc extent
* before trying to unmap the range. Otherwise we will be
* trying to remove a real extent (which requires a
* transaction) or a hole, which is probably a bad idea...
*/
error = xfs_bmapi(NULL, ip, offset_fsb, 1,
XFS_BMAPI_ENTIRE, NULL, 0, &imap,
&nimaps, NULL, NULL);
if (error) {
/* something screwed, just bail */
xfs_fs_cmn_err(CE_ALERT, ip->i_mount,
"page discard failed delalloc mapping lookup.");
break;
}
if (!nimaps) {
/* nothing there */
goto next_buffer;
}
if (imap.br_startblock != DELAYSTARTBLOCK) {
/* been converted, ignore */
goto next_buffer;
}
WARN_ON(imap.br_blockcount == 0);
/*
* Note: while we initialise the firstblock/flist pair, they
* should never be used because blocks should never be
* allocated or freed for a delalloc extent and hence we need
* don't cancel or finish them after the xfs_bunmapi() call.
*/
xfs_bmap_init(&flist, &firstblock);
error = xfs_bunmapi(NULL, ip, offset_fsb, 1, 0, 1, &firstblock,
&flist, NULL, &done);
ASSERT(!flist.xbf_count && !flist.xbf_first);
if (error) {
/* something screwed, just bail */
xfs_fs_cmn_err(CE_ALERT, ip->i_mount,
"page discard unable to remove delalloc mapping.");
break;
}
next_buffer:
offset += len;
} while ((bh = bh->b_this_page) != head);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
out_invalidate:
xfs_vm_invalidatepage(page, 0);
return;
}
/*
* 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)
xfs_aops_discard_page(page);
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);
}
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,
};