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linux/fs/xfs/xfs_aops.c

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/*
* 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_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_inode_item.h"
#include "xfs_alloc.h"
#include "xfs_error.h"
#include "xfs_iomap.h"
#include "xfs_trace.h"
#include "xfs_bmap.h"
#include "xfs_bmap_util.h"
#include "xfs_bmap_btree.h"
#include <linux/gfp.h>
#include <linux/mpage.h>
#include <linux/pagevec.h>
#include <linux/writeback.h>
/* flags for direct write completions */
#define XFS_DIO_FLAG_UNWRITTEN (1 << 0)
#define XFS_DIO_FLAG_APPEND (1 << 1)
/*
* structure owned by writepages passed to individual writepage calls
*/
struct xfs_writepage_ctx {
struct xfs_bmbt_irec imap;
bool imap_valid;
unsigned int io_type;
struct xfs_ioend *ioend;
sector_t last_block;
};
void
xfs_count_page_state(
struct page *page,
int *delalloc,
int *unwritten)
{
struct buffer_head *bh, *head;
*delalloc = *unwritten = 0;
bh = head = page_buffers(page);
do {
if (buffer_unwritten(bh))
(*unwritten) = 1;
else if (buffer_delay(bh))
(*delalloc) = 1;
} while ((bh = bh->b_this_page) != head);
}
struct block_device *
xfs_find_bdev_for_inode(
struct inode *inode)
{
struct xfs_inode *ip = XFS_I(inode);
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;
for (bh = ioend->io_buffer_head; bh; bh = next) {
next = bh->b_private;
bh->b_end_io(bh, !ioend->io_error);
}
mempool_free(ioend, xfs_ioend_pool);
}
/*
* Fast and loose check if this write could update the on-disk inode size.
*/
static inline bool xfs_ioend_is_append(struct xfs_ioend *ioend)
{
return ioend->io_offset + ioend->io_size >
XFS_I(ioend->io_inode)->i_d.di_size;
}
STATIC int
xfs_setfilesize_trans_alloc(
struct xfs_ioend *ioend)
{
struct xfs_mount *mp = XFS_I(ioend->io_inode)->i_mount;
struct xfs_trans *tp;
int error;
tp = xfs_trans_alloc(mp, XFS_TRANS_FSYNC_TS);
error = xfs_trans_reserve(tp, &M_RES(mp)->tr_fsyncts, 0, 0);
if (error) {
xfs_trans_cancel(tp);
return error;
}
ioend->io_append_trans = tp;
/*
* We may pass freeze protection with a transaction. So tell lockdep
* we released it.
*/
__sb_writers_release(ioend->io_inode->i_sb, SB_FREEZE_FS);
/*
* We hand off the transaction to the completion thread now, so
* clear the flag here.
*/
current_restore_flags_nested(&tp->t_pflags, PF_FSTRANS);
return 0;
}
/*
* Update on-disk file size now that data has been written to disk.
*/
STATIC int
xfs_setfilesize(
struct xfs_inode *ip,
struct xfs_trans *tp,
xfs_off_t offset,
size_t size)
{
xfs_fsize_t isize;
xfs_ilock(ip, XFS_ILOCK_EXCL);
isize = xfs_new_eof(ip, offset + size);
if (!isize) {
xfs_iunlock(ip, XFS_ILOCK_EXCL);
xfs_trans_cancel(tp);
return 0;
}
trace_xfs_setfilesize(ip, offset, size);
ip->i_d.di_size = isize;
xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE);
return xfs_trans_commit(tp);
}
STATIC int
xfs_setfilesize_ioend(
struct xfs_ioend *ioend)
{
struct xfs_inode *ip = XFS_I(ioend->io_inode);
struct xfs_trans *tp = ioend->io_append_trans;
/*
* The transaction may have been allocated in the I/O submission thread,
* thus we need to mark ourselves as being in a transaction manually.
* Similarly for freeze protection.
*/
current_set_flags_nested(&tp->t_pflags, PF_FSTRANS);
__sb_writers_acquired(VFS_I(ip)->i_sb, SB_FREEZE_FS);
/* we abort the update if there was an IO error */
if (ioend->io_error) {
xfs_trans_cancel(tp);
return ioend->io_error;
}
return xfs_setfilesize(ip, tp, ioend->io_offset, ioend->io_size);
}
/*
* Schedule IO completion handling on the final put of an ioend.
*
* If there is no work to do we might as well call it a day and free the
* ioend right now.
*/
STATIC void
xfs_finish_ioend(
struct xfs_ioend *ioend)
{
if (atomic_dec_and_test(&ioend->io_remaining)) {
struct xfs_mount *mp = XFS_I(ioend->io_inode)->i_mount;
if (ioend->io_type == XFS_IO_UNWRITTEN)
queue_work(mp->m_unwritten_workqueue, &ioend->io_work);
else if (ioend->io_append_trans)
queue_work(mp->m_data_workqueue, &ioend->io_work);
else
xfs_destroy_ioend(ioend);
}
}
/*
* 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;
/*
* Set an error if the mount has shut down and proceed with end I/O
* processing so it can perform whatever cleanups are necessary.
*/
if (XFS_FORCED_SHUTDOWN(ip->i_mount))
ioend->io_error = -EIO;
/*
* For unwritten extents we need to issue transactions to convert a
* range to normal written extens after the data I/O has finished.
* Detecting and handling completion IO errors is done individually
* for each case as different cleanup operations need to be performed
* on error.
*/
if (ioend->io_type == XFS_IO_UNWRITTEN) {
if (ioend->io_error)
goto done;
error = xfs_iomap_write_unwritten(ip, ioend->io_offset,
ioend->io_size);
} else if (ioend->io_append_trans) {
error = xfs_setfilesize_ioend(ioend);
} else {
ASSERT(!xfs_ioend_is_append(ioend));
}
done:
if (error)
ioend->io_error = error;
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;
INIT_LIST_HEAD(&ioend->io_list);
ioend->io_type = type;
ioend->io_inode = inode;
ioend->io_buffer_head = NULL;
ioend->io_buffer_tail = NULL;
ioend->io_offset = 0;
ioend->io_size = 0;
ioend->io_append_trans = NULL;
INIT_WORK(&ioend->io_work, xfs_end_io);
return ioend;
}
STATIC int
xfs_map_blocks(
struct inode *inode,
loff_t offset,
struct xfs_bmbt_irec *imap,
int type)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
ssize_t count = 1 << inode->i_blkbits;
xfs_fileoff_t offset_fsb, end_fsb;
int error = 0;
int bmapi_flags = XFS_BMAPI_ENTIRE;
int nimaps = 1;
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
if (type == XFS_IO_UNWRITTEN)
bmapi_flags |= XFS_BMAPI_IGSTATE;
xfs_ilock(ip, XFS_ILOCK_SHARED);
ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
(ip->i_df.if_flags & XFS_IFEXTENTS));
ASSERT(offset <= mp->m_super->s_maxbytes);
if (offset + count > mp->m_super->s_maxbytes)
count = mp->m_super->s_maxbytes - offset;
end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
offset_fsb = XFS_B_TO_FSBT(mp, offset);
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
imap, &nimaps, bmapi_flags);
xfs_iunlock(ip, XFS_ILOCK_SHARED);
if (error)
return error;
if (type == XFS_IO_DELALLOC &&
(!nimaps || isnullstartblock(imap->br_startblock))) {
error = xfs_iomap_write_allocate(ip, offset, imap);
if (!error)
trace_xfs_map_blocks_alloc(ip, offset, count, type, imap);
return error;
}
#ifdef DEBUG
if (type == XFS_IO_UNWRITTEN) {
ASSERT(nimaps);
ASSERT(imap->br_startblock != HOLESTARTBLOCK);
ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
}
#endif
if (nimaps)
trace_xfs_map_blocks_found(ip, offset, count, type, imap);
return 0;
}
STATIC bool
xfs_imap_valid(
struct inode *inode,
struct xfs_bmbt_irec *imap,
xfs_off_t offset)
{
offset >>= inode->i_blkbits;
return offset >= imap->br_startoff &&
offset < imap->br_startoff + imap->br_blockcount;
}
/*
* BIO completion handler for buffered IO.
*/
STATIC void
xfs_end_bio(
struct bio *bio)
{
xfs_ioend_t *ioend = bio->bi_private;
if (!ioend->io_error)
ioend->io_error = bio->bi_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);
}
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;
submit_bio(wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE, bio);
}
STATIC struct bio *
xfs_alloc_ioend_bio(
struct buffer_head *bh)
{
struct bio *bio = bio_alloc(GFP_NOIO, BIO_MAX_PAGES);
ASSERT(bio->bi_private == NULL);
bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9);
bio->bi_bdev = bh->b_bdev;
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)
{
ASSERT(PageLocked(page));
ASSERT(!PageWriteback(page));
/*
* if the page was not fully cleaned, we need to ensure that the higher
* layers come back to it correctly. That means we need to keep the page
* dirty, and for WB_SYNC_ALL writeback we need to ensure the
* PAGECACHE_TAG_TOWRITE index mark is not removed so another attempt to
* write this page in this writeback sweep will be made.
*/
if (clear_dirty) {
clear_page_dirty_for_io(page);
set_page_writeback(page);
} else
set_page_writeback_keepwrite(page);
unlock_page(page);
}
static inline int xfs_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 an ioend. We are only passed a single ioend at a
* time; the caller is responsible for chaining prior to submission.
*
* If @fail is non-zero, it means that we have a situation where some part of
* the submission process has failed after we have marked paged for writeback
* and unlocked them. In this situation, we need to fail the ioend chain rather
* than submit it to IO. This typically only happens on a filesystem shutdown.
*/
STATIC int
xfs_submit_ioend(
struct writeback_control *wbc,
xfs_ioend_t *ioend,
int status)
{
struct buffer_head *bh;
struct bio *bio;
sector_t lastblock = 0;
/* Reserve log space if we might write beyond the on-disk inode size. */
if (!status &&
ioend->io_type != XFS_IO_UNWRITTEN && xfs_ioend_is_append(ioend))
status = xfs_setfilesize_trans_alloc(ioend);
/*
* If we are failing the IO now, just mark the ioend with an
* error and finish it. This will run IO completion immediately
* as there is only one reference to the ioend at this point in
* time.
*/
if (status) {
ioend->io_error = status;
xfs_finish_ioend(ioend);
return status;
}
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 (xfs_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);
return 0;
}
/*
* 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 the ioend we finished off so that the caller can submit it
* once it has finished processing the dirty page.
*/
STATIC void
xfs_add_to_ioend(
struct inode *inode,
struct buffer_head *bh,
xfs_off_t offset,
struct xfs_writepage_ctx *wpc,
struct list_head *iolist)
{
if (!wpc->ioend || wpc->io_type != wpc->ioend->io_type ||
bh->b_blocknr != wpc->last_block + 1 ||
offset != wpc->ioend->io_offset + wpc->ioend->io_size) {
struct xfs_ioend *new;
if (wpc->ioend)
list_add(&wpc->ioend->io_list, iolist);
new = xfs_alloc_ioend(inode, wpc->io_type);
new->io_offset = offset;
new->io_buffer_head = bh;
new->io_buffer_tail = bh;
wpc->ioend = new;
} else {
wpc->ioend->io_buffer_tail->b_private = bh;
wpc->ioend->io_buffer_tail = bh;
}
bh->b_private = NULL;
wpc->ioend->io_size += bh->b_size;
wpc->last_block = bh->b_blocknr;
xfs_start_buffer_writeback(bh);
}
STATIC void
xfs_map_buffer(
struct inode *inode,
struct buffer_head *bh,
struct xfs_bmbt_irec *imap,
xfs_off_t offset)
{
sector_t bn;
struct xfs_mount *m = XFS_I(inode)->i_mount;
xfs_off_t iomap_offset = XFS_FSB_TO_B(m, imap->br_startoff);
xfs_daddr_t iomap_bn = xfs_fsb_to_db(XFS_I(inode), imap->br_startblock);
ASSERT(imap->br_startblock != HOLESTARTBLOCK);
ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
bn = (iomap_bn >> (inode->i_blkbits - BBSHIFT)) +
((offset - iomap_offset) >> inode->i_blkbits);
ASSERT(bn || XFS_IS_REALTIME_INODE(XFS_I(inode)));
bh->b_blocknr = bn;
set_buffer_mapped(bh);
}
STATIC void
xfs_map_at_offset(
struct inode *inode,
struct buffer_head *bh,
struct xfs_bmbt_irec *imap,
xfs_off_t offset)
{
ASSERT(imap->br_startblock != HOLESTARTBLOCK);
ASSERT(imap->br_startblock != DELAYSTARTBLOCK);
xfs_map_buffer(inode, bh, imap, offset);
set_buffer_mapped(bh);
clear_buffer_delay(bh);
clear_buffer_unwritten(bh);
}
/*
* Test if a given page contains at least one buffer of a given @type.
* If @check_all_buffers is true, then we walk all the buffers in the page to
* try to find one of the type passed in. If it is not set, then the caller only
* needs to check the first buffer on the page for a match.
*/
STATIC bool
xfs_check_page_type(
struct page *page,
unsigned int type,
bool check_all_buffers)
{
struct buffer_head *bh;
struct buffer_head *head;
if (PageWriteback(page))
return false;
if (!page->mapping)
return false;
if (!page_has_buffers(page))
return false;
bh = head = page_buffers(page);
do {
if (buffer_unwritten(bh)) {
if (type == XFS_IO_UNWRITTEN)
return true;
} else if (buffer_delay(bh)) {
if (type == XFS_IO_DELALLOC)
return true;
} else if (buffer_dirty(bh) && buffer_mapped(bh)) {
if (type == XFS_IO_OVERWRITE)
return true;
}
/* If we are only checking the first buffer, we are done now. */
if (!check_all_buffers)
break;
} while ((bh = bh->b_this_page) != head);
return false;
}
STATIC void
xfs_vm_invalidatepage(
struct page *page,
unsigned int offset,
unsigned int length)
{
trace_xfs_invalidatepage(page->mapping->host, page, offset,
length);
block_invalidatepage(page, offset, length);
}
/*
* 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);
if (!xfs_check_page_type(page, XFS_IO_DELALLOC, true))
goto out_invalidate;
if (XFS_FORCED_SHUTDOWN(ip->i_mount))
goto out_invalidate;
xfs_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 error;
xfs_fileoff_t start_fsb;
if (!buffer_delay(bh))
goto next_buffer;
start_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
error = xfs_bmap_punch_delalloc_range(ip, start_fsb, 1);
if (error) {
/* something screwed, just bail */
if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
xfs_alert(ip->i_mount,
"page discard unable to remove delalloc mapping.");
}
break;
}
next_buffer:
offset += 1 << inode->i_blkbits;
} while ((bh = bh->b_this_page) != head);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
out_invalidate:
xfs_vm_invalidatepage(page, 0, PAGE_SIZE);
return;
}
/*
* We implement an immediate ioend submission policy here to avoid needing to
* chain multiple ioends and hence nest mempool allocations which can violate
* forward progress guarantees we need to provide. The current ioend we are
* adding buffers to is cached on the writepage context, and if the new buffer
* does not append to the cached ioend it will create a new ioend and cache that
* instead.
*
* If a new ioend is created and cached, the old ioend is returned and queued
* locally for submission once the entire page is processed or an error has been
* detected. While ioends are submitted immediately after they are completed,
* batching optimisations are provided by higher level block plugging.
*
* At the end of a writeback pass, there will be a cached ioend remaining on the
* writepage context that the caller will need to submit.
*/
static int
xfs_writepage_map(
struct xfs_writepage_ctx *wpc,
struct writeback_control *wbc,
struct inode *inode,
struct page *page,
loff_t offset,
__uint64_t end_offset)
{
LIST_HEAD(submit_list);
struct xfs_ioend *ioend, *next;
struct buffer_head *bh, *head;
ssize_t len = 1 << inode->i_blkbits;
int error = 0;
int count = 0;
int uptodate = 1;
bh = head = page_buffers(page);
offset = page_offset(page);
do {
if (offset >= end_offset)
break;
if (!buffer_uptodate(bh))
uptodate = 0;
/*
* set_page_dirty dirties all buffers in a page, independent
* of their state. The dirty state however is entirely
* meaningless for holes (!mapped && uptodate), so skip
* buffers covering holes here.
*/
if (!buffer_mapped(bh) && buffer_uptodate(bh)) {
wpc->imap_valid = false;
continue;
}
if (buffer_unwritten(bh)) {
if (wpc->io_type != XFS_IO_UNWRITTEN) {
wpc->io_type = XFS_IO_UNWRITTEN;
wpc->imap_valid = false;
}
} else if (buffer_delay(bh)) {
if (wpc->io_type != XFS_IO_DELALLOC) {
wpc->io_type = XFS_IO_DELALLOC;
wpc->imap_valid = false;
}
} else if (buffer_uptodate(bh)) {
if (wpc->io_type != XFS_IO_OVERWRITE) {
wpc->io_type = XFS_IO_OVERWRITE;
wpc->imap_valid = false;
}
} else {
if (PageUptodate(page))
ASSERT(buffer_mapped(bh));
/*
* This buffer is not uptodate and will not be
* written to disk. Ensure that we will put any
* subsequent writeable buffers into a new
* ioend.
*/
wpc->imap_valid = false;
continue;
}
if (wpc->imap_valid)
wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap,
offset);
if (!wpc->imap_valid) {
error = xfs_map_blocks(inode, offset, &wpc->imap,
wpc->io_type);
if (error)
goto out;
wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap,
offset);
}
if (wpc->imap_valid) {
lock_buffer(bh);
if (wpc->io_type != XFS_IO_OVERWRITE)
xfs_map_at_offset(inode, bh, &wpc->imap, offset);
xfs_add_to_ioend(inode, bh, offset, wpc, &submit_list);
count++;
}
} while (offset += len, ((bh = bh->b_this_page) != head));
if (uptodate && bh == head)
SetPageUptodate(page);
ASSERT(wpc->ioend || list_empty(&submit_list));
out:
/*
* On error, we have to fail the ioend here because we have locked
* buffers in the ioend. If we don't do this, we'll deadlock
* invalidating the page as that tries to lock the buffers on the page.
* Also, because we may have set pages under writeback, we have to make
* sure we run IO completion to mark the error state of the IO
* appropriately, so we can't cancel the ioend directly here. That means
* we have to mark this page as under writeback if we included any
* buffers from it in the ioend chain so that completion treats it
* correctly.
*
* If we didn't include the page in the ioend, the on error we can
* simply discard and unlock it as there are no other users of the page
* or it's buffers right now. The caller will still need to trigger
* submission of outstanding ioends on the writepage context so they are
* treated correctly on error.
*/
if (count) {
xfs_start_page_writeback(page, !error);
/*
* Preserve the original error if there was one, otherwise catch
* submission errors here and propagate into subsequent ioend
* submissions.
*/
list_for_each_entry_safe(ioend, next, &submit_list, io_list) {
int error2;
list_del_init(&ioend->io_list);
error2 = xfs_submit_ioend(wbc, ioend, error);
if (error2 && !error)
error = error2;
}
} else if (error) {
xfs_aops_discard_page(page);
ClearPageUptodate(page);
unlock_page(page);
} else {
/*
* We can end up here with no error and nothing to write if we
* race with a partial page truncate on a sub-page block sized
* filesystem. In that case we need to mark the page clean.
*/
xfs_start_page_writeback(page, 1);
end_page_writeback(page);
}
mapping_set_error(page->mapping, error);
return error;
}
/*
* Write out a dirty page.
*
* For delalloc space on the page we need to allocate space and flush it.
* For unwritten space on the page we need to start the conversion to
* regular allocated space.
* For any other dirty buffer heads on the page we should flush them.
*/
STATIC int
xfs_do_writepage(
struct page *page,
struct writeback_control *wbc,
void *data)
{
struct xfs_writepage_ctx *wpc = data;
struct inode *inode = page->mapping->host;
loff_t offset;
__uint64_t end_offset;
pgoff_t end_index;
trace_xfs_writepage(inode, page, 0, 0);
ASSERT(page_has_buffers(page));
/*
* Refuse to write the page out if we are called from reclaim context.
*
* This avoids stack overflows when called from deeply used stacks in
* random callers for direct reclaim or memcg reclaim. We explicitly
* allow reclaim from kswapd as the stack usage there is relatively low.
*
* This should never happen except in the case of a VM regression so
* warn about it.
*/
if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) ==
PF_MEMALLOC))
goto redirty;
/*
* Given that we do not allow direct reclaim to call us, we should
* never be called while in a filesystem transaction.
*/
if (WARN_ON_ONCE(current->flags & PF_FSTRANS))
goto redirty;
/*
* Is this page beyond the end of the file?
*
* The page index is less than the end_index, adjust the end_offset
* to the highest offset that this page should represent.
* -----------------------------------------------------
* | file mapping | <EOF> |
* -----------------------------------------------------
* | Page ... | Page N-2 | Page N-1 | Page N | |
* ^--------------------------------^----------|--------
* | desired writeback range | see else |
* ---------------------------------^------------------|
*/
offset = i_size_read(inode);
end_index = offset >> PAGE_SHIFT;
if (page->index < end_index)
end_offset = (xfs_off_t)(page->index + 1) << PAGE_SHIFT;
else {
/*
* Check whether the page to write out is beyond or straddles
* i_size or not.
* -------------------------------------------------------
* | file mapping | <EOF> |
* -------------------------------------------------------
* | Page ... | Page N-2 | Page N-1 | Page N | Beyond |
* ^--------------------------------^-----------|---------
* | | Straddles |
* ---------------------------------^-----------|--------|
*/
unsigned offset_into_page = offset & (PAGE_SIZE - 1);
/*
* Skip the page if it is fully outside i_size, e.g. due to a
* truncate operation that is in progress. We must redirty the
* page so that reclaim stops reclaiming it. Otherwise
* xfs_vm_releasepage() is called on it and gets confused.
*
* Note that the end_index is unsigned long, it would overflow
* if the given offset is greater than 16TB on 32-bit system
* and if we do check the page is fully outside i_size or not
* via "if (page->index >= end_index + 1)" as "end_index + 1"
* will be evaluated to 0. Hence this page will be redirtied
* and be written out repeatedly which would result in an
* infinite loop, the user program that perform this operation
* will hang. Instead, we can verify this situation by checking
* if the page to write is totally beyond the i_size or if it's
* offset is just equal to the EOF.
*/
if (page->index > end_index ||
(page->index == end_index && offset_into_page == 0))
goto redirty;
/*
* The page straddles i_size. It must be zeroed out on each
* and every writepage invocation because it may be mmapped.
* "A file is mapped in multiples of the page size. For a file
* that is not a multiple of the page size, the remaining
* memory is zeroed when mapped, and writes to that region are
* not written out to the file."
*/
zero_user_segment(page, offset_into_page, PAGE_SIZE);
/* Adjust the end_offset to the end of file */
end_offset = offset;
}
return xfs_writepage_map(wpc, wbc, inode, page, offset, end_offset);
redirty:
redirty_page_for_writepage(wbc, page);
unlock_page(page);
return 0;
}
STATIC int
xfs_vm_writepage(
struct page *page,
struct writeback_control *wbc)
{
struct xfs_writepage_ctx wpc = {
.io_type = XFS_IO_INVALID,
};
int ret;
ret = xfs_do_writepage(page, wbc, &wpc);
if (wpc.ioend)
ret = xfs_submit_ioend(wbc, wpc.ioend, ret);
return ret;
}
STATIC int
xfs_vm_writepages(
struct address_space *mapping,
struct writeback_control *wbc)
{
struct xfs_writepage_ctx wpc = {
.io_type = XFS_IO_INVALID,
};
int ret;
xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
if (dax_mapping(mapping))
return dax_writeback_mapping_range(mapping,
xfs_find_bdev_for_inode(mapping->host), wbc);
ret = write_cache_pages(mapping, wbc, xfs_do_writepage, &wpc);
if (wpc.ioend)
ret = xfs_submit_ioend(wbc, wpc.ioend, ret);
return ret;
}
/*
* Called to move a page into cleanable state - and from there
* to be released. The page should already be clean. We always
* have buffer heads in this call.
*
* Returns 1 if the page is ok to release, 0 otherwise.
*/
STATIC int
xfs_vm_releasepage(
struct page *page,
gfp_t gfp_mask)
{
int delalloc, unwritten;
trace_xfs_releasepage(page->mapping->host, page, 0, 0);
xfs_count_page_state(page, &delalloc, &unwritten);
if (WARN_ON_ONCE(delalloc))
return 0;
if (WARN_ON_ONCE(unwritten))
return 0;
return try_to_free_buffers(page);
}
/*
* When we map a DIO buffer, we may need to pass flags to
* xfs_end_io_direct_write to tell it what kind of write IO we are doing.
*
* Note that for DIO, an IO to the highest supported file block offset (i.e.
* 2^63 - 1FSB bytes) will result in the offset + count overflowing a signed 64
* bit variable. Hence if we see this overflow, we have to assume that the IO is
* extending the file size. We won't know for sure until IO completion is run
* and the actual max write offset is communicated to the IO completion
* routine.
*/
static void
xfs_map_direct(
struct inode *inode,
struct buffer_head *bh_result,
struct xfs_bmbt_irec *imap,
xfs_off_t offset)
{
uintptr_t *flags = (uintptr_t *)&bh_result->b_private;
xfs_off_t size = bh_result->b_size;
trace_xfs_get_blocks_map_direct(XFS_I(inode), offset, size,
ISUNWRITTEN(imap) ? XFS_IO_UNWRITTEN : XFS_IO_OVERWRITE, imap);
if (ISUNWRITTEN(imap)) {
*flags |= XFS_DIO_FLAG_UNWRITTEN;
set_buffer_defer_completion(bh_result);
} else if (offset + size > i_size_read(inode) || offset + size < 0) {
*flags |= XFS_DIO_FLAG_APPEND;
set_buffer_defer_completion(bh_result);
}
}
/*
* If this is O_DIRECT or the mpage code calling tell them how large the mapping
* is, so that we can avoid repeated get_blocks calls.
*
* If the mapping spans EOF, then we have to break the mapping up as the mapping
* for blocks beyond EOF must be marked new so that sub block regions can be
* correctly zeroed. We can't do this for mappings within EOF unless the mapping
* was just allocated or is unwritten, otherwise the callers would overwrite
* existing data with zeros. Hence we have to split the mapping into a range up
* to and including EOF, and a second mapping for beyond EOF.
*/
static void
xfs_map_trim_size(
struct inode *inode,
sector_t iblock,
struct buffer_head *bh_result,
struct xfs_bmbt_irec *imap,
xfs_off_t offset,
ssize_t size)
{
xfs_off_t mapping_size;
mapping_size = imap->br_startoff + imap->br_blockcount - iblock;
mapping_size <<= inode->i_blkbits;
ASSERT(mapping_size > 0);
if (mapping_size > size)
mapping_size = size;
if (offset < i_size_read(inode) &&
offset + mapping_size >= i_size_read(inode)) {
/* limit mapping to block that spans EOF */
mapping_size = roundup_64(i_size_read(inode) - offset,
1 << inode->i_blkbits);
}
if (mapping_size > LONG_MAX)
mapping_size = LONG_MAX;
bh_result->b_size = mapping_size;
}
STATIC int
__xfs_get_blocks(
struct inode *inode,
sector_t iblock,
struct buffer_head *bh_result,
int create,
bool direct,
bool dax_fault)
{
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
xfs_fileoff_t offset_fsb, end_fsb;
int error = 0;
int lockmode = 0;
struct xfs_bmbt_irec imap;
int nimaps = 1;
xfs_off_t offset;
ssize_t size;
int new = 0;
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
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;
/*
* Direct I/O is usually done on preallocated files, so try getting
* a block mapping without an exclusive lock first. For buffered
* writes we already have the exclusive iolock anyway, so avoiding
* a lock roundtrip here by taking the ilock exclusive from the
* beginning is a useful micro optimization.
*/
if (create && !direct) {
lockmode = XFS_ILOCK_EXCL;
xfs_ilock(ip, lockmode);
} else {
lockmode = xfs_ilock_data_map_shared(ip);
}
ASSERT(offset <= mp->m_super->s_maxbytes);
if (offset + size > mp->m_super->s_maxbytes)
size = mp->m_super->s_maxbytes - offset;
end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + size);
offset_fsb = XFS_B_TO_FSBT(mp, offset);
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
&imap, &nimaps, XFS_BMAPI_ENTIRE);
if (error)
goto out_unlock;
/* for DAX, we convert unwritten extents directly */
if (create &&
(!nimaps ||
(imap.br_startblock == HOLESTARTBLOCK ||
imap.br_startblock == DELAYSTARTBLOCK) ||
(IS_DAX(inode) && ISUNWRITTEN(&imap)))) {
if (direct || xfs_get_extsz_hint(ip)) {
/*
* xfs_iomap_write_direct() expects the shared lock. It
* is unlocked on return.
*/
if (lockmode == XFS_ILOCK_EXCL)
xfs_ilock_demote(ip, lockmode);
error = xfs_iomap_write_direct(ip, offset, size,
&imap, nimaps);
if (error)
return error;
new = 1;
} else {
/*
* Delalloc reservations do not require a transaction,
* we can go on without dropping the lock here. If we
* are allocating a new delalloc block, make sure that
* we set the new flag so that we mark the buffer new so
* that we know that it is newly allocated if the write
* fails.
*/
if (nimaps && imap.br_startblock == HOLESTARTBLOCK)
new = 1;
error = xfs_iomap_write_delay(ip, offset, size, &imap);
if (error)
goto out_unlock;
xfs_iunlock(ip, lockmode);
}
trace_xfs_get_blocks_alloc(ip, offset, size,
ISUNWRITTEN(&imap) ? XFS_IO_UNWRITTEN
: XFS_IO_DELALLOC, &imap);
} else if (nimaps) {
trace_xfs_get_blocks_found(ip, offset, size,
ISUNWRITTEN(&imap) ? XFS_IO_UNWRITTEN
: XFS_IO_OVERWRITE, &imap);
xfs_iunlock(ip, lockmode);
} else {
trace_xfs_get_blocks_notfound(ip, offset, size);
goto out_unlock;
}
if (IS_DAX(inode) && create) {
ASSERT(!ISUNWRITTEN(&imap));
/* zeroing is not needed at a higher layer */
new = 0;
}
/* trim mapping down to size requested */
if (direct || size > (1 << inode->i_blkbits))
xfs_map_trim_size(inode, iblock, bh_result,
&imap, offset, size);
/*
* For unwritten extents do not report a disk address in the buffered
* read case (treat as if we're reading into a hole).
*/
if (imap.br_startblock != HOLESTARTBLOCK &&
imap.br_startblock != DELAYSTARTBLOCK &&
(create || !ISUNWRITTEN(&imap))) {
xfs_map_buffer(inode, bh_result, &imap, offset);
if (ISUNWRITTEN(&imap))
set_buffer_unwritten(bh_result);
/* direct IO needs special help */
if (create && direct) {
if (dax_fault)
ASSERT(!ISUNWRITTEN(&imap));
else
xfs_map_direct(inode, bh_result, &imap, offset);
}
}
/*
* 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 = xfs_find_bdev_for_inode(inode);
/*
* 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)) ||
(new || ISUNWRITTEN(&imap))))
set_buffer_new(bh_result);
if (imap.br_startblock == DELAYSTARTBLOCK) {
BUG_ON(direct);
if (create) {
set_buffer_uptodate(bh_result);
set_buffer_mapped(bh_result);
set_buffer_delay(bh_result);
}
}
return 0;
out_unlock:
xfs_iunlock(ip, lockmode);
return error;
}
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, false, false);
}
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, true, false);
}
int
xfs_get_blocks_dax_fault(
struct inode *inode,
sector_t iblock,
struct buffer_head *bh_result,
int create)
{
return __xfs_get_blocks(inode, iblock, bh_result, create, true, true);
}
/*
* Complete a direct I/O write request.
*
* xfs_map_direct passes us some flags in the private data to tell us what to
* do. If no flags are set, then the write IO is an overwrite wholly within
* the existing allocated file size and so there is nothing for us to do.
*
* Note that in this case the completion can be called in interrupt context,
* whereas if we have flags set we will always be called in task context
* (i.e. from a workqueue).
*/
STATIC int
xfs_end_io_direct_write(
struct kiocb *iocb,
loff_t offset,
ssize_t size,
void *private)
{
struct inode *inode = file_inode(iocb->ki_filp);
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
uintptr_t flags = (uintptr_t)private;
int error = 0;
trace_xfs_end_io_direct_write(ip, offset, size);
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
if (size <= 0)
return size;
/*
* The flags tell us whether we are doing unwritten extent conversions
* or an append transaction that updates the on-disk file size. These
* cases are the only cases where we should *potentially* be needing
* to update the VFS inode size.
*/
if (flags == 0) {
ASSERT(offset + size <= i_size_read(inode));
return 0;
}
/*
* We need to update the in-core inode size here so that we don't end up
* with the on-disk inode size being outside the in-core inode size. We
* have no other method of updating EOF for AIO, so always do it here
* if necessary.
*
* We need to lock the test/set EOF update as we can be racing with
* other IO completions here to update the EOF. Failing to serialise
* here can result in EOF moving backwards and Bad Things Happen when
* that occurs.
*/
spin_lock(&ip->i_flags_lock);
if (offset + size > i_size_read(inode))
i_size_write(inode, offset + size);
spin_unlock(&ip->i_flags_lock);
if (flags & XFS_DIO_FLAG_UNWRITTEN) {
trace_xfs_end_io_direct_write_unwritten(ip, offset, size);
error = xfs_iomap_write_unwritten(ip, offset, size);
} else if (flags & XFS_DIO_FLAG_APPEND) {
struct xfs_trans *tp;
trace_xfs_end_io_direct_write_append(ip, offset, size);
tp = xfs_trans_alloc(mp, XFS_TRANS_FSYNC_TS);
error = xfs_trans_reserve(tp, &M_RES(mp)->tr_fsyncts, 0, 0);
if (error) {
xfs_trans_cancel(tp);
return error;
}
error = xfs_setfilesize(ip, tp, offset, size);
}
return error;
}
STATIC ssize_t
xfs_vm_direct_IO(
struct kiocb *iocb,
struct iov_iter *iter,
loff_t offset)
{
struct inode *inode = iocb->ki_filp->f_mapping->host;
dio_iodone_t *endio = NULL;
int flags = 0;
struct block_device *bdev;
if (iov_iter_rw(iter) == WRITE) {
endio = xfs_end_io_direct_write;
flags = DIO_ASYNC_EXTEND;
}
if (IS_DAX(inode)) {
return dax_do_io(iocb, inode, iter, offset,
xfs_get_blocks_direct, endio, 0);
}
bdev = xfs_find_bdev_for_inode(inode);
return __blockdev_direct_IO(iocb, inode, bdev, iter, offset,
xfs_get_blocks_direct, endio, NULL, flags);
}
/*
* Punch out the delalloc blocks we have already allocated.
*
* Don't bother with xfs_setattr given that nothing can have made it to disk yet
* as the page is still locked at this point.
*/
STATIC void
xfs_vm_kill_delalloc_range(
struct inode *inode,
loff_t start,
loff_t end)
{
struct xfs_inode *ip = XFS_I(inode);
xfs_fileoff_t start_fsb;
xfs_fileoff_t end_fsb;
int error;
start_fsb = XFS_B_TO_FSB(ip->i_mount, start);
end_fsb = XFS_B_TO_FSB(ip->i_mount, end);
if (end_fsb <= start_fsb)
return;
xfs_ilock(ip, XFS_ILOCK_EXCL);
error = xfs_bmap_punch_delalloc_range(ip, start_fsb,
end_fsb - start_fsb);
if (error) {
/* something screwed, just bail */
if (!XFS_FORCED_SHUTDOWN(ip->i_mount)) {
xfs_alert(ip->i_mount,
"xfs_vm_write_failed: unable to clean up ino %lld",
ip->i_ino);
}
}
xfs_iunlock(ip, XFS_ILOCK_EXCL);
}
STATIC void
xfs_vm_write_failed(
struct inode *inode,
struct page *page,
loff_t pos,
unsigned len)
{
loff_t block_offset;
loff_t block_start;
loff_t block_end;
loff_t from = pos & (PAGE_SIZE - 1);
loff_t to = from + len;
struct buffer_head *bh, *head;
struct xfs_mount *mp = XFS_I(inode)->i_mount;
/*
* The request pos offset might be 32 or 64 bit, this is all fine
* on 64-bit platform. However, for 64-bit pos request on 32-bit
* platform, the high 32-bit will be masked off if we evaluate the
* block_offset via (pos & PAGE_MASK) because the PAGE_MASK is
* 0xfffff000 as an unsigned long, hence the result is incorrect
* which could cause the following ASSERT failed in most cases.
* In order to avoid this, we can evaluate the block_offset of the
* start of the page by using shifts rather than masks the mismatch
* problem.
*/
block_offset = (pos >> PAGE_SHIFT) << PAGE_SHIFT;
ASSERT(block_offset + from == pos);
head = page_buffers(page);
block_start = 0;
for (bh = head; bh != head || !block_start;
bh = bh->b_this_page, block_start = block_end,
block_offset += bh->b_size) {
block_end = block_start + bh->b_size;
/* skip buffers before the write */
if (block_end <= from)
continue;
/* if the buffer is after the write, we're done */
if (block_start >= to)
break;
/*
* Process delalloc and unwritten buffers beyond EOF. We can
* encounter unwritten buffers in the event that a file has
* post-EOF unwritten extents and an extending write happens to
* fail (e.g., an unaligned write that also involves a delalloc
* to the same page).
*/
if (!buffer_delay(bh) && !buffer_unwritten(bh))
continue;
if (!xfs_mp_fail_writes(mp) && !buffer_new(bh) &&
block_offset < i_size_read(inode))
continue;
if (buffer_delay(bh))
xfs_vm_kill_delalloc_range(inode, block_offset,
block_offset + bh->b_size);
/*
* This buffer does not contain data anymore. make sure anyone
* who finds it knows that for certain.
*/
clear_buffer_delay(bh);
clear_buffer_uptodate(bh);
clear_buffer_mapped(bh);
clear_buffer_new(bh);
clear_buffer_dirty(bh);
clear_buffer_unwritten(bh);
}
}
/*
* This used to call block_write_begin(), but it unlocks and releases the page
* on error, and we need that page to be able to punch stale delalloc blocks out
* on failure. hence we copy-n-waste it here and call xfs_vm_write_failed() at
* the appropriate point.
*/
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)
{
pgoff_t index = pos >> PAGE_SHIFT;
struct page *page;
int status;
struct xfs_mount *mp = XFS_I(mapping->host)->i_mount;
ASSERT(len <= PAGE_SIZE);
page = grab_cache_page_write_begin(mapping, index, flags);
if (!page)
return -ENOMEM;
status = __block_write_begin(page, pos, len, xfs_get_blocks);
if (xfs_mp_fail_writes(mp))
status = -EIO;
if (unlikely(status)) {
struct inode *inode = mapping->host;
size_t isize = i_size_read(inode);
xfs_vm_write_failed(inode, page, pos, len);
unlock_page(page);
/*
* If the write is beyond EOF, we only want to kill blocks
* allocated in this write, not blocks that were previously
* written successfully.
*/
if (xfs_mp_fail_writes(mp))
isize = 0;
if (pos + len > isize) {
ssize_t start = max_t(ssize_t, pos, isize);
truncate_pagecache_range(inode, start, pos + len);
}
put_page(page);
page = NULL;
}
*pagep = page;
return status;
}
/*
* On failure, we only need to kill delalloc blocks beyond EOF in the range of
* this specific write because they will never be written. Previous writes
* beyond EOF where block allocation succeeded do not need to be trashed, so
* only new blocks from this write should be trashed. For blocks within
* EOF, generic_write_end() zeros them so they are safe to leave alone and be
* written with all the other valid data.
*/
STATIC int
xfs_vm_write_end(
struct file *file,
struct address_space *mapping,
loff_t pos,
unsigned len,
unsigned copied,
struct page *page,
void *fsdata)
{
int ret;
ASSERT(len <= PAGE_SIZE);
ret = generic_write_end(file, mapping, pos, len, copied, page, fsdata);
if (unlikely(ret < len)) {
struct inode *inode = mapping->host;
size_t isize = i_size_read(inode);
loff_t to = pos + len;
if (to > isize) {
/* only kill blocks in this write beyond EOF */
if (pos > isize)
isize = pos;
xfs_vm_kill_delalloc_range(inode, isize, to);
truncate_pagecache_range(inode, isize, to);
}
}
return ret;
}
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);
trace_xfs_vm_bmap(XFS_I(inode));
xfs_ilock(ip, XFS_IOLOCK_SHARED);
filemap_write_and_wait(mapping);
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)
{
trace_xfs_vm_readpage(page->mapping->host, 1);
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)
{
trace_xfs_vm_readpages(mapping->host, nr_pages);
return mpage_readpages(mapping, pages, nr_pages, xfs_get_blocks);
}
/*
* This is basically a copy of __set_page_dirty_buffers() with one
* small tweak: buffers beyond EOF do not get marked dirty. If we mark them
* dirty, we'll never be able to clean them because we don't write buffers
* beyond EOF, and that means we can't invalidate pages that span EOF
* that have been marked dirty. Further, the dirty state can leak into
* the file interior if the file is extended, resulting in all sorts of
* bad things happening as the state does not match the underlying data.
*
* XXX: this really indicates that bufferheads in XFS need to die. Warts like
* this only exist because of bufferheads and how the generic code manages them.
*/
STATIC int
xfs_vm_set_page_dirty(
struct page *page)
{
struct address_space *mapping = page->mapping;
struct inode *inode = mapping->host;
loff_t end_offset;
loff_t offset;
int newly_dirty;
if (unlikely(!mapping))
return !TestSetPageDirty(page);
end_offset = i_size_read(inode);
offset = page_offset(page);
spin_lock(&mapping->private_lock);
if (page_has_buffers(page)) {
struct buffer_head *head = page_buffers(page);
struct buffer_head *bh = head;
do {
if (offset < end_offset)
set_buffer_dirty(bh);
bh = bh->b_this_page;
offset += 1 << inode->i_blkbits;
} while (bh != head);
}
/*
* Lock out page->mem_cgroup migration to keep PageDirty
* synchronized with per-memcg dirty page counters.
*/
lock_page_memcg(page);
newly_dirty = !TestSetPageDirty(page);
spin_unlock(&mapping->private_lock);
if (newly_dirty) {
/* sigh - __set_page_dirty() is static, so copy it here, too */
unsigned long flags;
spin_lock_irqsave(&mapping->tree_lock, flags);
if (page->mapping) { /* Race with truncate? */
WARN_ON_ONCE(!PageUptodate(page));
account_page_dirtied(page, mapping);
radix_tree_tag_set(&mapping->page_tree,
page_index(page), PAGECACHE_TAG_DIRTY);
}
spin_unlock_irqrestore(&mapping->tree_lock, flags);
}
unlock_page_memcg(page);
if (newly_dirty)
__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
return newly_dirty;
}
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,
.set_page_dirty = xfs_vm_set_page_dirty,
.releasepage = xfs_vm_releasepage,
.invalidatepage = xfs_vm_invalidatepage,
.write_begin = xfs_vm_write_begin,
.write_end = xfs_vm_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,
};
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