linux/fs/xfs/xfs_aops.c
Linus Torvalds 9e239bb939 Lots of bug fixes, cleanups and optimizations. In the bug fixes
category, of note is a fix for on-line resizing file systems where the
 block size is smaller than the page size (i.e., file systems 1k blocks
 on x86, or more interestingly file systems with 4k blocks on Power or
 ia64 systems.)
 
 In the cleanup category, the ext4's punch hole implementation was
 significantly improved by Lukas Czerner, and now supports bigalloc
 file systems.  In addition, Jan Kara significantly cleaned up the
 write submission code path.  We also improved error checking and added
 a few sanity checks.
 
 In the optimizations category, two major optimizations deserve
 mention.  The first is that ext4_writepages() is now used for
 nodelalloc and ext3 compatibility mode.  This allows writes to be
 submitted much more efficiently as a single bio request, instead of
 being sent as individual 4k writes into the block layer (which then
 relied on the elevator code to coalesce the requests in the block
 queue).  Secondly, the extent cache shrink mechanism, which was
 introduce in 3.9, no longer has a scalability bottleneck caused by the
 i_es_lru spinlock.  Other optimizations include some changes to reduce
 CPU usage and to avoid issuing empty commits unnecessarily.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4

Pull ext4 update from Ted Ts'o:
 "Lots of bug fixes, cleanups and optimizations.  In the bug fixes
  category, of note is a fix for on-line resizing file systems where the
  block size is smaller than the page size (i.e., file systems 1k blocks
  on x86, or more interestingly file systems with 4k blocks on Power or
  ia64 systems.)

  In the cleanup category, the ext4's punch hole implementation was
  significantly improved by Lukas Czerner, and now supports bigalloc
  file systems.  In addition, Jan Kara significantly cleaned up the
  write submission code path.  We also improved error checking and added
  a few sanity checks.

  In the optimizations category, two major optimizations deserve
  mention.  The first is that ext4_writepages() is now used for
  nodelalloc and ext3 compatibility mode.  This allows writes to be
  submitted much more efficiently as a single bio request, instead of
  being sent as individual 4k writes into the block layer (which then
  relied on the elevator code to coalesce the requests in the block
  queue).  Secondly, the extent cache shrink mechanism, which was
  introduce in 3.9, no longer has a scalability bottleneck caused by the
  i_es_lru spinlock.  Other optimizations include some changes to reduce
  CPU usage and to avoid issuing empty commits unnecessarily."

* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (86 commits)
  ext4: optimize starting extent in ext4_ext_rm_leaf()
  jbd2: invalidate handle if jbd2_journal_restart() fails
  ext4: translate flag bits to strings in tracepoints
  ext4: fix up error handling for mpage_map_and_submit_extent()
  jbd2: fix theoretical race in jbd2__journal_restart
  ext4: only zero partial blocks in ext4_zero_partial_blocks()
  ext4: check error return from ext4_write_inline_data_end()
  ext4: delete unnecessary C statements
  ext3,ext4: don't mess with dir_file->f_pos in htree_dirblock_to_tree()
  jbd2: move superblock checksum calculation to jbd2_write_superblock()
  ext4: pass inode pointer instead of file pointer to punch hole
  ext4: improve free space calculation for inline_data
  ext4: reduce object size when !CONFIG_PRINTK
  ext4: improve extent cache shrink mechanism to avoid to burn CPU time
  ext4: implement error handling of ext4_mb_new_preallocation()
  ext4: fix corruption when online resizing a fs with 1K block size
  ext4: delete unused variables
  ext4: return FIEMAP_EXTENT_UNKNOWN for delalloc extents
  jbd2: remove debug dependency on debug_fs and update Kconfig help text
  jbd2: use a single printk for jbd_debug()
  ...
2013-07-02 09:39:34 -07:00

1681 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_log.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_trans.h"
#include "xfs_mount.h"
#include "xfs_bmap_btree.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_alloc.h"
#include "xfs_error.h"
#include "xfs_iomap.h"
#include "xfs_vnodeops.h"
#include "xfs_trace.h"
#include "xfs_bmap.h"
#include <linux/aio.h>
#include <linux/gfp.h>
#include <linux/mpage.h>
#include <linux/pagevec.h>
#include <linux/writeback.h>
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);
}
STATIC 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);
}
if (ioend->io_iocb) {
inode_dio_done(ioend->io_inode);
if (ioend->io_isasync) {
aio_complete(ioend->io_iocb, ioend->io_error ?
ioend->io_error : ioend->io_result, 0);
}
}
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, 0, XFS_FSYNC_TS_LOG_RES(mp), 0, 0, 0);
if (error) {
xfs_trans_cancel(tp, 0);
return error;
}
ioend->io_append_trans = tp;
/*
* We may pass freeze protection with a transaction. So tell lockdep
* we released it.
*/
rwsem_release(&ioend->io_inode->i_sb->s_writers.lock_map[SB_FREEZE_FS-1],
1, _THIS_IP_);
/*
* 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_ioend *ioend)
{
struct xfs_inode *ip = XFS_I(ioend->io_inode);
struct xfs_trans *tp = ioend->io_append_trans;
xfs_fsize_t isize;
/*
* The transaction may have been allocated in the I/O submission thread,
* thus we need to mark ourselves as beeing in a transaction manually.
* Similarly for freeze protection.
*/
current_set_flags_nested(&tp->t_pflags, PF_FSTRANS);
rwsem_acquire_read(&VFS_I(ip)->i_sb->s_writers.lock_map[SB_FREEZE_FS-1],
0, 1, _THIS_IP_);
xfs_ilock(ip, XFS_ILOCK_EXCL);
isize = xfs_new_eof(ip, ioend->io_offset + ioend->io_size);
if (!isize) {
xfs_iunlock(ip, XFS_ILOCK_EXCL);
xfs_trans_cancel(tp, 0);
return 0;
}
trace_xfs_setfilesize(ip, ioend->io_offset, ioend->io_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, 0);
}
/*
* 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 ||
(ioend->io_isdirect && xfs_ioend_is_append(ioend)))
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;
if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
ioend->io_error = -EIO;
goto done;
}
if (ioend->io_error)
goto done;
/*
* 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 == XFS_IO_UNWRITTEN) {
error = xfs_iomap_write_unwritten(ip, ioend->io_offset,
ioend->io_size);
} else if (ioend->io_isdirect && xfs_ioend_is_append(ioend)) {
/*
* For direct I/O we do not know if we need to allocate blocks
* or not so we can't preallocate an append transaction as that
* results in nested reservations and log space deadlocks. Hence
* allocate the transaction here. While this is sub-optimal and
* can block IO completion for some time, we're stuck with doing
* it this way until we can pass the ioend to the direct IO
* allocation callbacks and avoid nesting that way.
*/
error = xfs_setfilesize_trans_alloc(ioend);
if (error)
goto done;
error = xfs_setfilesize(ioend);
} else if (ioend->io_append_trans) {
error = xfs_setfilesize(ioend);
} else {
ASSERT(!xfs_ioend_is_append(ioend));
}
done:
if (error)
ioend->io_error = -error;
xfs_destroy_ioend(ioend);
}
/*
* Call IO completion handling in caller context on the final put of an ioend.
*/
STATIC void
xfs_finish_ioend_sync(
struct xfs_ioend *ioend)
{
if (atomic_dec_and_test(&ioend->io_remaining))
xfs_end_io(&ioend->io_work);
}
/*
* 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_isasync = 0;
ioend->io_isdirect = 0;
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;
ioend->io_offset = 0;
ioend->io_size = 0;
ioend->io_iocb = NULL;
ioend->io_result = 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,
int nonblocking)
{
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 -XFS_ERROR(EIO);
if (type == XFS_IO_UNWRITTEN)
bmapi_flags |= XFS_BMAPI_IGSTATE;
if (!xfs_ilock_nowait(ip, XFS_ILOCK_SHARED)) {
if (nonblocking)
return -XFS_ERROR(EAGAIN);
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 -XFS_ERROR(error);
if (type == XFS_IO_DELALLOC &&
(!nimaps || isnullstartblock(imap->br_startblock))) {
error = xfs_iomap_write_allocate(ip, offset, count, imap);
if (!error)
trace_xfs_map_blocks_alloc(ip, offset, count, type, imap);
return -XFS_ERROR(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 int
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,
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);
}
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)
{
int nvecs = bio_get_nr_vecs(bh->b_bdev);
struct bio *bio = bio_alloc(GFP_NOIO, nvecs);
ASSERT(bio->bi_private == NULL);
bio->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,
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.
*
* 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 void
xfs_submit_ioend(
struct writeback_control *wbc,
xfs_ioend_t *ioend,
int fail)
{
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;
/*
* 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 (fail) {
ioend->io_error = -fail;
xfs_finish_ioend(ioend);
continue;
}
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);
} 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);
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 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 is suitable for writing as part of an unwritten
* or delayed allocate extent.
*/
STATIC int
xfs_check_page_type(
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 == XFS_IO_UNWRITTEN);
else if (buffer_delay(bh))
acceptable += (type == XFS_IO_DELALLOC);
else if (buffer_dirty(bh) && buffer_mapped(bh))
acceptable += (type == XFS_IO_OVERWRITE);
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,
struct xfs_bmbt_irec *imap,
xfs_ioend_t **ioendp,
struct writeback_control *wbc)
{
struct buffer_head *bh, *head;
xfs_off_t end_offset;
unsigned long p_offset;
unsigned int type;
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_check_page_type(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));
/*
* If the current map does not span the entire page we are about to try
* to write, then give up. The only way we can write a page that spans
* multiple mappings in a single writeback iteration is via the
* xfs_vm_writepage() function. Data integrity writeback requires the
* entire page to be written in a single attempt, otherwise the part of
* the page we don't write here doesn't get written as part of the data
* integrity sync.
*
* For normal writeback, we also don't attempt to write partial pages
* here as it simply means that write_cache_pages() will see it under
* writeback and ignore the page until some point in the future, at
* which time this will be the only page in the file that needs
* writeback. Hence for more optimal IO patterns, we should always
* avoid partial page writeback due to multiple mappings on a page here.
*/
if (!xfs_imap_valid(inode, imap, end_offset))
goto fail_unlock_page;
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) ||
buffer_mapped(bh)) {
if (buffer_unwritten(bh))
type = XFS_IO_UNWRITTEN;
else if (buffer_delay(bh))
type = XFS_IO_DELALLOC;
else
type = XFS_IO_OVERWRITE;
if (!xfs_imap_valid(inode, imap, offset)) {
done = 1;
continue;
}
lock_buffer(bh);
if (type != XFS_IO_OVERWRITE)
xfs_map_at_offset(inode, bh, imap, offset);
xfs_add_to_ioend(inode, bh, offset, type,
ioendp, done);
page_dirty--;
count++;
} else {
done = 1;
}
} while (offset += len, (bh = bh->b_this_page) != head);
if (uptodate && bh == head)
SetPageUptodate(page);
if (count) {
if (--wbc->nr_to_write <= 0 &&
wbc->sync_mode == WB_SYNC_NONE)
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,
struct xfs_bmbt_irec *imap,
xfs_ioend_t **ioendp,
struct writeback_control *wbc,
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++,
imap, ioendp, wbc);
if (done)
break;
}
pagevec_release(&pvec);
cond_resched();
}
}
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))
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_CACHE_SIZE);
return;
}
/*
* 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_vm_writepage(
struct page *page,
struct writeback_control *wbc)
{
struct inode *inode = page->mapping->host;
struct buffer_head *bh, *head;
struct xfs_bmbt_irec imap;
xfs_ioend_t *ioend = NULL, *iohead = NULL;
loff_t offset;
unsigned int type;
__uint64_t end_offset;
pgoff_t end_index, last_index;
ssize_t len;
int err, imap_valid = 0, uptodate = 1;
int count = 0;
int nonblocking = 0;
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(current->flags & PF_FSTRANS))
goto redirty;
/* 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) {
unsigned offset_into_page = offset & (PAGE_CACHE_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.
*/
if (page->index >= end_index + 1 || 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_CACHE_SIZE);
}
end_offset = min_t(unsigned long long,
(xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT,
offset);
len = 1 << inode->i_blkbits;
bh = head = page_buffers(page);
offset = page_offset(page);
type = XFS_IO_OVERWRITE;
if (wbc->sync_mode == WB_SYNC_NONE)
nonblocking = 1;
do {
int new_ioend = 0;
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)) {
imap_valid = 0;
continue;
}
if (buffer_unwritten(bh)) {
if (type != XFS_IO_UNWRITTEN) {
type = XFS_IO_UNWRITTEN;
imap_valid = 0;
}
} else if (buffer_delay(bh)) {
if (type != XFS_IO_DELALLOC) {
type = XFS_IO_DELALLOC;
imap_valid = 0;
}
} else if (buffer_uptodate(bh)) {
if (type != XFS_IO_OVERWRITE) {
type = XFS_IO_OVERWRITE;
imap_valid = 0;
}
} 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.
*/
imap_valid = 0;
continue;
}
if (imap_valid)
imap_valid = xfs_imap_valid(inode, &imap, offset);
if (!imap_valid) {
/*
* If we didn't have a valid mapping then we need to
* put the new mapping into a separate ioend structure.
* This ensures non-contiguous extents always have
* separate ioends, which is particularly important
* for unwritten extent conversion at I/O completion
* time.
*/
new_ioend = 1;
err = xfs_map_blocks(inode, offset, &imap, type,
nonblocking);
if (err)
goto error;
imap_valid = xfs_imap_valid(inode, &imap, offset);
}
if (imap_valid) {
lock_buffer(bh);
if (type != XFS_IO_OVERWRITE)
xfs_map_at_offset(inode, bh, &imap, offset);
xfs_add_to_ioend(inode, bh, offset, type, &ioend,
new_ioend);
count++;
}
if (!iohead)
iohead = ioend;
} while (offset += len, ((bh = bh->b_this_page) != head));
if (uptodate && bh == head)
SetPageUptodate(page);
xfs_start_page_writeback(page, 1, count);
/* if there is no IO to be submitted for this page, we are done */
if (!ioend)
return 0;
ASSERT(iohead);
/*
* Any errors from this point onwards need tobe reported through the IO
* completion path as we have marked the initial page as under writeback
* and unlocked it.
*/
if (imap_valid) {
xfs_off_t end_index;
end_index = imap.br_startoff + imap.br_blockcount;
/* to bytes */
end_index <<= inode->i_blkbits;
/* to pages */
end_index = (end_index - 1) >> PAGE_CACHE_SHIFT;
/* check against file size */
if (end_index > last_index)
end_index = last_index;
xfs_cluster_write(inode, page->index + 1, &imap, &ioend,
wbc, end_index);
}
/*
* Reserve log space if we might write beyond the on-disk inode size.
*/
err = 0;
if (ioend->io_type != XFS_IO_UNWRITTEN && xfs_ioend_is_append(ioend))
err = xfs_setfilesize_trans_alloc(ioend);
xfs_submit_ioend(wbc, iohead, err);
return 0;
error:
if (iohead)
xfs_cancel_ioend(iohead);
if (err == -EAGAIN)
goto redirty;
xfs_aops_discard_page(page);
ClearPageUptodate(page);
unlock_page(page);
return err;
redirty:
redirty_page_for_writepage(wbc, page);
unlock_page(page);
return 0;
}
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. 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(delalloc))
return 0;
if (WARN_ON(unwritten))
return 0;
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)
{
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 -XFS_ERROR(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_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;
if (create &&
(!nimaps ||
(imap.br_startblock == HOLESTARTBLOCK ||
imap.br_startblock == DELAYSTARTBLOCK))) {
if (direct || xfs_get_extsz_hint(ip)) {
/*
* Drop the ilock in preparation for starting the block
* allocation transaction. It will be retaken
* exclusively inside xfs_iomap_write_direct for the
* actual allocation.
*/
xfs_iunlock(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, 0, &imap);
} else if (nimaps) {
trace_xfs_get_blocks_found(ip, offset, size, 0, &imap);
xfs_iunlock(ip, lockmode);
} else {
trace_xfs_get_blocks_notfound(ip, offset, size);
goto out_unlock;
}
if (imap.br_startblock != HOLESTARTBLOCK &&
imap.br_startblock != DELAYSTARTBLOCK) {
/*
* For unwritten extents do not report a disk address on
* the read case (treat as if we're reading into a hole).
*/
if (create || !ISUNWRITTEN(&imap))
xfs_map_buffer(inode, bh_result, &imap, offset);
if (create && ISUNWRITTEN(&imap)) {
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 = 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);
}
}
/*
* 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 (direct || size > (1 << inode->i_blkbits)) {
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 (mapping_size > LONG_MAX)
mapping_size = LONG_MAX;
bh_result->b_size = mapping_size;
}
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, 0);
}
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);
}
/*
* Complete a direct I/O write request.
*
* If the private argument is non-NULL __xfs_get_blocks signals us that we
* need to issue a transaction to convert the range from unwritten to written
* extents. In case this is regular synchronous I/O we just call xfs_end_io
* to do this and we are done. But in case this was a successful AIO
* request this handler is called from interrupt context, from which we
* can't start transactions. In that case offload the I/O completion to
* the workqueues we also use for buffered I/O completion.
*/
STATIC void
xfs_end_io_direct_write(
struct kiocb *iocb,
loff_t offset,
ssize_t size,
void *private,
int ret,
bool is_async)
{
struct xfs_ioend *ioend = iocb->private;
/*
* While the generic direct I/O code updates the inode size, it does
* so only after the end_io handler is called, which means our
* end_io handler thinks the on-disk size is outside the in-core
* size. To prevent this just update it a little bit earlier here.
*/
if (offset + size > i_size_read(ioend->io_inode))
i_size_write(ioend->io_inode, offset + size);
/*
* 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;
ioend->io_offset = offset;
ioend->io_size = size;
ioend->io_iocb = iocb;
ioend->io_result = ret;
if (private && size > 0)
ioend->io_type = XFS_IO_UNWRITTEN;
if (is_async) {
ioend->io_isasync = 1;
xfs_finish_ioend(ioend);
} else {
xfs_finish_ioend_sync(ioend);
}
}
STATIC ssize_t
xfs_vm_direct_IO(
int rw,
struct kiocb *iocb,
const struct iovec *iov,
loff_t offset,
unsigned long nr_segs)
{
struct inode *inode = iocb->ki_filp->f_mapping->host;
struct block_device *bdev = xfs_find_bdev_for_inode(inode);
struct xfs_ioend *ioend = NULL;
ssize_t ret;
if (rw & WRITE) {
size_t size = iov_length(iov, nr_segs);
/*
* We cannot preallocate a size update transaction here as we
* don't know whether allocation is necessary or not. Hence we
* can only tell IO completion that one is necessary if we are
* not doing unwritten extent conversion.
*/
iocb->private = ioend = xfs_alloc_ioend(inode, XFS_IO_DIRECT);
if (offset + size > XFS_I(inode)->i_d.di_size)
ioend->io_isdirect = 1;
ret = __blockdev_direct_IO(rw, iocb, inode, bdev, iov,
offset, nr_segs,
xfs_get_blocks_direct,
xfs_end_io_direct_write, NULL, 0);
if (ret != -EIOCBQUEUED && iocb->private)
goto out_destroy_ioend;
} else {
ret = __blockdev_direct_IO(rw, iocb, inode, bdev, iov,
offset, nr_segs,
xfs_get_blocks_direct,
NULL, NULL, 0);
}
return ret;
out_destroy_ioend:
xfs_destroy_ioend(ioend);
return ret;
}
/*
* 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 = pos & PAGE_MASK;
loff_t block_start;
loff_t block_end;
loff_t from = pos & (PAGE_CACHE_SIZE - 1);
loff_t to = from + len;
struct buffer_head *bh, *head;
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;
if (!buffer_delay(bh))
continue;
if (!buffer_new(bh) && block_offset < i_size_read(inode))
continue;
xfs_vm_kill_delalloc_range(inode, block_offset,
block_offset + bh->b_size);
}
}
/*
* 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_CACHE_SHIFT;
struct page *page;
int status;
ASSERT(len <= PAGE_CACHE_SIZE);
page = grab_cache_page_write_begin(mapping, index,
flags | AOP_FLAG_NOFS);
if (!page)
return -ENOMEM;
status = __block_write_begin(page, pos, len, xfs_get_blocks);
if (unlikely(status)) {
struct inode *inode = mapping->host;
xfs_vm_write_failed(inode, page, pos, len);
unlock_page(page);
if (pos + len > i_size_read(inode))
truncate_pagecache(inode, pos + len, i_size_read(inode));
page_cache_release(page);
page = NULL;
}
*pagep = page;
return status;
}
/*
* On failure, we only need to kill delalloc blocks beyond EOF because they
* will never be written. 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_CACHE_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) {
truncate_pagecache(inode, to, isize);
xfs_vm_kill_delalloc_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)
{
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,
.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,
};