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Merge branch 'xfs-writepage-rework-4.6' into for-next

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This commit is contained in:
Dave Chinner 2016-03-07 09:34:02 +11:00
commit 3d93ec0364
2 changed files with 270 additions and 467 deletions
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733
fs/xfs/xfs_aops.c
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@ -40,6 +40,17 @@
#define XFS_DIO_FLAG_UNWRITTEN (1 << 0) #define XFS_DIO_FLAG_UNWRITTEN (1 << 0)
#define XFS_DIO_FLAG_APPEND (1 << 1) #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 void
xfs_count_page_state( xfs_count_page_state(
struct page *page, struct page *page,
@ -271,7 +282,7 @@ xfs_alloc_ioend(
*/ */
atomic_set(&ioend->io_remaining, 1); atomic_set(&ioend->io_remaining, 1);
ioend->io_error = 0; ioend->io_error = 0;
ioend->io_list = NULL; INIT_LIST_HEAD(&ioend->io_list);
ioend->io_type = type; ioend->io_type = type;
ioend->io_inode = inode; ioend->io_inode = inode;
ioend->io_buffer_head = NULL; ioend->io_buffer_head = NULL;
@ -289,8 +300,7 @@ xfs_map_blocks(
struct inode *inode, struct inode *inode,
loff_t offset, loff_t offset,
struct xfs_bmbt_irec *imap, struct xfs_bmbt_irec *imap,
int type, int type)
int nonblocking)
{ {
struct xfs_inode *ip = XFS_I(inode); struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount; struct xfs_mount *mp = ip->i_mount;
@ -306,12 +316,7 @@ xfs_map_blocks(
if (type == XFS_IO_UNWRITTEN) if (type == XFS_IO_UNWRITTEN)
bmapi_flags |= XFS_BMAPI_IGSTATE; bmapi_flags |= XFS_BMAPI_IGSTATE;
if (!xfs_ilock_nowait(ip, XFS_ILOCK_SHARED)) { xfs_ilock(ip, XFS_ILOCK_SHARED);
if (nonblocking)
return -EAGAIN;
xfs_ilock(ip, XFS_ILOCK_SHARED);
}
ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE || ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
(ip->i_df.if_flags & XFS_IFEXTENTS)); (ip->i_df.if_flags & XFS_IFEXTENTS));
ASSERT(offset <= mp->m_super->s_maxbytes); ASSERT(offset <= mp->m_super->s_maxbytes);
@ -347,7 +352,7 @@ xfs_map_blocks(
return 0; return 0;
} }
STATIC int STATIC bool
xfs_imap_valid( xfs_imap_valid(
struct inode *inode, struct inode *inode,
struct xfs_bmbt_irec *imap, struct xfs_bmbt_irec *imap,
@ -420,8 +425,7 @@ xfs_start_buffer_writeback(
STATIC void STATIC void
xfs_start_page_writeback( xfs_start_page_writeback(
struct page *page, struct page *page,
int clear_dirty, int clear_dirty)
int buffers)
{ {
ASSERT(PageLocked(page)); ASSERT(PageLocked(page));
ASSERT(!PageWriteback(page)); ASSERT(!PageWriteback(page));
@ -440,10 +444,6 @@ xfs_start_page_writeback(
set_page_writeback_keepwrite(page); set_page_writeback_keepwrite(page);
unlock_page(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 xfs_bio_add_buffer(struct bio *bio, struct buffer_head *bh) static inline int xfs_bio_add_buffer(struct bio *bio, struct buffer_head *bh)
@ -452,153 +452,101 @@ static inline int xfs_bio_add_buffer(struct bio *bio, struct buffer_head *bh)
} }
/* /*
* Submit all of the bios for all of the ioends we have saved up, covering the * Submit all of the bios for an ioend. We are only passed a single ioend at a
* initial writepage page and also any probed pages. * time; the caller is responsible for chaining prior to submission.
*
* 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 * 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 * 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 * 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. * than submit it to IO. This typically only happens on a filesystem shutdown.
*/ */
STATIC void STATIC int
xfs_submit_ioend( xfs_submit_ioend(
struct writeback_control *wbc, struct writeback_control *wbc,
xfs_ioend_t *ioend, xfs_ioend_t *ioend,
int fail) int status)
{ {
xfs_ioend_t *head = ioend;
xfs_ioend_t *next;
struct buffer_head *bh; struct buffer_head *bh;
struct bio *bio; struct bio *bio;
sector_t lastblock = 0; sector_t lastblock = 0;
/* Pass 1 - start writeback */ /* Reserve log space if we might write beyond the on-disk inode size. */
do { if (!status &&
next = ioend->io_list; ioend->io_type != XFS_IO_UNWRITTEN && xfs_ioend_is_append(ioend))
for (bh = ioend->io_buffer_head; bh; bh = bh->b_private) status = xfs_setfilesize_trans_alloc(ioend);
xfs_start_buffer_writeback(bh); /*
} while ((ioend = next) != NULL); * If we are failing the IO now, just mark the ioend with an
* error and finish it. This will run IO completion immediately
/* Pass 2 - submit I/O */ * as there is only one reference to the ioend at this point in
ioend = head; * time.
do { */
next = ioend->io_list; if (status) {
bio = NULL; ioend->io_error = status;
/*
* 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 (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); xfs_finish_ioend(ioend);
} while ((ioend = next) != NULL); return status;
} }
/* bio = NULL;
* Cancel submission of all buffer_heads so far in this endio. for (bh = ioend->io_buffer_head; bh; bh = bh->b_private) {
* 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 { if (!bio) {
next = ioend->io_list; retry:
bh = ioend->io_buffer_head; bio = xfs_alloc_ioend_bio(bh);
do { } else if (bh->b_blocknr != lastblock + 1) {
next_bh = bh->b_private; xfs_submit_ioend_bio(wbc, ioend, bio);
clear_buffer_async_write(bh); goto retry;
/* }
* The unwritten flag is cleared when added to the
* ioend. We're not submitting for I/O so mark the
* buffer unwritten again for next time around.
*/
if (ioend->io_type == XFS_IO_UNWRITTEN)
set_buffer_unwritten(bh);
unlock_buffer(bh);
} while ((bh = next_bh) != NULL);
mempool_free(ioend, xfs_ioend_pool); if (xfs_bio_add_buffer(bio, bh) != bh->b_size) {
} while ((ioend = next) != NULL); 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 * 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 * earlier buffers -- if so, we try to append to this ioend if we
* can, otherwise we finish off any current ioend and start another. * can, otherwise we finish off any current ioend and start another.
* Return true if we've finished the given ioend. * Return the ioend we finished off so that the caller can submit it
* once it has finished processing the dirty page.
*/ */
STATIC void STATIC void
xfs_add_to_ioend( xfs_add_to_ioend(
struct inode *inode, struct inode *inode,
struct buffer_head *bh, struct buffer_head *bh,
xfs_off_t offset, xfs_off_t offset,
unsigned int type, struct xfs_writepage_ctx *wpc,
xfs_ioend_t **result, struct list_head *iolist)
int need_ioend)
{ {
xfs_ioend_t *ioend = *result; 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 (!ioend || need_ioend || type != ioend->io_type) { if (wpc->ioend)
xfs_ioend_t *previous = *result; list_add(&wpc->ioend->io_list, iolist);
ioend = xfs_alloc_ioend(inode, type); new = xfs_alloc_ioend(inode, wpc->io_type);
ioend->io_offset = offset; new->io_offset = offset;
ioend->io_buffer_head = bh; new->io_buffer_head = bh;
ioend->io_buffer_tail = bh; new->io_buffer_tail = bh;
if (previous) wpc->ioend = new;
previous->io_list = ioend;
*result = ioend;
} else { } else {
ioend->io_buffer_tail->b_private = bh; wpc->ioend->io_buffer_tail->b_private = bh;
ioend->io_buffer_tail = bh; wpc->ioend->io_buffer_tail = bh;
} }
bh->b_private = NULL; bh->b_private = NULL;
ioend->io_size += bh->b_size; wpc->ioend->io_size += bh->b_size;
wpc->last_block = bh->b_blocknr;
xfs_start_buffer_writeback(bh);
} }
STATIC void STATIC void
@ -684,183 +632,6 @@ xfs_check_page_type(
return false; return false;
} }
/*
* 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, false))
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;
/*
* The moment we find a buffer that doesn't match our current type
* specification or can't be written, abort the loop and start
* writeback. As per the above xfs_imap_valid() check, only
* xfs_vm_writepage() can handle partial page writeback fully - we are
* limited here to the buffers that are contiguous with the current
* ioend, and hence a buffer we can't write breaks that contiguity and
* we have to defer the rest of the IO to xfs_vm_writepage().
*/
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;
break;
}
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;
/*
* imap should always be valid because of the above
* partial page end_offset check on the imap.
*/
ASSERT(xfs_imap_valid(inode, imap, offset));
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;
break;
}
} 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 STATIC void
xfs_vm_invalidatepage( xfs_vm_invalidatepage(
struct page *page, struct page *page,
@ -937,6 +708,164 @@ out_invalidate:
return; 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. * Write out a dirty page.
* *
@ -946,22 +875,16 @@ out_invalidate:
* For any other dirty buffer heads on the page we should flush them. * For any other dirty buffer heads on the page we should flush them.
*/ */
STATIC int STATIC int
xfs_vm_writepage( xfs_do_writepage(
struct page *page, struct page *page,
struct writeback_control *wbc) struct writeback_control *wbc,
void *data)
{ {
struct xfs_writepage_ctx *wpc = data;
struct inode *inode = page->mapping->host; 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; loff_t offset;
unsigned int type;
__uint64_t end_offset; __uint64_t end_offset;
pgoff_t end_index, last_index; pgoff_t end_index;
ssize_t len;
int err, imap_valid = 0, uptodate = 1;
int count = 0;
int nonblocking = 0;
trace_xfs_writepage(inode, page, 0, 0); trace_xfs_writepage(inode, page, 0, 0);
@ -988,12 +911,9 @@ xfs_vm_writepage(
if (WARN_ON_ONCE(current->flags & PF_FSTRANS)) if (WARN_ON_ONCE(current->flags & PF_FSTRANS))
goto redirty; 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;
/* /*
* Is this page beyond the end of the file?
*
* The page index is less than the end_index, adjust the end_offset * The page index is less than the end_index, adjust the end_offset
* to the highest offset that this page should represent. * to the highest offset that this page should represent.
* ----------------------------------------------------- * -----------------------------------------------------
@ -1004,6 +924,8 @@ xfs_vm_writepage(
* | desired writeback range | see else | * | desired writeback range | see else |
* ---------------------------------^------------------| * ---------------------------------^------------------|
*/ */
offset = i_size_read(inode);
end_index = offset >> PAGE_CACHE_SHIFT;
if (page->index < end_index) if (page->index < end_index)
end_offset = (xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT; end_offset = (xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT;
else { else {
@ -1055,152 +977,7 @@ xfs_vm_writepage(
end_offset = offset; end_offset = offset;
} }
len = 1 << inode->i_blkbits; return xfs_writepage_map(wpc, wbc, inode, page, offset, end_offset);
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:
redirty_page_for_writepage(wbc, page); redirty_page_for_writepage(wbc, page);
@ -1208,13 +985,37 @@ redirty:
return 0; 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 STATIC int
xfs_vm_writepages( xfs_vm_writepages(
struct address_space *mapping, struct address_space *mapping,
struct writeback_control *wbc) 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); xfs_iflags_clear(XFS_I(mapping->host), XFS_ITRUNCATED);
return generic_writepages(mapping, wbc); ret = write_cache_pages(mapping, wbc, xfs_do_writepage, &wpc);
if (wpc.ioend)
ret = xfs_submit_ioend(wbc, wpc.ioend, ret);
return ret;
} }
/* /*

4
fs/xfs/xfs_aops.h
View File

@ -24,12 +24,14 @@ extern mempool_t *xfs_ioend_pool;
* Types of I/O for bmap clustering and I/O completion tracking. * Types of I/O for bmap clustering and I/O completion tracking.
*/ */
enum { enum {
XFS_IO_INVALID, /* initial state */
XFS_IO_DELALLOC, /* covers delalloc region */ XFS_IO_DELALLOC, /* covers delalloc region */
XFS_IO_UNWRITTEN, /* covers allocated but uninitialized data */ XFS_IO_UNWRITTEN, /* covers allocated but uninitialized data */
XFS_IO_OVERWRITE, /* covers already allocated extent */ XFS_IO_OVERWRITE, /* covers already allocated extent */
}; };
#define XFS_IO_TYPES \ #define XFS_IO_TYPES \
{ XFS_IO_INVALID, "invalid" }, \
{ XFS_IO_DELALLOC, "delalloc" }, \ { XFS_IO_DELALLOC, "delalloc" }, \
{ XFS_IO_UNWRITTEN, "unwritten" }, \ { XFS_IO_UNWRITTEN, "unwritten" }, \
{ XFS_IO_OVERWRITE, "overwrite" } { XFS_IO_OVERWRITE, "overwrite" }
@ -39,7 +41,7 @@ enum {
* It can manage several multi-page bio's at once. * It can manage several multi-page bio's at once.
*/ */
typedef struct xfs_ioend { typedef struct xfs_ioend {
struct xfs_ioend *io_list; /* next ioend in chain */ struct list_head io_list; /* next ioend in chain */
unsigned int io_type; /* delalloc / unwritten */ unsigned int io_type; /* delalloc / unwritten */
int io_error; /* I/O error code */ int io_error; /* I/O error code */
atomic_t io_remaining; /* hold count */ atomic_t io_remaining; /* hold count */