From 68a9f5e7007c1afa2cf6830b690a90d0187c0684 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Tue, 21 Jun 2016 09:53:44 +1000
Subject: xfs: implement iomap based buffered write path
Convert XFS to use the new iomap based multipage write path. This involves
implementing the ->iomap_begin and ->iomap_end methods, and switching the
buffered file write, page_mkwrite and xfs_iozero paths to the new iomap
helpers.
With this change __xfs_get_blocks will never be used for buffered writes,
and the code handling them can be removed.
Based on earlier code from Dave Chinner.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
---
fs/xfs/xfs_aops.c | 212 ------------------------------------------------------
1 file changed, 212 deletions(-)
(limited to 'fs/xfs/xfs_aops.c')
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 4c463b99fe57..2ac9f7e5f504 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -1427,216 +1427,6 @@ xfs_vm_direct_IO(
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,
@@ -1747,8 +1537,6 @@ const struct address_space_operations xfs_address_space_operations = {
.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,
--
cgit v1.2.3
From 6e8a27a816390d1fbcc28903da4dd9bc348e19ca Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@lst.de>
Date: Tue, 21 Jun 2016 09:53:45 +1000
Subject: xfs: remove buffered write support from __xfs_get_blocks
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
---
fs/xfs/xfs_aops.c | 71 +++++++++++++++----------------------------------------
1 file changed, 19 insertions(+), 52 deletions(-)
(limited to 'fs/xfs/xfs_aops.c')
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 2ac9f7e5f504..80714ebd54c0 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -1143,6 +1143,8 @@ __xfs_get_blocks(
ssize_t size;
int new = 0;
+ BUG_ON(create && !direct);
+
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
@@ -1150,22 +1152,14 @@ __xfs_get_blocks(
ASSERT(bh_result->b_size >= (1 << inode->i_blkbits));
size = bh_result->b_size;
- if (!create && direct && offset >= i_size_read(inode))
+ if (!create && 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.
+ * a block mapping without an exclusive lock first.
*/
- if (create && !direct) {
- lockmode = XFS_ILOCK_EXCL;
- xfs_ilock(ip, lockmode);
- } else {
- lockmode = xfs_ilock_data_map_shared(ip);
- }
+ lockmode = xfs_ilock_data_map_shared(ip);
ASSERT(offset <= mp->m_super->s_maxbytes);
if (offset + size > mp->m_super->s_maxbytes)
@@ -1184,37 +1178,19 @@ __xfs_get_blocks(
(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;
+ /*
+ * xfs_iomap_write_direct() expects the shared lock. It
+ * is unlocked on return.
+ */
+ if (lockmode == XFS_ILOCK_EXCL)
+ xfs_ilock_demote(ip, lockmode);
- } 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;
+ error = xfs_iomap_write_direct(ip, offset, size,
+ &imap, nimaps);
+ if (error)
+ return error;
+ new = 1;
- xfs_iunlock(ip, lockmode);
- }
trace_xfs_get_blocks_alloc(ip, offset, size,
ISUNWRITTEN(&imap) ? XFS_IO_UNWRITTEN
: XFS_IO_DELALLOC, &imap);
@@ -1235,9 +1211,7 @@ __xfs_get_blocks(
}
/* trim mapping down to size requested */
- if (direct || size > (1 << inode->i_blkbits))
- xfs_map_trim_size(inode, iblock, bh_result,
- &imap, offset, size);
+ xfs_map_trim_size(inode, iblock, bh_result, &imap, offset, size);
/*
* For unwritten extents do not report a disk address in the buffered
@@ -1250,7 +1224,7 @@ __xfs_get_blocks(
if (ISUNWRITTEN(&imap))
set_buffer_unwritten(bh_result);
/* direct IO needs special help */
- if (create && direct) {
+ if (create) {
if (dax_fault)
ASSERT(!ISUNWRITTEN(&imap));
else
@@ -1279,14 +1253,7 @@ __xfs_get_blocks(
(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);
- }
- }
+ BUG_ON(direct && imap.br_startblock == DELAYSTARTBLOCK);
return 0;
--
cgit v1.2.3