[PATCH 15/15] gfs2: use iomap for buffered I/O in ordered and writeback mode

Christoph Hellwig
2019-07-01T21:56:51Z

Switch to using the iomap readpage and writepage helpers for all I/O in
the ordered and writeback modes, and thus eliminate using buffer_heads
for I/O in these cases. The journaled data mode is left untouched.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/gfs2/aops.c | 59 +++++++++++++++++++++++---------------------------
fs/gfs2/bmap.c | 47 ++++++++++++++++++++++++++++++----------
fs/gfs2/bmap.h | 1 +
3 files changed, 63 insertions(+), 44 deletions(-)

diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index 15a234fb8f88..9cdd61a44379 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -91,22 +91,13 @@ static int gfs2_writepage(struct page *page, struct writeback_control *wbc)
struct inode *inode = page->mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
- loff_t i_size = i_size_read(inode);
- pgoff_t end_index = i_size >> PAGE_SHIFT;
- unsigned offset;
+ struct iomap_writepage_ctx wpc = { };

if (gfs2_assert_withdraw(sdp, gfs2_glock_is_held_excl(ip->i_gl)))
goto out;
if (current->journal_info)
goto redirty;
- /* Is the page fully outside i_size? (truncate in progress) */
- offset = i_size & (PAGE_SIZE-1);
- if (page->index > end_index || (page->index == end_index && !offset)) {
- page->mapping->a_ops->invalidatepage(page, 0, PAGE_SIZE);
- goto out;
- }
-
- return nobh_writepage(page, gfs2_get_block_noalloc, wbc);
+ return iomap_writepage(page, wbc, &wpc, &gfs2_writeback_ops);

redirty:
redirty_page_for_writepage(wbc, page);
@@ -210,7 +201,8 @@ static int gfs2_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
struct gfs2_sbd *sdp = gfs2_mapping2sbd(mapping);
- int ret = mpage_writepages(mapping, wbc, gfs2_get_block_noalloc);
+ struct iomap_writepage_ctx wpc = { };
+ int ret;

/*
* Even if we didn't write any pages here, we might still be holding
@@ -218,9 +210,9 @@ static int gfs2_writepages(struct address_space *mapping,
* want balance_dirty_pages() to loop indefinitely trying to write out
* pages held in the ail that it can't find.
*/
+ ret = iomap_writepages(mapping, wbc, &wpc, &gfs2_writeback_ops);
if (ret == 0)
set_bit(SDF_FORCE_AIL_FLUSH, &sdp->sd_flags);
-
return ret;
}

@@ -469,7 +461,6 @@ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
return 0;
}

-
/**
* __gfs2_readpage - readpage
* @file: The file to read a page for
@@ -479,16 +470,15 @@ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
* reading code as in that case we already hold the glock. Also it's
* called by gfs2_readpage() once the required lock has been granted.
*/
-
static int __gfs2_readpage(void *file, struct page *page)
{
- struct gfs2_inode *ip = GFS2_I(page->mapping->host);
- struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
-
+ struct inode *inode = page->mapping->host;
+ struct gfs2_inode *ip = GFS2_I(inode);
+ struct gfs2_sbd *sdp = GFS2_SB(inode);
int error;

- if (i_blocksize(page->mapping->host) == PAGE_SIZE &&
- !page_has_buffers(page)) {
+ if (!gfs2_is_jdata(ip) ||
+ (i_blocksize(inode) == PAGE_SIZE && !page_has_buffers(page))) {
error = iomap_readpage(page, &gfs2_iomap_ops);
} else if (gfs2_is_stuffed(ip)) {
error = stuffed_readpage(ip, page);
@@ -609,8 +599,12 @@ static int gfs2_readpages(struct file *file, struct address_space *mapping,
ret = gfs2_glock_nq(&gh);
if (unlikely(ret))
goto out_uninit;
- if (!gfs2_is_stuffed(ip))
+ if (gfs2_is_stuffed(ip))
+ ;
+ else if (gfs2_is_jdata(ip))
ret = mpage_readpages(mapping, pages, nr_pages, gfs2_block_map);
+ else
+ ret = iomap_readpages(mapping, pages, nr_pages, &gfs2_iomap_ops);
gfs2_glock_dq(&gh);
out_uninit:
gfs2_holder_uninit(&gh);
@@ -827,17 +821,18 @@ int gfs2_releasepage(struct page *page, gfp_t gfp_mask)
}

static const struct address_space_operations gfs2_aops = {
- .writepage = gfs2_writepage,
- .writepages = gfs2_writepages,
- .readpage = gfs2_readpage,
- .readpages = gfs2_readpages,
- .bmap = gfs2_bmap,
- .invalidatepage = gfs2_invalidatepage,
- .releasepage = gfs2_releasepage,
- .direct_IO = noop_direct_IO,
- .migratepage = buffer_migrate_page,
- .is_partially_uptodate = block_is_partially_uptodate,
- .error_remove_page = generic_error_remove_page,
+ .writepage = gfs2_writepage,
+ .writepages = gfs2_writepages,
+ .readpage = gfs2_readpage,
+ .readpages = gfs2_readpages,
+ .set_page_dirty = iomap_set_page_dirty,
+ .releasepage = iomap_releasepage,
+ .invalidatepage = iomap_invalidatepage,
+ .bmap = gfs2_bmap,
+ .direct_IO = noop_direct_IO,
+ .migratepage = iomap_migrate_page,
+ .is_partially_uptodate = iomap_is_partially_uptodate,
+ .error_remove_page = generic_error_remove_page,
};

static const struct address_space_operations gfs2_jdata_aops = {
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index b7bd811872cb..b8d795d277c9 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -56,7 +56,6 @@ static int gfs2_unstuffer_page(struct gfs2_inode *ip, struct buffer_head *dibh,
u64 block, struct page *page)
{
struct inode *inode = &ip->i_inode;
- struct buffer_head *bh;
int release = 0;

if (!page || page->index) {
@@ -80,20 +79,20 @@ static int gfs2_unstuffer_page(struct gfs2_inode *ip, struct buffer_head *dibh,
SetPageUptodate(page);
}

- if (!page_has_buffers(page))
- create_empty_buffers(page, BIT(inode->i_blkbits),
- BIT(BH_Uptodate));
+ if (gfs2_is_jdata(ip)) {
+ struct buffer_head *bh;

- bh = page_buffers(page);
+ if (!page_has_buffers(page))
+ create_empty_buffers(page, BIT(inode->i_blkbits),
+ BIT(BH_Uptodate));

- if (!buffer_mapped(bh))
- map_bh(bh, inode->i_sb, block);
+ bh = page_buffers(page);
+ if (!buffer_mapped(bh))
+ map_bh(bh, inode->i_sb, block);

- set_buffer_uptodate(bh);
- if (gfs2_is_jdata(ip))
+ set_buffer_uptodate(bh);
gfs2_trans_add_data(ip->i_gl, bh);
- else {
- mark_buffer_dirty(bh);
+ } else {
gfs2_ordered_add_inode(ip);
}

@@ -1127,7 +1126,8 @@ static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
struct metapath mp = { .mp_aheight = 1, };
int ret;

- iomap->flags |= IOMAP_F_BUFFER_HEAD;
+ if (gfs2_is_jdata(ip))
+ iomap->flags |= IOMAP_F_BUFFER_HEAD;

trace_gfs2_iomap_start(ip, pos, length, flags);
if ((flags & IOMAP_WRITE) && !(flags & IOMAP_DIRECT)) {
@@ -2431,3 +2431,26 @@ int __gfs2_punch_hole(struct file *file, loff_t offset, loff_t length)
gfs2_trans_end(sdp);
return error;
}
+
+static int gfs2_map_blocks(struct iomap_writepage_ctx *wpc, struct inode *inode,
+ loff_t offset)
+{
+ struct metapath mp = { .mp_aheight = 1, };
+ int ret;
+
+ if (WARN_ON_ONCE(gfs2_is_stuffed(GFS2_I(inode))))
+ return -EIO;
+
+ if (offset >= wpc->iomap.offset &&
+ offset < wpc->iomap.offset + wpc->iomap.length)
+ return 0;
+
+ memset(&wpc->iomap, 0, sizeof(wpc->iomap));
+ ret = gfs2_iomap_get(inode, offset, INT_MAX, 0, &wpc->iomap, &mp);
+ release_metapath(&mp);
+ return ret;
+}
+
+const struct iomap_writeback_ops gfs2_writeback_ops = {
+ .map_blocks = gfs2_map_blocks,
+};
diff --git a/fs/gfs2/bmap.h b/fs/gfs2/bmap.h
index b88fd45ab79f..aed4632d47d3 100644
--- a/fs/gfs2/bmap.h
+++ b/fs/gfs2/bmap.h
@@ -44,6 +44,7 @@ static inline void gfs2_write_calc_reserv(const struct gfs2_inode *ip,
}

extern const struct iomap_ops gfs2_iomap_ops;
+extern const struct iomap_writeback_ops gfs2_writeback_ops;

extern int gfs2_unstuff_dinode(struct gfs2_inode *ip, struct page *page);
extern int gfs2_block_map(struct inode *inode, sector_t lblock,
--
2.20.1