Dan Magenheimer
2010-08-30T22:33:28Z

[PATCH V4 4/8] Cleancache: VFS hooks for cleancache

Implement core hooks in VFS for: initializing cleancache
per filesystem; capturing clean pages evicted by page cache;
attempting to get pages from cleancache before filesystem
read; and ensuring coherency between pagecache, disk,
and cleancache. All hooks become no-ops if CONFIG_CLEANCACHE
is unset, or become compare-function-pointer-to-NULL if
CONFIG_CLEANCACHE is set but no cleancache "backend" has
claimed cleancache_ops.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>

Diffstat:
fs/buffer.c | 5 +++++
fs/mpage.c | 7 +++++++
fs/super.c | 7 +++++++
mm/filemap.c | 11 +++++++++++
mm/truncate.c | 10 ++++++++++
5 files changed, 40 insertions(+)

--- linux-2.6.36-rc3/fs/super.c 2010-08-29 09:36:04.000000000 -0600
+++ linux-2.6.36-rc3-cleancache/fs/super.c 2010-08-30 09:20:43.000000000 -0600
@@ -30,6 +30,7 @@
#include <linux/idr.h>
#include <linux/mutex.h>
#include <linux/backing-dev.h>
+#include <linux/cleancache.h>
#include "internal.h"

@@ -110,6 +111,7 @@ static struct super_block *alloc_super(s
s->s_maxbytes = MAX_NON_LFS;
s->s_op = &default_op;
s->s_time_gran = 1000000000;
+ s->cleancache_poolid = -1;
}
out:
return s;
@@ -176,6 +178,11 @@ void deactivate_locked_super(struct supe
struct file_system_type *fs = s->s_type;
if (atomic_dec_and_test(&s->s_active)) {
fs->kill_sb(s);
+ if (s->cleancache_poolid >= 0) {
+ int cleancache_poolid = s->cleancache_poolid;
+ s->cleancache_poolid = -1; /* avoid races */
+ cleancache_flush_fs(cleancache_poolid);
+ }
put_filesystem(fs);
put_super(s);
} else {
--- linux-2.6.36-rc3/fs/buffer.c 2010-08-29 09:36:04.000000000 -0600
+++ linux-2.6.36-rc3-cleancache/fs/buffer.c 2010-08-30 09:20:42.000000000 -0600
@@ -41,6 +41,7 @@
#include <linux/bitops.h>
#include <linux/mpage.h>
#include <linux/bit_spinlock.h>
+#include <linux/cleancache.h>

static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);

@@ -277,6 +278,10 @@ void invalidate_bdev(struct block_device
invalidate_bh_lrus();
lru_add_drain_all(); /* make sure all lru add caches are flushed */
invalidate_mapping_pages(mapping, 0, -1);
+ /* 99% of the time, we don't need to flush the cleancache on the bdev.
+ * But, for the strange corners, lets be cautious
+ */
+ cleancache_flush_inode(mapping);
}
EXPORT_SYMBOL(invalidate_bdev);

--- linux-2.6.36-rc3/fs/mpage.c 2010-08-29 09:36:04.000000000 -0600
+++ linux-2.6.36-rc3-cleancache/fs/mpage.c 2010-08-30 09:20:43.000000000 -0600
@@ -27,6 +27,7 @@
#include <linux/writeback.h>
#include <linux/backing-dev.h>
#include <linux/pagevec.h>
+#include <linux/cleancache.h>

/*
* I/O completion handler for multipage BIOs.
@@ -286,6 +287,12 @@ do_mpage_readpage(struct bio *bio, struc
SetPageMappedToDisk(page);
}

+ if (fully_mapped && blocks_per_page == 1 && !PageUptodate(page) &&
+ cleancache_get_page(page) == 0) {
+ SetPageUptodate(page);
+ goto confused;
+ }
+
/*
* This page will go to BIO. Do we need to send this BIO off first?
*/
--- linux-2.6.36-rc3/mm/filemap.c 2010-08-29 09:36:04.000000000 -0600
+++ linux-2.6.36-rc3-cleancache/mm/filemap.c 2010-08-30 09:20:43.000000000 -0600
@@ -34,6 +34,7 @@
#include <linux/hardirq.h> /* for BUG_ON(!in_atomic()) only */
#include <linux/memcontrol.h>
#include <linux/mm_inline.h> /* for page_is_file_cache() */
+#include <linux/cleancache.h>
#include "internal.h"

/*
@@ -119,6 +120,16 @@ void __remove_from_page_cache(struct pag
{
struct address_space *mapping = page->mapping;

+ /*
+ * if we're uptodate, flush out into the cleancache, otherwise
+ * invalidate any existing cleancache entries. We can't leave
+ * stale data around in the cleancache once our page is gone
+ */
+ if (PageUptodate(page))
+ cleancache_put_page(page);
+ else
+ cleancache_flush_page(mapping, page);
+
radix_tree_delete(&mapping->page_tree, page->index);
page->mapping = NULL;
mapping->nrpages--;
--- linux-2.6.36-rc3/mm/truncate.c 2010-08-29 09:36:04.000000000 -0600
+++ linux-2.6.36-rc3-cleancache/mm/truncate.c 2010-08-30 09:20:43.000000000 -0600
@@ -19,6 +19,7 @@
#include <linux/task_io_accounting_ops.h>
#include <linux/buffer_head.h> /* grr. try_to_release_page,
do_invalidatepage */
+#include <linux/cleancache.h>
#include "internal.h"

@@ -51,6 +52,7 @@ void do_invalidatepage(struct page *page
static inline void truncate_partial_page(struct page *page, unsigned partial)
{
zero_user_segment(page, partial, PAGE_CACHE_SIZE);
+ cleancache_flush_page(page->mapping, page);
if (page_has_private(page))
do_invalidatepage(page, partial);
}
@@ -108,6 +110,10 @@ truncate_complete_page(struct address_sp
clear_page_mlock(page);
remove_from_page_cache(page);
ClearPageMappedToDisk(page);
+ /* this must be after the remove_from_page_cache which
+ * calls cleancache_put_page (and note page->mapping is now NULL)
+ */
+ cleancache_flush_page(mapping, page);
page_cache_release(page); /* pagecache ref */
return 0;
}
@@ -215,6 +221,7 @@ void truncate_inode_pages_range(struct a
pgoff_t next;
int i;

+ cleancache_flush_inode(mapping);
if (mapping->nrpages == 0)
return;

@@ -290,6 +297,7 @@ void truncate_inode_pages_range(struct a
pagevec_release(&pvec);
mem_cgroup_uncharge_end();
}
+ cleancache_flush_inode(mapping);
}
EXPORT_SYMBOL(truncate_inode_pages_range);

@@ -428,6 +436,7 @@ int invalidate_inode_pages2_range(struct
int did_range_unmap = 0;
int wrapped = 0;

+ cleancache_flush_inode(mapping);
pagevec_init(&pvec, 0);
next = start;
while (next <= end && !wrapped &&
@@ -486,6 +495,7 @@ int invalidate_inode_pages2_range(struct
mem_cgroup_uncharge_end();
cond_resched();
}
+ cleancache_flush_inode(mapping);
return ret;
}
EXPORT_SYMBOL_GPL(invalidate_inode_pages2_range);