Btrfs: Do metadata checksums for reads via a workqueue
Before, metadata checksumming was done by the callers of read_tree_block,
which would set EXTENT_CSUM bits in the extent tree to show that a given
range of pages was already checksummed and didn't need to be verified
again.
But, those bits could go away via try_to_releasepage, and the end
result was bogus checksum failures on pages that never left the cache.
The new code validates checksums when the page is read. It is a little
tricky because metadata blocks can span pages and a single read may
end up going via multiple bios.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 13cc236..cfc383c 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2592,6 +2592,22 @@
return p;
}
+int release_extent_buffer_tail_pages(struct extent_buffer *eb)
+{
+ unsigned long num_pages = num_extent_pages(eb->start, eb->len);
+ struct page *page;
+ unsigned long i;
+
+ if (num_pages == 1)
+ return 0;
+ for (i = 1; i < num_pages; i++) {
+ page = extent_buffer_page(eb, i);
+ page_cache_release(page);
+ }
+ return 0;
+}
+
+
int invalidate_extent_lru(struct extent_io_tree *tree, u64 start,
unsigned long len)
{
@@ -2609,9 +2625,6 @@
if (eb->start <= start && eb->start + eb->len > start) {
eb->flags &= ~EXTENT_UPTODATE;
}
- if (eb->start == start) {
- eb->flags &= ~EXTENT_CSUM;
- }
cur = cur->next;
} while (cur != lru);
out:
@@ -2682,7 +2695,6 @@
page_cache_get(page0);
mark_page_accessed(page0);
set_page_extent_mapped(page0);
- WARN_ON(!PageUptodate(page0));
set_page_extent_head(page0, len);
} else {
i = 0;
@@ -2933,13 +2945,39 @@
}
EXPORT_SYMBOL(set_extent_buffer_uptodate);
+int extent_range_uptodate(struct extent_io_tree *tree,
+ u64 start, u64 end)
+{
+ struct page *page;
+ int ret;
+ int pg_uptodate = 1;
+ int uptodate;
+ unsigned long index;
+
+ ret = test_range_bit(tree, start, end, EXTENT_UPTODATE, 1);
+ if (ret)
+ return 1;
+ while(start <= end) {
+ index = start >> PAGE_CACHE_SHIFT;
+ page = find_get_page(tree->mapping, index);
+ uptodate = PageUptodate(page);
+ page_cache_release(page);
+ if (!uptodate) {
+ pg_uptodate = 0;
+ break;
+ }
+ start += PAGE_CACHE_SIZE;
+ }
+ return pg_uptodate;
+}
+
int extent_buffer_uptodate(struct extent_io_tree *tree,
- struct extent_buffer *eb)
+ struct extent_buffer *eb)
{
int ret = 0;
int ret2;
- int num_pages;
- int i;
+ unsigned long num_pages;
+ unsigned long i;
struct page *page;
int pg_uptodate = 1;
@@ -2975,13 +3013,16 @@
struct page *page;
int err;
int ret = 0;
+ int locked_pages = 0;
+ int all_uptodate = 1;
+ int inc_all_pages = 0;
unsigned long num_pages;
struct bio *bio = NULL;
if (eb->flags & EXTENT_UPTODATE)
return 0;
- if (0 && test_range_bit(tree, eb->start, eb->start + eb->len - 1,
+ if (test_range_bit(tree, eb->start, eb->start + eb->len - 1,
EXTENT_UPTODATE, 1)) {
return 0;
}
@@ -2997,17 +3038,30 @@
num_pages = num_extent_pages(eb->start, eb->len);
for (i = start_i; i < num_pages; i++) {
page = extent_buffer_page(eb, i);
- if (PageUptodate(page)) {
- continue;
- }
if (!wait) {
- if (TestSetPageLocked(page)) {
- continue;
- }
+ if (TestSetPageLocked(page))
+ goto unlock_exit;
} else {
lock_page(page);
}
+ locked_pages++;
if (!PageUptodate(page)) {
+ all_uptodate = 0;
+ }
+ }
+ if (all_uptodate) {
+ if (start_i == 0)
+ eb->flags |= EXTENT_UPTODATE;
+ goto unlock_exit;
+ }
+
+ for (i = start_i; i < num_pages; i++) {
+ page = extent_buffer_page(eb, i);
+ if (inc_all_pages)
+ page_cache_get(page);
+ if (!PageUptodate(page)) {
+ if (start_i == 0)
+ inc_all_pages = 1;
err = __extent_read_full_page(tree, page,
get_extent, &bio);
if (err) {
@@ -3034,6 +3088,16 @@
if (!ret)
eb->flags |= EXTENT_UPTODATE;
return ret;
+
+unlock_exit:
+ i = start_i;
+ while(locked_pages > 0) {
+ page = extent_buffer_page(eb, i);
+ i++;
+ unlock_page(page);
+ locked_pages--;
+ }
+ return ret;
}
EXPORT_SYMBOL(read_extent_buffer_pages);
@@ -3048,7 +3112,6 @@
char *dst = (char *)dstv;
size_t start_offset = eb->start & ((u64)PAGE_CACHE_SIZE - 1);
unsigned long i = (start_offset + start) >> PAGE_CACHE_SHIFT;
- unsigned long num_pages = num_extent_pages(eb->start, eb->len);
WARN_ON(start > eb->len);
WARN_ON(start + len > eb->start + eb->len);
@@ -3057,11 +3120,6 @@
while(len > 0) {
page = extent_buffer_page(eb, i);
- if (!PageUptodate(page)) {
- printk("page %lu not up to date i %lu, total %lu, len %lu\n", page->index, i, num_pages, eb->len);
- WARN_ON(1);
- }
- WARN_ON(!PageUptodate(page));
cur = min(len, (PAGE_CACHE_SIZE - offset));
kaddr = kmap_atomic(page, KM_USER1);
@@ -3105,7 +3163,6 @@
}
p = extent_buffer_page(eb, i);
- WARN_ON(!PageUptodate(p));
kaddr = kmap_atomic(p, km);
*token = kaddr;
*map = kaddr + offset;
@@ -3165,7 +3222,6 @@
while(len > 0) {
page = extent_buffer_page(eb, i);
- WARN_ON(!PageUptodate(page));
cur = min(len, (PAGE_CACHE_SIZE - offset));