We want this for btrfs_extent_same. Basically readpage and friends do their
own extent locking but for the purposes of dedupe, we want to have both
files locked down across a set of readpage operations (so that we can
compare data). Introduce this variant and a flag which can be set for
extent_read_full_page() to indicate that we are already locked.
Signed-off-by: Mark Fasheh <mfas...@suse.de>
---
fs/btrfs/extent_io.c | 44 ++++++++++++++++++++++++++++++++------------
fs/btrfs/extent_io.h | 2 ++
2 files changed, 34 insertions(+), 12 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 1b319df..9256503 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2592,7 +2592,7 @@ static int __extent_read_full_page(struct extent_io_tree
*tree,
struct page *page,
get_extent_t *get_extent,
struct bio **bio, int mirror_num,
- unsigned long *bio_flags)
+ unsigned long *bio_flags, int parent_locked)
{
struct inode *inode = page->mapping->host;
u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
@@ -2625,7 +2625,7 @@ static int __extent_read_full_page(struct extent_io_tree
*tree,
}
end = page_end;
- while (1) {
+ while (1 && !parent_locked) {
lock_extent(tree, start, end);
ordered = btrfs_lookup_ordered_extent(inode, start);
if (!ordered)
@@ -2659,15 +2659,18 @@ static int __extent_read_full_page(struct
extent_io_tree *tree,
kunmap_atomic(userpage);
set_extent_uptodate(tree, cur, cur + iosize - 1,
&cached, GFP_NOFS);
- unlock_extent_cached(tree, cur, cur + iosize - 1,
- &cached, GFP_NOFS);
+ if (!parent_locked)
+ unlock_extent_cached(tree, cur,
+ cur + iosize - 1,
+ &cached, GFP_NOFS);
break;
}
em = get_extent(inode, page, pg_offset, cur,
end - cur + 1, 0);
if (IS_ERR_OR_NULL(em)) {
SetPageError(page);
- unlock_extent(tree, cur, end);
+ if (!parent_locked)
+ unlock_extent(tree, cur, end);
break;
}
extent_offset = cur - em->start;
@@ -2719,7 +2722,8 @@ static int __extent_read_full_page(struct extent_io_tree
*tree,
if (test_range_bit(tree, cur, cur_end,
EXTENT_UPTODATE, 1, NULL)) {
check_page_uptodate(tree, page);
- unlock_extent(tree, cur, cur + iosize - 1);
+ if (!parent_locked)
+ unlock_extent(tree, cur, cur + iosize - 1);
cur = cur + iosize;
pg_offset += iosize;
continue;
@@ -2729,7 +2733,8 @@ static int __extent_read_full_page(struct extent_io_tree
*tree,
*/
if (block_start == EXTENT_MAP_INLINE) {
SetPageError(page);
- unlock_extent(tree, cur, cur + iosize - 1);
+ if (!parent_locked)
+ unlock_extent(tree, cur, cur + iosize - 1);
cur = cur + iosize;
pg_offset += iosize;
continue;
@@ -2756,7 +2761,8 @@ static int __extent_read_full_page(struct extent_io_tree
*tree,
}
if (ret) {
SetPageError(page);
- unlock_extent(tree, cur, cur + iosize - 1);
+ if (!parent_locked)
+ unlock_extent(tree, cur, cur + iosize - 1);
}
cur = cur + iosize;
pg_offset += iosize;
@@ -2778,7 +2784,21 @@ int extent_read_full_page(struct extent_io_tree *tree,
struct page *page,
int ret;
ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
- &bio_flags);
+ &bio_flags, 0);
+ if (bio)
+ ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
+ return ret;
+}
+
+int extent_read_full_page_nolock(struct extent_io_tree *tree, struct page
*page,
+ get_extent_t *get_extent, int mirror_num)
+{
+ struct bio *bio = NULL;
+ unsigned long bio_flags = 0;
+ int ret;
+
+ ret = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num,
+ &bio_flags, 1);
if (bio)
ret = submit_one_bio(READ, bio, mirror_num, bio_flags);
return ret;
@@ -3648,14 +3668,14 @@ int extent_readpages(struct extent_io_tree *tree,
continue;
for (i = 0; i < nr; i++) {
__extent_read_full_page(tree, pagepool[i], get_extent,
- &bio, 0, &bio_flags);
+ &bio, 0, &bio_flags, 0);
page_cache_release(pagepool[i]);
}
nr = 0;
}
for (i = 0; i < nr; i++) {
__extent_read_full_page(tree, pagepool[i], get_extent,
- &bio, 0, &bio_flags);
+ &bio, 0, &bio_flags, 0);
page_cache_release(pagepool[i]);
}
@@ -4620,7 +4640,7 @@ int read_extent_buffer_pages(struct extent_io_tree *tree,
ClearPageError(page);
err = __extent_read_full_page(tree, page,
get_extent, &bio,
- mirror_num, &bio_flags);
+ mirror_num, &bio_flags,
0);
if (err)
ret = err;
} else {
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 2eacfab..71752fc 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -202,6 +202,8 @@ int unlock_extent_cached(struct extent_io_tree *tree, u64
start, u64 end,
int try_lock_extent(struct extent_io_tree *tree, u64 start, u64 end);
int extent_read_full_page(struct extent_io_tree *tree, struct page *page,
get_extent_t *get_extent, int mirror_num);
+int extent_read_full_page_nolock(struct extent_io_tree *tree, struct page
*page,
+ get_extent_t *get_extent, int mirror_num);
int __init extent_io_init(void);
void extent_io_exit(void);
--
1.7.10.4
--
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