As a preparation for incoming subpage support, we need bytenr passed to
__process_pages_contig() directly, not the current page index.
So change the parameter and all callers to pass bytenr in.
With the modification, here we need to replace the old @index_ret with
@processed_end for __process_pages_contig(), but this brings a small
problem.
Normally we follow the inclusive return value, meaning @processed_end
should be the last byte we processed.
If parameter @start is 0, and we failed to lock any page, then we would
return @processed_end as -1, causing more problems for
__unlock_for_delalloc().
So here for @processed_end, we use two different return value patterns.
If we have locked any page, @processed_end will be the last byte of
locked page.
Or it will be @start otherwise.
This change will impact lock_delalloc_pages(), so it needs to check
@processed_end to only unlock the range if we have locked any.
Signed-off-by: Qu Wenruo <w...@suse.com>
---
fs/btrfs/extent_io.c | 57 ++++++++++++++++++++++++++++----------------
1 file changed, 37 insertions(+), 20 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index ac01f29b00c9..ff24db8513b4 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1807,8 +1807,8 @@ bool btrfs_find_delalloc_range(struct extent_io_tree
*tree, u64 *start,
static int __process_pages_contig(struct address_space *mapping,
struct page *locked_page,
- pgoff_t start_index, pgoff_t end_index,
- unsigned long page_ops, pgoff_t *index_ret);
+ u64 start, u64 end, unsigned long page_ops,
+ u64 *processed_end);
static noinline void __unlock_for_delalloc(struct inode *inode,
struct page *locked_page,
@@ -1821,7 +1821,7 @@ static noinline void __unlock_for_delalloc(struct inode
*inode,
if (index == locked_page->index && end_index == index)
return;
- __process_pages_contig(inode->i_mapping, locked_page, index, end_index,
+ __process_pages_contig(inode->i_mapping, locked_page, start, end,
PAGE_UNLOCK, NULL);
}
@@ -1831,19 +1831,19 @@ static noinline int lock_delalloc_pages(struct inode *inode,
u64 delalloc_end)
{
unsigned long index = delalloc_start >> PAGE_SHIFT;
- unsigned long index_ret = index;
unsigned long end_index = delalloc_end >> PAGE_SHIFT;
+ u64 processed_end = delalloc_start;
int ret;
ASSERT(locked_page);
if (index == locked_page->index && index == end_index)
return 0;
- ret = __process_pages_contig(inode->i_mapping, locked_page, index,
- end_index, PAGE_LOCK, &index_ret);
- if (ret == -EAGAIN)
+ ret = __process_pages_contig(inode->i_mapping, locked_page,
delalloc_start,
+ delalloc_end, PAGE_LOCK, &processed_end);
+ if (ret == -EAGAIN && processed_end > delalloc_start)
__unlock_for_delalloc(inode, locked_page, delalloc_start,
- (u64)index_ret << PAGE_SHIFT);
+ processed_end);
return ret;
}
@@ -1938,12 +1938,14 @@ noinline_for_stack bool find_lock_delalloc_range(struct inode *inode,
static int __process_pages_contig(struct address_space *mapping,
struct page *locked_page,
- pgoff_t start_index, pgoff_t end_index,
- unsigned long page_ops, pgoff_t *index_ret)
+ u64 start, u64 end, unsigned long page_ops,
+ u64 *processed_end)
{
+ pgoff_t start_index = start >> PAGE_SHIFT;
+ pgoff_t end_index = end >> PAGE_SHIFT;
+ pgoff_t index = start_index;
unsigned long nr_pages = end_index - start_index + 1;
unsigned long pages_processed = 0;
- pgoff_t index = start_index;
struct page *pages[16];
unsigned ret;
int err = 0;
@@ -1951,17 +1953,19 @@ static int __process_pages_contig(struct address_space
*mapping,
if (page_ops & PAGE_LOCK) {
ASSERT(page_ops == PAGE_LOCK);
- ASSERT(index_ret && *index_ret == start_index);
+ ASSERT(processed_end && *processed_end == start);
}
if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
mapping_set_error(mapping, -EIO);
while (nr_pages > 0) {
- ret = find_get_pages_contig(mapping, index,
+ int found_pages;
+
+ found_pages = find_get_pages_contig(mapping, index,
min_t(unsigned long,
nr_pages, ARRAY_SIZE(pages)), pages);
- if (ret == 0) {
+ if (found_pages == 0) {
/*
* Only if we're going to lock these pages,
* can we find nothing at @index.
@@ -2004,13 +2008,27 @@ static int __process_pages_contig(struct address_space
*mapping,
put_page(pages[i]);
pages_processed++;
}
- nr_pages -= ret;
- index += ret;
+ nr_pages -= found_pages;
+ index += found_pages;
cond_resched();
}
out:
- if (err && index_ret)
- *index_ret = start_index + pages_processed - 1;
+ if (err && processed_end) {
+ /*
+ * Update @processed_end. I know this is awful since it has
+ * two different return value patterns (inclusive vs exclusive).
+ *
+ * But the exclusive pattern is necessary if @start is 0, or we
+ * underflow and check against processed_end won't work as
+ * expected.
+ */
+ if (pages_processed)
+ *processed_end = min(end,
+ ((u64)(start_index + pages_processed) << PAGE_SHIFT) -
1);
+ else
+ *processed_end = start;
