This patch will refactor btrfs_invalidatepage() for the incoming subpage
support.
The invovled modifcations are:
- Use while() loop instead of "goto again;"
- Use single variable to determine whether to delete extent states
Each branch will also have comments why we can or cannot delete the
extent states
- Do qgroup free and extent states deletion per-loop
Current code can only work for PAGE_SIZE == sectorsize case.
This refactor also makes it clear what we do for different sectors:
- Sectors without ordered extent
We're completely safe to remove all extent states for the sector(s)
- Sectors with ordered extent, but no Private2 bit
This means the endio has already been executed, we can't remove all
extent states for the sector(s).
- Sectors with ordere extent, still has Private2 bit
This means we need to decrease the ordered extent accounting.
And then it comes to two different variants:
* We have finished and removed the ordered extent
Then it's the same as "sectors without ordered extent"
* We didn't finished the ordered extent
We can remove some extent states, but not all.
Signed-off-by: Qu Wenruo <[email protected]>
---
fs/btrfs/inode.c | 173 +++++++++++++++++++++++++----------------------
1 file changed, 94 insertions(+), 79 deletions(-)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 4c894de2e813..93bb7c0482ba 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -8320,15 +8320,12 @@ static void btrfs_invalidatepage(struct page *page,
unsigned int offset,
{
struct btrfs_inode *inode = BTRFS_I(page->mapping->host);
struct extent_io_tree *tree = &inode->io_tree;
- struct btrfs_ordered_extent *ordered;
struct extent_state *cached_state = NULL;
u64 page_start = page_offset(page);
u64 page_end = page_start + PAGE_SIZE - 1;
- u64 start;
- u64 end;
+ u64 cur;
+ u32 sectorsize = inode->root->fs_info->sectorsize;
int inode_evicting = inode->vfs_inode.i_state & I_FREEING;
- bool found_ordered = false;
- bool completed_ordered = false;
/*
* We have page locked so no new ordered extent can be created on
@@ -8352,96 +8349,114 @@ static void btrfs_invalidatepage(struct page *page,
unsigned int offset,
if (!inode_evicting)
lock_extent_bits(tree, page_start, page_end, &cached_state);
- start = page_start;
-again:
- ordered = btrfs_lookup_ordered_range(inode, start, page_end - start +
1);
- if (ordered) {
- found_ordered = true;
- end = min(page_end,
- ordered->file_offset + ordered->num_bytes - 1);
+ cur = page_start;
+ while (cur < page_end) {
+ struct btrfs_ordered_extent *ordered;
+ bool delete_states = false;
+ u64 range_end;
+
+ /*
+ * Here we can't pass "file_offset = cur" and
+ * "len = page_end + 1 - cur", as btrfs_lookup_ordered_range()
+ * may not return the first ordered extent after @file_offset.
+ *
+ * Here we want to iterate through the range in byte order.
+ * This is slower but definitely correct.
+ *
+ * TODO: Make btrfs_lookup_ordered_range() to return the
+ * first ordered extent in the range to reduce the number
+ * of loops.
+ */
+ ordered = btrfs_lookup_ordered_range(inode, cur, sectorsize);
+ if (!ordered) {
+ range_end = cur + sectorsize - 1;
+ /*
+ * No ordered extent covering this sector, we are safe
+ * to delete all extent states in the range.
+ */
+ delete_states = true;
+ goto next;
+ }
+
+ range_end = min(ordered->file_offset + ordered->num_bytes - 1,
+ page_end);
+ if (!PagePrivate2(page)) {
+ /*
+ * If Private2 is cleared, it means endio has already
+ * been executed for the range.
+ * We can't delete the extent states as
+ * btrfs_finish_ordered_io() may still use some of them.
+ */
+ delete_states = false;
+ goto next;
+ }
+ ClearPagePrivate2(page);
+
/*
* IO on this page will never be started, so we need to account
* for any ordered extents now. Don't clear EXTENT_DELALLOC_NEW
* here, must leave that up for the ordered extent completion.
+ *
+ * This will also unlock the range for incoming
+ * btrfs_finish_ordered_io().
*/
if (!inode_evicting)
- clear_extent_bit(tree, start, end,
+ clear_extent_bit(tree, cur, range_end,
EXTENT_DELALLOC |
EXTENT_LOCKED | EXTENT_DO_ACCOUNTING |
EXTENT_DEFRAG, 1, 0, &cached_state);
+
+ spin_lock_irq(&inode->ordered_tree.lock);
+ set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
+ ASSERT(cur - ordered->file_offset < U32_MAX);
+ ordered->truncated_len = min_t(u32, ordered->truncated_len,
+ cur - ordered->file_offset);
+ spin_unlock_irq(&inode->ordered_tree.lock);
+
+ ASSERT(range_end + 1 - cur < U32_MAX);
+ if (btrfs_dec_test_ordered_pending(inode, &ordered,
+ cur, range_end + 1 - cur, 1)) {
+ btrfs_finish_ordered_io(ordered);
+ /*
+ * The ordered extent has finished, now we're again
+ * safe to delete all extent states of the range.
+ */
+ delete_states = true;
+ } else {
+ /*
+ * btrfs_finish_ordered_io() will get executed by endio
of
+ * other pages, thus we can't delete extent states any
more
+ */
+ delete_states = false;
+ }
+next:
+ if (ordered)
+ btrfs_put_ordered_extent(ordered);
/*
- * A page with Private2 bit means no bio has submitted covering
- * the page, thus we have to manually do the ordered extent
- * accounting.
+ * Qgroup reserved space handler
+ * Sector(s) here will be either
+ * 1) Already written to disk or bio already finished
+ * Then its QGROUP_RESERVED bit in io_tree is already
cleaned.
+ * Qgroup will be handled by its qgroup_record then.
+ * btrfs_qgroup_free_data() call will do nothing here.
*
- * For page without Private2, the ordered extent accounting is
- * done in its endio function of the submitted bio.
+ * 2) Not written to disk yet
+ * Then btrfs_qgroup_free_data() call will clear the
+ * QGROUP_RESERVED bit of its io_tree, and free the qgroup
+ * reserved data space.
+ * Since the IO will never happen for this page.
*/
- if (TestClearPagePrivate2(page)) {
- spin_lock_irq(&inode->ordered_tree.lock);
- set_bit(BTRFS_ORDERED_TRUNCATED, &ordered->flags);
- ASSERT(start - ordered->file_offset < U32_MAX);
- ordered->truncated_len = min_t(u32,
- ordered->truncated_len,
- start - ordered->file_offset);
- spin_unlock_irq(&inode->ordered_tree.lock);
-
- ASSERT(end - start + 1 < U32_MAX);
- if (btrfs_dec_test_ordered_pending(inode, &ordered,
- start,
- end - start + 1, 1))
{
- btrfs_finish_ordered_io(ordered);
- completed_ordered = true;
- }
- }
- btrfs_put_ordered_extent(ordered);
+ btrfs_qgroup_free_data(inode, NULL, cur, range_end + 1 - cur);
if (!inode_evicting) {
- cached_state = NULL;
- lock_extent_bits(tree, start, end,
- &cached_state);
- }
-
- start = end + 1;
- if (start < page_end)
- goto again;
- }
-
- /*
- * Qgroup reserved space handler
- * Page here will be either
- * 1) Already written to disk or ordered extent already submitted
- * Then its QGROUP_RESERVED bit in io_tree is already cleaned.
- * Qgroup will be handled by its qgroup_record then.
- * btrfs_qgroup_free_data() call will do nothing here.
- *
- * 2) Not written to disk yet
- * Then btrfs_qgroup_free_data() call will clear the QGROUP_RESERVED
- * bit of its io_tree, and free the qgroup reserved data space.
- * Since the IO will never happen for this page.
- */
- btrfs_qgroup_free_data(inode, NULL, page_start, PAGE_SIZE);
- if (!inode_evicting) {
- bool delete = true;
-
- /*
- * If there's an ordered extent for this range and we have not
- * finished it ourselves, we must leave EXTENT_DELALLOC_NEW set
- * in the range for the ordered extent completion. We must also
- * not delete the range, otherwise we would lose that bit (and
- * any other bits set in the range). Make sure EXTENT_UPTODATE
- * is cleared if we don't delete, otherwise it can lead to
- * corruptions if the i_size is extented later.
- */
- if (found_ordered && !completed_ordered)
- delete = false;
- clear_extent_bit(tree, page_start, page_end, EXTENT_LOCKED |
+ clear_extent_bit(tree, cur, range_end, EXTENT_LOCKED |
EXTENT_DELALLOC | EXTENT_UPTODATE |
EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 1,
- delete, &cached_state);
-
- __btrfs_releasepage(page, GFP_NOFS);
+ delete_states, &cached_state);
+ }
+ cur = range_end + 1;
}
-
+ if (!inode_evicting)
+ __btrfs_releasepage(page, GFP_NOFS);
ClearPageChecked(page);
clear_page_extent_mapped(page);
}
--
2.31.1
