This creates a helper to manipulate page bits to avoid duplicate uses.
Signed-off-by: Liu Bo <bo.li....@oracle.com>
---
fs/btrfs/extent_io.c | 202 ++++++++++++++++++++++++---------------------------
fs/btrfs/extent_io.h | 3 +-
2 files changed, 98 insertions(+), 107 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index d5f3edb..136fe96 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1549,94 +1549,122 @@ static noinline u64 find_delalloc_range(struct
extent_io_tree *tree,
return found;
}
-static noinline void __unlock_for_delalloc(struct inode *inode,
- struct page *locked_page,
- u64 start, u64 end)
+/*
+ * index_ret: record where we stop
+ * This only returns errors when page_ops has PAGE_LOCK.
+ */
+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)
{
- int ret;
+ unsigned long nr_pages = end_index - start_index + 1;
+ pgoff_t index = start_index;
struct page *pages[16];
- unsigned long index = start >> PAGE_SHIFT;
- unsigned long end_index = end >> PAGE_SHIFT;
- unsigned long nr_pages = end_index - index + 1;
+ unsigned pages_locked = 0;
+ unsigned ret;
+ int err = 0;
int i;
- if (index == locked_page->index && end_index == index)
- return;
+ /*
+ * Do NOT skip locked_page since we may need to set PagePrivate2 on it.
+ */
- while (nr_pages > 0) {
- ret = find_get_pages_contig(inode->i_mapping, index,
- min_t(unsigned long, nr_pages,
- ARRAY_SIZE(pages)), pages);
- for (i = 0; i < ret; i++) {
- if (pages[i] != locked_page)
- unlock_page(pages[i]);
- put_page(pages[i]);
- }
- nr_pages -= ret;
- index += ret;
- cond_resched();
+ /* PAGE_LOCK should not be mixed with other ops. */
+ if (page_ops & PAGE_LOCK) {
+ ASSERT(page_ops == PAGE_LOCK);
+ ASSERT(index_ret);
+ ASSERT(*index_ret == start_index);
}
-}
-static noinline int lock_delalloc_pages(struct inode *inode,
- struct page *locked_page,
- u64 delalloc_start,
- u64 delalloc_end)
-{
- unsigned long index = delalloc_start >> PAGE_SHIFT;
- unsigned long start_index = index;
- unsigned long end_index = delalloc_end >> PAGE_SHIFT;
- unsigned long pages_locked = 0;
- struct page *pages[16];
- unsigned long nrpages;
- int ret;
- int i;
-
- /* the caller is responsible for locking the start index */
- if (index == locked_page->index && index == end_index)
- return 0;
+ if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
+ mapping_set_error(mapping, -EIO);
- /* skip the page at the start index */
- nrpages = end_index - index + 1;
- while (nrpages > 0) {
- ret = find_get_pages_contig(inode->i_mapping, index,
+ while (nr_pages > 0) {
+ ret = find_get_pages_contig(mapping, index,
min_t(unsigned long,
- nrpages, ARRAY_SIZE(pages)), pages);
+ nr_pages, ARRAY_SIZE(pages)), pages);
if (ret == 0) {
- ret = -EAGAIN;
- goto done;
- }
- /* now we have an array of pages, lock them all */
- for (i = 0; i < ret; i++) {
/*
- * the caller is taking responsibility for
- * locked_page
+ * Only if we're going to lock these pages, can we find
+ * nothing at @index.
*/
+ ASSERT(page_ops & PAGE_LOCK);
+ goto out;
+ }
+
+ for (i = 0; i < ret; i++) {
+ if (page_ops & PAGE_SET_PRIVATE2)
+ SetPagePrivate2(pages[i]);
+
if (pages[i] != locked_page) {
- lock_page(pages[i]);
- if (!PageDirty(pages[i]) ||
- pages[i]->mapping != inode->i_mapping) {
- ret = -EAGAIN;
+ if (page_ops & PAGE_CLEAR_DIRTY)
+ clear_page_dirty_for_io(pages[i]);
+ if (page_ops & PAGE_SET_WRITEBACK)
+ set_page_writeback(pages[i]);
+ if (page_ops & PAGE_SET_ERROR)
+ SetPageError(pages[i]);
+ if (page_ops & PAGE_END_WRITEBACK)
+ end_page_writeback(pages[i]);
+ if (page_ops & PAGE_UNLOCK)
unlock_page(pages[i]);
- put_page(pages[i]);
- goto done;
+ if (page_ops & PAGE_LOCK) {
+ lock_page(pages[i]);
+ if (!PageDirty(pages[i]) ||
+ pages[i]->mapping != mapping) {
+ unlock_page(pages[i]);
+ put_page(pages[i]);
+ err = -EAGAIN;
+ goto out;
+ }
}
}
put_page(pages[i]);
pages_locked++;
}
- nrpages -= ret;
+ nr_pages -= ret;
index += ret;
cond_resched();
}
- ret = 0;
-done:
- if (ret && pages_locked) {
- __unlock_for_delalloc(inode, locked_page,
- delalloc_start,
- ((u64)(start_index + pages_locked - 1)) <<
- PAGE_SHIFT);
+out:
+ if (err && index_ret) {
+ *index_ret = start_index + pages_locked - 1;
+ }
+ return err;
+}
+
+static noinline void __unlock_for_delalloc(struct inode *inode,
+ struct page *locked_page,
+ u64 start, u64 end)
+{
+ unsigned long page_ops = PAGE_UNLOCK;
+
+ ASSERT(locked_page);
+ __process_pages_contig(inode->i_mapping, locked_page,
+ start >> PAGE_SHIFT, end >> PAGE_SHIFT,
+ page_ops, NULL);
+}
+
+static noinline int lock_delalloc_pages(struct inode *inode,
+ struct page *locked_page,
+ u64 delalloc_start,
+ u64 delalloc_end)
+{
+ pgoff_t index = delalloc_start >> PAGE_SHIFT;
+ pgoff_t start_index = index;
+ pgoff_t end_index = delalloc_end >> PAGE_SHIFT;
+ unsigned long page_ops = PAGE_LOCK;
+ int ret = 0;
+
+ ASSERT(locked_page);
+
+ ret = __process_pages_contig(inode->i_mapping, locked_page, start_index,
+ end_index, page_ops, &index);
+ if (ret == -EAGAIN) {
+ __unlock_for_delalloc(inode, locked_page, delalloc_start,
+ ((u64)index) << PAGE_SHIFT);
}
+
return ret;
}
@@ -1732,49 +1760,11 @@ void extent_clear_unlock_delalloc(struct inode *inode,
u64 start, u64 end,
unsigned long page_ops)
{
struct extent_io_tree *tree = &BTRFS_I(inode)->io_tree;
- int ret;
- struct page *pages[16];
- unsigned long index = start >> PAGE_SHIFT;
- unsigned long end_index = end >> PAGE_SHIFT;
- unsigned long nr_pages = end_index - index + 1;
- int i;
clear_extent_bit(tree, start, end, clear_bits, 1, 0, NULL, GFP_NOFS);
- if (page_ops == 0)
- return;
-
- if ((page_ops & PAGE_SET_ERROR) && nr_pages > 0)
- mapping_set_error(inode->i_mapping, -EIO);
-
- while (nr_pages > 0) {
- ret = find_get_pages_contig(inode->i_mapping, index,
- min_t(unsigned long,
- nr_pages, ARRAY_SIZE(pages)), pages);
- for (i = 0; i < ret; i++) {
-
- if (page_ops & PAGE_SET_PRIVATE2)
- SetPagePrivate2(pages[i]);
-
- if (pages[i] == locked_page) {
- put_page(pages[i]);
- continue;
- }
- if (page_ops & PAGE_CLEAR_DIRTY)
- clear_page_dirty_for_io(pages[i]);
- if (page_ops & PAGE_SET_WRITEBACK)
- set_page_writeback(pages[i]);
- if (page_ops & PAGE_SET_ERROR)
- SetPageError(pages[i]);
- if (page_ops & PAGE_END_WRITEBACK)
- end_page_writeback(pages[i]);
- if (page_ops & PAGE_UNLOCK)
- unlock_page(pages[i]);
- put_page(pages[i]);
- }
- nr_pages -= ret;
- index += ret;
- cond_resched();
- }
+ __process_pages_contig(inode->i_mapping, locked_page,
+ start >> PAGE_SHIFT, end >> PAGE_SHIFT,
+ page_ops, NULL);
}
/*
diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 17f9ce4..4551a5b 100644
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -45,13 +45,14 @@
#define EXTENT_BUFFER_IN_TREE 10
#define EXTENT_BUFFER_WRITE_ERR 11 /* write IO error */
-/* these are flags for extent_clear_unlock_delalloc */
+/* these are flags for __process_pages_contig */
#define PAGE_UNLOCK (1 << 0)
#define PAGE_CLEAR_DIRTY (1 << 1)
#define PAGE_SET_WRITEBACK (1 << 2)
#define PAGE_END_WRITEBACK (1 << 3)
#define PAGE_SET_PRIVATE2 (1 << 4)
#define PAGE_SET_ERROR (1 << 5)
+#define PAGE_LOCK (1 << 6)
/*
* page->private values. Every page that is controlled by the extent
--
2.5.5
--
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