This way the implementation doesn't depend on buffer_head internals.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/iomap.c | 85 +++++++++++++++++++++++++-----------------------------
1 file changed, 39 insertions(+), 46 deletions(-)
diff --git a/fs/iomap.c b/fs/iomap.c
index bef5e91d40bf..0900da23172c 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -589,36 +589,51 @@ int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi,
}
EXPORT_SYMBOL_GPL(iomap_fiemap);
-/*
- * Seek for SEEK_DATA / SEEK_HOLE within @page, starting at @lastoff.
- *
- * Returns the offset within the file on success, and -ENOENT otherwise.
- */
-static loff_t
-page_seek_hole_data(struct page *page, loff_t lastoff, int whence)
+static bool
+page_seek_hole_data(struct inode *inode, struct page *page, loff_t *lastoff,
+ int whence)
{
- loff_t offset = page_offset(page);
- struct buffer_head *bh, *head;
+ const struct address_space_operations *ops = inode->i_mapping->a_ops;
+ unsigned int bsize = i_blocksize(inode), off;
bool seek_data = whence == SEEK_DATA;
+ loff_t poff = page_offset(page);
- if (lastoff < offset)
- lastoff = offset;
-
- bh = head = page_buffers(page);
- do {
- offset += bh->b_size;
- if (lastoff >= offset)
- continue;
+ if (WARN_ON_ONCE(*lastoff >= poff + PAGE_SIZE))
+ return false;
+ if (*lastoff < poff) {
/*
- * Any buffer with valid data in it should have BH_Uptodate set.
+ * Last offset smaller than the start of the page means we found
+ * a hole:
*/
- if (buffer_uptodate(bh) == seek_data)
- return lastoff;
+ if (whence == SEEK_HOLE)
+ return true;
+ *lastoff = poff;
+ }
+
+ /*
+ * Just check the page unless we can and should check block ranges:
+ */
+ if (bsize == PAGE_SIZE || !ops->is_partially_uptodate)
+ return PageUptodate(page) == seek_data;
- lastoff = offset;
- } while ((bh = bh->b_this_page) != head);
- return -ENOENT;
+ lock_page(page);
+ if (unlikely(page->mapping != inode->i_mapping))
+ goto out_unlock_not_found;
+
+ for (off = 0; off < PAGE_SIZE; off += bsize) {
+ if ((*lastoff & ~PAGE_MASK) >= off + bsize)
+ continue;
+ if (ops->is_partially_uptodate(page, off, bsize) == seek_data) {
+ unlock_page(page);
+ return true;
+ }
+ *lastoff = poff + off + bsize;
+ }
+
+out_unlock_not_found:
+ unlock_page(page);
+ return false;
}
/*
@@ -655,30 +670,8 @@ page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length,
for (i = 0; i < nr_pages; i++) {
struct page *page = pvec.pages[i];
- /*
- * At this point, the page may be truncated or
- * invalidated (changing page->mapping to NULL), or
- * even swizzled back from swapper_space to tmpfs file
- * mapping. However, page->index will not change
- * because we have a reference on the page.
- *
- * If current page offset is beyond where we've ended,
- * we've found a hole.
- */
- if (whence == SEEK_HOLE &&
- lastoff < page_offset(page))
+ if (page_seek_hole_data(inode, page, &lastoff, whence))
goto check_range;
-
- lock_page(page);
- if (likely(page->mapping == inode->i_mapping) &&
- page_has_buffers(page)) {
- lastoff = page_seek_hole_data(page, lastoff, whence);
- if (lastoff >= 0) {
- unlock_page(page);
- goto check_range;
- }
- }
- unlock_page(page);
lastoff = page_offset(page) + PAGE_SIZE;
}
pagevec_release(&pvec);
--
2.17.0
--
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