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-rw-r--r--fs/iomap/buffered-io.c30
1 files changed, 18 insertions, 12 deletions
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index ae8673ce08b1..644479ccefbd 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -640,11 +640,13 @@ static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos,
size_t poff, plen;
/*
- * If the write completely overlaps the current folio, then
+ * If the write or zeroing completely overlaps the current folio, then
* entire folio will be dirtied so there is no need for
* per-block state tracking structures to be attached to this folio.
+ * For the unshare case, we must read in the ondisk contents because we
+ * are not changing pagecache contents.
*/
- if (pos <= folio_pos(folio) &&
+ if (!(iter->flags & IOMAP_UNSHARE) && pos <= folio_pos(folio) &&
pos + len >= folio_pos(folio) + folio_size(folio))
return 0;
@@ -1261,7 +1263,6 @@ static loff_t iomap_unshare_iter(struct iomap_iter *iter)
const struct iomap *srcmap = iomap_iter_srcmap(iter);
loff_t pos = iter->pos;
loff_t length = iomap_length(iter);
- long status = 0;
loff_t written = 0;
/* don't bother with blocks that are not shared to start with */
@@ -1272,28 +1273,33 @@ static loff_t iomap_unshare_iter(struct iomap_iter *iter)
return length;
do {
- unsigned long offset = offset_in_page(pos);
- unsigned long bytes = min_t(loff_t, PAGE_SIZE - offset, length);
struct folio *folio;
+ int status;
+ size_t offset;
+ size_t bytes = min_t(u64, SIZE_MAX, length);
status = iomap_write_begin(iter, pos, bytes, &folio);
if (unlikely(status))
return status;
- if (iter->iomap.flags & IOMAP_F_STALE)
+ if (iomap->flags & IOMAP_F_STALE)
break;
- status = iomap_write_end(iter, pos, bytes, bytes, folio);
- if (WARN_ON_ONCE(status == 0))
+ offset = offset_in_folio(folio, pos);
+ if (bytes > folio_size(folio) - offset)
+ bytes = folio_size(folio) - offset;
+
+ bytes = iomap_write_end(iter, pos, bytes, bytes, folio);
+ if (WARN_ON_ONCE(bytes == 0))
return -EIO;
cond_resched();
- pos += status;
- written += status;
- length -= status;
+ pos += bytes;
+ written += bytes;
+ length -= bytes;
balance_dirty_pages_ratelimited(iter->inode->i_mapping);
- } while (length);
+ } while (length > 0);
return written;
}