Looks good to me, I think the new comments are a lot more helpful
Reviewed-by: Allison Collins <allison.henderson@xxxxxxxxxx>
On 9/9/19 11:27 AM, Christoph Hellwig wrote:
The documentation for IOMAP_F_* is a bit disorganized, and doesn't
mention the fact that most flags are set by the file system and consumed
by the iomap core, while IOMAP_F_SIZE_CHANGED is set by the core and
consumed by the file system.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
include/linux/iomap.h | 31 +++++++++++++++++++++++--------
1 file changed, 23 insertions(+), 8 deletions(-)
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index e79af6b28410..8adcc8dd4498 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -30,21 +30,36 @@ struct vm_fault;
#define IOMAP_INLINE 0x05 /* data inline in the inode */
/*
- * Flags for all iomap mappings:
+ * Flags reported by the file system from iomap_begin:
+ *
+ * IOMAP_F_NEW indicates that the blocks have been newly allocated and need
+ * zeroing for areas that no data is copied to.
*
* IOMAP_F_DIRTY indicates the inode has uncommitted metadata needed to access
* written data and requires fdatasync to commit them to persistent storage.
+ *
+ * IOMAP_F_SHARED indicates that the blocks are shared, and will need to be
+ * unshared as part a write.
+ *
+ * IOMAP_F_MERGED indicates that the iomap contains the merge of multiple block
+ * mappings.
+ *
+ * IOMAP_F_BUFFER_HEAD indicates that the file system requires the use of
+ * buffer heads for this mapping.
*/
-#define IOMAP_F_NEW 0x01 /* blocks have been newly allocated */
-#define IOMAP_F_DIRTY 0x02 /* uncommitted metadata */
-#define IOMAP_F_BUFFER_HEAD 0x04 /* file system requires buffer heads */
-#define IOMAP_F_SIZE_CHANGED 0x08 /* file size has changed */
+#define IOMAP_F_NEW 0x01
+#define IOMAP_F_DIRTY 0x02
+#define IOMAP_F_SHARED 0x04
+#define IOMAP_F_MERGED 0x08
+#define IOMAP_F_BUFFER_HEAD 0x10
/*
- * Flags that only need to be reported for IOMAP_REPORT requests:
+ * Flags set by the core iomap code during operations:
+ *
+ * IOMAP_F_SIZE_CHANGED indicates to the iomap_end method that the file size
+ * has changed as the result of this write operation.
*/
-#define IOMAP_F_MERGED 0x10 /* contains multiple blocks/extents */
-#define IOMAP_F_SHARED 0x20 /* block shared with another file */
+#define IOMAP_F_SIZE_CHANGED 0x100
/*
* Flags from 0x1000 up are for file system specific usage:
