iomap: better document the IOMAP_F_* flags (65a60e86) · Commits · 戴 / test

include/linux/iomap.h

+23 −8

Original line number	Diff line number	Diff line
		@@ -30,23 +30,38 @@ 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.
		* This needs to take into account metadata changes that may be made at IO
		* completion, such as file size updates from direct IO.
		*
		* 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:

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