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: -- 2.20.1
