diff options
| author | Christoph Hellwig <hch@lst.de> | 2019-10-18 16:40:17 -0700 |
|---|---|---|
| committer | Darrick J. Wong <darrick.wong@oracle.com> | 2019-10-21 08:51:59 -0700 |
| commit | 65a60e8687c1c8f69aae3e77eafbf4a54b9f99e7 (patch) | |
| tree | a1ac6dc5df533bb98d77e101289b01a9fd74470b /include/linux/iomap.h | |
| parent | 9cd0ed63ca51411af2c8323cbbeaa33d16c62688 (diff) | |
iomap: better document the IOMAP_F_* flags
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@lst.de>
Reviewed-by: Allison Collins <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Diffstat (limited to 'include/linux/iomap.h')
| -rw-r--r-- | include/linux/iomap.h | 31 |
1 files changed, 23 insertions, 8 deletions
diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 0f741eebf3a7..8016700e6121 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -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: |