diff options
| -rw-r--r-- | fs/iomap/direct-io.c | 7 | ||||
| -rw-r--r-- | include/linux/iomap.h | 8 |
2 files changed, 15 insertions, 0 deletions
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index 947343730e2c..65d32364345d 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -485,6 +485,13 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, iomap_flags |= IOMAP_NOWAIT; } + if (dio_flags & IOMAP_DIO_OVERWRITE_ONLY) { + ret = -EAGAIN; + if (pos >= dio->i_size || pos + count > dio->i_size) + goto out_free_dio; + iomap_flags |= IOMAP_OVERWRITE_ONLY; + } + ret = filemap_write_and_wait_range(mapping, pos, end); if (ret) goto out_free_dio; diff --git a/include/linux/iomap.h b/include/linux/iomap.h index be4e1e1e01e8..1a86f520de56 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -122,6 +122,7 @@ struct iomap_page_ops { #define IOMAP_FAULT (1 << 3) /* mapping for page fault */ #define IOMAP_DIRECT (1 << 4) /* direct I/O */ #define IOMAP_NOWAIT (1 << 5) /* do not block */ +#define IOMAP_OVERWRITE_ONLY (1 << 6) /* only pure overwrites allowed */ struct iomap_ops { /* @@ -262,6 +263,13 @@ struct iomap_dio_ops { */ #define IOMAP_DIO_FORCE_WAIT (1 << 0) +/* + * Do not allocate blocks or zero partial blocks, but instead fall back to + * the caller by returning -EAGAIN. Used to optimize direct I/O writes that + * are not aligned to the file system block size. + */ +#define IOMAP_DIO_OVERWRITE_ONLY (1 << 1) + ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, const struct iomap_ops *ops, const struct iomap_dio_ops *dops, unsigned int dio_flags); |