diff options
| -rw-r--r-- | Documentation/filesystems/iomap/operations.rst | 16 | ||||
| -rw-r--r-- | fs/iomap/direct-io.c | 4 | ||||
| -rw-r--r-- | include/linux/iomap.h | 8 |
3 files changed, 24 insertions, 4 deletions
diff --git a/Documentation/filesystems/iomap/operations.rst b/Documentation/filesystems/iomap/operations.rst index 0b9d7be23bce..b08a79d11d9f 100644 --- a/Documentation/filesystems/iomap/operations.rst +++ b/Documentation/filesystems/iomap/operations.rst @@ -526,8 +526,20 @@ IOMAP_WRITE`` with any combination of the following enhancements: conversion or copy on write), all updates for the entire file range must be committed atomically as well. Only one space mapping is allowed per untorn write. - Untorn writes must be aligned to, and must not be longer than, a - single file block. + Untorn writes may be longer than a single file block. In all cases, + the mapping start disk block must have at least the same alignment as + the write offset. + + * ``IOMAP_ATOMIC_SW``: This write is being issued with torn-write + protection via a software mechanism provided by the filesystem. + All the disk block alignment and single bio restrictions which apply + to IOMAP_ATOMIC_HW do not apply here. + SW-based untorn writes would typically be used as a fallback when + HW-based untorn writes may not be issued, e.g. the range of the write + covers multiple extents, meaning that it is not possible to issue + a single bio. + All filesystem metadata updates for the entire file range must be + committed atomically as well. Callers commonly hold ``i_rwsem`` in shared or exclusive mode before calling this function. diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index c696ce980796..c594f2cf3ab4 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -686,7 +686,9 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, iomi.flags |= IOMAP_OVERWRITE_ONLY; } - if (iocb->ki_flags & IOCB_ATOMIC) + if (dio_flags & IOMAP_DIO_ATOMIC_SW) + iomi.flags |= IOMAP_ATOMIC_SW; + else if (iocb->ki_flags & IOCB_ATOMIC) iomi.flags |= IOMAP_ATOMIC_HW; /* for data sync or sync, we need sync completion processing */ diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 87cd7079aaf3..9cd93530013c 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -189,8 +189,9 @@ struct iomap_folio_ops { #else #define IOMAP_DAX 0 #endif /* CONFIG_FS_DAX */ -#define IOMAP_ATOMIC_HW (1 << 9) +#define IOMAP_ATOMIC_HW (1 << 9) /* HW-based torn-write protection */ #define IOMAP_DONTCACHE (1 << 10) +#define IOMAP_ATOMIC_SW (1 << 11)/* SW-based torn-write protection */ struct iomap_ops { /* @@ -502,6 +503,11 @@ struct iomap_dio_ops { */ #define IOMAP_DIO_PARTIAL (1 << 2) +/* + * Use software-based torn-write protection. + */ +#define IOMAP_DIO_ATOMIC_SW (1 << 3) + 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, void *private, size_t done_before); |