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Diffstat (limited to 'Documentation/filesystems/iomap/operations.rst')
| -rw-r--r-- | Documentation/filesystems/iomap/operations.rst | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/Documentation/filesystems/iomap/operations.rst b/Documentation/filesystems/iomap/operations.rst index b93115ab8748..ef082e5a4e0c 100644 --- a/Documentation/filesystems/iomap/operations.rst +++ b/Documentation/filesystems/iomap/operations.rst @@ -513,6 +513,21 @@ IOMAP_WRITE`` with any combination of the following enhancements: if the mapping is unwritten and the filesystem cannot handle zeroing the unaligned regions without exposing stale contents. + * ``IOMAP_ATOMIC``: This write is being issued with torn-write + protection. + Only a single bio can be created for the write, and the write must + not be split into multiple I/O requests, i.e. flag REQ_ATOMIC must be + set. + The file range to write must be aligned to satisfy the requirements + of both the filesystem and the underlying block device's atomic + commit capabilities. + If filesystem metadata updates are required (e.g. unwritten extent + 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. + Callers commonly hold ``i_rwsem`` in shared or exclusive mode before calling this function. |