Adding upstream version 14.2.21.upstream/14.2.21upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/doc/cephfs/lazyio.rst b/doc/cephfs/lazyio.rst
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+======
+LazyIO
+======
+
+LazyIO relaxes POSIX semantics. Buffered reads/writes are allowed even when a
+file is opened by multiple applications on multiple clients. Applications are
+responsible for managing cache coherency themselves.
+
+Libcephfs supports LazyIO since nautilus release.
+
+Enable LazyIO
+=============
+
+LazyIO can be enabled by following ways.
+
+- ``client_force_lazyio`` option enables LAZY_IO globally for libcephfs and
+  ceph-fuse mount.
+
+- ``ceph_lazyio(...)`` and ``ceph_ll_lazyio(...)`` enable LAZY_IO for file handle
+  in libcephfs.
+
+- ``ioctl(fd, CEPH_IOC_LAZYIO, 1UL)`` enables LAZY_IO for file handle in
+   ceph-fuse mount.