This is a note to let you know that I've just added the patch titled
Documentation: Add missing documentation for EXPORT_OP flags
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
documentation-add-missing-documentation-for-export_o.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c6533fd33aac7f52491c47d5289233ee21e923b3
Author: Chuck Lever <chuck.lever@xxxxxxxxxx>
Date: Fri Aug 25 15:04:23 2023 -0400
Documentation: Add missing documentation for EXPORT_OP flags
[ Upstream commit b38a6023da6a12b561f0421c6a5a1f7624a1529c ]
The commits that introduced these flags neglected to update the
Documentation/filesystems/nfs/exporting.rst file.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/Documentation/filesystems/nfs/exporting.rst b/Documentation/filesystems/nfs/exporting.rst
index 0e98edd353b5f..6f59a364f84cd 100644
--- a/Documentation/filesystems/nfs/exporting.rst
+++ b/Documentation/filesystems/nfs/exporting.rst
@@ -215,3 +215,29 @@ following flags are defined:
This flag causes nfsd to close any open files for this inode _before_
calling into the vfs to do an unlink or a rename that would replace
an existing file.
+
+ EXPORT_OP_REMOTE_FS - Backing storage for this filesystem is remote
+ PF_LOCAL_THROTTLE exists for loopback NFSD, where a thread needs to
+ write to one bdi (the final bdi) in order to free up writes queued
+ to another bdi (the client bdi). Such threads get a private balance
+ of dirty pages so that dirty pages for the client bdi do not imact
+ the daemon writing to the final bdi. For filesystems whose durable
+ storage is not local (such as exported NFS filesystems), this
+ constraint has negative consequences. EXPORT_OP_REMOTE_FS enables
+ an export to disable writeback throttling.
+
+ EXPORT_OP_NOATOMIC_ATTR - Filesystem does not update attributes atomically
+ EXPORT_OP_NOATOMIC_ATTR indicates that the exported filesystem
+ cannot provide the semantics required by the "atomic" boolean in
+ NFSv4's change_info4. This boolean indicates to a client whether the
+ returned before and after change attributes were obtained atomically
+ with the respect to the requested metadata operation (UNLINK,
+ OPEN/CREATE, MKDIR, etc).
+
+ EXPORT_OP_FLUSH_ON_CLOSE - Filesystem flushes file data on close(2)
+ On most filesystems, inodes can remain under writeback after the
+ file is closed. NFSD relies on client activity or local flusher
+ threads to handle writeback. Certain filesystems, such as NFS, flush
+ all of an inode's dirty data on last close. Exports that behave this
+ way should set EXPORT_OP_FLUSH_ON_CLOSE so that NFSD knows to skip
+ waiting for writeback when closing such files.
