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[v1] Documentation: Add missing documentation for EXPORT_OP flags

Message ID 169299026325.2390.1015871591753526415.stgit@manet.1015granger.net (mailing list archive)
State New, archived
Headers show
Series [v1] Documentation: Add missing documentation for EXPORT_OP flags | expand

Commit Message

Chuck Lever Aug. 25, 2023, 7:04 p.m. UTC 
From: Chuck Lever <chuck.lever@oracle.com>

The commits that introduced these flags neglected to update the
Documentation/filesystems/nfs/exporting.rst file.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 Documentation/filesystems/nfs/exporting.rst |   25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
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Patch

diff --git a/Documentation/filesystems/nfs/exporting.rst b/Documentation/filesystems/nfs/exporting.rst
index 3d97b8d8f735..02c8c6e9cdb2 100644
--- a/Documentation/filesystems/nfs/exporting.rst
+++ b/Documentation/filesystems/nfs/exporting.rst
@@ -215,3 +215,28 @@  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 loop-back 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_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.