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Diffstat (limited to 'Documentation/filesystems/nfs/exporting.rst')
| -rw-r--r-- | Documentation/filesystems/nfs/exporting.rst | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/Documentation/filesystems/nfs/exporting.rst b/Documentation/filesystems/nfs/exporting.rst index 3d97b8d8f735..4b30daee399a 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. |