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Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/nfs/exporting.rst | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/Documentation/filesystems/nfs/exporting.rst b/Documentation/filesystems/nfs/exporting.rst index cbe542ad5233..960be64446cb 100644 --- a/Documentation/filesystems/nfs/exporting.rst +++ b/Documentation/filesystems/nfs/exporting.rst @@ -190,3 +190,15 @@ following flags are defined: this on filesystems that have an expensive ->getattr inode operation, or when atomicity between pre and post operation attribute collection is impossible to guarantee. + + EXPORT_OP_NOSUBTREECHK - disallow subtree checking on this fs + Many NFS operations deal with filehandles, which the server must then + vet to ensure that they live inside of an exported tree. When the + export consists of an entire filesystem, this is trivial. nfsd can just + ensure that the filehandle live on the filesystem. When only part of a + filesystem is exported however, then nfsd must walk the ancestors of the + inode to ensure that it's within an exported subtree. This is an + expensive operation and not all filesystems can support it properly. + This flag exempts the filesystem from subtree checking and causes + exportfs to get back an error if it tries to enable subtree checking + on it. |