Add a row for this option in the Options table. Signed-off-by: Tingmao Wang <m@xxxxxxxxxx> --- New patch in v2 Documentation/filesystems/9p.rst | 42 ++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) diff --git a/Documentation/filesystems/9p.rst b/Documentation/filesystems/9p.rst index be3504ca034a..8b570a7ae698 100644 --- a/Documentation/filesystems/9p.rst +++ b/Documentation/filesystems/9p.rst @@ -238,6 +238,48 @@ Options cachetag cache tag to use the specified persistent cache. cache tags for existing cache sessions can be listed at /sys/fs/9p/caches. (applies only to cache=fscache) + + inodeident this setting controls how inodes work on this filesystem. + More specifically, how they are "reused". This is most + relevant when used with features like Landlock and + fanotify (in inode mark mode). These features rely on + holding a specific inode and identifying further access to + the same file (as identified by that inode). + + There are 2 possible values: + qid + This is the default and the only possible + option if loose or metadata cache is + enabled. In this mode, 9pfs assumes that + the server will not present different + files with the same inode number, and will + use the presented inode number to lookup + inodes. For QEMU users, this can be + ensured by setting multidevs=remap. If + the server does present inode number + collisions, this may lead to unpredictable + behaviour when both files are accessed. + path + This is the default if neither loose nor + metadata cache bits are enabled. This + option causes 9pfs to internally track the + file path that an inode originated from, + and will only use an existing inode + (instead of allocating a new one) if the + path matches, even if the file's inode + number matches that of an existing inode. + + .. note:: + For inodeident=path, when a directory is renamed + or moved, inodeident=path mode currently does not + update its children's inodes to point to the new + path, and thus further access to them via the new + location will use newly allocated inodes, and + existing inode marks placed by Landlock and + fanotify on them will no longer work. + + The inode path for the target being renamed itself + (not its children) *is* updated, however. ============= =============================================================== Behavior -- 2.51.0
