lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 14 Apr 2022 14:51:21 +0100 From: Luís Henriques <lhenriques@...e.de> To: Jeff Layton <jlayton@...nel.org>, Xiubo Li <xiubli@...hat.com>, Ilya Dryomov <idryomov@...il.com> Cc: ceph-devel@...r.kernel.org, linux-kernel@...r.kernel.org, Luís Henriques <lhenriques@...e.de> Subject: [PATCH v4 3/4] ceph: update documentation regarding snapshot naming limitations Signed-off-by: Luís Henriques <lhenriques@...e.de> --- Documentation/filesystems/ceph.rst | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/Documentation/filesystems/ceph.rst b/Documentation/filesystems/ceph.rst index 4942e018db85..d487cabe792d 100644 --- a/Documentation/filesystems/ceph.rst +++ b/Documentation/filesystems/ceph.rst @@ -57,6 +57,16 @@ a snapshot on any subdirectory (and its nested contents) in the system. Snapshot creation and deletion are as simple as 'mkdir .snap/foo' and 'rmdir .snap/foo'. +Snapshot names have two limitations: + +* They can not start with an underscore ('_'), as these names are reserved + for internal usage by the MDS. +* They can not exceed 240 characters in size. This is because the MDS makes + use of long snapshot names internally, which follow the format: + `_<SNAPSHOT-NAME>_<INODE-NUMBER>`. Since filenames in general can't have + more than 255 characters, and `<node-id>` takes 13 characters, the long + snapshot names can take as much as 255 - 1 - 1 - 13 = 240. + Ceph also provides some recursive accounting on directories for nested files and bytes. That is, a 'getfattr -d foo' on any directory in the system will reveal the total number of nested regular files and
Powered by blists - more mailing lists