[LU-15856] "lfs setdirstripe -D ... <dir>" should create directory if missing

• Type: Improvement
• Resolution: Unresolved
• Priority: Minor
• Affects Version/s: Lustre 2.14.0, Lustre 2.12.4
• Assignee: Lai Siyao
• Reporter: Andreas Dilger

Description

Currently, "lfs setdirstripe -D <layout> <dir>" will fail if "<dir>" does not already exist. However, from a usability point of view, it would make sense for the "lfs" utility to create the target "<dir>" if it does not yet exist using the specified "<layout>", and then set the same default "<layout>" on the directory for subdirectories created therein. It doesn't make sense to force the user to run the command twice to do this.

In the ideal case, the client could send a single "MDS_REINT" RPC to the MDS with "<layout>", the same as "lfs mkdir <layout> <dir>" and just add a flag that indicates "store the same layout as the default", rather than having to send two separate RPCs. However, for compatibility with older MDS nodes, and to backport this fix to older releases, it makes sense for "lfs_setdirstripe()" to handle this in userspace if the "llapi_dir_set_default_lmv()" command fails with "-ENOENT" by calling "llapi_dir_create()" and then retrying "llapi_dir_set_default_lmv()" once.

Issue Links

• Clones: LU-13560 'lfs mkdir -i N' should be 'sticky' on a particular MDT
• is related to: LU-5170 lfs usability
• is related to: LU-13417 DNE3: mkdir() automatically create remote directory on MDS which has more space
• is related to: LU-10784 DNE3: mkdir() automatically create remote directory on MDS which has more space