[NFS-Ganesha-Devel] READDIR slowdown while write is in progress.

If a client starts writing a large file, then the READDIR from that directory seems to be stuck. Debugging further, it appears to be caused by a lock contention between FSAL merge (vfs_merge()) and write or commit FSAL functions. - Since write started first, OPEN would have created a new MDCACHE entry. - As part of READDIR, MDCACHE tries to create a new entry for the same file, so mdcache_new_entry() will reach obj_ops->merge(). This seems to get stuck trying to get the obj_lock in write mode. - Since client is sending multiple writes and commits, the readdir thread seems to be stuck until it can get the write lock in vfs_merge(). Can be reproduced by the following commands (latest Ganesha, VFS FSAL): Let's say, /gsh4 is the mount point - mkdir /gsh4/dir.1 - touch /gsh4/dir.1/file.{1..100} - dd if=/dev/zero of=/gsh4/dir.1/largefile bs=1M count=100000 & - ls /gsh4/dir.1 Note that any other client doing a READDIR will also be slow. Is there a way this path can be optimized? Wouldn't share_counters be zero in readdir path (meaning there isn't anything to merge)? Thanks, Pradeep