JAGNYA DATTA TRIPATHY has uploaded this change for review. ( https://review.gerrithub.io/c/ffilz/nfs-ganesha/+/1258747?usp=email ) Change subject: MDCACHE: keep chunk num_entries exact and guard the split ...................................................................... MDCACHE: keep chunk num_entries exact and guard the split unchunk_dirent() removes a dirent from its chunk's dirent list but does not decrement chunk->num_entries. place_new_dirent() increments it on every insert, so on a cached directory each rename (remove plus insert) drives the counter one above the real list length. place_new_dirent() splits a chunk when num_entries reaches avl_chunk_split (192 with the default Dir_Chunk of 128). If the list is really shorter than avl_chunk_split / 2, the scan for the split point finds nothing, "here" stays NULL, and the following LogFullDebugAlt dereferences here->name. Release builds crash; debug builds hit the assert. With 3 entries in a cached directory the crash comes after 189 alternating renames of one file (seen in the cthon04 basic rename test). Decrement num_entries in unchunk_dirent() so it always equals the list length; every removal goes through it, and mdcache_clean_dirent_chunk() resets the count to 0 afterwards as before. In place_new_dirent(), scan for the split point before allocating the new chunk, and if there is none, log LogCrit, resync the counter and skip the split instead of dereferencing NULL. Change-Id: Ie1dee6417b331dcb33c849a8920a65d5110b14d4 Signed-off-by: Jagnya Datta Tripathy <jagnya.tripathy@gmail.com> --- M src/FSAL/Stackable_FSALs/FSAL_MDCACHE/mdcache_avl.c M src/FSAL/Stackable_FSALs/FSAL_MDCACHE/mdcache_helpers.c 2 files changed, 31 insertions(+), 11 deletions(-) git pull ssh://review.gerrithub.io:29418/ffilz/nfs-ganesha refs/changes/47/1258747/1 -- To view, visit https://review.gerrithub.io/c/ffilz/nfs-ganesha/+/1258747?usp=email To unsubscribe, or for help writing mail filters, visit https://review.gerrithub.io/settings?usp=email Gerrit-MessageType: newchange Gerrit-Project: ffilz/nfs-ganesha Gerrit-Branch: next Gerrit-Change-Id: Ie1dee6417b331dcb33c849a8920a65d5110b14d4 Gerrit-Change-Number: 1258747 Gerrit-PatchSet: 1 Gerrit-Owner: JAGNYA DATTA TRIPATHY <jagnya.tripathy@gmail.com>