PostgreSQL throwing "53100: could not extend file "base/xxxxx/xxxxx" with FileFallocate()" despite ample space in the volume

I recently upgraded PostgreSQL 14 to PostgreSQL 16 using --clone method. Both my data directories (old & new cluster) were on same volume. After few days, I started receiving below error. > 53100: could not extend file "base/160560/t64_168297303" with FileFallocate(): No space left on device Time when errors occur, I checked the volume free size using (df -hT) and found that more than 30% of space is available in the volume. In all cases, the query which gives this error is CREATE TEMP TABLE query. I also checked free iondes during same time (df -i) and found that there were enough available. I also removed old data directory but that did not resolve the error. I have one primary server and 1 replica server in async replication using patroni. PostgreSQL Version : PostgreSQL 16.6 (Ubuntu 16.6-1.pgdg22.04+1) on x86_64-pc-linux-gnu, compiled by gcc (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0, 64-bit I was able to manually create a large file of 40 GB using fallocate successfully which pushed the used space on volume up to 96%. It is an EBS volume attached to EC2 which storing nothing else but PG 16 data directory which has symbolic link of pg_wal pointing to different volume. I kept volume size at 96% and waited for a period where the error usually occurs but it didn't. One thing to mention: after removing the old PG 14 data directory, the error has occurred only once. Earlier, there were many occurrences but not continuous.