I'm encountering premature ENOSPC issues recently where my Btrfs testing partition will either prematurely return an ENOSPC, or lock up the operations trying to access the partition. I have bisected the problem to this commit: http://git.kernel.org/?p=linux/kernel/git/mason/btrfs-unstable.git;a=commit;h=914ee295af418e936ec20a08c1663eaabe4cd07a (Btrfs: pwrite blocked when writing from the mmaped buffer of the same page) I am encountering the problem on a small-ish 3.5 GB Btrfs partition. I can replicate the problem with and without compression. I can also replicate the problem with and without reformating the partition. For most operations I run on this partition, Btrfs is performing without error. But when I compile openmotif-2.3.3 on a kernel that is after the above referenced commit, I'll get either an ENOSPC error or the partition locks up. When I encounter a lock-up issue, there are no errors in dmesg, and no delayed processes are showing (unless I try to run an additional operation on that partition, such as 'ls', which will subsequently show up as delayed). However, the build process for openmotif-2.3.3 appears frozen, and several processes related to the build are shown as running, and will not even respond to 'kill -s 9 <pid>' The partition only has about 500 MB of data when I encounter the problems, and openmotif-2.3.3 typically only requires about 30-60 MB to compile. However, running 'btrfs fi show' indicates that btrfs has attempted to reserve all the space on the disk for data and metadata. When running a kernel prior to the above referenced commit, btrfs will compile openmotif-2.3.3 without needing to reserve much extra space on the partition. Let me know if you would like any additional information or tests. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
