Kernel message
Whoops: end_buffer_io_async: async io complete on unlocked pageappears occasionally. Not a good sign.
Error conditions are not handled too well. That is, if your disk gets corrupted, then it's possible for the kernel to hang. Note that the same caveat has always applied to the ext2 filesystem and people don't complain too much, but this is a problem it would be good to reduce or remove (in e2compr code, at least).
No other known bugs apply to the kernel. However, see sections Stability Comments and the TODO page of the manual.
There are no known bugs as such in e2fsprogs (i.e. e2fsck
and others), but if your computer goes down while some
files are being ext2-compressed, then e2fsck isn't
as good at restoring things to a consistent state as it should be.
The NOCOMPR flag should be scrapped; we can use an
appropriate combination of O_NOTRANS and mandatory
locking instead.
Anything else that you'd like to add, write to the e2compr mailing list or maintainer.
e2compr has been around since Linux 1.2. Many people say they've been using e2compr for years, without any problems.
People's good experience should be balanced by what's written under the bugs section above, of course.
Some time ago, Peter did a couple of simple stress tests (looping
around `make -j' in /usr/src/linux for a few
hours while doing `cp -R' with a couple of directories,
which is an attempt to catch race conditions) but no-one's done any
serious (as in methodical, exhaustive) testing. Some other people
using Antoine's patches for 1.2.13 or 1.3.56 commented that they'd had
no problems. Antoine says that the patch for linux-1.2 did receive
serious testing, but no-one else knows what the nature of that testing
was.