On Wed, May 31, 2017 at 08:45:23AM -0400, Jeff Layton wrote: > v5: don't retrofit old API over the new infrastructure > add fstype flag to indicate how wb errors are tracked within that fs > add more function variants that take a errseq_t "since" value > add second errseq_t to struct file to track metadata wb errors > convert ext4 and ext2 to use the new APIs > > v4: several more cleanup patches > documentation and kerneldoc comment updates > fix bugs in gfs2 patches > make sync_file_range use same error reporting semantics > bugfixes in buffer.c > convert nfs to new scheme (maybe bogus, can be dropped) > > v3: wb_err_t -> errseq_t conversion > clean up places that re-set errors after calling filemap_* functions > > v2: introduce wb_err_t, use atomics > > This is v5 of the patchset to improve how we're tracking and reporting > errors that occur during pagecache writeback. The main difference in > this set from the last one is that I've stopped trying to retrofit the > old error tracking API on top of the new one. This is more work since > we'll have to touch each fs individually, but should be safer as the > "since" values used for checking errors will be more deliberate. > > There are several situations where the kernel can "lose" errors that > occur during writeback, such that fsync will return success even > though it failed to write back some data previously. The basic idea > here is to have the kernel be more deliberate about the point from > which errors are checked to ensure that that doesn't happen. > > An additional aim of this set is to change the behavior of fsync in > Linux to report writeback errors on all fds instead of just the first > one. This allows writers to reliably tell whether their data made it to > the backing device without having to coordinate fsync calls with other > writers. > > To do this, we add a new typedef: errseq_t. This is a 32-bit value > that can store an error code, and a sequence number so we can tell > whether it has changed since we last sampled it. This allows us to > record errors in the address_space and then report those errors only > once per file description. > > This set just alters block device files, ext4 and the legacy ext2 > driver. If this general approach seems acceptable, then I'll start > converting other filesystems in follow-on patchsets. I'd also like > to get this into linux-next as soon as possible to ensure that we're > banging out any bugs that might be lurking here. > > I also have a couple of xfstests for this as well that I'll re-post > soon. Can you tell me a baseline that this applies cleanly to, or give me a link to a tree with these patches already applied? I've tried applying it to v4.11, linux/master and mmots/master, and so far nothing has worked.
