Miklos, While going over the code to prepare for getattr() passthrough I experienced a WTF moment that resulted in the two fix patches. Patch 3/3 is included for reference and to give Sweet Tea a starting point for getattr() passthrough. What puzzled me is that some ff->iomode state bugs were so blunt that I needed to figure out how I did not see any WARN_ON in my tests of rc1. There are different reasons for different types of bugs. 1. For concurrent dio writes without any passthrough open, fuse_file_cached_io_start() was supposed to hit WARN_ON(ff->iomode == IOM_UNCACHED) if there is already a dio write in-flight. My conclusion is that the set of fstests that run on passthrough_hp, on my small test VM do not excercise concurrent dio writes. 2. For dio write, where the file was opened passthrough, every write was going to hit WARN_ON(ff->iomode == IOM_UNCACHED) and also fuse_file_cached_io_end() was going to set ff->iomode == IOM_NONE and leak the fuse_backing object. However, the bug fixed by patch 2/3 made sure that parallel dio write would always fallback to exclusive dio if file was open with a backing file. Testing: I ran fstests with passthrough_hp with options: 1) FOPEN_PASSTHROUGH 2) FOPEN_DIRECT_IO | FOPEN_PARALLEL_DIRECT_WRITES 3) FOPEN_PASSTHROUGH | FOPEN_DIRECT_IO | FOPEN_PARALLEL_DIRECT_WRITES Did not observe any regressions (not any improvments) from rc1. Ran some multi threads aiodio tests with just patch 2/3 and the assertions in fuse_evict_inode() from patch 3/3. First two configs did not hit any assertion. The passthrough+direct_io+parallel_direct_writes config always hits the assertion in fuse_file_cached_io_start() and always hits the leaked fuse_backing assertion in fuse_evict_inode(). Bernd do you have different tests to cover concurrent dio writes in your setup? Any ideas on how to improve the fstests test coverage? Thanks, Amir. Amir Goldstein (3): fuse: fix wrong ff->iomode state changes from parallel dio write fuse: fix parallel dio write on file open in passthrough mode fuse: prepare for long lived reference on backing file fs/fuse/file.c | 18 +++++++----- fs/fuse/fuse_i.h | 10 +++++-- fs/fuse/inode.c | 7 +++++ fs/fuse/iomode.c | 73 +++++++++++++++++++++++++++++++++--------------- 4 files changed, 76 insertions(+), 32 deletions(-) -- 2.34.1
