On Wed, Jan 15, 2020 at 9:28 AM Ondrej Holy <oholy@xxxxxxxxxx> wrote: > > Hi, > > I have been directed here from https://github.com/libfuse/libfuse/issues/488. > > My issue is that with Linux Kernel 5.4, one read kernel call (e.g. > made by cat tool) triggers two fuse_operations.read executions and in > both cases with 0 offset even though that first read successfully > returned some bytes. > > For gvfs, it leads to redundant I/O operations, or to "Operation not > supported" errors if seeking is not supported. This doesn't happen > with Linux 5.3. Any idea what is wrong here? > > $ strace cat /run/user/1000/gvfs/ftp\:host\=server\,user\=user/foo > ... > openat(AT_FDCWD, "/run/user/1000/gvfs/ftp:host=server,user=user/foo", Hi, I'm trying to reproduce this on fedora30, but even failing to get that "cat" to work. I've replaced "server" with a public ftp server, but it's not even getting to the ftp backend. Is there a trick to enable the ftp backend? Haven't found the answer by googling... Thanks, Miklos > O_RDONLY) = 3 > fstat(3, {st_mode=S_IFREG|0644, st_size=20, ...}) = 0 > fadvise64(3, 0, 0, POSIX_FADV_SEQUENTIAL) = 0 > mmap(NULL, 139264, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, > -1, 0) = 0x7fbc42b92000 > read(3, 0x7fbc42b93000, 131072) = -1 EOPNOTSUPP (Operation not > supported) > ... > > $ /usr/libexec/gvfsd-fuse /run/user/1000/gvfs -d > ... > open flags: 0x8000 /ftp:host=server,user=user/foo > open[139679517117488] flags: 0x8000 /ftp:host=server,user=user/foo > unique: 8, success, outsize: 32 > unique: 10, opcode: READ (15), nodeid: 3, insize: 80, pid: 5053 > read[139679517117488] 4096 bytes from 0 flags: 0x8000 > read[139679517117488] 20 bytes from 0 > unique: 10, success, outsize: 36 > unique: 12, opcode: READ (15), nodeid: 3, insize: 80, pid: 5053 > read[139679517117488] 4096 bytes from 0 flags: 0x8000 > unique: 12, error: -95 (Operation not supported), outsize: 16 > ... > > See for other information: https://gitlab.gnome.org/GNOME/gvfs/issues/441 > > Regards > > Ondrej > -- > Ondrej Holy > Software Engineer, Core Desktop Development > Red Hat Czech s.r.o >
