On 8.01.19 г. 21:38 ч., Florian Stecker wrote: > Hi everyone, > > I extended the btrfs volume on my laptop by adding a second partition to > it which lies on the same SSD (using btrfs device add). Since I did > this, all kinds of applications regularly hang for up to 30 seconds. It > seems they are stuck in the fdatasync syscall. For example: > > $ strace -tt -T gajim 2>&1 | grep fdatasync > [...] > 11:36:31.112200 fdatasync(25) = 0 <0.006958> > 11:36:32.147525 fdatasync(25) = 0 <0.008138> > 11:36:32.156882 fdatasync(25) = 0 <0.006866> > 11:36:32.165979 fdatasync(25) = 0 <0.011797> > 11:36:32.178867 fdatasync(25) = 0 <23.636614> > 11:36:55.827726 fdatasync(25) = 0 <0.009595> > 11:36:55.838702 fdatasync(25) = 0 <0.007261> > 11:36:55.850440 fdatasync(25) = 0 <0.006807> > 11:36:55.858168 fdatasync(25) = 0 <0.006767> > [...] > > File descriptor 25 here points to a file which is just ~90KB, so it > really shouldn't take that long. > > Removing the second partition again resolves the problem. Does anyone > know this issue? Is it related to btrfs? Or am I just doing something > wrong? > > Best, > Florian > > Some more info: > > $ btrfs device usage / > /dev/sda2, ID: 2 > Device size: 52.16GiB > Device slack: 0.00B > Data,single: 1.00GiB > Unallocated: 51.16GiB > > /dev/sda8, ID: 1 > Device size: 174.92GiB > Device slack: 0.00B > Data,single: 168.91GiB > Metadata,single: 3.01GiB > System,single: 4.00MiB > Unallocated: 3.00GiB > > $ fdisk -l /dev/sda > Disk /dev/sda: 238.5 GiB, 256060514304 bytes, 500118192 sectors > Disk model: SAMSUNG SSD PM87 > Units: sectors of 1 * 512 = 512 bytes > Sector size (logical/physical): 512 bytes / 512 bytes > I/O size (minimum/optimal): 512 bytes / 512 bytes > Disklabel type: gpt > Disk identifier: A48B5A25-AA84-4D3F-90DD-E8A4991BDF03 > > Device Start End Sectors Size Type > /dev/sda1 2048 1026047 1024000 500M EFI System > /dev/sda2 1026048 110422015 109395968 52.2G Linux filesystem > /dev/sda8 110422016 477263871 366841856 174.9G Linux filesystem > /dev/sda9 477263872 481458175 4194304 2G Linux swap > > $ uname -a > Linux dell 4.20.0-arch1-1-ARCH #1 SMP PREEMPT Mon Dec 24 03:00:40 UTC > 2018 x86_64 GNU/Linux Provide output of echo w > /proc/sysrq-trigger when the hang occurs otherwise it's hard to figure what's going on. > >
