handle broken locking on remote filesystems better #685
Description
On my CentOS 5.8 system, fish hangs for a long time (minutes) after every command, built-in or external, though not after a blank line. The command output and new prompt will be printed, then the hang occurs.
It also hangs after entering a comment, although in this case before printing a prompt.
It does not hang when a command is executed as 'fish -c ls'
strace snippet executing 'ls', the blank lines indicate long waits:
write(1, "assmann@n101 \33[32m~\33[30m\33(B\33[m> "..., 35) = 35
fstat(1, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 1), ...}) = 0
fstat(2, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 1), ...}) = 0
ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig -icanon -echo
...}) = 0
ioctl(0, SNDCTL_TMR_START or TCSETS, {B38400 opost isig -icanon -echo
...}) = 0
ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig -icanon -echo
...}) = 0
select(5, [0 3 4], NULL, NULL, NULL) = 1 (in [4])
read(4, "\2", 1) = 1
futex(0x9980030, FUTEX_WAIT_PRIVATE, 2, NULL
) = 0
rt_sigprocmask(SIG_BLOCK, ~[RTMIN RT_1], NULL, 8) = 0
open("/home/assmann/.config/fish/fish_history", O_WRONLY|O_APPEND) = 6
fcntl(6, F_GETFD) = 0
fcntl(6, F_SETFD, FD_CLOEXEC) = 0
fstat(6, {st_mode=S_IFREG|0644, st_size=30, ...}) = 0
fcntl(6, F_SETLKW, {type=F_WRLCK, whence=SEEK_SET, start=0, len=0}
) = -1 EIO (Input/output error)
close(6) = 0
rt_sigprocmask(SIG_UNBLOCK, ~[RTMIN RT_1], NULL, 8) = 0
open("/home/assmann/.config/fish/fish_history", O_RDONLY) = 6
fcntl(6, F_GETFD) = 0
fcntl(6, F_SETFD, FD_CLOEXEC) = 0
fcntl(6, F_SETLKW, {type=F_RDLCK, whence=SEEK_SET, start=0, len=0}
) = -1 ENOLCK (No locks available)
close(6) = 0