I have written a small program to use O_DIRECT (attached), after
applying your patch o_direct-14 to kernel 2.4.9. Opening the file with
O_DIRECT is successful, but attempts to write to the fd return EINVAL.
Am I doing something wrong? Should I have to recompile glibc too?
(0)<root@draal:/usr/src/mjpeg_play> gcc -o testopen testopen.c
(0)<root@draal:/usr/src/mjpeg_play> strace ./testopen > /dev/null
execve("./testopen", ["./testopen"], [/* 54 vars */]) = 0
uname({sys="Linux", node="draal.physics.wisc.edu", ...}) = 0
brk(0) = 0x120010d90
open("/etc/ld.so.preload", O_RDONLY) = -1 ENOENT (No such file or directory)
open("/etc/ld.so.cache", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=62527, ...}) = 0
mmap(NULL, 62527, PROT_READ, MAP_PRIVATE, 3, 0) = 0x20000030000
close(3) = 0
open("/lib/libc.so.6.1", O_RDONLY) = 3
read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0&\220\1\0\0\0`\201\3"..., 1024) = 1024
fstat(3, {st_mode=S_IFREG|0755, st_size=9653762, ...}) = 0
mmap(NULL, 1558648, PROT_READ|PROT_EXEC, MAP_PRIVATE, 3, 0) = 0x20000040000
mprotect(0x2000019a000, 141432, PROT_NONE) = 0
mmap(0x200001a0000, 98304, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 0x150000) = 0x200001a0000
mmap(0x200001b8000, 18552, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x200001b8000
close(3) = 0
munmap(0x20000030000, 62527) = 0
getxpid() = 2387
open("testopen.txt", O_RDWR|O_CREAT|O_SYNC|0x100000, 0644) = 3
fstat(1, {st_mode=S_IFCHR|0666, st_rdev=makedev(1, 3), ...}) = 0
mmap(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2000001e000
ioctl(1, TCGETS, 0x11fffea50) = -1 ENOTTY (Inappropriate ioctl for device)
write(3, "Welcome to the winter of my disc"..., 40) = -1 EINVAL (Invalid argument)
close(3) = 0
write(1, "Got fd 3.\nUnable to write to fil"..., 77) = 77
munmap(0x2000001e000, 8192) = 0
exit(0) = ?
Cheers,
-- Bob
Bob McElrath (rsmcelrath@students.wisc.edu)
Univ. of Wisconsin at Madison, Department of Physics
This archive was generated by hypermail 2b29 : Fri Sep 07 2001 - 21:00:20 EST