我正在写一个FUSE文件系统,它通过sqlite执行一些映射,然后将调用传递到底层文件系统(某种程度上是bbfs上的扩展)。当我尝试开始制作文件时,它开始给我带来麻烦。当我打电话给mknod时,它会返回ERANGE。下面是一个strace的尾部(文件系统被安装在测试/):从FUSE调试系统调用
$ ./p4fs test/
$ strace touch test/kilo 2> logs
$ cat logs
...
fstat(3, {st_mode=S_IFREG|0644, st_size=56467024, ...}) = 0
mmap(NULL, 56467024, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7fbf006bf000
close(3) = 0
close(0) = 0
open("test/kilo", O_WRONLY|O_CREAT|O_NOCTTY|O_NONBLOCK, 0666) = -1 ERANGE (Numerical result out of range)
futimesat(AT_FDCWD, "test/kilo", NULL) = 0
close(1) = 0
exit_group(0) = ?
,这里是从我的内部记录的相关章节:
getattr: database opened
getattr: requesting attr for /kilo
db_getrowid: statement executed: finding rowid of /kilo
db_getrowid: mapped /kilo to rowid 0
getattr: does not exist: /kilo
mknod: database opened
mknod: statement executed: checking for existing path
mknod: calling db_mkdentry(db, /kilo, 100644, 0, 0)
db_mkdentry: parent is/
db_getrowid: statement executed: finding rowid of/
db_getrowid: mapped/to rowid 1
db_mkdentry: statement executed: creating dentry /kilo
db_getrowid: statement executed: finding rowid of /kilo
db_getrowid: mapped /kilo to rowid 3
p4fs: calling system mknod(3, 100644, 0)
p4fs: got errno 13
我要找(1)解决方案这个直接的问题和(2)一般调试FUSE的好方法。我偷偷怀疑ERANGE是来自strtol(),但我不知道如何检查。我希望当它回弹时可以使gdb弹出...
谢谢!
编辑:哦,这里是我的mknod的源()函数:
static int p4_mknod(const char *path, mode_t mode, dev_t dev) {
sqlite3 *db;
sqlite3_stmt *statement;
char query[MAX_QUERY_LENGTH];
int rc;
int return_value;
int path_exists = -1;
OPEN_LOG("mknod")
OPEN_DB(db_path, db)
/* check for existing filename */
sprintf(query,
"SELECT COUNT(*) FROM dentry "
"WHERE name = '%s'",
path);
sqlite3_prepare(db,
query,
-1,
&statement,
NULL);
rc = sqlite3_step(statement);
SQLITE3_ERRCHK("checking for existing path")
path_exists = sqlite3_column_int(statement, 0);
sqlite3_finalize(statement);
if (path_exists <= 0) {
int physical_rowid;
char physical_name[MAX_QUERY_LENGTH];
/* path is not already in db */
syslog(LOG_DEBUG, "calling db_mkdentry(db, %s, %o, 0, 0)",
path, mode);
db_mkdentry(db, (char *) path, mode, 0, 0);
/* make the actual file */
physical_rowid = db_getrowid(db, (char *) path);
sprintf(physical_name, "%i", physical_rowid);
syslog(LOG_DEBUG, "calling system mknod(%s, %o, %li)",
physical_name, mode, dev);
return_value = mknod(physical_name, mode, dev);
} else {
syslog(LOG_INFO, "called on existing path");
return_value = -EEXIST;
}
syslog(LOG_DEBUG, "errno %i", errno);
return errno;
}
感谢您的提示!我对sqlite很新,所以我很感激他们。我没有意识到让我的回调函数在gdb中运行的方法,但是如果有我喜欢听到的方法。我很担心strtol,因为我曾经看过mknod.c的几个实现的源代码并看到它。 – Jay 2010-12-04 22:31:33