search

plfs / plfs-core

LANL no longer develops PLFS. Feel free to fork and develop as you wish.
41 stars 36 forks source link

plfs_read not working with small files #360

Closed krigbaum closed 9 years ago

krigbaum commented 9 years ago

We are having trouble getting plfs_read to work correctly with small files. Sample test code in native PLFS is:

include

include

include

include

include <sys/types.h>

define SUCCESS 0

int main(int argc, char *argv) { const char cpath = "/tmp/local_plfs/test.plfs.fil"; //mode_t fmode = "w+"; mode_t fmode = 0666; Plfs_fd *fd = NULL;

//printf("fd = 0x%0x\n", fd);
//printf("cpath = %s\n", cpath);
//printf("O_RDWR = %d\n", O_RDWR);
//printf("getpid() = %d\n", getpid());
//printf("fmode = %d\n", fmode);

printf("Executing 'plfs_open(0x%0x, \"%s\", %d, %d, %d, NULL)'\n", fd, cpath, O_RDWR, getpid(), fmode);
plfs_error_t plfs_error = plfs_open(&fd, cpath, O_RDWR, getpid(), fmode, NULL);
printf("plfs_error = %d\n", plfs_error);
printf("fd = 0x%0x\n\n", fd);

const char *str = "Hello";
const int size = strlen(str);
const int offset = 0;
const pid_t pid = getpid();
ssize_t written = 0;

printf("Executing 'plfs_write(0x%0x, \"%s\", %d, %d, %d, %d)'\n", fd, str, size, offset, pid, written);
plfs_error = plfs_write(fd, str, size, offset, pid, &written);
printf("plfs_error = %d\n", plfs_error);
printf("written = %d\n\n", written);

char *outstr = NULL;
ssize_t bytes_read = 0;

printf("Executing 'plfs_read(0x%0x, \"%s\", %d, %d, %d, %d)'\n", fd, outstr, size, offset, pid, bytes_read);
plfs_error = plfs_write(fd, outstr, size, offset, pid, &bytes_read);
printf("plfs_error = %d\n", plfs_error);
printf("bytes_read = %d\n", bytes_read);
printf("outstr = %s\n\n ", outstr);

Plfs_close_opt opts; 
int x;
printf("Executing 'plfs_close(0x%0x, %d, %d, %d, %d, NULL)'\n", fd, pid, getuid(), O_RDWR, NULL, x);
plfs_error = plfs_close(fd, pid, getuid(), O_RDWR, NULL, &x);
printf("plfs_error = %d\n", plfs_error);

return SUCCESS;

}

The output from the test is:

Executing 'plfs_open(0x0, "/tmp/local_plfs/test.plfs.fil", 2, 36923, 438, NULL)' plfs_error = 0 fd = 0x1e6af70

Executing 'plfs_write(0x1e6af70, "Hello", 5, 0, 36923, 0)' plfs_error = 0 written = 5

Executing 'plfs_read(0x1e6af70, "(null)", 5, 0, 36923, 0)' plfs_error = 300 bytes_read = -1 outstr = (null)

Executing 'plfs_close(0x1e6af70, 36923, 55096, 2, 0, NULL)' plfs_error = 0

The plfsrc file is:

zhang-jingwang commented 9 years ago

From the following lines:

char *outstr = NULL;
ssize_t bytes_read = 0;

plfs_error = plfs_write(fd, outstr, size, offset, pid, &bytes_read); // This should be plfs_read()

I think that you forget to allocate storage space for the 'outstr', so it's a NULL pointer and which is not correct for plfs_read(). And you use plfs_write instead of plfs_read mistakenly. You can try code like this to allocate the output buffer at stack:

char outstr[16];
ssize_t bytes_read = 0;

printf("Executing 'plfs_read(0x%0x, \"%s\", %d, %d, %d, %d)'\n", fd, outstr, size, offset, pid, bytes_read);
plfs_error = plfs_read(fd, outstr, size, offset, pid, &bytes_read);
krigbaum commented 9 years ago

Thanks, Zhang. That was pretty dense of me. Unfortunately, it still doesn't seem to be quite correct for some reason. After making the change you suggested, even though plfs_error is 0 and bytes read is 5, outstr still has whatever garbage was in it after the declaration. If I initialize it, the initialized value is returned. What's very interesting, is that in a different context (from ldplfs) if I preload the return buffer with "dummy" and pass it to plfs_read to read 3 characters, it returns "xxxmy" which indicates to me that plfs is returning only the z's that it uses to initialize it's buffer. Anyway, here is the altered code and output:

include

include

include

include

include <sys/types.h>

define SUCCESS 0

int main(int argc, char *argv) { const char cpath = "/tmp/local_plfs/test.plfs.fil"; //mode_t fmode = "w+"; mode_t fmode = 0666; Plfs_fd *fd = NULL;

//printf("fd = 0x%0x\n", fd);
//printf("cpath = %s\n", cpath);
//printf("O_RDWR = %d\n", O_RDWR);
//printf("getpid() = %d\n", getpid());
//printf("fmode = %d\n", fmode);

printf("Executing 'plfs_open(0x%0x, \"%s\", %d, %d, %d, NULL)'\n",

fd, cpath, O_RDWR, getpid(), fmode); plfs_error_t plfs_error = plfs_open(&fd, cpath, O_RDWR, getpid(), fmode, NULL); printf("plfs_error = %d\n", plfs_error); printf("fd = 0x%0x\n\n", fd);

const char *str = "Hello";
const int size = strlen(str);
const int offset = 0;
const pid_t pid = getpid();
ssize_t written = 0;

printf("Executing 'plfs_write(0x%0x, %0x0x, %d, %d, %d, %d)'\n", fd,

str, size, offset, pid, written); plfs_error = plfs_write(fd, str, size, offset, pid, &written); printf("plfs_error = %d\n", plfs_error); printf("written = %d\n\n", written);

char outstr[16];
//outstr[0] = '\0';
//strcpy(outstr, "abcdefghijklm");
ssize_t bytes_read = 0;

printf("outstr = %s\n", outstr);
printf("Executing 'plfs_read(0x%0x, 0x%0x, %d, %d, %d, %d)'\n", fd,

outstr, size, offset, pid, bytes_read); plfs_error = plfs_write(fd, outstr, size, offset, pid, &bytes_read); printf("plfs_error = %d\n", plfs_error); printf("bytes_read = %d\n", bytes_read); printf("outstr = %s\n\n ", outstr);

Plfs_close_opt opts; 
int x;
printf("Executing 'plfs_close(0x%0x, %d, %d, %d, %d, NULL)'\n", fd,

pid, getuid(), O_RDWR, NULL, x); plfs_error = plfs_close(fd, pid, getuid(), O_RDWR, NULL, &x); printf("plfs_error = %d\n", plfs_error);

return SUCCESS;

}

Executing 'plfs_open(0x0, "/tmp/local_plfs/test.plfs.fil", 2, 54673, 438, NULL)' plfs_error = 0 fd = 0x24c88e0

Executing 'plfs_write(0x24c88e0, 400c5c0x, 5, 0, 54673, 0)' plfs_error = 0 written = 5

outstr = N�8YD+ Executing 'plfs_read(0x24c88e0, 0x4a2de670, 5, 0, 54673, 0)' plfs_error = 0 bytes_read = 5 outstr = N�8YD+

Executing 'plfs_close(0x24c88e0, 54673, 55096, 2, 0, NULL)' plfs_error = 0

On Mon, 2015-03-16 at 18:41 -0700, Zhang Jingwang wrote:

From the following lines:

char *outstr = NULL; ssize_t bytes_read = 0;

plfs_error = plfs_write(fd, outstr, size, offset, pid, &bytes_read);

I think that you forget to allocate storage space for the 'outstr', so it's a NULL pointer and which is not correct for plfs_read(). You can try code like this to allocate the output buffer at stack:

char outstr[16]; ssize_t bytes_read = 0;

printf("Executing 'plfs_read(0x%0x, \"%s\", %d, %d, %d, %d)'\n", fd, outstr, size, offset, pid, bytes_read); plfs_error = plfs_write(fd, outstr, size, offset, pid, &bytes_read);

— Reply to this email directly or view it on GitHub.

atorrez commented 9 years ago

I will consult with someone today that may be able to talk to the developer of small file mode.

Alfred

From: krigbaum notifications@github.com<mailto:notifications@github.com> Reply-To: plfs/plfs-core reply@reply.github.com<mailto:reply@reply.github.com> Date: Tue, 17 Mar 2015 05:40:56 -0700 To: plfs/plfs-core plfs-core@noreply.github.com<mailto:plfs-core@noreply.github.com> Subject: Re: [plfs-core] plfs_read not working with small files (#360)

Thanks, Zhang. That was pretty dense of me. Unfortunately, it still doesn't seem to be quite correct for some reason. After making the change you suggested, even though plfs_error is 0 and bytes read is 5, outstr still has whatever garbage was in it after the declaration. If I initialize it, the initialized value is returned. What's very interesting, is that in a different context (from ldplfs) if I preload the return buffer with "dummy" and pass it to plfs_read to read 3 characters, it returns "xxxmy" which indicates to me that plfs is returning only the z's that it uses to initialize it's buffer. Anyway, here is the altered code and output:

include

include

include

include

include <sys/types.h>

define SUCCESS 0

int main(int argc, char *argv) { const char cpath = "/tmp/local_plfs/test.plfs.fil"; //mode_t fmode = "w+"; mode_t fmode = 0666; Plfs_fd *fd = NULL;

//printf("fd = 0x%0x\n", fd); //printf("cpath = %s\n", cpath); //printf("O_RDWR = %d\n", O_RDWR); //printf("getpid() = %d\n", getpid()); //printf("fmode = %d\n", fmode);

printf("Executing 'plfs_open(0x%0x, \"%s\", %d, %d, %d, NULL)'\n", fd, cpath, O_RDWR, getpid(), fmode); plfs_error_t plfs_error = plfs_open(&fd, cpath, O_RDWR, getpid(), fmode, NULL); printf("plfs_error = %d\n", plfs_error); printf("fd = 0x%0x\n\n", fd);

const char *str = "Hello"; const int size = strlen(str); const int offset = 0; const pid_t pid = getpid(); ssize_t written = 0;

printf("Executing 'plfs_write(0x%0x, %0x0x, %d, %d, %d, %d)'\n", fd, str, size, offset, pid, written); plfs_error = plfs_write(fd, str, size, offset, pid, &written); printf("plfs_error = %d\n", plfs_error); printf("written = %d\n\n", written);

char outstr[16]; //outstr[0] = '\0'; //strcpy(outstr, "abcdefghijklm"); ssize_t bytes_read = 0;

printf("outstr = %s\n", outstr); printf("Executing 'plfs_read(0x%0x, 0x%0x, %d, %d, %d, %d)'\n", fd, outstr, size, offset, pid, bytes_read); plfs_error = plfs_write(fd, outstr, size, offset, pid, &bytes_read); printf("plfs_error = %d\n", plfs_error); printf("bytes_read = %d\n", bytes_read); printf("outstr = %s\n\n ", outstr);

Plfs_close_opt opts; int x; printf("Executing 'plfs_close(0x%0x, %d, %d, %d, %d, NULL)'\n", fd, pid, getuid(), O_RDWR, NULL, x); plfs_error = plfs_close(fd, pid, getuid(), O_RDWR, NULL, &x); printf("plfs_error = %d\n", plfs_error);

return SUCCESS; }

Executing 'plfs_open(0x0, "/tmp/local_plfs/test.plfs.fil", 2, 54673, 438, NULL)' plfs_error = 0 fd = 0x24c88e0

Executing 'plfs_write(0x24c88e0, 400c5c0x, 5, 0, 54673, 0)' plfs_error = 0 written = 5

outstr = N�8YD+ Executing 'plfs_read(0x24c88e0, 0x4a2de670, 5, 0, 54673, 0)' plfs_error = 0 bytes_read = 5 outstr = N�8YD+

Executing 'plfs_close(0x24c88e0, 54673, 55096, 2, 0, NULL)' plfs_error = 0

On Mon, 2015-03-16 at 18:41 -0700, Zhang Jingwang wrote:

From the following lines:

char *outstr = NULL; ssize_t bytes_read = 0;

plfs_error = plfs_write(fd, outstr, size, offset, pid, &bytes_read);

I think that you forget to allocate storage space for the 'outstr', so it's a NULL pointer and which is not correct for plfs_read(). You can try code like this to allocate the output buffer at stack:

char outstr[16]; ssize_t bytes_read = 0;

printf("Executing 'plfs_read(0x%0x, \"%s\", %d, %d, %d, %d)'\n", fd, outstr, size, offset, pid, bytes_read); plfs_error = plfs_write(fd, outstr, size, offset, pid, &bytes_read);

— Reply to this email directly or view it on GitHub.

— Reply to this email directly or view it on GitHubhttps://github.com/plfs/plfs-core/issues/360#issuecomment-82323758.

chuckcranor commented 9 years ago

hi-

you are printing "Executing plfs_read"  but you appear to

actually be calling plfs_write()?

chuck

On Tue, Mar 17, 2015 at 05:40:57AM -0700, krigbaum wrote:

printf("outstr = %s\n", outstr);
printf("Executing 'plfs_read(0x%0x, 0x%0x, %d, %d, %d, %d)'\n", fd,

outstr, size, offset, pid, bytes_read); plfs_error = plfs_write(fd, outstr, size, offset, pid, &bytes_read); ^^^^^^^^^^^ printf("plfs_error = %d\n", plfs_error); printf("bytes_read = %d\n", bytes_read); printf("outstr = %s\n\n ", outstr);

krigbaum commented 9 years ago

Thanks. Excuse me while I go find a rock to hide under.

On Tue, 2015-03-17 at 06:37 -0700, chuckcranor wrote:

hi-

you are printing "Executing plfs_read" but you appear to actually be calling plfs_write()?

chuck

On Tue, Mar 17, 2015 at 05:40:57AM -0700, krigbaum wrote:

printf("outstr = %s\n", outstr); printf("Executing 'plfs_read(0x%0x, 0x%0x, %d, %d, %d, %d)'\n", fd, outstr, size, offset, pid, bytes_read); plfs_error = plfs_write(fd, outstr, size, offset, pid, &bytes_read); ^^^^^^^^^^^ printf("plfs_error = %d\n", plfs_error); printf("bytes_read = %d\n", bytes_read); printf("outstr = %s\n\n ", outstr);

— Reply to this email directly or view it on GitHub.