Help with file system issue diagnosis when swapping between littlefs and fatfs. #12496
Comments
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@g2gps I think some FS doesn't support all the features required by smart_test testing too. Not sure if this is the issue with FATFS, Also you can enable File System debug to collect more information and find the root causes |
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I set up an example program to look at seek's behaviour: #ifdef __NuttX__
#include <nuttx/config.h>
#else
#define FAR
#endif
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
char* vbuffer;
FILE *test_open(const char *name, const char *mode, size_t bufsiz)
{
FILE *fp = NULL;
fp = fopen(name, mode);
if(!fp)
{
return fp;
}
printf("open %s with mode %s\n", name, mode);
if (bufsiz)
{
vbuffer = malloc(bufsiz);
if (!vbuffer)
{
return NULL;
}
setbuffer(fp, vbuffer, bufsiz);
printf("set stdio buffer to: %p size: %zu\n", vbuffer, bufsiz);
}
return fp;
}
int test_close(FILE *fp)
{
if(vbuffer)
{
free(vbuffer);
}
return fclose(fp);
}
ssize_t test_read(FILE *fp, char* buffer, size_t buflen)
{
ssize_t ret = fread(buffer, 1, buflen, fp);
printf("read: '%s' len: %zd\n", buffer, ret);
return ret;
}
ssize_t test_write(FILE *fp, const char* text)
{
ssize_t ret = fwrite(text, 1, strlen(text) + 1, fp);
printf("write: %s, len: %zd\n", text, ret);
return ret;
}
ssize_t test_ftell(FILE *fp)
{
ssize_t pos = ftell(fp);
printf("file position %zu\n", pos);
return pos;
}
ssize_t test_seek(FILE *fp, size_t pos)
{
int ret = fseek(fp, pos, SEEK_SET);
printf("seek to: %zu, ret: %d\n", pos, ret);
return test_ftell(fp);
}
ssize_t test_file_size(FILE *fp)
{
ssize_t current = ftell(fp);
fseek(fp, 0, SEEK_END);
ssize_t end = ftell(fp);
fseek(fp, current, SEEK_SET);
printf("file size %zd\n", end);
return end;
}
int main(int argc, FAR char *argv[])
{
const char *filename = "test_file";
char read_buffer[80] = { 0 };
size_t stdio_buffer_size = 0;
FILE *fp;
fp = test_open(filename, "w", stdio_buffer_size);
test_ftell(fp);
test_write(fp, filename);
test_ftell(fp);
test_file_size(fp);
test_close(fp);
fp = test_open(filename, "r", stdio_buffer_size);
test_ftell(fp);
test_read(fp, read_buffer, sizeof(read_buffer));
test_ftell(fp);
test_file_size(fp);
// Seek past the end of the file.
test_seek(fp, strlen(filename) * 2);
test_ftell(fp);
memset(read_buffer, 0, sizeof(read_buffer));
test_read(fp, read_buffer, sizeof(read_buffer));
test_ftell(fp);
test_file_size(fp);
test_close(fp);
return 0;
}When this is run on a However, when run on a fatfs based file system: The second read, when seek is set past the eof seems incorrect for FAT. I'm expecting it to return 0 bytes read, not modify the buffer, and not move the file position. I'm not sure yet if this is the exact cause of the issue, but as far as I understand this behaviour isn't quite right. The number of bytes read is 80, which is the size of the buffer I provided, so perhaps there is an issue with the return value of the buffer passed down to fatfs when it is larger the the stdio buffer, whose default is 64. Thanks for the suggestion @acassis, I added file system logging, but it doesn't give any hints. |
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Adding a larger stream buffer changes the behaviour for fatfs. Setting |
g2gps
added a commit
to motec-research/incubator-nuttx
that referenced
this issue
Jun 24, 2024
When fseek is used to set the file pointer past the end of the file, fread should return EOF. See apache#12496.
xiaoxiang781216
pushed a commit
that referenced
this issue
Jun 24, 2024
When fseek is used to set the file pointer past the end of the file, fread should return EOF. See #12496.
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@xiaoxiang781216 @g2gps why to reopen it? |
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I still have an issue when switching between littlefs and fatfs. However, I'm currently unable to come up with a reproducible test case. |
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I've encountered an issue while swapping the file system used for our application from LittleFS to FatFS, and would appreciate any help diagnosing the problem.
For my initial investigation, I've been conducting testing with the file system utilities in NuttX, in an attempt to narrow down the scope of the issue
In each case I'm testing using the
rv-virt:citestconfiguration, with the following changes:and a rc.sysinit with:
I move the mount points to
/mntfor the cmocka and fstestsHere's the testing I've done so far
smart test
smart_testfails on both fatfs and littlefs with multiple errors, for example:cmocka
cmocka --suite fshas failures on fatfs:and littlefs:
fstest
Passes on littlefs:
Passes on fatfs:
Some initial thoughts:
fstestdoesn't make use of file streams, or seek, so it may not be catching the test which fails.Possibly there is further testing which could be done to further narrow down the issue? Or somebody else has noticed a similar issue?
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