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Re: [fuse-devel] mounting a block device
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From: D.Edmons <dem...@co...> - 2007-06-07 07:51:11
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Gerald,
In case 1 you use strchr(), in case 2 you use strcmp(). I don't know what
your filesystem uses to determine whether a file is a directory or not,
but it seems to me that this is a problem that needs redesigned.
As the gentleman said on the fuse-devel list, your myfs_mkdir() will
only get called if the file doesn't already exist (myfs_getattr() returns
-ENOEN). If you have a file already with that name, myfs_mkdir() won't
generally get called. Do 'rmdir mydir', 'mkdir mydir' or just 'mkdir
uniquename'.
Then you should get it right.
I do like cramfs does. I have a routine myfs_lookup(), that is called
from myfs_getattr() which searches the directory entries for the
path. If the entry is found it fills the stbuf, otherwise it returns
-NOENT.
Here is my myfs_getattr(). It is short, to the point, and
works....well, I do
have a couple of bugs I haven't figured out yet, but I don't get errors.
/* modified --D.E. */
int rtxfs_real_getattr(const char *path, struct stat *stbuf)
{
fprintf(stdout, "rtxfs_real_getattr(): path = %s\n", path); /* debug */
rtxfs_inode_context *node_context = rtxfs_lookup(path);
if(!node_context) {
// this is too common to report each one
return -ENOENT;
} else {
printf("rtxfs_real_getattr(): found %s, size %d\n", path,
node_context->inode->size); /* debug */
}
memset(stbuf, 0, sizeof(struct stat));
stbuf->st_ino = ENTRYNO2INODE(node_context->raw->entry_no);
stbuf->st_mode = node_context->inode->mode;
stbuf->st_uid = getuid();
stbuf->st_gid = getgid();
stbuf->st_size = node_context->raw->size * BLKSIZ;
stbuf->st_blksize = BLKSIZ;
stbuf->st_blocks = node_context->raw->size; // Native size is in
blocks
stbuf->st_nlink = 1; /* Should this be 2 for directories? */
#define RT11TIME 1179495000 /* debug */
stbuf->st_atime = RT11TIME; // When in doubt, fake it....
stbuf->st_ctime = RT11TIME;
stbuf->st_mtime = RT11TIME;
return 0;
}
I hope this helps.
Dale
Sur...@gm... wrote:
> hi,
> i its crazy getattr effects my mkdir!
> mkdir is only called with this code in getattr:
> if(strcmp(path, "/") == 0) {
> stbuf->st_mode = S_IFDIR | 0755;
> stbuf->st_nlink = 2;
> }
> else if(strcmp(path, hello_path) == 0) {
> stbuf->st_mode = S_IFREG | 0444;
> stbuf->st_nlink = 1;
> stbuf->st_size = strlen(hello_str);
> }
> else
> res = -ENOENT;
>
> without "else res = -ENOENT" mkdir is not called!!! hmmmm....
> i tried to set the attributes for default (see Screenshot-4.png), but still the case that mkdir is not called! any idea?
>
> the error which i get with case 1 is:
> mkdir: cannot create directory 'tmp/fuse/SOS': File exists
> the error which i get with case 2 is:
> mkdir: cannot create directory 'tmp/fuse/SOS': No such file or directory
>
> case2 calls mkdir (i also can see it with ls) but not case1! i printed out to syslog when mkdir is called!!!
>
> Gerald
>
> static int hello_getattr(const char *path, struct stat *stbuf)
> {
> int res = 0;
>
> memset(stbuf, 0, sizeof(struct stat));
>
> ///////////// case 1: mkdir doesnt work with this code ///////////////////////
> /*stbuf->st_dev = 2;
> //stbuf->st_ino = 0;
>
> if(strrchr(path,'.')) {
> stbuf->st_mode = S_IFREG | 0755;
> stbuf->st_size = 5389;
> }
> else
> stbuf->st_mode = S_IFDIR | 0444;
>
> stbuf->st_nlink = 1;
> //stbuf->st_uid = 0;
> //stbuf->st_gid = 0;
> //stbuf->st_rdev = 0;
> //stbuf->st_blksize = 4096;
> //stbuf->st_blocks = 16;
> stbuf->st_atime = 1181118196;
> stbuf->st_mtime = 1181118191;
> stbuf->st_ctime = 1181118191;*/
> //////////////////////////////////////////////////////////////////////
>
>
> ////////////// case 2: mkdir only works with this code with -ENOENT //////////
> if(strcmp(path, "/") == 0) {
> stbuf->st_mode = S_IFDIR | 0755;
> stbuf->st_nlink = 2;
> }
> else if(strcmp(path, hello_path) == 0) {
> stbuf->st_mode = S_IFREG | 0444;
> stbuf->st_nlink = 1;
> stbuf->st_size = strlen(hello_str);
> }
> else
> res = -ENOENT;
> /////////////////////////////////////////////////////////////////////
>
> return res;
> }
>
> static int hello_readdir(const char *path, void *buf, fuse_fill_dir_t filler,
> off_t offset, struct fuse_file_info *fi)
> {
> (void) offset;
> (void) fi;
> adn_dir_info_t info = {0};
> struct dirent *dir_entry;
> struct stat stbuf;
>
> if(strcmp(path, "/") != 0)
> return -ENOENT;
>
> memset(&stbuf, 0, sizeof(stbuf));
> stbuf.st_dev = 2;
> //stbuf.st_ino = 0;
> stbuf.st_mode = S_IFDIR;
> stbuf.st_nlink = 1;
> stbuf.st_uid = 0;
> stbuf.st_gid = 0;
> stbuf.st_rdev = 0;
> //stbuf.st_size = 5389;
> //stbuf.st_blksize = 4096;
> ///stbuf.st_blocks = 16;
> stbuf.st_atime = 1181118196;
> stbuf.st_mtime = 1181118191;
> stbuf.st_ctime = 1181118191;
> filler(buf, ".", &stbuf, 0);
> filler(buf, "..", &stbuf, 0);
>
> strcpy(info.dirname, path);
> fatfs_opendir(&info);
> memset(&stbuf, 0, sizeof(stbuf));
>
> while((dir_entry = fatfs_readdir(&info)) != NULL) {
> stbuf.st_dev = 2;
> //stbuf.st_ino = 0;
>
> if(strrchr(dir_entry->d_name,'.')) {
> stbuf.st_size = 5389;
> stbuf.st_mode = S_IFREG;
> }
> else
> stbuf.st_mode = S_IFDIR;
>
> stbuf.st_nlink = 1;
> stbuf.st_uid = 0;
> stbuf.st_gid = 0;
> stbuf.st_rdev = 0;
> //stbuf.st_size = 5389;
> //stbuf.st_blksize = 4096;
> //stbuf.st_blocks = 16;
> stbuf.st_atime = 1181118196;
> stbuf.st_mtime = 1181118191;
> stbuf.st_ctime = 1181118191;
>
> filler(buf, dir_entry->d_name, &stbuf, 0);
> }
>
> fatfs_closedir(&info);
>
> return 0;
> }
>
> static int hello_mkdir(const char *path, mode_t mode)
> {
> int res;
> adn_dir_info_t info = {0};
>
>
> strcpy(info.dirname, path);
> res = fatfs_mkdir(&info);
>
> return 0; <--- i send always 0, that means tell vfs my fs_mkdir works fine in any case, just for now!
> }
>
>
> -------- Original-Nachricht --------
> Datum: Wed, 06 Jun 2007 01:10:40 -0700
> Von: "D.Edmons" <dem...@co...>
> An: Sur...@gm...
> CC: fus...@li...
> Betreff: Re: [fuse-devel] mounting a block device
>
>
>> Gerald,
>>
>> I really have no way of knowing, but doing:
>> ls -al TEST
>> will be more helpful. Also, do:
>> stat TEST
>> and this will tell you what attributes are
>> being set. You need to set your attributes
>> when myfs_getattr() is called. Do:
>> man fstat
>> and this will give you an idea of what needs
>> to be set, then start fixing one bug at a time.
>> This will make things work much better.
>>
>> Next, after ls/stat looks better, check all of
>> your error returns in myfs_mkdir(). If you are
>> sending a return other than 0, then make certain
>> it is for the right reason.
>>
>> This has been my approach and it seems to be
>> a slow way to make progress, but it does seem
>> to work until you know what needs to be done
>> and why.
>>
>> The biggest help is to use man to tell you what
>> the function is actually being used for.
>>
>> Dale
>>
>> Sur...@gm... wrote:
>>
>>> Hi,
>>> i did integrated readdir and mkdir! all files and directories are red
>>>
>> because i didnt set the attibutes like time, date, filesize,...
>>
>>> do you why i get this strange error at mkdir? because the creation of
>>>
>> the directory works fine for my filesystem!
>>
>>> now i want to mount with a formated partition and not with the file as
>>>
>> blockdevice! how could i mount to a partition? do i need some code like open
>> which i used for the file in the init function?
>>
>>> Gerald
>>>
>>>
>>>
>>> -------- Original-Nachricht --------
>>> Datum: Tue, 05 Jun 2007 08:10:09 -0700
>>> Von: "D.Edmons" <dem...@co...>
>>> An: Sur...@gm...
>>> CC: fus...@li...
>>> Betreff: Re: [fuse-devel] mounting a block device
>>>
>>>
>>>
>>>> cramfs was a link on the fuse website where the list
>>>> of drivers is. or do a google. or check sourceforge.
>>>>
>>>> If you want a new driver, you'll have to write it.
>>>>
>>>> Dale
>>>>
>>>> Sur...@gm... wrote:
>>>>
>>>>
>>>>> Hi,
>>>>> thanks for your answere!
>>>>> where could i find the sources of cramfs?
>>>>> why do you need to do that myfuse /dev/sdb ~/mnt -d ? what do i have
>>>>>
>> to
>>
>>>>>
>>>>>
>>>> do if i use a file as an blockdevice?
>>>>
>>>>
>>>>> is it possible to manually mount a blockdice + mointpoint with
>>>>>
>>>>>
>>>> fusermount? somthing like: fusermount -n devicename -m mountpoint ?
>>>>
>>>>
>>>>> Gerald
>>>>>
>>>>> -------- Original-Nachricht --------
>>>>> Datum: Tue, 05 Jun 2007 00:36:33 -0700
>>>>> Von: "D.Edmons" <dem...@co...>
>>>>> An: Sur...@gm...
>>>>> CC: fus...@li...
>>>>> Betreff: Re: [fuse-devel] mounting a block device
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>> Gerald,
>>>>>>
>>>>>> For me a real good example was cramfs. I've now got my fs
>>>>>> up and running for the read section. I'm still working on the
>>>>>> write section. I've got it about 80%, but still have major
>>>>>> issues.
>>>>>>
>>>>>> In a nutshell, you can parse out your own options in your main(),
>>>>>> then pass fuse_main() just what it needs. In your myfs_init() you
>>>>>> can open your block device and away you go.
>>>>>>
>>>>>> I had to rewrite everything in the cramfs, but it was a good
>>>>>> skeleton to start with. I just wish there was a very similar
>>>>>> driver that was read/write.
>>>>>>
>>>>>> Then I compile and run:
>>>>>> myfuse /dev/sdb ~/mnt -d
>>>>>> but don't pass /dev/sdb to fuse_main(). I also add and
>>>>>> option to fuse_main() so that the mount name is changed
>>>>>> to /dev/sdb.
>>>>>>
>>>>>> Hope this helps.
>>>>>>
>>>>>>
>>>>>> Dale E. Edmons
>>>>>>
>>>>>>
>>>>>> Sur...@gm... wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>>> hi,
>>>>>>>
>>>>>>> could someone explain how to mount a blockdevice for fuse? i saw in
>>>>>>>
>> an
>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> ext2 example:
>>>>>>
>>>>>>
>>>>>>
>>>>>>> static struct fuse_lowlevel_ops ext2fs_ops = {
>>>>>>> .init = op_init
>>>>>>>
>>>>>>> they are doing a ext2fs_open in op_init:
>>>>>>> ret = ext2fs_open(fs_device_name,
>>>>>>> EXT2_FLAG_RW | EXT2_FLAG_JOURNAL_DEV_OK,
>>>>>>> 0, 0, unix_io_manager, &fs);
>>>>>>>
>>>>>>> could i just use a open? do i need a fuse_mount to set the
>>>>>>>
>> mountpoint
>>
>>>>>>>
>>>>>>>
>>>> in
>>>>
>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> the blockdevice? why is fuse_mount not taking the file descriptor
>>>>>>
>> which
>>
>>>>>>
>>>>>>
>>>> i
>>>>
>>>>
>>>>>> get from open?
>>>>>>
>>>>>>
>>>>>>
>>>>>>> is it possible to manually mount a blockdice + mointpoint with
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> fusermount? somthing like: fusermount -n devicename -m mountpoint ?
>>>>>>
>>>>>>
>>>>>>
>>>>>>> thanks,
>>>>>>> Gerald
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>
>>>>>
>>>>>
>>>
>>>
>>> ------------------------------------------------------------------------
>>>
>>>
>
>
>
> ------------------------------------------------------------------------
>
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