> > what happens if it IS_ERR?
>
> Good point - I need to clean up if things fail (and akpm would
> like to see me re-factor so that there is only one "return"
> statement for better maintainabiliy). I'll fix up stuff here.
Here's what I'll have in the next version. With all the error
handling the pstore_mkfile() routine was getting a bit big, so
I split out the writing-to-the-file part into another function.
The pair of functions now look like this:
/*
* Set up a file structure as if we had opened this file and
* write our data to it.
*/
static int pstore_writefile(struct inode *inode, struct dentry *dentry,
char *data, size_t size)
{
struct file f;
ssize_t n;
mm_segment_t old_fs = get_fs();
memset(&f, '0', sizeof f);
f.f_mapping = inode->i_mapping;
f.f_path.dentry = dentry;
f.f_path.mnt = pstore_mnt;
f.f_pos = 0;
f.f_op = inode->i_fop;
set_fs(KERNEL_DS);
n = do_sync_write(&f, data, size, &f.f_pos);
set_fs(old_fs);
return n == size;
}
/*
* Make a regular file in the root directory of our file system.
* Load it up with "size" bytes of data from "buf".
* Set the mtime & ctime to the date that this record was originally stored.
*/
int pstore_mkfile(char *name, char *data, size_t size, struct timespec time,
void *private)
{
struct dentry *root = pstore_sb->s_root;
struct dentry *dentry;
struct inode *inode;
int rc = 0;
inode = pstore_get_inode(pstore_sb, root->d_inode, S_IFREG | 0444, 0);
if (!inode) {
rc = -ENOMEM;
goto fail;
}
inode->i_private = private;
mutex_lock(&root->d_inode->i_mutex);
dentry = d_alloc_name(root, name);
if (IS_ERR(dentry)) {
mutex_unlock(&root->d_inode->i_mutex);
rc = -ENOSPC;
goto fail1;
}
d_add(dentry, inode);
mutex_unlock(&root->d_inode->i_mutex);
if (!pstore_writefile(inode, dentry, data, size)) {
inode->i_nlink--;
mutex_lock(&root->d_inode->i_mutex);
d_delete(dentry);
dput(dentry);
mutex_unlock(&root->d_inode->i_mutex);
rc = -ENOSPC;
goto fail;
}
if (time.tv_sec)
inode->i_mtime = inode->i_ctime = time;
return 0;
fail1:
iput(inode);
fail:
return rc;
}
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