Re: [PATCH 06/10] AXFS: axfs_super.c

From: Bernhard Reutner-Fischer
Date: Fri Aug 22 2008 - 08:08:23 EST


On Wed, Aug 20, 2008 at 10:45:37PM -0700, Jared Hulbert wrote:
>+static int axfs_get_onmedia_super(struct super_block *sb)
>+{
>+ int err;
>+ struct axfs_super *sbi = AXFS_SB(sb);
>+ struct axfs_super_onmedia *sbo;
>+
>+ sbo = kmalloc(sizeof(*sbo), GFP_KERNEL);
>+ if (!sbo)
>+ return -ENOMEM;
>+
>+ axfs_copy_metadata(sb, (void *)sbo, 0, sizeof(*sbo));
>+
>+ /* Do sanity checks on the superblock */
>+ if (be32_to_cpu(sbo->magic) != AXFS_MAGIC) {
>+ printk(KERN_ERR "axfs: wrong magic\n");
>+ err = -EINVAL;
>+ goto out;
>+ }
>+
>+ /* verify the signiture is correct */
>+ if (strncmp(sbo->signature, AXFS_SIGNATURE, sizeof(AXFS_SIGNATURE))) {
>+ printk(KERN_ERR "axfs: wrong axfs signature,"
>+ " read %s, expected %s\n",
>+ sbo->signature, AXFS_SIGNATURE);
>+ err = -EINVAL;
>+ goto out;
>+ }

As Phillip mentioned for some other cases, just initialize err to
EINVAL.
>+
>+ sbi->magic = be32_to_cpu(sbo->magic);
>+ sbi->version_major = sbo->version_major;
>+ sbi->version_minor = sbo->version_minor;
>+ sbi->version_sub = sbo->version_sub;
>+ sbi->files = be64_to_cpu(sbo->files);
>+ sbi->size = be64_to_cpu(sbo->size);
>+ sbi->blocks = be64_to_cpu(sbo->blocks);
>+ sbi->mmap_size = be64_to_cpu(sbo->mmap_size);
>+ sbi->cblock_size = be32_to_cpu(sbo->cblock_size);
>+ sbi->timestamp.tv_sec = be64_to_cpu(sbo->timestamp);
>+ sbi->timestamp.tv_nsec = 0;
>+ sbi->compression_type = sbo->compression_type;
>+
>+ err = axfs_set_compression_type(sbi);
>+ if (err)
>+ goto out;
>+
>+ /* If no block or MTD device, adjust mmapable to cover all image */
>+ if (AXFS_NODEV(sb))
>+ sbi->mmap_size = sbi->size;
>+
>+ err = axfs_fill_region_descriptors(sb, sbo);
[as already mentioned the clipped snippet here is unneeded]
>+out:
>+ kfree(sbo);
>+ return err;
>+}

>+int axfs_verify_device_sizes(struct super_block *sb)
>+{
>+ struct axfs_super *sbi = AXFS_SB(sb);
>+ struct mtd_info *mtd0 = AXFS_MTD(sb);
>+ struct mtd_info *mtd1 = AXFS_MTD1(sb);
>+ int sndsize = sbi->size - sbi->mmap_size;
>+
>+ /* Whole FS on one device */
>+ if (mtd0 && !mtd1 && (mtd0->size < sbi->size)) {
>+ printk(KERN_ERR "axfs: ERROR: Filesystem extends beyond end of"
>+ "MTD! Filesystem cannot be safely mounted!\n");

missing space in "end ofMTD"
You're mixing the style of where you put such a space, so potential
errors are not easy to spot (manually).
e.g.:

>+ printk(KERN_ERR "axfs: ERROR: Mmap segment extends"
>+ " beyond end of MTD!");
>+ printk(KERN_ERR "mtd name: %s, mtd size: 0x%x, mmap "
>+ "size: 0x%llx",
>+ mtd0->name, mtd0->size, sbi->mmap_size);

>+static int axfs_check_options(char *options, struct axfs_super *sbi)
>+{
>+ unsigned long address = 0;
>+ char *iomem = NULL;
>+ unsigned long length = 0;
>+ char *p;
>+ int err = -EINVAL;
>+ substring_t args[MAX_OPT_ARGS];
>+
>+ if (!options)
>+ return 0;
>+
>+ if (!*options)
>+ return 0;
>+
>+ while ((p = strsep(&options, ",")) != NULL) {
>+ int token;
>+ if (!*p)
>+ continue;
>+
>+ token = match_token(p, tokens, args);
>+ switch (token) {
>+ case OPTION_SECOND_DEV:
>+ sbi->second_dev = match_strdup(&args[0]);
>+ if (!(sbi->second_dev)) {
>+ err = -ENOMEM;
>+ goto out;
>+ }
>+ if (!*(sbi->second_dev))
>+ goto bad_value;
>+ break;
>+ case OPTION_IOMEM:
>+ iomem = match_strdup(&args[0]);
>+ if (!(iomem)) {
>+ err = -ENOMEM;
>+ goto out;
>+ }
>+ if (!*iomem)
>+ goto bad_value;
>+ break;
>+ case OPTION_PHYSICAL_ADDRESS_LOWER_X:
>+ case OPTION_PHYSICAL_ADDRESS_UPPER_X:
>+ if (match_hex(&args[0], (int *)&address))
>+ goto out;
>+ if (!address)
>+ goto bad_value;
>+ break;
>+ default:

just:
goto bad_value;

>+ printk(KERN_ERR
>+ "axfs: unrecognized mount option \"%s\" "
>+ "or missing value\n", p);
>+ goto out;
>+ }
>+ }
>+
>+ if (iomem) {
>+ if (address)
>+ goto out;
>+ err = axfs_get_uml_address(iomem, &address, &length);

missing:
if (err)
goto out;

>+ kfree(iomem);
>+ sbi->iomem_size = length;
>+ sbi->virt_start_addr = address;
>+ }
>+
>+ sbi->phys_start_addr = address;
>+ return 0;
>+
>+bad_value:
>+ printk(KERN_ERR
>+ "axfs: unrecognized mount option \"%s\" "
>+ "or missing value\n", p);
>+out:
>+ if (iomem)
>+ kfree(iomem);

just kfree(iomem);

>+ return err;
>+}
>+

>+static int axfs_statfs(struct dentry *dentry, struct kstatfs *buf)
>+{
>+ struct axfs_super *sbi = AXFS_SB(dentry->d_sb);
>+
>+ buf->f_type = AXFS_MAGIC;
>+ buf->f_bsize = AXFS_PAGE_SIZE;

What will happen if i transfer the filesystem to a box with a different
pagesize?

>+ buf->f_blocks = sbi->blocks;
>+ buf->f_bfree = 0;
>+ buf->f_bavail = 0;
>+ buf->f_files = sbi->files;
>+ buf->f_ffree = 0;
>+ buf->f_namelen = AXFS_MAXPATHLEN;
>+ return 0;
>+}

I think i have seen the string "compessed" in one of your patches,
should be "compressed".

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