On Fri, Feb 19, 2016 at 03:49:15PM +0100, yegorslists@xxxxxxxxxxxxxx wrote: > From: Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> > > The driver was imported from Linux 4.4. > > +++ b/fs/squashfs/Kconfig > @@ -0,0 +1,31 @@ > +menuconfig FS_SQUASHFS > + bool > + prompt "squashfs support" > + help > + Saying Y here includes support for SquashFS 4.0 (a Compressed > + Read-Only File System). Squashfs is a highly compressed read-only > + filesystem for Linux. It uses zlib, lzo or xz compression to > + compress both files, inodes and directories. Inodes in the system > + are very small and all blocks are packed to minimise data overhead. > + Block sizes greater than 4K are supported up to a maximum of 1 Mbytes > + (default block size 128K). SquashFS 4.0 supports 64 bit filesystems > + and files (larger than 4GB), full uid/gid information, hard links and > + timestamps. > + > + Squashfs is intended for general read-only filesystem use, for > + archival use (i.e. in cases where a .tar.gz file may be used), and in > + embedded systems where low overhead is needed. Further information > + and tools are available from http://squashfs.sourceforge.net. > + > +config SQUASHFS_XZ > + bool "Include support for XZ compressed file systems" > + depends on FS_SQUASHFS > + select XZ_DECOMPRESS > + help > + Saying Y here includes support for reading Squashfs file systems > + compressed with XZ compression. XZ gives better compression than > + the default zlib compression, at the expense of greater CPU and > + memory overhead. > + > + XZ is not the standard compression used in Squashfs and so most > + file systems will be readable without selecting this option. As long as XZ is the only option, does it make sense to make this visible? I rather suggest an invisible "default y" option. > + > +struct squashfs_priv { > + struct super_block *sb; > +}; > + > +static struct inode *squashfs_findfile(struct super_block *sb, > + const char *filename, char *buf) > +{ > + char *next; > + char fpath[128]; > + char *name = fpath; > + struct inode *inode; > + struct inode *t_inode = NULL; > + > + strcpy(fpath, filename); > + > + /* Remove all leading slashes */ > + while (*name == '/') > + name++; > + > + inode = duplicate_inode(sb->s_root->d_inode); > + > + /* > + * Handle root-direcoty ('/') s/direcoty/directory/ > + */ > + if (!name || *name == '\0') > + return inode; > + > + for (;;) { > + /* Extract the actual part from the pathname. */ > + next = strchr(name, '/'); > + if (next) { > + /* Remove all leading slashes. */ > + while (*next == '/') > + *(next++) = '\0'; > + } > + > + t_inode = squashfs_lookup(inode, name, 0); > + if (t_inode == NULL) > + break; > + > + /* > + * Check if directory with this name exists > + */ > + > + /* Found the node! */ > + if (!next || *next == '\0') { > + if (buf != NULL) > + sprintf(buf, "%s", name); > + > + free(squashfs_i(inode)); > + return t_inode; > + } > + > + name = next; > + > + free(squashfs_i(inode)); > + inode = t_inode; > + } > + > + free(squashfs_i(inode)); > + return NULL; > +} > + > +static int squashfs_probe(struct device_d *dev) > +{ > + struct fs_device_d *fsdev; > + struct squashfs_priv *priv; > + int ret; > + > + fsdev = dev_to_fs_device(dev); > + > + priv = xmalloc(sizeof(struct squashfs_priv)); xzalloc is usually safer here. Even if you know that all fields are initialized properly later, once we add new fields we usually expect them to be initialized to zero. > + dev->priv = priv; > + > + ret = fsdev_open_cdev(fsdev); > + if (ret) > + goto err_out; > + > + > + priv->sb = squashfs_mount(fsdev, 0); You could embed a struct super_block into struct squashfs_priv. That would save you one extra allocation. > + if (IS_ERR(priv->sb)) { > + dev_info(dev, "no valid squashfs found\n"); > + ret = PTR_ERR(priv->sb); > + goto err_out; > + } > + > + return 0; > + > +err_out: > + free(priv); > + > + return ret; > +} > + > +static void squashfs_remove(struct device_d *dev) > +{ > + struct squashfs_priv *priv = dev->priv; > + > + squashfs_put_super(priv->sb); > + free(priv->sb); > + free(priv); > +} > + > +static int squashfs_open(struct device_d *dev, FILE *file, const char *filename) > +{ > + struct squashfs_priv *priv = dev->priv; > + struct inode *inode; > + struct squashfs_page *page; > + int i; > + > + inode = squashfs_findfile(priv->sb, filename, NULL); > + if (!inode) > + return -ENOENT; > + > + page = malloc(sizeof(struct squashfs_page)); > + page->buf = calloc(32, sizeof(*page->buf)); > + for (i = 0; i < 32; i++) > + page->buf[i] = malloc(PAGE_CACHE_SIZE); Given the amount of memory you allocate here malloc is a good choice, but please check the return value. > + > + page->data_block = 0; > + page->idx = 0; > + page->real_page.inode = inode; > + file->size = inode->i_size; > + file->priv = page; > + > + return 0; > +} > + > +static int squashfs_close(struct device_d *dev, FILE *f) > +{ > + struct squashfs_page *page = f->priv; > + int i; > + > + for (i = 0; i < 32; i++) > + free(page->buf[i]); > + > + free(page->buf); > + free(squashfs_i(page->real_page.inode)); > + free(page); > + > + return 0; > +} > + > +static int squashfs_read(struct device_d *_dev, FILE *f, void *buf, > + size_t insize) > +{ > + unsigned int size = insize; > + int offset, idx; > + int data_block_pos; > + struct squashfs_page *page = f->priv; > + > + if (f->pos >= (page->data_block + 1) * 32 * PAGE_CACHE_SIZE) { > + page->data_block++; > + page->idx = 0; > + } You seem to assume here that files are only read linearly. You have to do something more clever here to support lseek. > + > + data_block_pos = f->pos - page->data_block * 32 * PAGE_CACHE_SIZE; > + idx = data_block_pos / PAGE_CACHE_SIZE; > + page->real_page.index = (page->data_block)*32; > + offset = data_block_pos - idx * PAGE_CACHE_SIZE; > + > + if (page->idx == 0) > + squashfs_readpage(NULL, &page->real_page); > + > + memcpy(buf, page->buf[idx] + offset, size); > + > + return insize; > +} > + > +static loff_t squashfs_lseek(struct device_d *dev, FILE *f, loff_t pos) > +{ > + f->pos = pos; > + > + return pos; > +} > + Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
