From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1dGMXW-0000Ac-2s for barebox@lists.infradead.org; Thu, 01 Jun 2017 09:37:12 +0000 From: Philipp Zabel Date: Thu, 1 Jun 2017 11:36:39 +0200 Message-Id: <1496309800-28632-2-git-send-email-p.zabel@pengutronix.de> In-Reply-To: <1496309800-28632-1-git-send-email-p.zabel@pengutronix.de> References: <1496309800-28632-1-git-send-email-p.zabel@pengutronix.de> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH v2 2/3] fs: add cdev_create_from_file for loop mount option To: barebox@lists.infradead.org Allow to create a loopback cdev from a file. Signed-off-by: Philipp Zabel --- Changes since v1: - Add cdev file operation to close the backing file descriptor on umount. --- fs/devfs-core.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/fs.c | 21 ++++++++++--- include/driver.h | 1 + 3 files changed, 107 insertions(+), 4 deletions(-) diff --git a/fs/devfs-core.c b/fs/devfs-core.c index 382606f1cf..dc07df2268 100644 --- a/fs/devfs-core.c +++ b/fs/devfs-core.c @@ -20,11 +20,14 @@ #include #include #include +#include #include #include #include #include +#include #include +#include LIST_HEAD(cdev_list); @@ -407,3 +410,89 @@ int devfs_create_partitions(const char *devname, return 0; } + +struct loop_priv { + int fd; +}; + +static ssize_t loop_read(struct cdev *cdev, void *buf, size_t count, + loff_t offset, ulong flags) +{ + struct loop_priv *priv = cdev->priv; + loff_t ofs; + + ofs = lseek(priv->fd, offset, SEEK_SET); + if (ofs < 0) + return ofs; + + return read(priv->fd, buf, count); +} + +static ssize_t loop_write(struct cdev *cdev, const void *buf, size_t count, + loff_t offset, ulong flags) +{ + struct loop_priv *priv = cdev->priv; + loff_t ofs; + + ofs = lseek(priv->fd, offset, SEEK_SET); + if (ofs < 0) + return ofs; + + return write(priv->fd, buf, count); +} + +static void loop_close(struct cdev *cdev) +{ + struct loop_priv *priv = cdev->priv; + + close(priv->fd); +} + +static const struct file_operations loop_ops = { + .read = loop_read, + .write = loop_write, + .memmap = generic_memmap_rw, + .lseek = dev_lseek_default, + .close = loop_close, +}; + +struct cdev *cdev_create_from_file(const char *path, ulong flags) +{ + struct cdev *new; + struct loop_priv *priv; + static int loopno; + loff_t ofs; + + priv = xzalloc(sizeof(*priv)); + + priv->fd = open(path, flags); + if (priv->fd < 0) { + free(priv); + return NULL; + } + + new = xzalloc(sizeof(*new)); + + new->name = strdup(path); + + new->ops = &loop_ops; + new->name = basprintf("loop%u", loopno); + new->priv = priv; + + ofs = lseek(priv->fd, 0, SEEK_END); + if (ofs < 0) { + free(new); + free(priv); + return NULL; + } + lseek(priv->fd, 0, SEEK_SET); + + new->size = ofs; + new->offset = 0; + new->dev = NULL; + new->flags = 0; + + devfs_create(new); + + return new; +} diff --git a/fs/fs.c b/fs/fs.c index 1901c94ad1..621ea19749 100644 --- a/fs/fs.c +++ b/fs/fs.c @@ -36,6 +36,8 @@ #include #include +#include "parseopt.h" + char *mkmodestr(unsigned long mode, char *str) { static const char *l = "xwr"; @@ -1222,13 +1224,18 @@ int register_fs_driver(struct fs_driver_d *fsdrv) } EXPORT_SYMBOL(register_fs_driver); -static const char *detect_fs(const char *filename) +static const char *detect_fs(const char *filename, const char *fsoptions) { enum filetype type; struct driver_d *drv; struct fs_driver_d *fdrv; + bool loop; - type = cdev_detect_type(filename); + parseopt_b(fsoptions, "loop", &loop); + if (loop) + type = file_name_detect_type(filename); + else + type = cdev_detect_type(filename); if (type == filetype_unknown) return NULL; @@ -1245,7 +1252,13 @@ static const char *detect_fs(const char *filename) int fsdev_open_cdev(struct fs_device_d *fsdev) { - fsdev->cdev = cdev_open(fsdev->backingstore, O_RDWR); + bool loop; + + parseopt_b(fsdev->options, "loop", &loop); + if (loop) + fsdev->cdev = cdev_create_from_file(fsdev->backingstore, O_RDWR); + else + fsdev->cdev = cdev_open(fsdev->backingstore, O_RDWR); if (!fsdev->cdev) return -EINVAL; @@ -1292,7 +1305,7 @@ int mount(const char *device, const char *fsname, const char *_path, } if (!fsname) - fsname = detect_fs(device); + fsname = detect_fs(device, fsoptions); if (!fsname) return -ENOENT; diff --git a/include/driver.h b/include/driver.h index 086e44636b..daa9453a3b 100644 --- a/include/driver.h +++ b/include/driver.h @@ -473,6 +473,7 @@ struct cdev *lcdev_by_name(const char *filename); struct cdev *cdev_readlink(struct cdev *cdev); struct cdev *cdev_by_device_node(struct device_node *node); struct cdev *cdev_open(const char *name, unsigned long flags); +struct cdev *cdev_create_from_file(const char *path, ulong flags); int cdev_do_open(struct cdev *, unsigned long flags); void cdev_close(struct cdev *cdev); int cdev_flush(struct cdev *cdev); -- 2.11.0 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox