From: Philipp Zabel <p.zabel@pengutronix.de>
To: barebox@lists.infradead.org
Subject: [PATCH 3/3] fs: add support loop mount offset
Date: Thu, 1 Feb 2018 11:37:17 +0100 [thread overview]
Message-ID: <20180201103717.17429-3-p.zabel@pengutronix.de> (raw)
In-Reply-To: <20180201103717.17429-1-p.zabel@pengutronix.de>
When loop mounting, allow to specify an offset into the file, similarly
to the losetup offset option. Multiplicative suffixes are supported.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
---
fs/devfs-core.c | 8 ++++----
fs/fs.c | 12 +++++++++---
include/driver.h | 2 +-
3 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/fs/devfs-core.c b/fs/devfs-core.c
index be56edd18d..ea5887c720 100644
--- a/fs/devfs-core.c
+++ b/fs/devfs-core.c
@@ -464,7 +464,7 @@ static const struct file_operations loop_ops = {
.lseek = dev_lseek_default,
};
-struct cdev *cdev_create_loop(const char *path, ulong flags)
+struct cdev *cdev_create_loop(const char *path, ulong flags, loff_t offset)
{
struct cdev *new;
struct loop_priv *priv;
@@ -486,15 +486,15 @@ struct cdev *cdev_create_loop(const char *path, ulong flags)
new->priv = priv;
ofs = lseek(priv->fd, 0, SEEK_END);
- if (ofs < 0) {
+ if (ofs < 0 || ofs <= offset) {
free(new);
free(priv);
return NULL;
}
- lseek(priv->fd, 0, SEEK_SET);
+ lseek(priv->fd, offset, SEEK_SET);
new->size = ofs;
- new->offset = 0;
+ new->offset = offset;
new->dev = NULL;
new->flags = 0;
diff --git a/fs/fs.c b/fs/fs.c
index 6f15e93ba9..56e67aac2a 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -1279,11 +1279,13 @@ 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;
+ bool loop = false;
+ unsigned long long offset = 0;
parseopt_b(fsoptions, "loop", &loop);
+ parseopt_llu_suffix(fsoptions, "offset", &offset);
if (loop)
- type = file_name_detect_type(filename);
+ type = file_name_detect_type_offset(filename, offset);
else
type = cdev_detect_type(filename);
@@ -1302,9 +1304,13 @@ static const char *detect_fs(const char *filename, const char *fsoptions)
int fsdev_open_cdev(struct fs_device_d *fsdev)
{
+ unsigned long long offset = 0;
+
parseopt_b(fsdev->options, "loop", &fsdev->loop);
+ parseopt_llu_suffix(fsdev->options, "offset", &offset);
if (fsdev->loop)
- fsdev->cdev = cdev_create_loop(fsdev->backingstore, O_RDWR);
+ fsdev->cdev = cdev_create_loop(fsdev->backingstore, O_RDWR,
+ offset);
else
fsdev->cdev = cdev_open(fsdev->backingstore, O_RDWR);
if (!fsdev->cdev)
diff --git a/include/driver.h b/include/driver.h
index e571fbbec5..f37805db17 100644
--- a/include/driver.h
+++ b/include/driver.h
@@ -475,7 +475,7 @@ struct cdev *cdev_readlink(struct cdev *cdev);
struct cdev *cdev_by_device_node(struct device_node *node);
struct cdev *cdev_by_partuuid(const char *partuuid);
struct cdev *cdev_open(const char *name, unsigned long flags);
-struct cdev *cdev_create_loop(const char *path, ulong flags);
+struct cdev *cdev_create_loop(const char *path, ulong flags, loff_t offset);
void cdev_remove_loop(struct cdev *cdev);
int cdev_do_open(struct cdev *, unsigned long flags);
void cdev_close(struct cdev *cdev);
--
2.15.1
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next prev parent reply other threads:[~2018-02-01 10:37 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-01 10:37 [PATCH 1/3] fs/parseopt: Add parseopt_llu_suffix Philipp Zabel
2018-02-01 10:37 ` [PATCH 2/3] filetype: Add type detection at an offset Philipp Zabel
2018-02-01 10:37 ` Philipp Zabel [this message]
2018-02-05 7:26 ` [PATCH 1/3] fs/parseopt: Add parseopt_llu_suffix Sascha Hauer
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