| Message ID | 1438235311-23788-9-git-send-email-yangds.fnst@cn.fujitsu.com |
|---|---|
| State | Superseded |
| Headers | show |
On Thu 30-07-15 13:48:04, Dongsheng Yang wrote: > This commit introduce a file of fs/dev.c at first. This is > a internal file shared by block_dev and char_dev. There is > only one function in it __lookup_dev which will be wrapped > to be lookup_bdev and loopup_cdev. > > We will put more code in this file which is shared by > block_dev and char_dev. > > Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com> > --- > fs/Makefile | 2 +- > fs/block_dev.c | 26 ++------------------ > fs/dev.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > fs/internal.h | 14 +++++++++++ > 4 files changed, 94 insertions(+), 25 deletions(-) > create mode 100644 fs/dev.c > ... > +/** > + * __lookup_dev - lookup a block_device or cdev by name > + * @pathname: special file representing the device > + * @cdevp: cdev would be returned by cdevp > + * @bdevp: block_device would be returned by bdevp > + * > + * Get a reference to the block_deivce or cdev at @pathname in > + * the current namespace if possible and return it. > + */ > +int __lookup_dev(const char *pathname, struct cdev **cdevp, > + struct block_device **bdevp) > +{ > + struct inode *inode; > + struct path path; > + int error = 0; > + > + if (!pathname || !*pathname) > + return -EINVAL; > + > + error = kern_path(pathname, LOOKUP_FOLLOW, &path); > + if (error) > + return error; > + > + inode = d_backing_inode(path.dentry); > + > + /** > + * We need at least one of bdevp and cdevp to be NULL, > + * but cdevp and bdevp can not be both NULL. > + */ > + error = -EINVAL; > + if (!(cdevp || bdevp) || (cdevp && bdevp)) > + goto out; Why don't you allow both cdevp and bdevp to be set and in that case accept both block & character device and just set appropriate pointer and the other one to NULL? Then quota code wouldn't have to search twice... Honza
On Mon 03-08-15 22:08:06, Jan Kara wrote: > On Thu 30-07-15 13:48:04, Dongsheng Yang wrote: > > This commit introduce a file of fs/dev.c at first. This is > > a internal file shared by block_dev and char_dev. There is > > only one function in it __lookup_dev which will be wrapped > > to be lookup_bdev and loopup_cdev. > > > > We will put more code in this file which is shared by > > block_dev and char_dev. > > > > Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com> > > --- > > fs/Makefile | 2 +- > > fs/block_dev.c | 26 ++------------------ > > fs/dev.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > fs/internal.h | 14 +++++++++++ > > 4 files changed, 94 insertions(+), 25 deletions(-) > > create mode 100644 fs/dev.c > > > ... > > +/** > > + * __lookup_dev - lookup a block_device or cdev by name > > + * @pathname: special file representing the device > > + * @cdevp: cdev would be returned by cdevp > > + * @bdevp: block_device would be returned by bdevp > > + * > > + * Get a reference to the block_deivce or cdev at @pathname in > > + * the current namespace if possible and return it. > > + */ > > +int __lookup_dev(const char *pathname, struct cdev **cdevp, > > + struct block_device **bdevp) > > +{ > > + struct inode *inode; > > + struct path path; > > + int error = 0; > > + > > + if (!pathname || !*pathname) > > + return -EINVAL; > > + > > + error = kern_path(pathname, LOOKUP_FOLLOW, &path); > > + if (error) > > + return error; > > + > > + inode = d_backing_inode(path.dentry); > > + > > + /** > > + * We need at least one of bdevp and cdevp to be NULL, > > + * but cdevp and bdevp can not be both NULL. > > + */ > > + error = -EINVAL; > > + if (!(cdevp || bdevp) || (cdevp && bdevp)) > > + goto out; > > Why don't you allow both cdevp and bdevp to be set and in that case accept > both block & character device and just set appropriate pointer and the > other one to NULL? Then quota code wouldn't have to search twice... On a second thought it's probably not worth the hassle with using the function directly from quota code. So OK. You can add: Reviewed-by: Jan Kara <jack@suse.com> Honza > -- > Jan Kara <jack@suse.com> > SUSE Labs, CR
diff --git a/fs/Makefile b/fs/Makefile index cb92fd4..d2f12b6 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -5,7 +5,7 @@ # Rewritten to use lists instead of if-statements. # -obj-y := open.o read_write.o file_table.o super.o \ +obj-y := open.o read_write.o file_table.o super.o dev.o\ char_dev.o stat.o exec.o pipe.o namei.o fcntl.o \ ioctl.o readdir.o select.o dcache.o inode.o \ attr.o bad_inode.o file.o filesystems.o namespace.o \ diff --git a/fs/block_dev.c b/fs/block_dev.c index c7e4163..07e434a 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -654,7 +654,7 @@ void bdput(struct block_device *bdev) EXPORT_SYMBOL(bdput); -static struct block_device *bd_acquire(struct inode *inode) +struct block_device *bd_acquire(struct inode *inode) { struct block_device *bdev; @@ -1706,34 +1706,12 @@ EXPORT_SYMBOL(ioctl_by_bdev); struct block_device *lookup_bdev(const char *pathname) { struct block_device *bdev; - struct inode *inode; - struct path path; int error; - if (!pathname || !*pathname) - return ERR_PTR(-EINVAL); - - error = kern_path(pathname, LOOKUP_FOLLOW, &path); + error = __lookup_dev(pathname, NULL, &bdev); if (error) return ERR_PTR(error); - - inode = d_backing_inode(path.dentry); - error = -ENOTBLK; - if (!S_ISBLK(inode->i_mode)) - goto fail; - error = -EACCES; - if (path.mnt->mnt_flags & MNT_NODEV) - goto fail; - error = -ENOMEM; - bdev = bd_acquire(inode); - if (!bdev) - goto fail; -out: - path_put(&path); return bdev; -fail: - bdev = ERR_PTR(error); - goto out; } EXPORT_SYMBOL(lookup_bdev); diff --git a/fs/dev.c b/fs/dev.c new file mode 100644 index 0000000..5356a47 --- /dev/null +++ b/fs/dev.c @@ -0,0 +1,77 @@ +/* + * This file contains some functions shared by block_dev and char_dev + */ +#include <linux/fs.h> +#include <linux/namei.h> +#include <linux/mount.h> + +#include "internal.h" + +/** + * __lookup_dev - lookup a block_device or cdev by name + * @pathname: special file representing the device + * @cdevp: cdev would be returned by cdevp + * @bdevp: block_device would be returned by bdevp + * + * Get a reference to the block_deivce or cdev at @pathname in + * the current namespace if possible and return it. + */ +int __lookup_dev(const char *pathname, struct cdev **cdevp, + struct block_device **bdevp) +{ + struct inode *inode; + struct path path; + int error = 0; + + if (!pathname || !*pathname) + return -EINVAL; + + error = kern_path(pathname, LOOKUP_FOLLOW, &path); + if (error) + return error; + + inode = d_backing_inode(path.dentry); + + /** + * We need at least one of bdevp and cdevp to be NULL, + * but cdevp and bdevp can not be both NULL. + */ + error = -EINVAL; + if (!(cdevp || bdevp) || (cdevp && bdevp)) + goto out; + + if (cdevp) { + if (!S_ISCHR(inode->i_mode)) { + error = -EINVAL; + goto out; + } + } else { + if (!S_ISBLK(inode->i_mode)) { + error = -ENOTBLK; + goto out; + } + } + error = -EACCES; + if (path.mnt->mnt_flags & MNT_NODEV) + goto out; + error = -ENXIO; + if (S_ISCHR(inode->i_mode)) { + struct cdev *cdev; + + cdev = cd_acquire(inode); + if (!cdev) + goto out; + *cdevp = cdev; + } else { + struct block_device *bdev; + + bdev = bd_acquire(inode); + if (!bdev) + goto out; + *bdevp = bdev; + } + error = 0; +out: + path_put(&path); + return error; +} diff --git a/fs/internal.h b/fs/internal.h index 01dce1d..1e48f9e 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -17,6 +17,12 @@ struct mount; struct shrink_control; /* + * dev.c + */ +extern int __lookup_dev(const char *pathname, struct cdev **cdevp, + struct block_device **bdevp); + +/* * block_dev.c */ #ifdef CONFIG_BLOCK @@ -24,6 +30,8 @@ extern void __init bdev_cache_init(void); extern int __sync_blockdev(struct block_device *bdev, int wait); +extern struct block_device *bd_acquire(struct inode *inode); + #else static inline void bdev_cache_init(void) { @@ -33,6 +41,11 @@ static inline int __sync_blockdev(struct block_device *bdev, int wait) { return 0; } + +static struct block_device *bd_acquire(struct inode *inode) +{ + return NULL; +} #endif /* @@ -44,6 +57,7 @@ extern void guard_bio_eod(int rw, struct bio *bio); * char_dev.c */ extern void __init chrdev_init(void); +extern struct cdev *cd_acquire(struct inode *inode); /* * namei.c
This commit introduce a file of fs/dev.c at first. This is a internal file shared by block_dev and char_dev. There is only one function in it __lookup_dev which will be wrapped to be lookup_bdev and loopup_cdev. We will put more code in this file which is shared by block_dev and char_dev. Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com> --- fs/Makefile | 2 +- fs/block_dev.c | 26 ++------------------ fs/dev.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/internal.h | 14 +++++++++++ 4 files changed, 94 insertions(+), 25 deletions(-) create mode 100644 fs/dev.c