Commit d4d77629 authored by Tejun Heo's avatar Tejun Heo
Browse files

block: clean up blkdev_get() wrappers and their users



After recent blkdev_get() modifications, open_by_devnum() and
open_bdev_exclusive() are simple wrappers around blkdev_get().
Replace them with blkdev_get_by_dev() and blkdev_get_by_path().

blkdev_get_by_dev() is identical to open_by_devnum().
blkdev_get_by_path() is slightly different in that it doesn't
automatically add %FMODE_EXCL to @mode.

All users are converted.  Most conversions are mechanical and don't
introduce any behavior difference.  There are several exceptions.

* btrfs now sets FMODE_EXCL in btrfs_device->mode, so there's no
  reason to OR it explicitly on blkdev_put().

* gfs2, nilfs2 and the generic mount_bdev() now set FMODE_EXCL in
  sb->s_mode.

* With the above changes, sb->s_mode now always should contain
  FMODE_EXCL.  WARN_ON_ONCE() added to kill_block_super() to detect
  errors.

The new blkdev_get_*() functions are with proper docbook comments.
While at it, add function description to blkdev_get() too.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Philipp Reisner <philipp.reisner@linbit.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Joern Engel <joern@lazybastard.org>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jan Kara <jack@suse.cz>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp>
Cc: reiserfs-devel@vger.kernel.org
Cc: xfs-masters@oss.sgi.com
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
parent 75f1dc0d
......@@ -902,8 +902,8 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
}
}
bdev = open_bdev_exclusive(nbc->dc.backing_dev,
FMODE_READ | FMODE_WRITE, mdev);
bdev = blkdev_get_by_path(nbc->dc.backing_dev,
FMODE_READ | FMODE_WRITE | FMODE_EXCL, mdev);
if (IS_ERR(bdev)) {
dev_err(DEV, "open(\"%s\") failed with %ld\n", nbc->dc.backing_dev,
PTR_ERR(bdev));
......@@ -920,10 +920,10 @@ static int drbd_nl_disk_conf(struct drbd_conf *mdev, struct drbd_nl_cfg_req *nlp
* should check it for you already; but if you don't, or
* someone fooled it, we need to double check here)
*/
bdev = open_bdev_exclusive(nbc->dc.meta_dev,
FMODE_READ | FMODE_WRITE,
(nbc->dc.meta_dev_idx < 0) ?
(void *)mdev : (void *)drbd_m_holder);
bdev = blkdev_get_by_path(nbc->dc.meta_dev,
FMODE_READ | FMODE_WRITE | FMODE_EXCL,
(nbc->dc.meta_dev_idx < 0) ?
(void *)mdev : (void *)drbd_m_holder);
if (IS_ERR(bdev)) {
dev_err(DEV, "open(\"%s\") failed with %ld\n", nbc->dc.meta_dev,
PTR_ERR(bdev));
......
......@@ -325,7 +325,7 @@ static int open_dev(struct dm_dev_internal *d, dev_t dev,
BUG_ON(d->dm_dev.bdev);
bdev = open_by_devnum(dev, d->dm_dev.mode | FMODE_EXCL, _claim_ptr);
bdev = blkdev_get_by_dev(dev, d->dm_dev.mode | FMODE_EXCL, _claim_ptr);
if (IS_ERR(bdev))
return PTR_ERR(bdev);
......
......@@ -1934,8 +1934,8 @@ static int lock_rdev(mdk_rdev_t *rdev, dev_t dev, int shared)
struct block_device *bdev;
char b[BDEVNAME_SIZE];
bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
shared ? (mdk_rdev_t *)lock_rdev : rdev);
bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
shared ? (mdk_rdev_t *)lock_rdev : rdev);
if (IS_ERR(bdev)) {
printk(KERN_ERR "md: could not open %s.\n",
__bdevname(dev, b));
......
......@@ -247,7 +247,7 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size)
return NULL;
/* Get a handle on the device */
bdev = open_bdev_exclusive(devname, mode, dev);
bdev = blkdev_get_by_path(devname, mode, dev);
#ifndef MODULE
if (IS_ERR(bdev)) {
......@@ -256,7 +256,7 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size)
dev_t devt = name_to_dev_t(devname);
if (devt)
bdev = open_by_devnum(devt, mode, dev);
bdev = blkdev_get_by_dev(devt, mode, dev);
}
#endif
......
......@@ -854,24 +854,6 @@ static inline void bd_unlink_disk_holder(struct block_device *bdev)
{ }
#endif
/*
* Tries to open block device by device number. Use it ONLY if you
* really do not have anything better - i.e. when you are behind a
* truly sucky interface and all you are given is a device number. _Never_
* to be used for internal purposes. If you ever need it - reconsider
* your API.
*/
struct block_device *open_by_devnum(dev_t dev, fmode_t mode, void *holder)
{
struct block_device *bdev = bdget(dev);
int err = -ENOMEM;
if (bdev)
err = blkdev_get(bdev, mode, holder);
return err ? ERR_PTR(err) : bdev;
}
EXPORT_SYMBOL(open_by_devnum);
/**
* flush_disk - invalidates all buffer-cache entries on a disk
*
......@@ -1132,6 +1114,25 @@ static int __blkdev_get(struct block_device *bdev, fmode_t mode, int for_part)
return ret;
}
/**
* blkdev_get - open a block device
* @bdev: block_device to open
* @mode: FMODE_* mask
* @holder: exclusive holder identifier
*
* Open @bdev with @mode. If @mode includes %FMODE_EXCL, @bdev is
* open with exclusive access. Specifying %FMODE_EXCL with %NULL
* @holder is invalid. Exclusive opens may nest for the same @holder.
*
* On success, the reference count of @bdev is unchanged. On failure,
* @bdev is put.
*
* CONTEXT:
* Might sleep.
*
* RETURNS:
* 0 on success, -errno on failure.
*/
int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
{
struct block_device *whole = NULL;
......@@ -1186,6 +1187,80 @@ int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
}
EXPORT_SYMBOL(blkdev_get);
/**
* blkdev_get_by_path - open a block device by name
* @path: path to the block device to open
* @mode: FMODE_* mask
* @holder: exclusive holder identifier
*
* Open the blockdevice described by the device file at @path. @mode
* and @holder are identical to blkdev_get().
*
* On success, the returned block_device has reference count of one.
*
* CONTEXT:
* Might sleep.
*
* RETURNS:
* Pointer to block_device on success, ERR_PTR(-errno) on failure.
*/
struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
void *holder)
{
struct block_device *bdev;
int err;
bdev = lookup_bdev(path);
if (IS_ERR(bdev))
return bdev;
err = blkdev_get(bdev, mode, holder);
if (err)
return ERR_PTR(err);
return bdev;
}
EXPORT_SYMBOL(blkdev_get_by_path);
/**
* blkdev_get_by_dev - open a block device by device number
* @dev: device number of block device to open
* @mode: FMODE_* mask
* @holder: exclusive holder identifier
*
* Open the blockdevice described by device number @dev. @mode and
* @holder are identical to blkdev_get().
*
* Use it ONLY if you really do not have anything better - i.e. when
* you are behind a truly sucky interface and all you are given is a
* device number. _Never_ to be used for internal purposes. If you
* ever need it - reconsider your API.
*
* On success, the returned block_device has reference count of one.
*
* CONTEXT:
* Might sleep.
*
* RETURNS:
* Pointer to block_device on success, ERR_PTR(-errno) on failure.
*/
struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
{
struct block_device *bdev;
int err;
bdev = bdget(dev);
if (!bdev)
return ERR_PTR(-ENOMEM);
err = blkdev_get(bdev, mode, holder);
if (err)
return ERR_PTR(err);
return bdev;
}
EXPORT_SYMBOL(blkdev_get_by_dev);
static int blkdev_open(struct inode * inode, struct file * filp)
{
struct block_device *bdev;
......@@ -1436,34 +1511,6 @@ fail:
}
EXPORT_SYMBOL(lookup_bdev);
/**
* open_bdev_exclusive - open a block device by name and set it up for use
*
* @path: special file representing the block device
* @mode: FMODE_... combination to pass be used
* @holder: owner for exclusion
*
* Open the blockdevice described by the special file at @path, claim it
* for the @holder.
*/
struct block_device *open_bdev_exclusive(const char *path, fmode_t mode, void *holder)
{
struct block_device *bdev;
int error;
bdev = lookup_bdev(path);
if (IS_ERR(bdev))
return bdev;
error = blkdev_get(bdev, mode | FMODE_EXCL, holder);
if (error)
return ERR_PTR(error);
return bdev;
}
EXPORT_SYMBOL(open_bdev_exclusive);
int __invalidate_device(struct block_device *bdev)
{
struct super_block *sb = get_super(bdev);
......
......@@ -489,7 +489,7 @@ again:
continue;
if (device->bdev) {
blkdev_put(device->bdev, device->mode | FMODE_EXCL);
blkdev_put(device->bdev, device->mode);
device->bdev = NULL;
fs_devices->open_devices--;
}
......@@ -523,7 +523,7 @@ static int __btrfs_close_devices(struct btrfs_fs_devices *fs_devices)
list_for_each_entry(device, &fs_devices->devices, dev_list) {
if (device->bdev) {
blkdev_put(device->bdev, device->mode | FMODE_EXCL);
blkdev_put(device->bdev, device->mode);
fs_devices->open_devices--;
}
if (device->writeable) {
......@@ -580,13 +580,15 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
int seeding = 1;
int ret = 0;
flags |= FMODE_EXCL;
list_for_each_entry(device, head, dev_list) {
if (device->bdev)
continue;
if (!device->name)
continue;
bdev = open_bdev_exclusive(device->name, flags, holder);
bdev = blkdev_get_by_path(device->name, flags, holder);
if (IS_ERR(bdev)) {
printk(KERN_INFO "open %s failed\n", device->name);
goto error;
......@@ -638,7 +640,7 @@ static int __btrfs_open_devices(struct btrfs_fs_devices *fs_devices,
error_brelse:
brelse(bh);
error_close:
blkdev_put(bdev, flags | FMODE_EXCL);
blkdev_put(bdev, flags);
error:
continue;
}
......@@ -684,7 +686,8 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
mutex_lock(&uuid_mutex);
bdev = open_bdev_exclusive(path, flags, holder);
flags |= FMODE_EXCL;
bdev = blkdev_get_by_path(path, flags, holder);
if (IS_ERR(bdev)) {
ret = PTR_ERR(bdev);
......@@ -716,7 +719,7 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
brelse(bh);
error_close:
blkdev_put(bdev, flags | FMODE_EXCL);
blkdev_put(bdev, flags);
error:
mutex_unlock(&uuid_mutex);
return ret;
......@@ -1179,8 +1182,8 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
goto out;
}
} else {
bdev = open_bdev_exclusive(device_path, FMODE_READ,
root->fs_info->bdev_holder);
bdev = blkdev_get_by_path(device_path, FMODE_READ | FMODE_EXCL,
root->fs_info->bdev_holder);
if (IS_ERR(bdev)) {
ret = PTR_ERR(bdev);
goto out;
......@@ -1244,7 +1247,7 @@ int btrfs_rm_device(struct btrfs_root *root, char *device_path)
root->fs_info->fs_devices->latest_bdev = next_device->bdev;
if (device->bdev) {
blkdev_put(device->bdev, device->mode | FMODE_EXCL);
blkdev_put(device->bdev, device->mode);
device->bdev = NULL;
device->fs_devices->open_devices--;
}
......@@ -1439,7 +1442,8 @@ int btrfs_init_new_device(struct btrfs_root *root, char *device_path)
if ((sb->s_flags & MS_RDONLY) && !root->fs_info->fs_devices->seeding)
return -EINVAL;
bdev = open_bdev_exclusive(device_path, 0, root->fs_info->bdev_holder);
bdev = blkdev_get_by_path(device_path, FMODE_EXCL,
root->fs_info->bdev_holder);
if (IS_ERR(bdev))
return PTR_ERR(bdev);
......
......@@ -49,7 +49,7 @@ struct btrfs_device {
struct block_device *bdev;
/* the mode sent to open_bdev_exclusive */
/* the mode sent to blkdev_get */
fmode_t mode;
char *name;
......
......@@ -347,7 +347,7 @@ static struct block_device *ext3_blkdev_get(dev_t dev, struct super_block *sb)
struct block_device *bdev;
char b[BDEVNAME_SIZE];
bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
if (IS_ERR(bdev))
goto fail;
return bdev;
......
......@@ -647,7 +647,7 @@ static struct block_device *ext4_blkdev_get(dev_t dev, struct super_block *sb)
struct block_device *bdev;
char b[BDEVNAME_SIZE];
bdev = open_by_devnum(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
bdev = blkdev_get_by_dev(dev, FMODE_READ|FMODE_WRITE|FMODE_EXCL, sb);
if (IS_ERR(bdev))
goto fail;
return bdev;
......
......@@ -1268,7 +1268,7 @@ static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags,
{
struct block_device *bdev;
struct super_block *s;
fmode_t mode = FMODE_READ;
fmode_t mode = FMODE_READ | FMODE_EXCL;
int error;
struct gfs2_args args;
struct gfs2_sbd *sdp;
......@@ -1276,7 +1276,7 @@ static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags,
if (!(flags & MS_RDONLY))
mode |= FMODE_WRITE;
bdev = open_bdev_exclusive(dev_name, mode, fs_type);
bdev = blkdev_get_by_path(dev_name, mode, fs_type);
if (IS_ERR(bdev))
return ERR_CAST(bdev);
......@@ -1298,7 +1298,7 @@ static struct dentry *gfs2_mount(struct file_system_type *fs_type, int flags,
goto error_bdev;
if (s->s_root)
blkdev_put(bdev, mode | FMODE_EXCL);
blkdev_put(bdev, mode);
memset(&args, 0, sizeof(args));
args.ar_quota = GFS2_QUOTA_DEFAULT;
......@@ -1342,7 +1342,7 @@ error_super:
deactivate_locked_super(s);
return ERR_PTR(error);
error_bdev:
blkdev_put(bdev, mode | FMODE_EXCL);
blkdev_put(bdev, mode);
return ERR_PTR(error);
}
......
......@@ -1120,8 +1120,8 @@ int lmLogOpen(struct super_block *sb)
* file systems to log may have n-to-1 relationship;
*/
bdev = open_by_devnum(sbi->logdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
log);
bdev = blkdev_get_by_dev(sbi->logdev, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
log);
if (IS_ERR(bdev)) {
rc = -PTR_ERR(bdev);
goto free;
......
......@@ -325,7 +325,8 @@ int logfs_get_sb_bdev(struct logfs_super *p, struct file_system_type *type,
{
struct block_device *bdev;
bdev = open_bdev_exclusive(devname, FMODE_READ|FMODE_WRITE, type);
bdev = blkdev_get_by_path(devname, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
type);
if (IS_ERR(bdev))
return PTR_ERR(bdev);
......
......@@ -1147,14 +1147,14 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
{
struct nilfs_super_data sd;
struct super_block *s;
fmode_t mode = FMODE_READ;
fmode_t mode = FMODE_READ | FMODE_EXCL;
struct dentry *root_dentry;
int err, s_new = false;
if (!(flags & MS_RDONLY))
mode |= FMODE_WRITE;
sd.bdev = open_bdev_exclusive(dev_name, mode, fs_type);
sd.bdev = blkdev_get_by_path(dev_name, mode, fs_type);
if (IS_ERR(sd.bdev))
return ERR_CAST(sd.bdev);
......@@ -1233,7 +1233,7 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
}
if (!s_new)
blkdev_put(sd.bdev, mode | FMODE_EXCL);
blkdev_put(sd.bdev, mode);
return root_dentry;
......@@ -1242,7 +1242,7 @@ nilfs_mount(struct file_system_type *fs_type, int flags,
failed:
if (!s_new)
blkdev_put(sd.bdev, mode | FMODE_EXCL);
blkdev_put(sd.bdev, mode);
return ERR_PTR(err);
}
......
......@@ -2585,7 +2585,8 @@ static int journal_init_dev(struct super_block *super,
if ((!jdev_name || !jdev_name[0])) {
if (jdev == super->s_dev)
blkdev_mode &= ~FMODE_EXCL;
journal->j_dev_bd = open_by_devnum(jdev, blkdev_mode, journal);
journal->j_dev_bd = blkdev_get_by_dev(jdev, blkdev_mode,
journal);
journal->j_dev_mode = blkdev_mode;
if (IS_ERR(journal->j_dev_bd)) {
result = PTR_ERR(journal->j_dev_bd);
......@@ -2601,8 +2602,7 @@ static int journal_init_dev(struct super_block *super,
}
journal->j_dev_mode = blkdev_mode;
journal->j_dev_bd = open_bdev_exclusive(jdev_name,
blkdev_mode, journal);
journal->j_dev_bd = blkdev_get_by_path(jdev_name, blkdev_mode, journal);
if (IS_ERR(journal->j_dev_bd)) {
result = PTR_ERR(journal->j_dev_bd);
journal->j_dev_bd = NULL;
......
......@@ -766,13 +766,13 @@ struct dentry *mount_bdev(struct file_system_type *fs_type,
{
struct block_device *bdev;
struct super_block *s;
fmode_t mode = FMODE_READ;
fmode_t mode = FMODE_READ | FMODE_EXCL;
int error = 0;
if (!(flags & MS_RDONLY))
mode |= FMODE_WRITE;
bdev = open_bdev_exclusive(dev_name, mode, fs_type);
bdev = blkdev_get_by_path(dev_name, mode, fs_type);
if (IS_ERR(bdev))
return ERR_CAST(bdev);
......@@ -807,7 +807,7 @@ struct dentry *mount_bdev(struct file_system_type *fs_type,
* holding an active reference.
*/
up_write(&s->s_umount);
blkdev_put(bdev, mode | FMODE_EXCL);
blkdev_put(bdev, mode);
down_write(&s->s_umount);
} else {
char b[BDEVNAME_SIZE];
......@@ -831,7 +831,7 @@ struct dentry *mount_bdev(struct file_system_type *fs_type,
error_s:
error = PTR_ERR(s);
error_bdev:
blkdev_put(bdev, mode | FMODE_EXCL);
blkdev_put(bdev, mode);
error:
return ERR_PTR(error);
}
......@@ -862,6 +862,7 @@ void kill_block_super(struct super_block *sb)
bdev->bd_super = NULL;
generic_shutdown_super(sb);
sync_blockdev(bdev);
WARN_ON_ONCE(!(mode & FMODE_EXCL));
blkdev_put(bdev, mode | FMODE_EXCL);
}
......
......@@ -609,7 +609,8 @@ xfs_blkdev_get(
{
int error = 0;
*bdevp = open_bdev_exclusive(name, FMODE_READ|FMODE_WRITE, mp);
*bdevp = blkdev_get_by_path(name, FMODE_READ|FMODE_WRITE|FMODE_EXCL,
mp);
if (IS_ERR(*bdevp)) {
error = PTR_ERR(*bdevp);
printk("XFS: Invalid device [%s], error=%d\n", name, error);
......
......@@ -2006,8 +2006,6 @@ extern struct block_device *bdgrab(struct block_device *bdev);
extern void bd_set_size(struct block_device *, loff_t size);
extern void bd_forget(struct inode *inode);
extern void bdput(struct block_device *);
extern struct block_device *open_by_devnum(dev_t dev, fmode_t mode,
void *holder);
extern void invalidate_bdev(struct block_device *);
extern int sync_blockdev(struct block_device *bdev);
extern struct super_block *freeze_bdev(struct block_device *);
......@@ -2039,6 +2037,10 @@ extern int ioctl_by_bdev(struct block_device *, unsigned, unsigned long);
extern int blkdev_ioctl(struct block_device *, fmode_t, unsigned, unsigned long);
extern long compat_blkdev_ioctl(struct file *, unsigned, unsigned long);
extern int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder);
extern struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
void *holder);
extern struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode,
void *holder);
extern int blkdev_put(struct block_device *bdev, fmode_t mode);
#ifdef CONFIG_SYSFS
extern int bd_link_disk_holder(struct block_device *bdev, struct gendisk *disk);
......@@ -2083,7 +2085,6 @@ static inline void unregister_chrdev(unsigned int major, const char *name)
extern const char *__bdevname(dev_t, char *buffer);
extern const char *bdevname(struct block_device *bdev, char *buffer);
extern struct block_device *lookup_bdev(const char *);
extern struct block_device *open_bdev_exclusive(const char *, fmode_t, void *);
extern void blkdev_show(struct seq_file *,off_t);
#else
......
......@@ -907,8 +907,8 @@ int swsusp_check(void)
{
int error;
hib_resume_bdev = open_by_devnum(swsusp_resume_device,
FMODE_READ, NULL);
hib_resume_bdev = blkdev_get_by_dev(swsusp_resume_device,
FMODE_READ, NULL);
if (!IS_ERR(hib_resume_bdev)) {
set_blocksize(hib_resume_bdev, PAGE_SIZE);
clear_page(swsusp_header);
......
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