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block: remove i_bdev

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Switch the block device lookup interfaces to directly work with a dev_t
so that struct block_device references are only acquired by the
blkdev_get variants (and the blk-cgroup special case).  This means that
we now don't need an extra reference in the inode and can generally
simplify handling of struct block_device to keep the lookups contained
in the core block layer code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Coly Li <colyli@suse.de>		[bcache]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2020-11-23 13:38:40 +01:00 committed by Jens Axboe
parent 7918f0f6fd
commit 4e7b5671c6
18 changed files with 121 additions and 252 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
block/ioctl.c
View File

@ -590,8 +590,7 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
{
int ret;
void __user *argp = compat_ptr(arg);
struct inode *inode = file->f_mapping->host;
struct block_device *bdev = inode->i_bdev;
struct block_device *bdev = I_BDEV(file->f_mapping->host);
struct gendisk *disk = bdev->bd_disk;
fmode_t mode = file->f_mode;
loff_t size;

8
drivers/block/loop.c
View File

@ -675,10 +675,10 @@ static int loop_validate_file(struct file *file, struct block_device *bdev)
while (is_loop_device(f)) {
struct loop_device *l;
if (f->f_mapping->host->i_bdev == bdev)
if (f->f_mapping->host->i_rdev == bdev->bd_dev)
return -EBADF;
l = f->f_mapping->host->i_bdev->bd_disk->private_data;
l = I_BDEV(f->f_mapping->host)->bd_disk->private_data;
if (l->lo_state != Lo_bound) {
return -EINVAL;
}
@ -885,9 +885,7 @@ static void loop_config_discard(struct loop_device *lo)
* file-backed loop devices: discarded regions read back as zero.
*/
if (S_ISBLK(inode->i_mode) && !lo->lo_encrypt_key_size) {
struct request_queue *backingq;
backingq = bdev_get_queue(inode->i_bdev);
struct request_queue *backingq = bdev_get_queue(I_BDEV(inode));
max_discard_sectors = backingq->limits.max_write_zeroes_sectors;
granularity = backingq->limits.discard_granularity ?:

20
drivers/md/bcache/super.c
View File

@ -2380,38 +2380,38 @@ kobj_attribute_write(register, register_bcache);
kobj_attribute_write(register_quiet, register_bcache);
kobj_attribute_write(pendings_cleanup, bch_pending_bdevs_cleanup);
static bool bch_is_open_backing(struct block_device *bdev)
static bool bch_is_open_backing(dev_t dev)
{
struct cache_set *c, *tc;
struct cached_dev *dc, *t;
list_for_each_entry_safe(c, tc, &bch_cache_sets, list)
list_for_each_entry_safe(dc, t, &c->cached_devs, list)
if (dc->bdev == bdev)
if (dc->bdev->bd_dev == dev)
return true;
list_for_each_entry_safe(dc, t, &uncached_devices, list)
if (dc->bdev == bdev)
if (dc->bdev->bd_dev == dev)
return true;
return false;
}
static bool bch_is_open_cache(struct block_device *bdev)
static bool bch_is_open_cache(dev_t dev)
{
struct cache_set *c, *tc;
list_for_each_entry_safe(c, tc, &bch_cache_sets, list) {
struct cache *ca = c->cache;
if (ca->bdev == bdev)
if (ca->bdev->bd_dev == dev)
return true;
}
return false;
}
static bool bch_is_open(struct block_device *bdev)
static bool bch_is_open(dev_t dev)
{
return bch_is_open_cache(bdev) || bch_is_open_backing(bdev);
return bch_is_open_cache(dev) || bch_is_open_backing(dev);
}
struct async_reg_args {
@ -2535,9 +2535,11 @@ static ssize_t register_bcache(struct kobject *k, struct kobj_attribute *attr,
sb);
if (IS_ERR(bdev)) {
if (bdev == ERR_PTR(-EBUSY)) {
bdev = lookup_bdev(strim(path));
dev_t dev;
mutex_lock(&bch_register_lock);
if (!IS_ERR(bdev) && bch_is_open(bdev))
if (lookup_bdev(strim(path), &dev) == 0 &&
bch_is_open(dev))
err = "device already registered";
else
err = "device busy";

9
drivers/md/dm-table.c
View File

@ -348,16 +348,9 @@ static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
dev_t dm_get_dev_t(const char *path)
{
dev_t dev;
struct block_device *bdev;
bdev = lookup_bdev(path);
if (IS_ERR(bdev))
if (lookup_bdev(path, &dev))
dev = name_to_dev_t(path);
else {
dev = bdev->bd_dev;
bdput(bdev);
}
return dev;
}
EXPORT_SYMBOL_GPL(dm_get_dev_t);

17
drivers/mtd/mtdsuper.c
View File

@ -120,8 +120,8 @@ int get_tree_mtd(struct fs_context *fc,
struct fs_context *fc))
{
#ifdef CONFIG_BLOCK
struct block_device *bdev;
int ret, major;
dev_t dev;
int ret;
#endif
int mtdnr;
@ -169,20 +169,15 @@ int get_tree_mtd(struct fs_context *fc,
/* try the old way - the hack where we allowed users to mount
* /dev/mtdblock$(n) but didn't actually _use_ the blockdev
*/
bdev = lookup_bdev(fc->source);
if (IS_ERR(bdev)) {
ret = PTR_ERR(bdev);
ret = lookup_bdev(fc->source, &dev);
if (ret) {
errorf(fc, "MTD: Couldn't look up '%s': %d", fc->source, ret);
return ret;
}
pr_debug("MTDSB: lookup_bdev() returned 0\n");
major = MAJOR(bdev->bd_dev);
mtdnr = MINOR(bdev->bd_dev);
bdput(bdev);
if (major == MTD_BLOCK_MAJOR)
return mtd_get_sb_by_nr(fc, mtdnr, fill_super);
if (MAJOR(dev) == MTD_BLOCK_MAJOR)
return mtd_get_sb_by_nr(fc, MINOR(dev), fill_super);
#endif /* CONFIG_BLOCK */

6
drivers/target/target_core_file.c
View File

@ -133,10 +133,10 @@ static int fd_configure_device(struct se_device *dev)
*/
inode = file->f_mapping->host;
if (S_ISBLK(inode->i_mode)) {
struct request_queue *q = bdev_get_queue(inode->i_bdev);
struct request_queue *q = bdev_get_queue(I_BDEV(inode));
unsigned long long dev_size;
fd_dev->fd_block_size = bdev_logical_block_size(inode->i_bdev);
fd_dev->fd_block_size = bdev_logical_block_size(I_BDEV(inode));
/*
* Determine the number of bytes from i_size_read() minus
* one (1) logical sector from underlying struct block_device
@ -559,7 +559,7 @@ fd_execute_unmap(struct se_cmd *cmd, sector_t lba, sector_t nolb)
if (S_ISBLK(inode->i_mode)) {
/* The backend is block device, use discard */
struct block_device *bdev = inode->i_bdev;
struct block_device *bdev = I_BDEV(inode);
struct se_device *dev = cmd->se_dev;
ret = blkdev_issue_discard(bdev,

8
drivers/usb/gadget/function/storage_common.c
View File

@ -204,7 +204,7 @@ int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
if (!(filp->f_mode & FMODE_WRITE))
ro = 1;
inode = file_inode(filp);
inode = filp->f_mapping->host;
if ((!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))) {
LINFO(curlun, "invalid file type: %s\n", filename);
goto out;
@ -221,7 +221,7 @@ int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
if (!(filp->f_mode & FMODE_CAN_WRITE))
ro = 1;
size = i_size_read(inode->i_mapping->host);
size = i_size_read(inode);
if (size < 0) {
LINFO(curlun, "unable to find file size: %s\n", filename);
rc = (int) size;
@ -231,8 +231,8 @@ int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
if (curlun->cdrom) {
blksize = 2048;
blkbits = 11;
} else if (inode->i_bdev) {
blksize = bdev_logical_block_size(inode->i_bdev);
} else if (S_ISBLK(inode->i_mode)) {
blksize = bdev_logical_block_size(I_BDEV(inode));
blkbits = blksize_bits(blksize);
} else {
blksize = 512;

196
fs/block_dev.c
View File

@ -883,7 +883,6 @@ static struct block_device *bdget(dev_t dev)
bdev->bd_dev = dev;
inode->i_mode = S_IFBLK;
inode->i_rdev = dev;
inode->i_bdev = bdev;
inode->i_data.a_ops = &def_blk_aops;
mapping_set_gfp_mask(&inode->i_data, GFP_USER);
unlock_new_inode(inode);
@ -928,67 +927,8 @@ void bdput(struct block_device *bdev)
{
iput(bdev->bd_inode);
}
EXPORT_SYMBOL(bdput);
static struct block_device *bd_acquire(struct inode *inode)
{
struct block_device *bdev;
spin_lock(&bdev_lock);
bdev = inode->i_bdev;
if (bdev && !inode_unhashed(bdev->bd_inode)) {
bdgrab(bdev);
spin_unlock(&bdev_lock);
return bdev;
}
spin_unlock(&bdev_lock);
/*
* i_bdev references block device inode that was already shut down
* (corresponding device got removed). Remove the reference and look
* up block device inode again just in case new device got
* reestablished under the same device number.
*/
if (bdev)
bd_forget(inode);
bdev = bdget(inode->i_rdev);
if (bdev) {
spin_lock(&bdev_lock);
if (!inode->i_bdev) {
/*
* We take an additional reference to bd_inode,
* and it's released in clear_inode() of inode.
* So, we can access it via ->i_mapping always
* without igrab().
*/
bdgrab(bdev);
inode->i_bdev = bdev;
inode->i_mapping = bdev->bd_inode->i_mapping;
}
spin_unlock(&bdev_lock);
}
return bdev;
}
/* Call when you free inode */
void bd_forget(struct inode *inode)
{
struct block_device *bdev = NULL;
spin_lock(&bdev_lock);
if (!sb_is_blkdev_sb(inode->i_sb))
bdev = inode->i_bdev;
inode->i_bdev = NULL;
inode->i_mapping = &inode->i_data;
spin_unlock(&bdev_lock);
if (bdev)
bdput(bdev);
}
/**
* bd_may_claim - test whether a block device can be claimed
* @bdev: block device of interest
@ -1497,38 +1437,45 @@ static int __blkdev_get(struct block_device *bdev, struct gendisk *disk,
}
/**
* blkdev_get - open a block device
* @bdev: block_device to open
* 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 @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.
* Open the block device described by device number @dev. If @mode includes
* %FMODE_EXCL, the block device is opened with exclusive access. Specifying
* %FMODE_EXCL with a %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.
* Use this interface 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. Everything else should use blkdev_get_by_path().
*
* CONTEXT:
* Might sleep.
*
* RETURNS:
* 0 on success, -errno on failure.
* Reference to the block_device on success, ERR_PTR(-errno) on failure.
*/
static int blkdev_get(struct block_device *bdev, fmode_t mode, void *holder)
struct block_device *blkdev_get_by_dev(dev_t dev, fmode_t mode, void *holder)
{
struct block_device *claiming;
bool unblock_events = true;
struct block_device *bdev;
struct gendisk *disk;
int partno;
int ret;
ret = devcgroup_check_permission(DEVCG_DEV_BLOCK,
imajor(bdev->bd_inode), iminor(bdev->bd_inode),
MAJOR(dev), MINOR(dev),
((mode & FMODE_READ) ? DEVCG_ACC_READ : 0) |
((mode & FMODE_WRITE) ? DEVCG_ACC_WRITE : 0));
if (ret)
goto bdput;
return ERR_PTR(ret);
bdev = bdget(dev);
if (!bdev)
return ERR_PTR(-ENOMEM);
/*
* If we lost a race with 'disk' being deleted, try again. See md.c.
@ -1589,10 +1536,13 @@ put_disk:
if (ret == -ERESTARTSYS)
goto retry;
bdput:
if (ret)
if (ret) {
bdput(bdev);
return ret;
return ERR_PTR(ret);
}
return bdev;
}
EXPORT_SYMBOL(blkdev_get_by_dev);
/**
* blkdev_get_by_path - open a block device by name
@ -1600,32 +1550,30 @@ bdput:
* @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.
* Open the block device described by the device file at @path. If @mode
* includes %FMODE_EXCL, the block device is opened with exclusive access.
* Specifying %FMODE_EXCL with a %NULL @holder is invalid. Exclusive opens may
* nest for the same @holder.
*
* CONTEXT:
* Might sleep.
*
* RETURNS:
* Pointer to block_device on success, ERR_PTR(-errno) on failure.
* Reference to the 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;
dev_t dev;
int error;
bdev = lookup_bdev(path);
if (IS_ERR(bdev))
return bdev;
error = lookup_bdev(path, &dev);
if (error)
return ERR_PTR(error);
err = blkdev_get(bdev, mode, holder);
if (err)
return ERR_PTR(err);
if ((mode & FMODE_WRITE) && bdev_read_only(bdev)) {
bdev = blkdev_get_by_dev(dev, mode, holder);
if (!IS_ERR(bdev) && (mode & FMODE_WRITE) && bdev_read_only(bdev)) {
blkdev_put(bdev, mode);
return ERR_PTR(-EACCES);
}
@ -1634,45 +1582,6 @@ struct block_device *blkdev_get_by_path(const char *path, fmode_t mode,
}
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;
@ -1694,14 +1603,12 @@ static int blkdev_open(struct inode * inode, struct file * filp)
if ((filp->f_flags & O_ACCMODE) == 3)
filp->f_mode |= FMODE_WRITE_IOCTL;
bdev = bd_acquire(inode);
if (bdev == NULL)
return -ENOMEM;
bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp);
if (IS_ERR(bdev))
return PTR_ERR(bdev);
filp->f_mapping = bdev->bd_inode->i_mapping;
filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
return blkdev_get(bdev, filp->f_mode, filp);
return 0;
}
static void __blkdev_put(struct block_device *bdev, fmode_t mode, int for_part)
@ -2010,37 +1917,32 @@ const struct file_operations def_blk_fops = {
* namespace if possible and return it. Return ERR_PTR(error)
* otherwise.
*/
struct block_device *lookup_bdev(const char *pathname)
int lookup_bdev(const char *pathname, dev_t *dev)
{
struct block_device *bdev;
struct inode *inode;
struct path path;
int error;
if (!pathname || !*pathname)
return ERR_PTR(-EINVAL);
return -EINVAL;
error = kern_path(pathname, LOOKUP_FOLLOW, &path);
if (error)
return ERR_PTR(error);
return error;
inode = d_backing_inode(path.dentry);
error = -ENOTBLK;
if (!S_ISBLK(inode->i_mode))
goto fail;
goto out_path_put;
error = -EACCES;
if (!may_open_dev(&path))
goto fail;
error = -ENOMEM;
bdev = bd_acquire(inode);
if (!bdev)
goto fail;
out:
goto out_path_put;
*dev = inode->i_rdev;
error = 0;
out_path_put:
path_put(&path);
return bdev;
fail:
bdev = ERR_PTR(error);
goto out;
return error;
}
EXPORT_SYMBOL(lookup_bdev);

13
fs/btrfs/volumes.c
View File

@ -929,16 +929,16 @@ static noinline struct btrfs_device *device_list_add(const char *path,
* make sure it's the same device if the device is mounted
*/
if (device->bdev) {
struct block_device *path_bdev;
int error;
dev_t path_dev;
path_bdev = lookup_bdev(path);
if (IS_ERR(path_bdev)) {
error = lookup_bdev(path, &path_dev);
if (error) {
mutex_unlock(&fs_devices->device_list_mutex);
return ERR_CAST(path_bdev);
return ERR_PTR(error);
}
if (device->bdev != path_bdev) {
bdput(path_bdev);
if (device->bdev->bd_dev != path_dev) {
mutex_unlock(&fs_devices->device_list_mutex);
btrfs_warn_in_rcu(device->fs_info,
"duplicate device %s devid %llu generation %llu scanned by %s (%d)",
@ -947,7 +947,6 @@ static noinline struct btrfs_device *device_list_add(const char *path,
task_pid_nr(current));
return ERR_PTR(-EEXIST);
}
bdput(path_bdev);
btrfs_info_in_rcu(device->fs_info,
"devid %llu device path %s changed to %s scanned by %s (%d)",
devid, rcu_str_deref(device->name),

3
fs/inode.c
View File

@ -155,7 +155,6 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
inode->i_bytes = 0;
inode->i_generation = 0;
inode->i_pipe = NULL;
inode->i_bdev = NULL;
inode->i_cdev = NULL;
inode->i_link = NULL;
inode->i_dir_seq = 0;
@ -580,8 +579,6 @@ static void evict(struct inode *inode)
truncate_inode_pages_final(&inode->i_data);
clear_inode(inode);
}
if (S_ISBLK(inode->i_mode) && inode->i_bdev)
bd_forget(inode);
if (S_ISCHR(inode->i_mode) && inode->i_cdev)
cd_forget(inode);

7
fs/internal.h
View File

@ -25,7 +25,6 @@ extern void __init bdev_cache_init(void);
extern int __sync_blockdev(struct block_device *bdev, int wait);
void iterate_bdevs(void (*)(struct block_device *, void *), void *);
void emergency_thaw_bdev(struct super_block *sb);
void bd_forget(struct inode *inode);
#else
static inline void bdev_cache_init(void)
{
@ -43,9 +42,6 @@ static inline int emergency_thaw_bdev(struct super_block *sb)
{
return 0;
}
static inline void bd_forget(struct inode *inode)
{
}
#endif /* CONFIG_BLOCK */
/*
@ -114,8 +110,7 @@ extern struct file *alloc_empty_file_noaccount(int, const struct cred *);
*/
extern int reconfigure_super(struct fs_context *);
extern bool trylock_super(struct super_block *sb);
struct super_block *__get_super(struct block_device *bdev, bool excl);
extern struct super_block *user_get_super(dev_t);
struct super_block *user_get_super(dev_t, bool excl);
void put_super(struct super_block *sb);
extern bool mount_capable(struct fs_context *);

10
fs/io_uring.c
View File

@ -2716,11 +2716,7 @@ static struct file *__io_file_get(struct io_submit_state *state, int fd)
static bool io_bdev_nowait(struct block_device *bdev)
{
#ifdef CONFIG_BLOCK
return !bdev || blk_queue_nowait(bdev_get_queue(bdev));
#else
return true;
#endif
}
/*
@ -2733,14 +2729,16 @@ static bool io_file_supports_async(struct file *file, int rw)
umode_t mode = file_inode(file)->i_mode;
if (S_ISBLK(mode)) {
if (io_bdev_nowait(file->f_inode->i_bdev))
if (IS_ENABLED(CONFIG_BLOCK) &&
io_bdev_nowait(I_BDEV(file->f_mapping->host)))
return true;
return false;
}
if (S_ISCHR(mode) || S_ISSOCK(mode))
return true;
if (S_ISREG(mode)) {
if (io_bdev_nowait(file->f_inode->i_sb->s_bdev) &&
if (IS_ENABLED(CONFIG_BLOCK) &&
io_bdev_nowait(file->f_inode->i_sb->s_bdev) &&
file->f_op != &io_uring_fops)
return true;
return false;

5
fs/pipe.c
View File

@ -1342,9 +1342,8 @@ out_revert_acct:
}
/*
* After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same
* location, so checking ->i_pipe is not enough to verify that this is a
* pipe.
* Note that i_pipe and i_cdev share the same location, so checking ->i_pipe is
* not enough to verify that this is a pipe.
*/
struct pipe_inode_info *get_pipe_info(struct file *file, bool for_splice)
{

19
fs/quota/quota.c
View File

@ -866,17 +866,18 @@ static bool quotactl_cmd_onoff(int cmd)
static struct super_block *quotactl_block(const char __user *special, int cmd)
{
#ifdef CONFIG_BLOCK
struct block_device *bdev;
struct super_block *sb;
struct filename *tmp = getname(special);
bool excl = false, thawed = false;
int error;
dev_t dev;
if (IS_ERR(tmp))
return ERR_CAST(tmp);
bdev = lookup_bdev(tmp->name);
error = lookup_bdev(tmp->name, &dev);
putname(tmp);
if (IS_ERR(bdev))
return ERR_CAST(bdev);
if (error)
return ERR_PTR(error);
if (quotactl_cmd_onoff(cmd)) {
excl = true;
@ -886,8 +887,10 @@ static struct super_block *quotactl_block(const char __user *special, int cmd)
}
retry:
sb = __get_super(bdev, excl);
if (thawed && sb && sb->s_writers.frozen != SB_UNFROZEN) {
sb = user_get_super(dev, excl);
if (!sb)
return ERR_PTR(-ENODEV);
if (thawed && sb->s_writers.frozen != SB_UNFROZEN) {
if (excl)
up_write(&sb->s_umount);
else
@ -897,10 +900,6 @@ retry:
put_super(sb);
goto retry;
}
bdput(bdev);
if (!sb)
return ERR_PTR(-ENODEV);
return sb;
#else

2
fs/statfs.c
View File

@ -235,7 +235,7 @@ SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user
static int vfs_ustat(dev_t dev, struct kstatfs *sbuf)
{
struct super_block *s = user_get_super(dev);
struct super_block *s = user_get_super(dev, false);
int err;
if (!s)
return -EINVAL;

44
fs/super.c
View File

@ -740,7 +740,14 @@ void iterate_supers_type(struct file_system_type *type,
EXPORT_SYMBOL(iterate_supers_type);
struct super_block *__get_super(struct block_device *bdev, bool excl)
/**
* get_super - get the superblock of a device
* @bdev: device to get the superblock for
*
* Scans the superblock list and finds the superblock of the file system
* mounted on the device given. %NULL is returned if no match is found.
*/
struct super_block *get_super(struct block_device *bdev)
{
struct super_block *sb;
@ -755,17 +762,11 @@ rescan:
if (sb->s_bdev == bdev) {
sb->s_count++;
spin_unlock(&sb_lock);
if (!excl)
down_read(&sb->s_umount);
else
down_write(&sb->s_umount);
down_read(&sb->s_umount);
/* still alive? */
if (sb->s_root && (sb->s_flags & SB_BORN))
return sb;
if (!excl)
up_read(&sb->s_umount);
else
up_write(&sb->s_umount);
up_read(&sb->s_umount);
/* nope, got unmounted */
spin_lock(&sb_lock);
__put_super(sb);
@ -776,19 +777,6 @@ rescan:
return NULL;
}
/**
* get_super - get the superblock of a device
* @bdev: device to get the superblock for
*
* Scans the superblock list and finds the superblock of the file system
* mounted on the device given. %NULL is returned if no match is found.
*/
struct super_block *get_super(struct block_device *bdev)
{
return __get_super(bdev, false);
}
EXPORT_SYMBOL(get_super);
/**
* get_active_super - get an active reference to the superblock of a device
* @bdev: device to get the superblock for
@ -820,7 +808,7 @@ restart:
return NULL;
}
struct super_block *user_get_super(dev_t dev)
struct super_block *user_get_super(dev_t dev, bool excl)
{
struct super_block *sb;
@ -832,11 +820,17 @@ rescan:
if (sb->s_dev == dev) {
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
if (excl)
down_write(&sb->s_umount);
else
down_read(&sb->s_umount);
/* still alive? */
if (sb->s_root && (sb->s_flags & SB_BORN))
return sb;
up_read(&sb->s_umount);
if (excl)
up_write(&sb->s_umount);
else
up_read(&sb->s_umount);
/* nope, got unmounted */
spin_lock(&sb_lock);
__put_super(sb);

2
include/linux/blkdev.h
View File

@ -1973,7 +1973,7 @@ int bdev_read_only(struct block_device *bdev);
int set_blocksize(struct block_device *bdev, int size);
const char *bdevname(struct block_device *bdev, char *buffer);
struct block_device *lookup_bdev(const char *);
int lookup_bdev(const char *pathname, dev_t *dev);
void blkdev_show(struct seq_file *seqf, off_t offset);

1
include/linux/fs.h
View File

@ -696,7 +696,6 @@ struct inode {
struct list_head i_devices;
union {
struct pipe_inode_info *i_pipe;
struct block_device *i_bdev;
struct cdev *i_cdev;
char *i_link;
unsigned i_dir_seq;