Add two new helpers to allow opening block devices as files.
This is not the final infrastructure. This still opens the block device
before opening a struct a file. Until we have removed all references to
struct bdev_handle we can't switch the order:
* Introduce blk_to_file_flags() to translate from block specific to
flags usable to pen a new file.
* Introduce bdev_file_open_by_{dev,path}().
* Introduce temporary sb_bdev_handle() helper to retrieve a struct
bdev_handle from a block device file and update places that directly
reference struct bdev_handle to rely on it.
* Don't count block device openes against the number of open files. A
bdev_file_open_by_{dev,path}() file is never installed into any
file descriptor table.
One idea that came to mind was to use kernel_tmpfile_open() which
would require us to pass a path and it would then call do_dentry_open()
going through the regular fops->open::blkdev_open() path. But then we're
back to the problem of routing block specific flags such as
BLK_OPEN_RESTRICT_WRITES through the open path and would have to waste
FMODE_* flags every time we add a new one. With this we can avoid using
a flag bit and we have more leeway in how we open block devices from
bdev_open_by_{dev,path}().
Link: https://lore.kernel.org/r/20240123-vfs-bdev-file-v2-1-adbd023e19cc@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
}
EXPORT_SYMBOL(I_BDEV);
+struct block_device *file_bdev(struct file *bdev_file)
+{
+ struct bdev_handle *handle = bdev_file->private_data;
+ return handle->bdev;
+}
+EXPORT_SYMBOL(file_bdev);
+
static void bdev_write_inode(struct block_device *bdev)
{
struct inode *inode = bdev->bd_inode;
};
struct super_block *blockdev_superblock __ro_after_init;
+struct vfsmount *blockdev_mnt __ro_after_init;
EXPORT_SYMBOL_GPL(blockdev_superblock);
void __init bdev_cache_init(void)
{
int err;
- static struct vfsmount *bd_mnt __ro_after_init;
bdev_cachep = kmem_cache_create("bdev_cache", sizeof(struct bdev_inode),
0, (SLAB_HWCACHE_ALIGN|SLAB_RECLAIM_ACCOUNT|
err = register_filesystem(&bd_type);
if (err)
panic("Cannot register bdev pseudo-fs");
- bd_mnt = kern_mount(&bd_type);
- if (IS_ERR(bd_mnt))
+ blockdev_mnt = kern_mount(&bd_type);
+ if (IS_ERR(blockdev_mnt))
panic("Cannot create bdev pseudo-fs");
- blockdev_superblock = bd_mnt->mnt_sb; /* For writeback */
+ blockdev_superblock = blockdev_mnt->mnt_sb; /* For writeback */
}
struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
}
EXPORT_SYMBOL(bdev_open_by_dev);
+/*
+ * If BLK_OPEN_WRITE_IOCTL is set then this is a historical quirk
+ * associated with the floppy driver where it has allowed ioctls if the
+ * file was opened for writing, but does not allow reads or writes.
+ * Make sure that this quirk is reflected in @f_flags.
+ *
+ * It can also happen if a block device is opened as O_RDWR | O_WRONLY.
+ */
+static unsigned blk_to_file_flags(blk_mode_t mode)
+{
+ unsigned int flags = 0;
+
+ if ((mode & (BLK_OPEN_READ | BLK_OPEN_WRITE)) ==
+ (BLK_OPEN_READ | BLK_OPEN_WRITE))
+ flags |= O_RDWR;
+ else if (mode & BLK_OPEN_WRITE_IOCTL)
+ flags |= O_RDWR | O_WRONLY;
+ else if (mode & BLK_OPEN_WRITE)
+ flags |= O_WRONLY;
+ else if (mode & BLK_OPEN_READ)
+ flags |= O_RDONLY; /* homeopathic, because O_RDONLY is 0 */
+ else
+ WARN_ON_ONCE(true);
+
+ if (mode & BLK_OPEN_NDELAY)
+ flags |= O_NDELAY;
+
+ return flags;
+}
+
+struct file *bdev_file_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
+ const struct blk_holder_ops *hops)
+{
+ struct file *bdev_file;
+ struct bdev_handle *handle;
+ unsigned int flags;
+
+ handle = bdev_open_by_dev(dev, mode, holder, hops);
+ if (IS_ERR(handle))
+ return ERR_CAST(handle);
+
+ flags = blk_to_file_flags(mode);
+ bdev_file = alloc_file_pseudo_noaccount(handle->bdev->bd_inode,
+ blockdev_mnt, "", flags | O_LARGEFILE, &def_blk_fops);
+ if (IS_ERR(bdev_file)) {
+ bdev_release(handle);
+ return bdev_file;
+ }
+ ihold(handle->bdev->bd_inode);
+
+ bdev_file->f_mode |= FMODE_BUF_RASYNC | FMODE_CAN_ODIRECT;
+ if (bdev_nowait(handle->bdev))
+ bdev_file->f_mode |= FMODE_NOWAIT;
+
+ bdev_file->f_mapping = handle->bdev->bd_inode->i_mapping;
+ bdev_file->f_wb_err = filemap_sample_wb_err(bdev_file->f_mapping);
+ bdev_file->private_data = handle;
+ return bdev_file;
+}
+EXPORT_SYMBOL(bdev_file_open_by_dev);
+
+struct file *bdev_file_open_by_path(const char *path, blk_mode_t mode,
+ void *holder,
+ const struct blk_holder_ops *hops)
+{
+ struct file *bdev_file;
+ dev_t dev;
+ int error;
+
+ error = lookup_bdev(path, &dev);
+ if (error)
+ return ERR_PTR(error);
+
+ bdev_file = bdev_file_open_by_dev(dev, mode, holder, hops);
+ if (!IS_ERR(bdev_file) && (mode & BLK_OPEN_WRITE)) {
+ struct bdev_handle *handle = bdev_file->private_data;
+ if (bdev_read_only(handle->bdev)) {
+ fput(bdev_file);
+ bdev_file = ERR_PTR(-EACCES);
+ }
+ }
+
+ return bdev_file;
+}
+EXPORT_SYMBOL(bdev_file_open_by_path);
+
/**
* bdev_open_by_path - open a block device by name
* @path: path to the block device to open
sb->s_mtd = NULL;
} else if (IS_ENABLED(CONFIG_CRAMFS_BLOCKDEV) && sb->s_bdev) {
sync_blockdev(sb->s_bdev);
- bdev_release(sb->s_bdev_handle);
+ fput(sb->s_bdev_file);
}
kfree(sbi);
}
for (i = 0; i < max_devices; i++) {
if (i == 0)
- FDEV(0).bdev_handle = sbi->sb->s_bdev_handle;
+ FDEV(0).bdev_handle = sb_bdev_handle(sbi->sb);
else if (!RDEV(i).path[0])
break;
init_waitqueue_head(&log->syncwait);
set_bit(log_INLINELOG, &log->flag);
- log->bdev_handle = sb->s_bdev_handle;
+ log->bdev_handle = sb_bdev_handle(sb);
log->base = addressPXD(&JFS_SBI(sb)->logpxd);
log->size = lengthPXD(&JFS_SBI(sb)->logpxd) >>
(L2LOGPSIZE - sb->s_blocksize_bits);
#ifdef CONFIG_ROMFS_ON_BLOCK
if (sb->s_bdev) {
sync_blockdev(sb->s_bdev);
- bdev_release(sb->s_bdev_handle);
+ fput(sb->s_bdev_file);
}
#endif
}
struct fs_context *fc)
{
blk_mode_t mode = sb_open_mode(sb_flags);
- struct bdev_handle *bdev_handle;
+ struct file *bdev_file;
struct block_device *bdev;
- bdev_handle = bdev_open_by_dev(sb->s_dev, mode, sb, &fs_holder_ops);
- if (IS_ERR(bdev_handle)) {
+ bdev_file = bdev_file_open_by_dev(sb->s_dev, mode, sb, &fs_holder_ops);
+ if (IS_ERR(bdev_file)) {
if (fc)
errorf(fc, "%s: Can't open blockdev", fc->source);
- return PTR_ERR(bdev_handle);
+ return PTR_ERR(bdev_file);
}
- bdev = bdev_handle->bdev;
+ bdev = file_bdev(bdev_file);
/*
* This really should be in blkdev_get_by_dev, but right now can't due
* writable from userspace even for a read-only block device.
*/
if ((mode & BLK_OPEN_WRITE) && bdev_read_only(bdev)) {
- bdev_release(bdev_handle);
+ fput(bdev_file);
return -EACCES;
}
if (atomic_read(&bdev->bd_fsfreeze_count) > 0) {
if (fc)
warnf(fc, "%pg: Can't mount, blockdev is frozen", bdev);
- bdev_release(bdev_handle);
+ fput(bdev_file);
return -EBUSY;
}
spin_lock(&sb_lock);
- sb->s_bdev_handle = bdev_handle;
+ sb->s_bdev_file = bdev_file;
sb->s_bdev = bdev;
sb->s_bdi = bdi_get(bdev->bd_disk->bdi);
if (bdev_stable_writes(bdev))
generic_shutdown_super(sb);
if (bdev) {
sync_blockdev(bdev);
- bdev_release(sb->s_bdev_handle);
+ fput(sb->s_bdev_file);
}
}
* Setup xfs_mount buffer target pointers
*/
error = -ENOMEM;
- mp->m_ddev_targp = xfs_alloc_buftarg(mp, sb->s_bdev_handle);
+ mp->m_ddev_targp = xfs_alloc_buftarg(mp, sb_bdev_handle(sb));
if (!mp->m_ddev_targp)
goto out_close_rtdev;
#include <linux/sbitmap.h>
#include <linux/uuid.h>
#include <linux/xarray.h>
+#include <linux/file.h>
struct module;
struct request_queue;
(BLK_OPEN_READ | BLK_OPEN_RESTRICT_WRITES | \
(((flags) & SB_RDONLY) ? 0 : BLK_OPEN_WRITE))
+/* @bdev_handle will be removed soon. */
struct bdev_handle {
struct block_device *bdev;
void *holder;
const struct blk_holder_ops *hops);
struct bdev_handle *bdev_open_by_path(const char *path, blk_mode_t mode,
void *holder, const struct blk_holder_ops *hops);
+struct file *bdev_file_open_by_dev(dev_t dev, blk_mode_t mode, void *holder,
+ const struct blk_holder_ops *hops);
+struct file *bdev_file_open_by_path(const char *path, blk_mode_t mode,
+ void *holder, const struct blk_holder_ops *hops);
int bd_prepare_to_claim(struct block_device *bdev, void *holder,
const struct blk_holder_ops *hops);
void bd_abort_claiming(struct block_device *bdev, void *holder);
void blkdev_put_no_open(struct block_device *bdev);
struct block_device *I_BDEV(struct inode *inode);
+struct block_device *file_bdev(struct file *bdev_file);
#ifdef CONFIG_BLOCK
void invalidate_bdev(struct block_device *bdev);
#endif
struct hlist_bl_head s_roots; /* alternate root dentries for NFS */
struct list_head s_mounts; /* list of mounts; _not_ for fs use */
- struct block_device *s_bdev;
- struct bdev_handle *s_bdev_handle;
+ struct block_device *s_bdev; /* can go away once we use an accessor for @s_bdev_file */
+ struct file *s_bdev_file;
struct backing_dev_info *s_bdi;
struct mtd_info *s_mtd;
struct hlist_node s_instances;
struct list_head s_inodes_wb; /* writeback inodes */
} __randomize_layout;
+/* Temporary helper that will go away. */
+static inline struct bdev_handle *sb_bdev_handle(struct super_block *sb)
+{
+ return sb->s_bdev_file->private_data;
+}
+
static inline struct user_namespace *i_user_ns(const struct inode *inode)
{
return inode->i_sb->s_user_ns;
projects / thirdparty / linux.git / commitdiff
