linux-stable/fs/btrfs/ioctl.h
Mark Harmstone 34310c442e btrfs: add io_uring command for encoded reads (ENCODED_READ ioctl)
Add an io_uring command for encoded reads, using the same interface as
the existing BTRFS_IOC_ENCODED_READ ioctl.

btrfs_uring_encoded_read() is an io_uring version of
btrfs_ioctl_encoded_read(), which validates the user input and calls
btrfs_encoded_read() to read the appropriate metadata. If we determine
that we need to read an extent from disk, we call
btrfs_encoded_read_regular_fill_pages() through
btrfs_uring_read_extent() to prepare the bio.

The existing btrfs_encoded_read_regular_fill_pages() is changed so that
if it is passed a valid uring_ctx, rather than waking up any waiting
threads it calls btrfs_uring_read_extent_endio(). This in turn copies
the read data back to userspace, and calls io_uring_cmd_done() to
complete the io_uring command.

Because we're potentially doing a non-blocking read,
btrfs_uring_read_extent() doesn't clean up after itself if it returns
-EIOCBQUEUED. Instead, it allocates a priv struct, populates the fields
there that we will need to unlock the inode and free our allocations,
and defers this to the btrfs_uring_read_finished() that gets called when
the bio completes.

Signed-off-by: Mark Harmstone <maharmstone@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2024-11-11 14:34:21 +01:00

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C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef BTRFS_IOCTL_H
#define BTRFS_IOCTL_H
#include <linux/types.h>
struct file;
struct dentry;
struct mnt_idmap;
struct fileattr;
struct btrfs_fs_info;
struct btrfs_ioctl_balance_args;
long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
long btrfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
int btrfs_fileattr_get(struct dentry *dentry, struct fileattr *fa);
int btrfs_fileattr_set(struct mnt_idmap *idmap,
struct dentry *dentry, struct fileattr *fa);
int btrfs_ioctl_get_supported_features(void __user *arg);
void btrfs_sync_inode_flags_to_i_flags(struct inode *inode);
int __pure btrfs_is_empty_uuid(const u8 *uuid);
void btrfs_update_ioctl_balance_args(struct btrfs_fs_info *fs_info,
struct btrfs_ioctl_balance_args *bargs);
int btrfs_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags);
void btrfs_uring_read_extent_endio(void *ctx, int err);
#endif