[RFC PATCH 4/6] fs: btrfs: move fstrim to file_operation

From: Enrico Weigelt, metux IT consult
Date: Tue Jun 22 2021 - 08:12:03 EST


Use the newly introduced file_operation callback for FITRIM ioctl.
This removes some common code, eg. permission check, buffer copying,
which is now done by generic vfs code.
---
fs/btrfs/ctree.h | 1 +
fs/btrfs/inode.c | 1 +
fs/btrfs/ioctl.c | 26 +++++++-------------------
3 files changed, 9 insertions(+), 19 deletions(-)

diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
index 9fb76829a281..0361d95fe690 100644
--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -3206,6 +3206,7 @@ void btrfs_update_inode_bytes(struct btrfs_inode *inode,

/* ioctl.c */
long btrfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
+long btrfs_ioctl_fitrim(struct file *file, struct fstrim_range *range);
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 user_namespace *mnt_userns,
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 46f392943f4d..5f0d1032c890 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -10640,6 +10640,7 @@ static const struct file_operations btrfs_dir_file_operations = {
#endif
.release = btrfs_release_file,
.fsync = btrfs_sync_file,
+ .fitrim = btrfs_ioctl_fitrim,
};

/*
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 5dc2fd843ae3..38b1de381836 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -372,19 +372,16 @@ static int btrfs_ioctl_getversion(struct file *file, int __user *arg)
return put_user(inode->i_generation, arg);
}

-static noinline int btrfs_ioctl_fitrim(struct btrfs_fs_info *fs_info,
- void __user *arg)
+long btrfs_ioctl_fitrim(struct file *file, struct fstrim_range *range)
{
+ struct inode *inode = file_inode(file);
+ struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct btrfs_device *device;
struct request_queue *q;
- struct fstrim_range range;
u64 minlen = ULLONG_MAX;
u64 num_devices = 0;
int ret;

- if (!capable(CAP_SYS_ADMIN))
- return -EPERM;
-
/*
* btrfs_trim_block_group() depends on space cache, which is not
* available in zoned filesystem. So, disallow fitrim on a zoned
@@ -419,26 +416,19 @@ static noinline int btrfs_ioctl_fitrim(struct btrfs_fs_info *fs_info,

if (!num_devices)
return -EOPNOTSUPP;
- if (copy_from_user(&range, arg, sizeof(range)))
- return -EFAULT;

/*
* NOTE: Don't truncate the range using super->total_bytes. Bytenr of
* block group is in the logical address space, which can be any
* sectorsize aligned bytenr in the range [0, U64_MAX].
*/
- if (range.len < fs_info->sb->s_blocksize)
+ if (range->len < fs_info->sb->s_blocksize)
return -EINVAL;

- range.minlen = max(range.minlen, minlen);
- ret = btrfs_trim_fs(fs_info, &range);
- if (ret < 0)
- return ret;
-
- if (copy_to_user(arg, &range, sizeof(range)))
- return -EFAULT;
+ range->minlen = max(range->minlen, minlen);
+ ret = btrfs_trim_fs(fs_info, range);

- return 0;
+ return ret;
}

int __pure btrfs_is_empty_uuid(u8 *uuid)
@@ -4796,8 +4786,6 @@ long btrfs_ioctl(struct file *file, unsigned int
return btrfs_ioctl_get_fslabel(fs_info, argp);
case FS_IOC_SETFSLABEL:
return btrfs_ioctl_set_fslabel(file, argp);
- case FITRIM:
- return btrfs_ioctl_fitrim(fs_info, argp);
case BTRFS_IOC_SNAP_CREATE:
return btrfs_ioctl_snap_create(file, argp, 0);
case BTRFS_IOC_SNAP_CREATE_V2:
--
2.20.1