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Re: [PATCH v2 1/4] linux-user: Add support for a group of btrfs inode io
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From: |
Laurent Vivier |
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Subject: |
Re: [PATCH v2 1/4] linux-user: Add support for a group of btrfs inode ioctls |
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Date: |
Wed, 29 Jul 2020 18:18:19 +0200 |
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User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 |
Le 17/07/2020 à 16:44, Filip Bozuta a écrit :
> This patch implements functionality of following ioctls:
>
> BTRFS_IOC_INO_LOOKUP - Reading tree root id and path
>
> Read tree root id and path for a given file or directory.
> The name and tree root id are returned in an ioctl's third
> argument that represents a pointer to a following type:
>
> struct btrfs_ioctl_ino_lookup_args {
> __u64 treeid;
> __u64 objectid;
> char name[BTRFS_INO_LOOKUP_PATH_MAX];
> };
>
> Before calling this ioctl, field 'objectid' should be filled
> with the object id value for which the tree id and path are
> to be read. Value 'BTRFS_FIRST_FREE_OBJECTID' represents the
> object id for the first available btrfs object (directory or
> file).
>
> BTRFS_IOC_INO_PATHS - Reading paths to all files
>
> Read path to all files with a certain inode number. The paths
> are returned in the ioctl's third argument which represents
> a pointer to a following type:
>
> struct btrfs_ioctl_ino_path_args {
> __u64 inum; /* in */
> __u64 size; /* in */
> __u64 reserved[4];
> /* struct btrfs_data_container *fspath; out */
> __u64 fspath; /* out */
> };
>
> Before calling this ioctl, the 'inum' and 'size' field should
> be filled with the aproppriate inode number and size of the
> directory where file paths should be looked for. For now, the
> paths are returned in an '__u64' (unsigned long long) value
> 'fspath'.
>
> BTRFS_IOC_LOGICAL_INO - Reading inode numbers
>
> Read inode numbers for files on a certain logical adress. The
> inode numbers are returned in the ioctl's third argument which
> represents a pointer to a following type:
>
> struct btrfs_ioctl_logical_ino_args {
> __u64 logical; /* in */
> __u64 size; /* in */
> __u64 reserved[3]; /* must be 0 for now */
> __u64 flags; /* in, v2 only */
> /* struct btrfs_data_container *inodes; out */
> __u64 inodes;
> };
>
> Before calling this ioctl, the 'logical' and 'size' field should
> be filled with the aproppriate logical adress and size of where
> the inode numbers of files should be looked for. For now, the
> inode numbers are returned in an '__u64' (unsigned long long)
> value 'inodes'.
>
> BTRFS_IOC_LOGICAL_INO_V2 - Reading inode numbers
>
> Same as the above mentioned ioctl except that it allows passing
> a flags 'BTRFS_LOGICAL_INO_ARGS_IGNORE_OFFSET'.
>
> BTRFS_IOC_INO_LOOKUP_USER - Reading subvolume name and path
>
> Read name and path of a subvolume. The tree root id and
> path are read in an ioctl's third argument which represents a
> pointer to a following type:
>
> struct btrfs_ioctl_ino_lookup_user_args {
> /* in, inode number containing the subvolume of 'subvolid' */
> __u64 dirid;
> /* in */
> __u64 treeid;
> /* out, name of the subvolume of 'treeid' */
> char name[BTRFS_VOL_NAME_MAX + 1];
> /*
> * out, constructed path from the directory with which the ioctl is
> * called to dirid
> */
> char path[BTRFS_INO_LOOKUP_USER_PATH_MAX];
> };
>
> Before calling this ioctl, the 'dirid' and 'treeid' field should
> be filled with aproppriate values which represent the inode number
> of the directory that contains the subvolume and treeid of the
> subvolume.
>
> Implementation notes:
>
> All of the ioctls in this patch use structure types as third arguments.
> That is the reason why aproppriate thunk definitions were added in file
> 'syscall_types.h'.
>
> Signed-off-by: Filip Bozuta <Filip.Bozuta@syrmia.com>
> ---
> linux-user/ioctls.h | 20 ++++++++++++++++++++
> linux-user/syscall_defs.h | 10 ++++++++++
> linux-user/syscall_types.h | 24 ++++++++++++++++++++++++
> 3 files changed, 54 insertions(+)
>
...
> diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
> index 9db6f46cba..7bb105428b 100644
> --- a/linux-user/syscall_defs.h
> +++ b/linux-user/syscall_defs.h
> @@ -982,12 +982,18 @@ struct target_rtc_pll_info {
> 14, struct
> btrfs_ioctl_vol_args)
> #define TARGET_BTRFS_IOC_SNAP_DESTROY
> TARGET_IOW(BTRFS_IOCTL_MAGIC, \
> 15, struct
> btrfs_ioctl_vol_args)
> +#define TARGET_BTRFS_IOC_INO_LOOKUP
> TARGET_IOWR(BTRFS_IOCTL_MAGIC,\
> + 18, struct
> btrfs_ioctl_ino_lookup_args)
> #define TARGET_BTRFS_IOC_SUBVOL_GETFLAGS
> TARGET_IOR(BTRFS_IOCTL_MAGIC, \
> 25, abi_ullong)
> #define TARGET_BTRFS_IOC_SUBVOL_SETFLAGS
> TARGET_IOW(BTRFS_IOCTL_MAGIC, \
> 26, abi_ullong)
> #define TARGET_BTRFS_IOC_DEV_INFO
> TARGET_IOWR(BTRFS_IOCTL_MAGIC,\
> 30, struct
> btrfs_ioctl_dev_info_args)
> +#define TARGET_BTRFS_IOC_INO_PATHS
> TARGET_IOWR(BTRFS_IOCTL_MAGIC,\
> + 35, struct
> btrfs_ioctl_ino_path_args)
> +#define TARGET_BTRFS_IOC_LOGICAL_INO
> TARGET_IOWR(BTRFS_IOCTL_MAGIC,\
> + 36, struct
> btrfs_ioctl_logical_ino_args)
> #define TARGET_BTRFS_IOC_GET_DEV_STATS
> TARGET_IOWR(BTRFS_IOCTL_MAGIC,\
> 52, struct
> btrfs_ioctl_get_dev_stats)
> #define TARGET_BTRFS_IOC_GET_FEATURES
> TARGET_IOR(BTRFS_IOCTL_MAGIC, \
> @@ -996,8 +1002,12 @@ struct target_rtc_pll_info {
> 57, struct
> btrfs_ioctl_feature_flags[2])
> #define TARGET_BTRFS_IOC_GET_SUPPORTED_FEATURES
> TARGET_IOR(BTRFS_IOCTL_MAGIC, \
> 57, struct
> btrfs_ioctl_feature_flags[3])
> +#define TARGET_BTRFS_IOC_LOGICAL_INO_V2
> TARGET_IOWR(BTRFS_IOCTL_MAGIC,\
> + 59, struct
> btrfs_ioctl_logical_ino_args)
> #define TARGET_BTRFS_IOC_GET_SUBVOL_INFO
> TARGET_IOR(BTRFS_IOCTL_MAGIC, \
> 60, struct
> btrfs_ioctl_get_subvol_info_args)
> +#define TARGET_BTRFS_IOC_INO_LOOKUP_USER
> TARGET_IOWR(BTRFS_IOCTL_MAGIC,\
> + 62, struct
> btrfs_ioctl_ino_lookup_user_args)
Use the 'U' variant.
>
> /* usb ioctls */
> #define TARGET_USBDEVFS_CONTROL TARGET_IOWRU('U', 0)
> diff --git a/linux-user/syscall_types.h b/linux-user/syscall_types.h
> index e26ab01e8f..980c29000a 100644
> --- a/linux-user/syscall_types.h
> +++ b/linux-user/syscall_types.h
> @@ -349,6 +349,30 @@ STRUCT(btrfs_ioctl_get_subvol_info_args,
> MK_STRUCT(STRUCT_btrfs_ioctl_timespec), /* rtime */
> MK_ARRAY(TYPE_ULONGLONG, 8)) /* reserved */
>
> +STRUCT(btrfs_ioctl_ino_lookup_args,
> + TYPE_ULONGLONG, /* treeid */
> + TYPE_ULONGLONG, /* objectid */
> + MK_ARRAY(TYPE_CHAR, BTRFS_INO_LOOKUP_PATH_MAX)) /* name */
> +
> +STRUCT(btrfs_ioctl_ino_path_args,
> + TYPE_ULONGLONG, /* inum */
> + TYPE_ULONGLONG, /* size */
> + TYPE_ULONGLONG, /* reserved */
This is reserved[4], use MK_ARRAY() here
> + TYPE_ULONGLONG) /* fspath */
> +
> +STRUCT(btrfs_ioctl_logical_ino_args,
> + TYPE_ULONGLONG, /* logical */
> + TYPE_ULONGLONG, /* size */
> + TYPE_ULONGLONG, /* reserved */
reserved[3]
> + TYPE_ULONGLONG, /* flags */
> + TYPE_ULONGLONG) /* inodes */
> +
> +STRUCT(btrfs_ioctl_ino_lookup_user_args,
> + TYPE_ULONGLONG, /* dirid */
> + TYPE_ULONGLONG, /* treeid */
> + MK_ARRAY(TYPE_CHAR, BTRFS_VOL_NAME_MAX + 1), /* name */
> + MK_ARRAY(TYPE_CHAR, BTRFS_INO_LOOKUP_USER_PATH_MAX)) /* path */
> +
> STRUCT(btrfs_ioctl_dev_info_args,
> TYPE_ULONGLONG, /* devid */
> MK_ARRAY(TYPE_CHAR, BTRFS_UUID_SIZE), /* uuid */
>
Thanks,
Laurent