| Message ID | f0784a42dda08a596fcea31de73179dad5987d64.1526002757.git.misono.tomohiro@jp.fujitsu.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 2018/05/15 15:31, Gu, Jinxiang/顾 金香 wrote: > Hi, > >> -----Original Message----- >> From: linux-btrfs-owner@vger.kernel.org [mailto:linux-btrfs-owner@vger.kernel.org] On Behalf Of Tomohiro Misono >> Sent: Friday, May 11, 2018 3:26 PM >> To: linux-btrfs@vger.kernel.org >> Subject: [PATCH v4 1/3] btrfs: Add unprivileged ioctl which returns subvolume information >> >> Add new unprivileged ioctl BTRFS_IOC_GET_SUBVOL_INFO which returns the information of subvolume containing this inode. >> (i.e. returns the information in ROOT_ITEM and ROOT_BACKREF.) >> >> Signed-off-by: Tomohiro Misono <misono.tomohiro@jp.fujitsu.com> >> --- >> fs/btrfs/ioctl.c | 129 +++++++++++++++++++++++++++++++++++++++++++++ >> include/uapi/linux/btrfs.h | 51 ++++++++++++++++++ >> 2 files changed, 180 insertions(+) >> >> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 48e2ddff32bd..64b23e22852f 100644 >> --- a/fs/btrfs/ioctl.c >> +++ b/fs/btrfs/ioctl.c >> @@ -2242,6 +2242,133 @@ static noinline int btrfs_ioctl_ino_lookup(struct file *file, >> return ret; >> } >> >> +/* Get the subvolume information in BTRFS_ROOT_ITEM and >> +BTRFS_ROOT_BACKREF */ static noinline int btrfs_ioctl_get_subvol_info(struct file *file, >> + void __user *argp) >> +{ >> + struct btrfs_ioctl_get_subvol_info_args *subvol_info; >> + struct btrfs_root *root; >> + struct btrfs_path *path; >> + struct btrfs_key key; >> + >> + struct btrfs_root_item root_item; >> + struct btrfs_root_ref *rref; >> + struct extent_buffer *l; >> + int slot; >> + >> + unsigned long item_off; >> + unsigned long item_len; >> + >> + struct inode *inode; >> + int ret; >> + >> + path = btrfs_alloc_path(); >> + if (!path) >> + return -ENOMEM; >> + >> + subvol_info = kzalloc(sizeof(*subvol_info), GFP_KERNEL); >> + if (!subvol_info) { >> + btrfs_free_path(path); >> + return -ENOMEM; >> + } >> + inode = file_inode(file); >> + >> + root = BTRFS_I(inode)->root->fs_info->tree_root; >> + key.objectid = BTRFS_I(inode)->root->root_key.objectid; >> + key.type = BTRFS_ROOT_ITEM_KEY; >> + key.offset = 0; >> + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); >> + if (ret < 0) { >> + goto out; >> + } else if (ret > 0) { >> + u64 objectid = key.objectid; >> + >> + if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) { >> + ret = btrfs_next_leaf(root, path); >> + if (ret < 0) >> + return ret; > Should goto out; to free subvol_info and path. Thanks, will update both. >> + } >> + >> + /* If the subvolume is a snapshot, offset is not zero */ >> + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); >> + if (key.objectid != objectid || >> + key.type != BTRFS_ROOT_ITEM_KEY) { >> + ret = -ENOENT; >> + goto out; >> + } >> + } >> + >> + l = path->nodes[0]; >> + slot = path->slots[0]; >> + item_off = btrfs_item_ptr_offset(l, slot); >> + item_len = btrfs_item_size_nr(l, slot); >> + read_extent_buffer(l, &root_item, item_off, item_len); >> + >> + subvol_info->id = key.objectid; >> + >> + subvol_info->generation = btrfs_root_generation(&root_item); >> + subvol_info->flags = btrfs_root_flags(&root_item); >> + >> + memcpy(subvol_info->uuid, root_item.uuid, BTRFS_UUID_SIZE); >> + memcpy(subvol_info->parent_uuid, root_item.parent_uuid, >> + BTRFS_UUID_SIZE); >> + memcpy(subvol_info->received_uuid, root_item.received_uuid, >> + BTRFS_UUID_SIZE); >> + >> + subvol_info->ctransid = btrfs_root_ctransid(&root_item); >> + subvol_info->ctime.sec = btrfs_stack_timespec_sec(&root_item.ctime); >> + subvol_info->ctime.nsec = btrfs_stack_timespec_nsec(&root_item.ctime); >> + >> + subvol_info->otransid = btrfs_root_otransid(&root_item); >> + subvol_info->otime.sec = btrfs_stack_timespec_sec(&root_item.otime); >> + subvol_info->otime.nsec = btrfs_stack_timespec_nsec(&root_item.otime); >> + >> + subvol_info->stransid = btrfs_root_stransid(&root_item); >> + subvol_info->stime.sec = btrfs_stack_timespec_sec(&root_item.stime); >> + subvol_info->stime.nsec = btrfs_stack_timespec_nsec(&root_item.stime); >> + >> + subvol_info->rtransid = btrfs_root_rtransid(&root_item); >> + subvol_info->rtime.sec = btrfs_stack_timespec_sec(&root_item.rtime); >> + subvol_info->rtime.nsec = btrfs_stack_timespec_nsec(&root_item.rtime); >> + >> + btrfs_release_path(path); >> + key.type = BTRFS_ROOT_BACKREF_KEY; >> + key.offset = 0; >> + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); >> + if (ret < 0) { >> + goto out; >> + } else if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) { >> + ret = btrfs_next_leaf(root, path); >> + if (ret < 0) >> + return ret; > Should goto out; to free subvol_info and path. >> + } >> + >> + l = path->nodes[0]; >> + slot = path->slots[0]; >> + btrfs_item_key_to_cpu(l, &key, slot); >> + if (key.objectid == subvol_info->id && >> + key.type == BTRFS_ROOT_BACKREF_KEY){ >> + subvol_info->parent_id = key.offset; >> + >> + rref = btrfs_item_ptr(l, slot, struct btrfs_root_ref); >> + subvol_info->dirid = btrfs_root_ref_dirid(l, rref); >> + >> + item_off = btrfs_item_ptr_offset(l, slot) >> + + sizeof(struct btrfs_root_ref); >> + item_len = btrfs_item_size_nr(l, slot) >> + - sizeof(struct btrfs_root_ref); >> + read_extent_buffer(l, subvol_info->name, item_off, item_len); >> + } > If this if is not correct(ex. corrupt filesystem without backref), > should it return -ENOENT, or its be ok without parent_id, dirid and name. > Suggest to add logic of else. If backref does not exist (except top-level subvolume), it means filesystem corruption. So, I'd like to return -EUCLEAN here. Thanks, Tomohiro Misono > >> + >> + if (copy_to_user(argp, subvol_info, sizeof(*subvol_info))) >> + ret = -EFAULT; >> + >> +out: >> + kzfree(subvol_info); >> + btrfs_free_path(path); >> + return ret; >> +} >> + >> static noinline int btrfs_ioctl_snap_destroy(struct file *file, >> void __user *arg) >> { >> @@ -5374,6 +5501,8 @@ long btrfs_ioctl(struct file *file, unsigned int >> return btrfs_ioctl_get_features(file, argp); >> case BTRFS_IOC_SET_FEATURES: >> return btrfs_ioctl_set_features(file, argp); >> + case BTRFS_IOC_GET_SUBVOL_INFO: >> + return btrfs_ioctl_get_subvol_info(file, argp); >> } >> >> return -ENOTTY; >> diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index c8d99b9ca550..ed053852c71f 100644 >> --- a/include/uapi/linux/btrfs.h >> +++ b/include/uapi/linux/btrfs.h >> @@ -725,6 +725,55 @@ struct btrfs_ioctl_send_args { >> __u64 reserved[4]; /* in */ >> }; >> >> +struct btrfs_ioctl_get_subvol_info_args { >> + /* All filed is out */ >> + /* Id of this subvolume */ >> + __u64 id; >> + /* Name of this subvolume, used to get the real name at mount point */ >> + char name[BTRFS_VOL_NAME_MAX + 1]; >> + /* >> + * Id of the subvolume which contains this subvolume. >> + * Zero for top-level subvolume or deleted subvolume >> + */ >> + __u64 parent_id; >> + /* >> + * Inode number of the directory which contains this subvolume. >> + * Zero for top-level subvolume or deleted subvolume >> + */ >> + __u64 dirid; >> + >> + /* Latest transaction id of this subvolume */ >> + __u64 generation; >> + /* Flags of this subvolume */ >> + __u64 flags; >> + >> + /* uuid of this subvolume */ >> + __u8 uuid[BTRFS_UUID_SIZE]; >> + /* >> + * uuid of the subvolume of which this subvolume is a snapshot. >> + * All zero for non-snapshot subvolume >> + */ >> + __u8 parent_uuid[BTRFS_UUID_SIZE]; >> + /* >> + * uuid of the subvolume from which this subvolume is received. >> + * All zero for non-received subvolume >> + */ >> + __u8 received_uuid[BTRFS_UUID_SIZE]; >> + >> + /* Transaction id indicates when change/create/send/receive happens */ >> + __u64 ctransid; >> + __u64 otransid; >> + __u64 stransid; >> + __u64 rtransid; >> + /* Time corresponds to c/o/s/rtransid */ >> + struct btrfs_ioctl_timespec ctime; >> + struct btrfs_ioctl_timespec otime; >> + struct btrfs_ioctl_timespec stime; >> + struct btrfs_ioctl_timespec rtime; >> + >> + __u64 reserved[8]; >> +}; >> + >> /* Error codes as returned by the kernel */ enum btrfs_err_code { >> BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET = 1, @@ -843,5 +892,7 @@ enum btrfs_err_code { >> struct btrfs_ioctl_vol_args_v2) >> #define BTRFS_IOC_LOGICAL_INO_V2 _IOWR(BTRFS_IOCTL_MAGIC, 59, \ >> struct btrfs_ioctl_logical_ino_args) >> +#define BTRFS_IOC_GET_SUBVOL_INFO _IOR(BTRFS_IOCTL_MAGIC, 60, \ >> + struct btrfs_ioctl_get_subvol_info_args) >> >> #endif /* _UAPI_LINUX_BTRFS_H */ >> -- >> 2.14.3 >> > > Reviewed-by: Gu Jinxiang <gujx@cn.fujitsu.com> >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 2018/05/15 16:57, Gu, Jinxiang/顾 金香 wrote: > Hi, add a missed a comment. > >> -----Original Message----- >> From: Misono Tomohiro [mailto:misono.tomohiro@jp.fujitsu.com] >> Sent: Tuesday, May 15, 2018 3:04 PM >> To: Gu, Jinxiang/顾 金香 <gujx@cn.fujitsu.com>; linux-btrfs@vger.kernel.org >> Subject: Re: [PATCH v4 1/3] btrfs: Add unprivileged ioctl which returns subvolume information >> >> On 2018/05/15 15:31, Gu, Jinxiang/顾 金香 wrote: >>> Hi, >>> >>>> -----Original Message----- >>>> From: linux-btrfs-owner@vger.kernel.org >>>> [mailto:linux-btrfs-owner@vger.kernel.org] On Behalf Of Tomohiro >>>> Misono >>>> Sent: Friday, May 11, 2018 3:26 PM >>>> To: linux-btrfs@vger.kernel.org >>>> Subject: [PATCH v4 1/3] btrfs: Add unprivileged ioctl which returns >>>> subvolume information >>>> >>>> Add new unprivileged ioctl BTRFS_IOC_GET_SUBVOL_INFO which returns the information of subvolume containing this inode. >>>> (i.e. returns the information in ROOT_ITEM and ROOT_BACKREF.) >>>> >>>> Signed-off-by: Tomohiro Misono <misono.tomohiro@jp.fujitsu.com> >>>> --- >>>> fs/btrfs/ioctl.c | 129 +++++++++++++++++++++++++++++++++++++++++++++ >>>> include/uapi/linux/btrfs.h | 51 ++++++++++++++++++ >>>> 2 files changed, 180 insertions(+) >>>> >>>> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index >>>> 48e2ddff32bd..64b23e22852f 100644 >>>> --- a/fs/btrfs/ioctl.c >>>> +++ b/fs/btrfs/ioctl.c >>>> @@ -2242,6 +2242,133 @@ static noinline int btrfs_ioctl_ino_lookup(struct file *file, >>>> return ret; >>>> } >>>> >>>> +/* Get the subvolume information in BTRFS_ROOT_ITEM and >>>> +BTRFS_ROOT_BACKREF */ static noinline int btrfs_ioctl_get_subvol_info(struct file *file, >>>> + void __user *argp) >>>> +{ >>>> + struct btrfs_ioctl_get_subvol_info_args *subvol_info; >>>> + struct btrfs_root *root; >>>> + struct btrfs_path *path; >>>> + struct btrfs_key key; >>>> + >>>> + struct btrfs_root_item root_item; >>>> + struct btrfs_root_ref *rref; >>>> + struct extent_buffer *l; >>>> + int slot; >>>> + >>>> + unsigned long item_off; >>>> + unsigned long item_len; >>>> + >>>> + struct inode *inode; >>>> + int ret; >>>> + >>>> + path = btrfs_alloc_path(); >>>> + if (!path) >>>> + return -ENOMEM; >>>> + >>>> + subvol_info = kzalloc(sizeof(*subvol_info), GFP_KERNEL); >>>> + if (!subvol_info) { >>>> + btrfs_free_path(path); >>>> + return -ENOMEM; >>>> + } >>>> + inode = file_inode(file); >>>> + >>>> + root = BTRFS_I(inode)->root->fs_info->tree_root; >>>> + key.objectid = BTRFS_I(inode)->root->root_key.objectid; >>>> + key.type = BTRFS_ROOT_ITEM_KEY; >>>> + key.offset = 0; >>>> + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); >>>> + if (ret < 0) { >>>> + goto out; >>>> + } else if (ret > 0) { >>>> + u64 objectid = key.objectid; >>>> + >>>> + if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) { >>>> + ret = btrfs_next_leaf(root, path); >>>> + if (ret < 0) >>>> + return ret; >>> Should goto out; to free subvol_info and path. >> Thanks, will update both. >> > > Since btrfs_next_leaf may return 1 when nritems of next leaf is 0, > So, btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); may goes wrong. > And I think it should add a judge before btrfs_item_key_to_cpu. Ok, I will update to handle all cases. [snip]>>>> + l = path->nodes[0]; >>>> + slot = path->slots[0]; >>>> + btrfs_item_key_to_cpu(l, &key, slot); >>>> + if (key.objectid == subvol_info->id && >>>> + key.type == BTRFS_ROOT_BACKREF_KEY){ >>>> + subvol_info->parent_id = key.offset; >>>> + >>>> + rref = btrfs_item_ptr(l, slot, struct btrfs_root_ref); >>>> + subvol_info->dirid = btrfs_root_ref_dirid(l, rref); >>>> + >>>> + item_off = btrfs_item_ptr_offset(l, slot) >>>> + + sizeof(struct btrfs_root_ref); >>>> + item_len = btrfs_item_size_nr(l, slot) >>>> + - sizeof(struct btrfs_root_ref); >>>> + read_extent_buffer(l, subvol_info->name, item_off, item_len); >>>> + } >>> If this if is not correct(ex. corrupt filesystem without backref), >>> should it return -ENOENT, or its be ok without parent_id, dirid and name. >>> Suggest to add logic of else. >> >> If backref does not exist (except top-level subvolume), it means filesystem corruption. >> So, I'd like to return -EUCLEAN here. On second thought, I notice if this ioctl is called after containing subvolume is deleted, the entry may not exist. So, -ENOENT is fine. Thanks, Tomohiro Misono >> >> Thanks, >> Tomohiro Misono >> >>> >>>> + >>>> + if (copy_to_user(argp, subvol_info, sizeof(*subvol_info))) >>>> + ret = -EFAULT; >>>> + >>>> +out: >>>> + kzfree(subvol_info); >>>> + btrfs_free_path(path); >>>> + return ret; >>>> +} >>>> + >>>> static noinline int btrfs_ioctl_snap_destroy(struct file *file, >>>> void __user *arg) >>>> { >>>> @@ -5374,6 +5501,8 @@ long btrfs_ioctl(struct file *file, unsigned int >>>> return btrfs_ioctl_get_features(file, argp); >>>> case BTRFS_IOC_SET_FEATURES: >>>> return btrfs_ioctl_set_features(file, argp); >>>> + case BTRFS_IOC_GET_SUBVOL_INFO: >>>> + return btrfs_ioctl_get_subvol_info(file, argp); >>>> } >>>> >>>> return -ENOTTY; >>>> diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h >>>> index c8d99b9ca550..ed053852c71f 100644 >>>> --- a/include/uapi/linux/btrfs.h >>>> +++ b/include/uapi/linux/btrfs.h >>>> @@ -725,6 +725,55 @@ struct btrfs_ioctl_send_args { >>>> __u64 reserved[4]; /* in */ >>>> }; >>>> >>>> +struct btrfs_ioctl_get_subvol_info_args { >>>> + /* All filed is out */ >>>> + /* Id of this subvolume */ >>>> + __u64 id; >>>> + /* Name of this subvolume, used to get the real name at mount point */ >>>> + char name[BTRFS_VOL_NAME_MAX + 1]; >>>> + /* >>>> + * Id of the subvolume which contains this subvolume. >>>> + * Zero for top-level subvolume or deleted subvolume >>>> + */ >>>> + __u64 parent_id; >>>> + /* >>>> + * Inode number of the directory which contains this subvolume. >>>> + * Zero for top-level subvolume or deleted subvolume >>>> + */ >>>> + __u64 dirid; >>>> + >>>> + /* Latest transaction id of this subvolume */ >>>> + __u64 generation; >>>> + /* Flags of this subvolume */ >>>> + __u64 flags; >>>> + >>>> + /* uuid of this subvolume */ >>>> + __u8 uuid[BTRFS_UUID_SIZE]; >>>> + /* >>>> + * uuid of the subvolume of which this subvolume is a snapshot. >>>> + * All zero for non-snapshot subvolume >>>> + */ >>>> + __u8 parent_uuid[BTRFS_UUID_SIZE]; >>>> + /* >>>> + * uuid of the subvolume from which this subvolume is received. >>>> + * All zero for non-received subvolume >>>> + */ >>>> + __u8 received_uuid[BTRFS_UUID_SIZE]; >>>> + >>>> + /* Transaction id indicates when change/create/send/receive happens */ >>>> + __u64 ctransid; >>>> + __u64 otransid; >>>> + __u64 stransid; >>>> + __u64 rtransid; >>>> + /* Time corresponds to c/o/s/rtransid */ >>>> + struct btrfs_ioctl_timespec ctime; >>>> + struct btrfs_ioctl_timespec otime; >>>> + struct btrfs_ioctl_timespec stime; >>>> + struct btrfs_ioctl_timespec rtime; >>>> + >>>> + __u64 reserved[8]; >>>> +}; >>>> + >>>> /* Error codes as returned by the kernel */ enum btrfs_err_code { >>>> BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET = 1, @@ -843,5 +892,7 @@ enum btrfs_err_code { >>>> struct btrfs_ioctl_vol_args_v2) #define >>>> BTRFS_IOC_LOGICAL_INO_V2 _IOWR(BTRFS_IOCTL_MAGIC, 59, \ >>>> struct btrfs_ioctl_logical_ino_args) >>>> +#define BTRFS_IOC_GET_SUBVOL_INFO _IOR(BTRFS_IOCTL_MAGIC, 60, \ >>>> + struct btrfs_ioctl_get_subvol_info_args) >>>> >>>> #endif /* _UAPI_LINUX_BTRFS_H */ >>>> -- >>>> 2.14.3 >>>> >>> >>> Reviewed-by: Gu Jinxiang <gujx@cn.fujitsu.com> >>>> >>>> -- >>>> To unsubscribe from this list: send the line "unsubscribe >>>> linux-btrfs" in the body of a message to majordomo@vger.kernel.org >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>>> >>> -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 48e2ddff32bd..64b23e22852f 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -2242,6 +2242,133 @@ static noinline int btrfs_ioctl_ino_lookup(struct file *file, return ret; } +/* Get the subvolume information in BTRFS_ROOT_ITEM and BTRFS_ROOT_BACKREF */ +static noinline int btrfs_ioctl_get_subvol_info(struct file *file, + void __user *argp) +{ + struct btrfs_ioctl_get_subvol_info_args *subvol_info; + struct btrfs_root *root; + struct btrfs_path *path; + struct btrfs_key key; + + struct btrfs_root_item root_item; + struct btrfs_root_ref *rref; + struct extent_buffer *l; + int slot; + + unsigned long item_off; + unsigned long item_len; + + struct inode *inode; + int ret; + + path = btrfs_alloc_path(); + if (!path) + return -ENOMEM; + + subvol_info = kzalloc(sizeof(*subvol_info), GFP_KERNEL); + if (!subvol_info) { + btrfs_free_path(path); + return -ENOMEM; + } + inode = file_inode(file); + + root = BTRFS_I(inode)->root->fs_info->tree_root; + key.objectid = BTRFS_I(inode)->root->root_key.objectid; + key.type = BTRFS_ROOT_ITEM_KEY; + key.offset = 0; + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) { + goto out; + } else if (ret > 0) { + u64 objectid = key.objectid; + + if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) { + ret = btrfs_next_leaf(root, path); + if (ret < 0) + return ret; + } + + /* If the subvolume is a snapshot, offset is not zero */ + btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]); + if (key.objectid != objectid || + key.type != BTRFS_ROOT_ITEM_KEY) { + ret = -ENOENT; + goto out; + } + } + + l = path->nodes[0]; + slot = path->slots[0]; + item_off = btrfs_item_ptr_offset(l, slot); + item_len = btrfs_item_size_nr(l, slot); + read_extent_buffer(l, &root_item, item_off, item_len); + + subvol_info->id = key.objectid; + + subvol_info->generation = btrfs_root_generation(&root_item); + subvol_info->flags = btrfs_root_flags(&root_item); + + memcpy(subvol_info->uuid, root_item.uuid, BTRFS_UUID_SIZE); + memcpy(subvol_info->parent_uuid, root_item.parent_uuid, + BTRFS_UUID_SIZE); + memcpy(subvol_info->received_uuid, root_item.received_uuid, + BTRFS_UUID_SIZE); + + subvol_info->ctransid = btrfs_root_ctransid(&root_item); + subvol_info->ctime.sec = btrfs_stack_timespec_sec(&root_item.ctime); + subvol_info->ctime.nsec = btrfs_stack_timespec_nsec(&root_item.ctime); + + subvol_info->otransid = btrfs_root_otransid(&root_item); + subvol_info->otime.sec = btrfs_stack_timespec_sec(&root_item.otime); + subvol_info->otime.nsec = btrfs_stack_timespec_nsec(&root_item.otime); + + subvol_info->stransid = btrfs_root_stransid(&root_item); + subvol_info->stime.sec = btrfs_stack_timespec_sec(&root_item.stime); + subvol_info->stime.nsec = btrfs_stack_timespec_nsec(&root_item.stime); + + subvol_info->rtransid = btrfs_root_rtransid(&root_item); + subvol_info->rtime.sec = btrfs_stack_timespec_sec(&root_item.rtime); + subvol_info->rtime.nsec = btrfs_stack_timespec_nsec(&root_item.rtime); + + btrfs_release_path(path); + key.type = BTRFS_ROOT_BACKREF_KEY; + key.offset = 0; + ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + if (ret < 0) { + goto out; + } else if (path->slots[0] >= btrfs_header_nritems(path->nodes[0])) { + ret = btrfs_next_leaf(root, path); + if (ret < 0) + return ret; + } + + l = path->nodes[0]; + slot = path->slots[0]; + btrfs_item_key_to_cpu(l, &key, slot); + if (key.objectid == subvol_info->id && + key.type == BTRFS_ROOT_BACKREF_KEY){ + subvol_info->parent_id = key.offset; + + rref = btrfs_item_ptr(l, slot, struct btrfs_root_ref); + subvol_info->dirid = btrfs_root_ref_dirid(l, rref); + + item_off = btrfs_item_ptr_offset(l, slot) + + sizeof(struct btrfs_root_ref); + item_len = btrfs_item_size_nr(l, slot) + - sizeof(struct btrfs_root_ref); + read_extent_buffer(l, subvol_info->name, item_off, item_len); + } + + if (copy_to_user(argp, subvol_info, sizeof(*subvol_info))) + ret = -EFAULT; + +out: + kzfree(subvol_info); + btrfs_free_path(path); + return ret; +} + static noinline int btrfs_ioctl_snap_destroy(struct file *file, void __user *arg) { @@ -5374,6 +5501,8 @@ long btrfs_ioctl(struct file *file, unsigned int return btrfs_ioctl_get_features(file, argp); case BTRFS_IOC_SET_FEATURES: return btrfs_ioctl_set_features(file, argp); + case BTRFS_IOC_GET_SUBVOL_INFO: + return btrfs_ioctl_get_subvol_info(file, argp); } return -ENOTTY; diff --git a/include/uapi/linux/btrfs.h b/include/uapi/linux/btrfs.h index c8d99b9ca550..ed053852c71f 100644 --- a/include/uapi/linux/btrfs.h +++ b/include/uapi/linux/btrfs.h @@ -725,6 +725,55 @@ struct btrfs_ioctl_send_args { __u64 reserved[4]; /* in */ }; +struct btrfs_ioctl_get_subvol_info_args { + /* All filed is out */ + /* Id of this subvolume */ + __u64 id; + /* Name of this subvolume, used to get the real name at mount point */ + char name[BTRFS_VOL_NAME_MAX + 1]; + /* + * Id of the subvolume which contains this subvolume. + * Zero for top-level subvolume or deleted subvolume + */ + __u64 parent_id; + /* + * Inode number of the directory which contains this subvolume. + * Zero for top-level subvolume or deleted subvolume + */ + __u64 dirid; + + /* Latest transaction id of this subvolume */ + __u64 generation; + /* Flags of this subvolume */ + __u64 flags; + + /* uuid of this subvolume */ + __u8 uuid[BTRFS_UUID_SIZE]; + /* + * uuid of the subvolume of which this subvolume is a snapshot. + * All zero for non-snapshot subvolume + */ + __u8 parent_uuid[BTRFS_UUID_SIZE]; + /* + * uuid of the subvolume from which this subvolume is received. + * All zero for non-received subvolume + */ + __u8 received_uuid[BTRFS_UUID_SIZE]; + + /* Transaction id indicates when change/create/send/receive happens */ + __u64 ctransid; + __u64 otransid; + __u64 stransid; + __u64 rtransid; + /* Time corresponds to c/o/s/rtransid */ + struct btrfs_ioctl_timespec ctime; + struct btrfs_ioctl_timespec otime; + struct btrfs_ioctl_timespec stime; + struct btrfs_ioctl_timespec rtime; + + __u64 reserved[8]; +}; + /* Error codes as returned by the kernel */ enum btrfs_err_code { BTRFS_ERROR_DEV_RAID1_MIN_NOT_MET = 1, @@ -843,5 +892,7 @@ enum btrfs_err_code { struct btrfs_ioctl_vol_args_v2) #define BTRFS_IOC_LOGICAL_INO_V2 _IOWR(BTRFS_IOCTL_MAGIC, 59, \ struct btrfs_ioctl_logical_ino_args) +#define BTRFS_IOC_GET_SUBVOL_INFO _IOR(BTRFS_IOCTL_MAGIC, 60, \ + struct btrfs_ioctl_get_subvol_info_args) #endif /* _UAPI_LINUX_BTRFS_H */
Add new unprivileged ioctl BTRFS_IOC_GET_SUBVOL_INFO which returns the information of subvolume containing this inode. (i.e. returns the information in ROOT_ITEM and ROOT_BACKREF.) Signed-off-by: Tomohiro Misono <misono.tomohiro@jp.fujitsu.com> --- fs/btrfs/ioctl.c | 129 +++++++++++++++++++++++++++++++++++++++++++++ include/uapi/linux/btrfs.h | 51 ++++++++++++++++++ 2 files changed, 180 insertions(+)