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Cephfs kernel client's file_operations operation for dir

Const struct file_operations ceph_dir_fops = {

.read = ceph_read_dir

.iterate = ceph_readdir

.llcards = ceph_dir_llseek

.open = ceph_open

.release = ceph_release

.unloaded _ ioctl = ceph_ioctl

.fsync = ceph_fsync

}

Ceph_read_dir (struct file * file, char _ _ user * buf, size_t size, loff_t * ppos) is valid only when mount takes the parameter-o dirstat

| | _ _ call the ceph_test_mount_opt () function to check whether DIRSTAT is included in the mount options, and return directly if it does not include it |

| | _ _ if the dir_info in struct ceph_file_info is empty |

| | _ _ call kmalloc () function to allocate space for dir_info |

| | _ _ use the snprintf () function to format output to the memory space of dir_info |

| | _ _ call the copy_to_user () function to copy the contents of dir_info to the user state space buf |

Ceph_readdir (struct file * file, struct dir_context * ctx)

| _ _ call the dir_emit () function to publish "." And ".." information

| | _ _ if DCACHE is included in mount options, you should read dir information from dcache as much as possible. |

| | _ _ call _ _ dcache_readdir () function to read dir from dcache |

| | _ _ returned value is not equal to EAGAIN |

| | _ _ return directly |

| | _ _ call the need_send_readdir () function to check whether the contents of dir should be read from the cluster |

| | _ _ get the opcode op=CEPH_MDS_OP_LSSNAP or CEPH_MDS_OP_READDIR |

| | _ _ call the ceph_mdsc_create_request () function to create a mds request |

| | _ _ call the ceph_alloc_readdir_reply_buffer () function to allocate memory space for the dir content read from the cluster |

| | _ _ call the ceph_mdsc_do_request () function to send the request to the mds process synchronously |

| | _ _ traversal struct ceph_file_info- > last_readdir- > rroomreplyinformation-> dir_nr |

| | _ _ call dir_emit () function to publish dir information |

Ceph_dir_llseek (struct file * file, loff_t offset, int whence)

| | _ _ update the value of whence according to the different values of offset |

| | _ if offset > = 0 |

| | _ _ call the need_reset_readdir () function to check whether reset readdir is required |

| | _ _ call reset_readdir () function |

| | _ _ adjust file- > f _ posvalue to offset value |

Ceph_open (struct inode * inode, struct file * file) this function is called when the file is opened

| | _ _ call the prepare_open_request () function to create a ceph_mds_request request |

| | _ _ call ceph_mdsc_do_request () function to send the ceph_mds_request request to the mds process synchronously |

| | _ _ call the ceph_init_file () function to create a ceph_file_info data structure and put the data structure into file- > private_data |

Ceph_release (struct inode * inode, struct file * file) this function is called when the file is closed

| | _ _ call the ceph_put_fmode () function to reduce the number of references to a file. If the number of references is 0, the file will be deleted from the local cache. |

Ceph_ioctl (struct file * file, unsigned int cmd, unsigned long arg)

| | _ _ do different processing according to the value of cmd |

| | _ cmd==CEPH_IOC_GET_LAYOUT |

| | _ ceph_ioctl_get_layout () |

| | _ _ ceph_do_getattr (CEPH_STAT_CAP_LAYOUT) reads the layout information of the inode corresponding to file from the mds cluster to the i_layout of ceph_inode_info |

| | _ _ write the i_layout information to the struct ceph_ioctl_layout data structure and return the data to the user state through the copy_to_user () function |

| | _ cmd==CEPH_IOC_SET_LAYOUT |

| | _ ceph_ioctl_set_layout () |

| | _ _ call the copy_from_user () function to copy the new layout information from user mode to kernel mode |

| | _ _ call ceph_do_getattr () function to read the current layout information from the mds cluster |

| | _ _ call _ _ validate_layout () function to check whether the newly set layout is valid |

| | _ _ call the ceph_mdsc_create_request () function to create a request request |

| | _ _ call the ceph_mdsc_do_request () function to send a request request to the mds cluster synchronously |

| | _ cmd==CEPH_IOC_SET_LAYOUT_POLICY |

| | _ ceph_ioctl_set_layout_policy () |

| | _ _ call the copy_from_user () function to copy the new layout information from user mode to kernel mode |

| | _ _ call _ _ validate_layout () function to check whether the newly set layout is valid |

| | _ _ call the ceph_mdsc_create_request () function to create a request request |

| | _ _ call the ceph_mdsc_do_request () function to send a request request to the mds cluster synchronously |

| | _ _ cmd==CEPH_IOC_GET_DATALOC calculates the location information in the ceph cluster where the data resides |

| | _ ceph_ioctl_get_dataloc () |

| | _ _ call copy_from_user () function to copy ceph_ioctl_dataloc information to kernel state |

| | _ _ call the ceph_calc_file_object_mapping () function to calculate the oid and other information of the specified file in the ceph_ioctl_dataloc information |

| | _ _ call the ceph_object_locator_to_pg () function to calculate the pg information where the oid is located |

| | _ _ call the ceph_pg_to_acting_primary () function to calculate the information of the main osd where the pg is located |

| | _ _ call the copy_to_user () function to send the calculated information back to the user state |

| | _ _ cmd==CEPH_IOC_LAZYIO sets the LAZYIO ID |

| | _ ceph_ioctl_lazyio () |

| | _ _ determines whether the fmode in struct ceph_file_info does not have CEPH_FILE_MODE_LAZY set |

| | _ _ sets the fmode in struct ceph_file_info to have the CEPH_FILE_MODE_LAZY ID |

| | _ _ update the i_nr_by_mode array in ceph_inode_info |

| | _ _ call ceph_check_caps () function to update caps |

| | _ cmd==CEPH_IOC_SYNCIO |

| | _ ceph_ioctl_syncio () |

| | _ _ sets the CEPH_F_ sync bit of flags in struct ceph_file_info structure |

Ceph_fsync (struct file * file, loff_t start, loff_t end, int datasync)

| | _ _ call the ceph_sync_write_wait () function to wait for the execution of all outstanding osd requests on inode. |

| | _ _ call the try_flush_caps () function to brush the caps of all dirty back to mds |

| | _ _ call the unsafe_request_wait () function to wait for the execution of all mds requests on the inode. |

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