/* * mapper.h - Kernel cache for VFS files/directories definition. * * Authors Mohamed Lamine Karaoui (2015) * Alain Greiner (2016,2017,2018,2019) * * Copyright (c) UPMC Sorbonne Universites * * This file is part of ALMOS-MKH. * * ALMOS-MKH is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2.0 of the License. * * ALMOS-MKH is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with ALMOS-MKH; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #ifndef _MAPPER_H_ #define _MAPPER_H_ #include #include #include #include #include /**** Forward declarations ****/ struct page_s; struct vfs_inode_s; /******************************************************************************************* * This mapper_t object implements the kernel cache for a given VFS file or directory. * There is one mapper per file/dir. It is implemented as a three levels radix tree, * entirely stored in the same cluster as the inode representing the file/dir. * - The fast retrieval key is the page index in the file. * The ix1_width, ix2_width, ix3_width sub-indexes are configuration parameters. * - The leaves are pointers on physical page descriptors, dynamically allocated * in the local cluster. * - The mapper is protected by a "remote_rwlock", to support several simultaneous * "readers", and only one "writer". * - A "reader" thread, calling the mapper_remote_get_page() function to get a page * descriptor pointer from the page index in file, can be running in any cluster. * - A "writer" thread, calling the mapper_handle_miss() function to handle a page miss * must be local (running in the mapper cluster). * - The vfs_fs_move_page() function access the file system to handle a mapper miss, * or update a dirty page on device. * - The vfs_mapper_load_all() functions is used to load all pages of a directory * into the mapper (prefetch). * - the mapper_move_user() function is used to move data to or from an user buffer. * This user space buffer can be physically distributed in several clusters. * - the mapper_move_kernel() function is used to move data to or from a remote kernel * buffer, that can be physically located in any cluster. * - In the present implementation the cache size for a given file increases on demand, * and the allocated memory is only released when the mapper/inode is destroyed. * * TODO (1) the mapper being only used to implement the VFS cache(s), the mapper.c * and mapper.h file should be trandfered to the fs directory. * TODO (2) the "type" field is probably unused... ******************************************************************************************/ /******************************************************************************************* * This structure defines the mapper descriptor. ******************************************************************************************/ typedef struct mapper_s { struct vfs_inode_s * inode; /*! owner inode */ uint32_t type; /*! file system type */ grdxt_t rt; /*! embedded pages cache descriptor (radix tree) */ remote_rwlock_t lock; /*! several readers / only one writer */ uint32_t refcount; /*! several vsegs can refer the same file */ xlist_entry_t vsegs_root; /*! root of list of vsegs refering this mapper */ xlist_entry_t wait_root; /*! root of list of threads waiting on mapper */ list_entry_t dirty_root; /*! root of list of dirty pages */ } mapper_t; /******************************************************************************************* * This function allocates physical memory for a mapper descriptor, and initializes it * (refcount <= 0) / inode <= NULL). * It must be executed by a thread running in the cluster containing the mapper. ******************************************************************************************* * @ type : type of the mapper to create. * @ return : pointer on created mapper if success / return NULL if no memory ******************************************************************************************/ mapper_t * mapper_create( vfs_fs_type_t type ); /******************************************************************************************* * This function releases all physical memory allocated for a mapper. * Both the mapper descriptor and the radix tree are released. * It does NOT synchronize dirty pages. Use the vfs_sync_inode() function if required. * It must be executed by a thread running in the cluster containing the mapper. ******************************************************************************************* * @ mapper : target mapper. ******************************************************************************************/ void mapper_destroy( mapper_t * mapper ); /******************************************************************************************* * This function load from device a missing page identified by the argument * into the mapper identified by the local pointer. * It allocates a physical page from the local cluster, initialise by accessing device, * and register the page in the mapper radix tree. * It must be executed by a thread running in the cluster containing the mapper. * WARNING : the calling function mapper_remote_get_page() is supposed to take and release * the lock protecting the mapper in WRITE_MODE. ******************************************************************************************* * @ mapper : [in] target mapper. * @ page_id : [in] missing page index in file. * @ page_xp : [out] buffer for extended pointer on missing page descriptor. * @ return 0 if success / return -1 if a dirty page cannot be updated on device. ******************************************************************************************/ error_t mapper_handle_miss( mapper_t * mapper, uint32_t page_id, xptr_t * page_xp ); /******************************************************************************************* * This function move data between a remote mapper, identified by the argument, * and a distributed user buffer. It can be called by a thread running in any cluster. * It is called by the vfs_user_move() to implement sys_read() and sys_write() syscalls. * If required, the data transfer is split in "fragments", where one fragment contains * contiguous bytes in the same mapper page. * It uses "hal_uspace" accesses to move a fragment to/from the user buffer. * In case of write, the dirty bit is set for all pages written in the mapper. * The mapper being an extendable cache, it is automatically extended when required. * The "offset" field in the file descriptor, and the "size" field in inode descriptor * are not modified by this function. ******************************************************************************************* * @ mapper_xp : extended pointer on mapper. * @ to_buffer : mapper -> buffer if true / buffer -> mapper if false. * @ file_offset : first byte to move in file. * @ u_buf : user space pointer on user buffer. * @ size : number of bytes to move. * returns O if success / returns -1 if error. ******************************************************************************************/ error_t mapper_move_user( xptr_t mapper_xp, bool_t to_buffer, uint32_t file_offset, void * u_buf, uint32_t size ); /******************************************************************************************** * This function move data between a remote mapper, identified by the argument, * and a localised remote kernel buffer. It can be called by a thread running any cluster. * If required, the data transfer is split in "fragments", where one fragment contains * contiguous bytes in the same mapper page. * It uses a "remote_memcpy" to move a fragment to/from the kernel buffer. * In case of write, the dirty bit is set for all pages written in the mapper. ******************************************************************************************* * @ mapper_xp : extended pointer on mapper. * @ to_buffer : mapper -> buffer if true / buffer -> mapper if false. * @ file_offset : first byte to move in file. * @ buffer_xp : extended pointer on kernel buffer. * @ size : number of bytes to move. * returns O if success / returns -1 if error. ******************************************************************************************/ error_t mapper_move_kernel( xptr_t mapper_xp, bool_t to_buffer, uint32_t file_offset, xptr_t buffer_xp, uint32_t size ); /******************************************************************************************* * This function removes a physical page from the mapper, and releases * the page to the local PPM. It is called by the mapper_destroy() function. * It must be executed by a thread running in the cluster containing the mapper. * It takes the mapper lock in WRITE_MODE to update the mapper. ******************************************************************************************* * @ mapper : local pointer on the mapper. * @ page : pointer on page to remove. ******************************************************************************************/ void mapper_release_page( mapper_t * mapper, struct page_s * page ); /******************************************************************************************* * This function returns an extended pointer on a page descriptor. * The - possibly remote - mapper is identified by the argument. * The page is identified by argument (page index in the file). * It can be executed by a thread running in any cluster, as it uses remote * access primitives to scan the mapper. * In case of miss, this function takes the mapper lock in WRITE_MODE, and call the * mapper_handle_miss() to load the missing page from device to mapper, using an RPC * when the mapper is remote. ******************************************************************************************* * @ mapper_xp : extended pointer on the mapper. * @ page_id : page index in file * @ returns extended pointer on page descriptor if success / return XPTR_NULL if error. ******************************************************************************************/ xptr_t mapper_remote_get_page( xptr_t mapper_xp, uint32_t page_id ); /******************************************************************************************* * This function allows to read a single word in a mapper seen as and array of uint32_t. * It has bee designed to support remote access to the FAT mapper of the FATFS. * It can be called by any thread running in any cluster. * In case of miss, it takes the mapper lock in WRITE_MODE, load the missing * page from device to mapper, and release the mapper lock. ******************************************************************************************* * @ mapper_xp : [in] extended pointer on the mapper. * @ page_id : [in] page index in mapper. * @ word_id : [in] 32 bits word index in page. * @ value : [out] local pointer on destination buffer. * @ returns 0 if success / return -1 if error. ******************************************************************************************/ error_t mapper_remote_get_32( xptr_t mapper_xp, uint32_t page_id, uint32_t word_id, uint32_t * value ); /******************************************************************************************* * This function allows to write a single word to a mapper seen as and array of uint32_t. * It has been designed to support remote access to the FAT mapper of the FATFS. * It can be called by any thread running in any cluster. * In case of miss, it takes the mapper lock in WRITE_MODE, load the missing * page from device to mapper, and release the mapper lock. * It does not update the FAT on IOC device. ******************************************************************************************* * @ mapper_xp : [in] extended pointer on the mapper. * @ page_id : [in] page index in mapper. * @ word_id : [in] 32 bits word index in page. * @ value : [in] value to be written. * @ returns 0 if success / return -1 if error. ******************************************************************************************/ error_t mapper_remote_set_32( xptr_t mapper_xp, uint32_t page_id, uint32_t word_id, uint32_t value ); /******************************************************************************************* * This function scan all pages present in the mapper identified by the argument, * and synchronize all pages maked as dirty" on disk. * These pages are unmarked and removed from the local PPM dirty_list. * This function must be called by a local thread running in same cluster as the mapper. * A remote thread must call the RPC_MAPPER_SYNC function. ******************************************************************************************* * @ mapper : [in] local pointer on local mapper. * @ returns 0 if success / return -1 if error. ******************************************************************************************/ error_t mapper_sync( mapper_t * mapper ); /******************************************************************************************* * This debug function displays the content of a given page of a given mapper. * - the mapper is identified by the argument. * - the page is identified by the argument. * - the number of bytes to display in page is defined by the argument. * The format is eigth (32 bits) words per line in hexadecimal. * It can be called by any thread running in any cluster. * In case of miss in mapper, it load the missing page from device to mapper. ******************************************************************************************* * @ mapper_xp : [in] extended pointer on the mapper. * @ page_id : [in] page index in file. * @ nbytes : [in] value to be written. * @ returns 0 if success / return -1 if error. ******************************************************************************************/ error_t mapper_display_page( xptr_t mapper_xp, uint32_t page_id, uint32_t nbytes ); #endif /* _MAPPER_H_ */