/* * mapper.h - Kernel cache for FS files or directories definition. * * Authors Mohamed Lamine Karaoui (2015) * Alain Greiner (2016,2017,2018) * * 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; /******************************************************************************************* * The mapper implements the kernel cache for a given 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. * - In a given cluster, a mapper is a "private" structure: a thread accessing the mapper * must be running in the cluster containing it (can be a local thread or a RPC thread). * - The mapper is protected by a blocking "rwlock", to support several simultaneous * readers, and only one writer. This lock implement a busy waiting policy. * - The mapper_get_page() function that return a page descriptor pointer from a page * index in file is in charge of handling the miss on the mapper cache. * - The vfs_mapper_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 given file * or directory into the mapper. * - 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. ******************************************************************************************/ /******************************************************************************************* * 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 structure defines a "fragment". It is used to move data between the kernel mapper, * and an user buffer, that can be split in several distributed physical pages located * in different clusters. A fragment is a set of contiguous bytes in the file. * - It can be stored in one single physical page in the user buffer. * - It can spread two successive physical pages in the kernel mapper. ******************************************************************************************/ typedef struct fragment_s { uint32_t file_offset; /*! offset of fragment in file (i.e. in mapper) */ uint32_t size; /*! number of bytes in fragment */ cxy_t buf_cxy; /*! user buffer cluster identifier */ void * buf_ptr; /*! local pointer on first byte in user buffer */ } fragment_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 local mapper, and a distributed user buffer. * It must be called by a thread running in cluster containing the mapper. * 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 * for both read and write accesses. * The "offset" field in the file descriptor, and the "size" field in inode descriptor * are not modified by this function. ******************************************************************************************* * @ mapper : local 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( mapper_t * mapper, bool_t to_buffer, uint32_t file_offset, void * u_buf, uint32_t size ); /******************************************************************************************** * This function move data between a remote mapper and a 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 mapper page, identified by , * index in the file. The - possibly remote - mapper is identified by the * argument. 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 base 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 tho 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. * @ index : [in] 32 bits word index in file. * @ p_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 word_id, uint32_t * p_value ); /******************************************************************************************* * This function allows to write a single word to a mapper seen as and array of uint32_t. * It has bee designed to support remote access tho 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. * @ index : [in] 32 bits word index in file. * @ p_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 word_id, uint32_t value ); #endif /* _MAPPER_H_ */