diff --git a/weed/mount/weedfs_file_io.go b/weed/mount/weedfs_file_io.go new file mode 100644 index 000000000..0a31c3d70 --- /dev/null +++ b/weed/mount/weedfs_file_io.go @@ -0,0 +1,217 @@ +package mount + +import ( + "github.com/hanwen/go-fuse/v2/fuse" +) + +/** + * Read data + * + * Read should send exactly the number of bytes requested except + * on EOF or error, otherwise the rest of the data will be + * substituted with zeroes. An exception to this is when the file + * has been opened in 'direct_io' mode, in which case the return + * value of the read system call will reflect the return value of + * this operation. + * + * fi->fh will contain the value set by the open method, or will + * be undefined if the open method didn't set any value. + * + * Valid replies: + * fuse_reply_buf + * fuse_reply_iov + * fuse_reply_data + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param size number of bytes to read + * @param off offset to read from + * @param fi file information + */ +func (wfs *WFS) Read(cancel <-chan struct{}, in *fuse.ReadIn, buf []byte) (fuse.ReadResult, fuse.Status) { + return nil, fuse.ENOSYS +} + +/** + * Write data + * + * Write should return exactly the number of bytes requested + * except on error. An exception to this is when the file has + * been opened in 'direct_io' mode, in which case the return value + * of the write system call will reflect the return value of this + * operation. + * + * Unless FUSE_CAP_HANDLE_KILLPRIV is disabled, this method is + * expected to reset the setuid and setgid bits. + * + * fi->fh will contain the value set by the open method, or will + * be undefined if the open method didn't set any value. + * + * Valid replies: + * fuse_reply_write + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param buf data to write + * @param size number of bytes to write + * @param off offset to write to + * @param fi file information + */ +func (wfs *WFS) Write(cancel <-chan struct{}, in *fuse.WriteIn, data []byte) (written uint32, code fuse.Status) { + return 0, fuse.ENOSYS +} + +/** + * Open a file + * + * Open flags are available in fi->flags. The following rules + * apply. + * + * - Creation (O_CREAT, O_EXCL, O_NOCTTY) flags will be + * filtered out / handled by the kernel. + * + * - Access modes (O_RDONLY, O_WRONLY, O_RDWR) should be used + * by the filesystem to check if the operation is + * permitted. If the ``-o default_permissions`` mount + * option is given, this check is already done by the + * kernel before calling open() and may thus be omitted by + * the filesystem. + * + * - When writeback caching is enabled, the kernel may send + * read requests even for files opened with O_WRONLY. The + * filesystem should be prepared to handle this. + * + * - When writeback caching is disabled, the filesystem is + * expected to properly handle the O_APPEND flag and ensure + * that each write is appending to the end of the file. + * + * - When writeback caching is enabled, the kernel will + * handle O_APPEND. However, unless all changes to the file + * come through the kernel this will not work reliably. The + * filesystem should thus either ignore the O_APPEND flag + * (and let the kernel handle it), or return an error + * (indicating that reliably O_APPEND is not available). + * + * Filesystem may store an arbitrary file handle (pointer, + * index, etc) in fi->fh, and use this in other all other file + * operations (read, write, flush, release, fsync). + * + * Filesystem may also implement stateless file I/O and not store + * anything in fi->fh. + * + * There are also some flags (direct_io, keep_cache) which the + * filesystem may set in fi, to change the way the file is opened. + * See fuse_file_info structure in for more details. + * + * If this request is answered with an error code of ENOSYS + * and FUSE_CAP_NO_OPEN_SUPPORT is set in + * `fuse_conn_info.capable`, this is treated as success and + * future calls to open and release will also succeed without being + * sent to the filesystem process. + * + * Valid replies: + * fuse_reply_open + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param fi file information +*/ +func (wfs *WFS) Open(cancel <-chan struct{}, in *fuse.OpenIn, out *fuse.OpenOut) (status fuse.Status) { + return fuse.ENOSYS +} + +/** + * Flush method + * + * This is called on each close() of the opened file. + * + * Since file descriptors can be duplicated (dup, dup2, fork), for + * one open call there may be many flush calls. + * + * Filesystems shouldn't assume that flush will always be called + * after some writes, or that if will be called at all. + * + * fi->fh will contain the value set by the open method, or will + * be undefined if the open method didn't set any value. + * + * NOTE: the name of the method is misleading, since (unlike + * fsync) the filesystem is not forced to flush pending writes. + * One reason to flush data is if the filesystem wants to return + * write errors during close. However, such use is non-portable + * because POSIX does not require [close] to wait for delayed I/O to + * complete. + * + * If the filesystem supports file locking operations (setlk, + * getlk) it should remove all locks belonging to 'fi->owner'. + * + * If this request is answered with an error code of ENOSYS, + * this is treated as success and future calls to flush() will + * succeed automatically without being send to the filesystem + * process. + * + * Valid replies: + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param fi file information + * + * [close]: http://pubs.opengroup.org/onlinepubs/9699919799/functions/close.html + */ +func (wfs *WFS) Flush(cancel <-chan struct{}, in *fuse.FlushIn) fuse.Status { + return fuse.ENOSYS +} + +/** + * Release an open file + * + * Release is called when there are no more references to an open + * file: all file descriptors are closed and all memory mappings + * are unmapped. + * + * For every open call there will be exactly one release call (unless + * the filesystem is force-unmounted). + * + * The filesystem may reply with an error, but error values are + * not returned to close() or munmap() which triggered the + * release. + * + * fi->fh will contain the value set by the open method, or will + * be undefined if the open method didn't set any value. + * fi->flags will contain the same flags as for open. + * + * Valid replies: + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param fi file information + */ +func (wfs *WFS) Release(cancel <-chan struct{}, in *fuse.ReleaseIn) { +} + +/** + * Synchronize file contents + * + * If the datasync parameter is non-zero, then only the user data + * should be flushed, not the meta data. + * + * If this request is answered with an error code of ENOSYS, + * this is treated as success and future calls to fsync() will + * succeed automatically without being send to the filesystem + * process. + * + * Valid replies: + * fuse_reply_err + * + * @param req request handle + * @param ino the inode number + * @param datasync flag indicating if only data should be flushed + * @param fi file information + */ +func (wfs *WFS) Fsync(cancel <-chan struct{}, in *fuse.FsyncIn) (code fuse.Status) { + return fuse.ENOSYS +}