// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2010 Red Hat, Inc. * Copyright (c) 2016-2021 Christoph Hellwig. */ #include #include #include "trace.h" static inline void iomap_iter_reset_iomap(struct iomap_iter *iter) { iter->status = 0; memset(&iter->iomap, 0, sizeof(iter->iomap)); memset(&iter->srcmap, 0, sizeof(iter->srcmap)); } /* * Advance the current iterator position and output the length remaining for the * current mapping. */ int iomap_iter_advance(struct iomap_iter *iter, u64 *count) { if (WARN_ON_ONCE(*count > iomap_length(iter))) return -EIO; iter->pos += *count; iter->len -= *count; *count = iomap_length(iter); return 0; } static inline void iomap_iter_done(struct iomap_iter *iter) { WARN_ON_ONCE(iter->iomap.offset > iter->pos); WARN_ON_ONCE(iter->iomap.length == 0); WARN_ON_ONCE(iter->iomap.offset + iter->iomap.length <= iter->pos); WARN_ON_ONCE(iter->iomap.flags & IOMAP_F_STALE); iter->iter_start_pos = iter->pos; trace_iomap_iter_dstmap(iter->inode, &iter->iomap); if (iter->srcmap.type != IOMAP_HOLE) trace_iomap_iter_srcmap(iter->inode, &iter->srcmap); } /** * iomap_iter - iterate over a ranges in a file * @iter: iteration structue * @ops: iomap ops provided by the file system * * Iterate over filesystem-provided space mappings for the provided file range. * * This function handles cleanup of resources acquired for iteration when the * filesystem indicates there are no more space mappings, which means that this * function must be called in a loop that continues as long it returns a * positive value. If 0 or a negative value is returned, the caller must not * return to the loop body. Within a loop body, there are two ways to break out * of the loop body: leave @iter.status unchanged, or set it to a negative * errno. */ int iomap_iter(struct iomap_iter *iter, const struct iomap_ops *ops) { bool stale = iter->iomap.flags & IOMAP_F_STALE; ssize_t advanced; u64 olen; int ret; trace_iomap_iter(iter, ops, _RET_IP_); if (!iter->iomap.length) goto begin; /* * Calculate how far the iter was advanced and the original length bytes * for ->iomap_end(). */ advanced = iter->pos - iter->iter_start_pos; olen = iter->len + advanced; if (ops->iomap_end) { ret = ops->iomap_end(iter->inode, iter->iter_start_pos, iomap_length_trim(iter, iter->iter_start_pos, olen), advanced, iter->flags, &iter->iomap); if (ret < 0 && !advanced) return ret; } /* detect old return semantics where this would advance */ if (WARN_ON_ONCE(iter->status > 0)) iter->status = -EIO; /* * Use iter->len to determine whether to continue onto the next mapping. * Explicitly terminate on error status or if the current iter has not * advanced at all (i.e. no work was done for some reason) unless the * mapping has been marked stale and needs to be reprocessed. */ if (iter->status < 0) ret = iter->status; else if (iter->len == 0 || (!advanced && !stale)) ret = 0; else ret = 1; iomap_iter_reset_iomap(iter); if (ret <= 0) return ret; begin: ret = ops->iomap_begin(iter->inode, iter->pos, iter->len, iter->flags, &iter->iomap, &iter->srcmap); if (ret < 0) return ret; iomap_iter_done(iter); return 1; }