diff options
Diffstat (limited to 'fs/iomap/iter.c')
| -rw-r--r-- | fs/iomap/iter.c | 97 |
1 files changed, 58 insertions, 39 deletions
diff --git a/fs/iomap/iter.c b/fs/iomap/iter.c index 3790918646af..6ffc6a7b9ba5 100644 --- a/fs/iomap/iter.c +++ b/fs/iomap/iter.c @@ -7,40 +7,25 @@ #include <linux/iomap.h> #include "trace.h" -/* - * Advance to the next range we need to map. - * - * If the iomap is marked IOMAP_F_STALE, it means the existing map was not fully - * processed - it was aborted because the extent the iomap spanned may have been - * changed during the operation. In this case, the iteration behaviour is to - * remap the unprocessed range of the iter, and that means we may need to remap - * even when we've made no progress (i.e. iter->processed = 0). Hence the - * "finished iterating" case needs to distinguish between - * (processed = 0) meaning we are done and (processed = 0 && stale) meaning we - * need to remap the entire remaining range. - */ -static inline int iomap_iter_advance(struct iomap_iter *iter) +static inline void iomap_iter_reset_iomap(struct iomap_iter *iter) { - bool stale = iter->iomap.flags & IOMAP_F_STALE; - int ret = 1; - - /* handle the previous iteration (if any) */ - if (iter->iomap.length) { - if (iter->processed < 0) - return iter->processed; - if (WARN_ON_ONCE(iter->processed > iomap_length(iter))) - return -EIO; - iter->pos += iter->processed; - iter->len -= iter->processed; - if (!iter->len || (!iter->processed && !stale)) - ret = 0; - } - - /* clear the per iteration state */ - iter->processed = 0; + iter->status = 0; memset(&iter->iomap, 0, sizeof(iter->iomap)); memset(&iter->srcmap, 0, sizeof(iter->srcmap)); - return ret; +} + +/* + * 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) @@ -50,6 +35,8 @@ static inline void iomap_iter_done(struct iomap_iter *iter) 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); @@ -67,26 +54,58 @@ static inline void iomap_iter_done(struct iomap_iter *iter) * 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.processed unchanged, or set it to a negative + * 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; - if (iter->iomap.length && ops->iomap_end) { - ret = ops->iomap_end(iter->inode, iter->pos, iomap_length(iter), - iter->processed > 0 ? iter->processed : 0, - iter->flags, &iter->iomap); - if (ret < 0 && !iter->processed) + 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; } - trace_iomap_iter(iter, ops, _RET_IP_); - ret = iomap_iter_advance(iter); + /* 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) |