diff options
| -rw-r--r-- | block.c | 135 | ||||
| -rw-r--r-- | include/block/block.h | 1 | ||||
| -rw-r--r-- | include/block/block_int.h | 6 |
3 files changed, 142 insertions, 0 deletions
@@ -964,6 +964,7 @@ static int bdrv_open_common(BlockDriverState *bs, BlockDriverState *file, } else { bs->filename[0] = '\0'; } + pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->filename); bs->drv = drv; bs->opaque = g_malloc0(drv->instance_size); @@ -1505,6 +1506,8 @@ int bdrv_open(BlockDriverState **pbs, const char *filename, } } + bdrv_refresh_filename(bs); + /* For snapshot=on, create a temporary qcow2 overlay. bs points to the * temporary snapshot afterwards. */ if (snapshot_flags) { @@ -1845,6 +1848,8 @@ void bdrv_close(BlockDriverState *bs) bs->zero_beyond_eof = false; QDECREF(bs->options); bs->options = NULL; + QDECREF(bs->full_open_options); + bs->full_open_options = NULL; if (bs->file != NULL) { bdrv_unref(bs->file); @@ -5894,3 +5899,133 @@ void bdrv_flush_io_queue(BlockDriverState *bs) bdrv_flush_io_queue(bs->file); } } + +static bool append_open_options(QDict *d, BlockDriverState *bs) +{ + const QDictEntry *entry; + bool found_any = false; + + for (entry = qdict_first(bs->options); entry; + entry = qdict_next(bs->options, entry)) + { + /* Only take options for this level and exclude all non-driver-specific + * options */ + if (!strchr(qdict_entry_key(entry), '.') && + strcmp(qdict_entry_key(entry), "node-name")) + { + qobject_incref(qdict_entry_value(entry)); + qdict_put_obj(d, qdict_entry_key(entry), qdict_entry_value(entry)); + found_any = true; + } + } + + return found_any; +} + +/* Updates the following BDS fields: + * - exact_filename: A filename which may be used for opening a block device + * which (mostly) equals the given BDS (even without any + * other options; so reading and writing must return the same + * results, but caching etc. may be different) + * - full_open_options: Options which, when given when opening a block device + * (without a filename), result in a BDS (mostly) + * equalling the given one + * - filename: If exact_filename is set, it is copied here. Otherwise, + * full_open_options is converted to a JSON object, prefixed with + * "json:" (for use through the JSON pseudo protocol) and put here. + */ +void bdrv_refresh_filename(BlockDriverState *bs) +{ + BlockDriver *drv = bs->drv; + QDict *opts; + + if (!drv) { + return; + } + + /* This BDS's file name will most probably depend on its file's name, so + * refresh that first */ + if (bs->file) { + bdrv_refresh_filename(bs->file); + } + + if (drv->bdrv_refresh_filename) { + /* Obsolete information is of no use here, so drop the old file name + * information before refreshing it */ + bs->exact_filename[0] = '\0'; + if (bs->full_open_options) { + QDECREF(bs->full_open_options); + bs->full_open_options = NULL; + } + + drv->bdrv_refresh_filename(bs); + } else if (bs->file) { + /* Try to reconstruct valid information from the underlying file */ + bool has_open_options; + + bs->exact_filename[0] = '\0'; + if (bs->full_open_options) { + QDECREF(bs->full_open_options); + bs->full_open_options = NULL; + } + + opts = qdict_new(); + has_open_options = append_open_options(opts, bs); + + /* If no specific options have been given for this BDS, the filename of + * the underlying file should suffice for this one as well */ + if (bs->file->exact_filename[0] && !has_open_options) { + strcpy(bs->exact_filename, bs->file->exact_filename); + } + /* Reconstructing the full options QDict is simple for most format block + * drivers, as long as the full options are known for the underlying + * file BDS. The full options QDict of that file BDS should somehow + * contain a representation of the filename, therefore the following + * suffices without querying the (exact_)filename of this BDS. */ + if (bs->file->full_open_options) { + qdict_put_obj(opts, "driver", + QOBJECT(qstring_from_str(drv->format_name))); + QINCREF(bs->file->full_open_options); + qdict_put_obj(opts, "file", QOBJECT(bs->file->full_open_options)); + + bs->full_open_options = opts; + } else { + QDECREF(opts); + } + } else if (!bs->full_open_options && qdict_size(bs->options)) { + /* There is no underlying file BDS (at least referenced by BDS.file), + * so the full options QDict should be equal to the options given + * specifically for this block device when it was opened (plus the + * driver specification). + * Because those options don't change, there is no need to update + * full_open_options when it's already set. */ + + opts = qdict_new(); + append_open_options(opts, bs); + qdict_put_obj(opts, "driver", + QOBJECT(qstring_from_str(drv->format_name))); + + if (bs->exact_filename[0]) { + /* This may not work for all block protocol drivers (some may + * require this filename to be parsed), but we have to find some + * default solution here, so just include it. If some block driver + * does not support pure options without any filename at all or + * needs some special format of the options QDict, it needs to + * implement the driver-specific bdrv_refresh_filename() function. + */ + qdict_put_obj(opts, "filename", + QOBJECT(qstring_from_str(bs->exact_filename))); + } + + bs->full_open_options = opts; + } + + if (bs->exact_filename[0]) { + pstrcpy(bs->filename, sizeof(bs->filename), bs->exact_filename); + } else if (bs->full_open_options) { + QString *json = qobject_to_json(QOBJECT(bs->full_open_options)); + snprintf(bs->filename, sizeof(bs->filename), "json:%s", + qstring_get_str(json)); + QDECREF(json); + } +} diff --git a/include/block/block.h b/include/block/block.h index e94b701667..8f4ad16d8f 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -274,6 +274,7 @@ int coroutine_fn bdrv_co_write_zeroes(BlockDriverState *bs, int64_t sector_num, BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs, const char *backing_file); int bdrv_get_backing_file_depth(BlockDriverState *bs); +void bdrv_refresh_filename(BlockDriverState *bs); int bdrv_truncate(BlockDriverState *bs, int64_t offset); int64_t bdrv_nb_sectors(BlockDriverState *bs); int64_t bdrv_getlength(BlockDriverState *bs); diff --git a/include/block/block_int.h b/include/block/block_int.h index 7b541a0691..233489547e 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -123,6 +123,9 @@ struct BlockDriver { int (*bdrv_create)(const char *filename, QemuOpts *opts, Error **errp); int (*bdrv_set_key)(BlockDriverState *bs, const char *key); int (*bdrv_make_empty)(BlockDriverState *bs); + + void (*bdrv_refresh_filename)(BlockDriverState *bs); + /* aio */ BlockDriverAIOCB *(*bdrv_aio_readv)(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, @@ -323,6 +326,9 @@ struct BlockDriverState { this file image */ char backing_format[16]; /* if non-zero and backing_file exists */ + QDict *full_open_options; + char exact_filename[1024]; + BlockDriverState *backing_hd; BlockDriverState *file; |