v1: https://lists.nongnu.org/archive/html/qemu-block/2019-12/msg00451.html v2: https://lists.nongnu.org/archive/html/qemu-block/2020-09/msg01611.html
Branch: https://github.com/XanClic/qemu.git fuse-exports-v3 Branch: https://git.xanclic.moe/XanClic/qemu.git fuse-exports-v3 Hi, Ever since I found out that you can mount FUSE filesystems on regular files (not just directories), I had the idea of adding FUSE block exports to qemu where you can export block nodes as raw images. The best thing is that you’d be able to mount an image on itself, so whatever format it may be in, qemu lets it appear as a raw image (and you can then use regular tools like dd on it). The performance is quite bad so far, but we can always try to improve it if the need arises. For now I consider it mostly a cute feature to get easy access to the raw contents of image files in any format (without requiring root rights). This series does the following: First, add the FUSE export module (block/export/fuse.c) that implements the basic file access functions. (Note that you need libfuse 3.8.0 or later for SEEK_HOLE/SEEK_DATA.) Second, it allows using FUSE exports as a protocol in the iotests and makes many iotests work with it. (The file node is exported by a background qemu instance to $SOCK_DIR.) This gives us a lot of coverage for, well, not free (it does take twelve patches), but for cheap; but there are still some more specialized things we want to test, so third and last, this series adds an iotest dedicated to FUSE exports. Changes from v2: - Let meson handle the libfuse and feature (lseek) detection - Rebase on top of vhost-user-blk export - Patch 2: - %s/5\.2/6.0/ - Renamed init_fuse() to init_exports_table(), so I can add a fuse_init() without being too confusing - Set max read/write request sizes (using that fuse_init() function, and mount options that libfuse still needs for max_read) - Run fuse_session_receive_buf() in a loop until something other than EINTR is returned - Let setup_fuse_export() clean up - Unmount and destroy the FUSE session only in fuse_export_delete() (after all I/O has settled and thus all references have been dropped) - Add MAINTAINERS entry - Patch 3: - Don't use bdrv_query_image_info() when all we want is bdrv_get_allocated_file_size() - Optionally let fuse_do_truncate() require zeroes in the added areas (there is one fallocate() case where we don't need zeroes there) - Error out if the max read/write request sizes have been exceeded instead of (wrongly) limiting the request size - Rename fuse_flush() to fuse_fsync(), and let a new fuse_flush() invoke fuse_fsync() - Patch 4: - Keep RESIZE permission for growable exports - Patch 5: - Fix two bugs where I forgot to increment the offset when iterating over some area - Patch 17: - %s/QEMU_STGD/QSD/ - Patch 18: - %s/QEMU_STGD/QSD/ - Drop superfluous -T from df invocation git-backport-diff against v3: Key: [----] : patches are identical [####] : number of functional differences between upstream/downstream patch [down] : patch is downstream-only The flags [FC] indicate (F)unctional and (C)ontextual differences, respectively 001/20:[down] 'meson: Detect libfuse' 002/20:[0103] [FC] 'fuse: Allow exporting BDSs via FUSE' 003/20:[0058] [FC] 'fuse: Implement standard FUSE operations' 004/20:[0034] [FC] 'fuse: Allow growable exports' 005/20:[0011] [FC] 'fuse: (Partially) implement fallocate()' 006/20:[0063] [FC] 'fuse: Implement hole detection through lseek' 007/20:[----] [--] 'iotests: Do not needlessly filter _make_test_img' 008/20:[----] [--] 'iotests: Do not pipe _make_test_img' 009/20:[----] [--] 'iotests: Use convert -n in some cases' 010/20:[----] [--] 'iotests/046: Avoid renaming images' 011/20:[----] [--] 'iotests: Derive image names from $TEST_IMG' 012/20:[----] [--] 'iotests/091: Use _cleanup_qemu instad of "wait"' 013/20:[----] [--] 'iotests: Restrict some Python tests to file' 014/20:[----] [--] 'iotests: Let _make_test_img guess $TEST_IMG_FILE' 015/20:[----] [--] 'iotests/287: Clean up subshell test image' 016/20:[----] [--] 'storage-daemon: Call bdrv_close_all() on exit' 017/20:[0018] [FC] 'iotests: Give access to the qemu-storage-daemon' 018/20:[0004] [FC] 'iotests: Allow testing FUSE exports' 019/20:[----] [--] 'iotests: Enable fuse for many tests' 020/20:[----] [--] 'iotests/308: Add test for FUSE exports' Max Reitz (20): meson: Detect libfuse fuse: Allow exporting BDSs via FUSE fuse: Implement standard FUSE operations fuse: Allow growable exports fuse: (Partially) implement fallocate() fuse: Implement hole detection through lseek iotests: Do not needlessly filter _make_test_img iotests: Do not pipe _make_test_img iotests: Use convert -n in some cases iotests/046: Avoid renaming images iotests: Derive image names from $TEST_IMG iotests/091: Use _cleanup_qemu instad of "wait" iotests: Restrict some Python tests to file iotests: Let _make_test_img guess $TEST_IMG_FILE iotests/287: Clean up subshell test image storage-daemon: Call bdrv_close_all() on exit iotests: Give access to the qemu-storage-daemon iotests: Allow testing FUSE exports iotests: Enable fuse for many tests iotests/308: Add test for FUSE exports configure | 13 + meson.build | 26 + qapi/block-export.json | 27 +- include/block/fuse.h | 30 ++ block.c | 1 + block/export/export.c | 4 + block/export/fuse.c | 726 +++++++++++++++++++++++++++ storage-daemon/qemu-storage-daemon.c | 3 + MAINTAINERS | 6 + block/export/meson.build | 1 + meson_options.txt | 4 + tests/qemu-iotests/025 | 2 +- tests/qemu-iotests/026 | 2 +- tests/qemu-iotests/028 | 16 +- tests/qemu-iotests/028.out | 3 + tests/qemu-iotests/031 | 2 +- tests/qemu-iotests/034 | 2 +- tests/qemu-iotests/036 | 2 +- tests/qemu-iotests/037 | 2 +- tests/qemu-iotests/038 | 2 +- tests/qemu-iotests/039 | 2 +- tests/qemu-iotests/046 | 7 +- tests/qemu-iotests/046.out | 2 +- tests/qemu-iotests/050 | 2 +- tests/qemu-iotests/054 | 2 +- tests/qemu-iotests/060 | 2 +- tests/qemu-iotests/071 | 21 +- tests/qemu-iotests/079 | 2 +- tests/qemu-iotests/080 | 2 +- tests/qemu-iotests/089 | 5 +- tests/qemu-iotests/089.out | 1 + tests/qemu-iotests/090 | 2 +- tests/qemu-iotests/091 | 5 +- tests/qemu-iotests/095 | 2 +- tests/qemu-iotests/097 | 2 +- tests/qemu-iotests/098 | 2 +- tests/qemu-iotests/102 | 2 +- tests/qemu-iotests/103 | 2 +- tests/qemu-iotests/106 | 2 +- tests/qemu-iotests/107 | 2 +- tests/qemu-iotests/108 | 2 +- tests/qemu-iotests/111 | 2 +- tests/qemu-iotests/112 | 2 +- tests/qemu-iotests/115 | 2 +- tests/qemu-iotests/117 | 2 +- tests/qemu-iotests/120 | 2 +- tests/qemu-iotests/121 | 2 +- tests/qemu-iotests/127 | 2 +- tests/qemu-iotests/133 | 2 +- tests/qemu-iotests/137 | 2 +- tests/qemu-iotests/138 | 2 +- tests/qemu-iotests/140 | 2 +- tests/qemu-iotests/154 | 2 +- tests/qemu-iotests/161 | 14 +- tests/qemu-iotests/171 | 2 +- tests/qemu-iotests/174 | 10 +- tests/qemu-iotests/175 | 8 +- tests/qemu-iotests/176 | 2 +- tests/qemu-iotests/177 | 2 +- tests/qemu-iotests/179 | 2 +- tests/qemu-iotests/183 | 2 +- tests/qemu-iotests/186 | 2 +- tests/qemu-iotests/187 | 2 +- tests/qemu-iotests/191 | 2 +- tests/qemu-iotests/195 | 2 +- tests/qemu-iotests/200 | 5 +- tests/qemu-iotests/200.out | 4 +- tests/qemu-iotests/204 | 2 +- tests/qemu-iotests/206 | 3 +- tests/qemu-iotests/214 | 2 +- tests/qemu-iotests/217 | 2 +- tests/qemu-iotests/220 | 2 +- tests/qemu-iotests/221 | 2 +- tests/qemu-iotests/229 | 5 +- tests/qemu-iotests/229.out | 6 +- tests/qemu-iotests/242 | 3 +- tests/qemu-iotests/247 | 2 +- tests/qemu-iotests/249 | 8 +- tests/qemu-iotests/250 | 2 +- tests/qemu-iotests/252 | 2 +- tests/qemu-iotests/265 | 2 +- tests/qemu-iotests/268 | 2 +- tests/qemu-iotests/272 | 2 +- tests/qemu-iotests/273 | 2 +- tests/qemu-iotests/279 | 2 +- tests/qemu-iotests/286 | 2 +- tests/qemu-iotests/287 | 6 +- tests/qemu-iotests/289 | 2 +- tests/qemu-iotests/290 | 2 +- tests/qemu-iotests/291 | 2 +- tests/qemu-iotests/292 | 2 +- tests/qemu-iotests/293 | 2 +- tests/qemu-iotests/294 | 2 +- tests/qemu-iotests/305 | 2 +- tests/qemu-iotests/308 | 339 +++++++++++++ tests/qemu-iotests/308.out | 97 ++++ tests/qemu-iotests/check | 17 + tests/qemu-iotests/common.filter | 5 +- tests/qemu-iotests/common.rc | 181 ++++++- tests/qemu-iotests/group | 1 + 100 files changed, 1615 insertions(+), 126 deletions(-) create mode 100644 include/block/fuse.h create mode 100644 block/export/fuse.c create mode 100755 tests/qemu-iotests/308 create mode 100644 tests/qemu-iotests/308.out -- 2.26.2
