Hi robbieko, Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on btrfs/next] [also build test WARNING on v5.1-rc2 next-20190329] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/robbieko/Btrfs-send-improve-clone-range/20190331-162406 base: https://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs.git next config: i386-randconfig-x005-201913 (attached as .config) compiler: gcc-7 (Debian 7.3.0-1) 7.3.0 reproduce: # save the attached .config to linux build tree make ARCH=i386 Note: it may well be a FALSE warning. FWIW you are at least aware of it now. http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings All warnings (new ones prefixed by >>): fs/btrfs/send.c: In function 'process_extent': >> fs/btrfs/send.c:5195:60: warning: 'clone_data_offset' may be used >> uninitialized in this function [-Wmaybe-uninitialized] if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte && ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~ clone_data_offset == data_offset) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ fs/btrfs/send.c:5125:7: note: 'clone_data_offset' was declared here u64 clone_data_offset; ^~~~~~~~~~~~~~~~~ vim +/clone_data_offset +5195 fs/btrfs/send.c d906d49f Filipe Manana 2015-10-02 5048 d906d49f Filipe Manana 2015-10-02 5049 static int clone_range(struct send_ctx *sctx, d906d49f Filipe Manana 2015-10-02 5050 struct clone_root *clone_root, d906d49f Filipe Manana 2015-10-02 5051 const u64 disk_byte, d906d49f Filipe Manana 2015-10-02 5052 u64 data_offset, d906d49f Filipe Manana 2015-10-02 5053 u64 offset, d906d49f Filipe Manana 2015-10-02 5054 u64 len) d906d49f Filipe Manana 2015-10-02 5055 { d906d49f Filipe Manana 2015-10-02 5056 struct btrfs_path *path; d906d49f Filipe Manana 2015-10-02 5057 struct btrfs_key key; d906d49f Filipe Manana 2015-10-02 5058 int ret; d906d49f Filipe Manana 2015-10-02 5059 72610b1b Filipe Manana 2017-08-10 5060 /* 72610b1b Filipe Manana 2017-08-10 5061 * Prevent cloning from a zero offset with a length matching the sector 72610b1b Filipe Manana 2017-08-10 5062 * size because in some scenarios this will make the receiver fail. 72610b1b Filipe Manana 2017-08-10 5063 * 72610b1b Filipe Manana 2017-08-10 5064 * For example, if in the source filesystem the extent at offset 0 72610b1b Filipe Manana 2017-08-10 5065 * has a length of sectorsize and it was written using direct IO, then 72610b1b Filipe Manana 2017-08-10 5066 * it can never be an inline extent (even if compression is enabled). 72610b1b Filipe Manana 2017-08-10 5067 * Then this extent can be cloned in the original filesystem to a non 72610b1b Filipe Manana 2017-08-10 5068 * zero file offset, but it may not be possible to clone in the 72610b1b Filipe Manana 2017-08-10 5069 * destination filesystem because it can be inlined due to compression 72610b1b Filipe Manana 2017-08-10 5070 * on the destination filesystem (as the receiver's write operations are 72610b1b Filipe Manana 2017-08-10 5071 * always done using buffered IO). The same happens when the original 72610b1b Filipe Manana 2017-08-10 5072 * filesystem does not have compression enabled but the destination 72610b1b Filipe Manana 2017-08-10 5073 * filesystem has. 72610b1b Filipe Manana 2017-08-10 5074 */ 72610b1b Filipe Manana 2017-08-10 5075 if (clone_root->offset == 0 && 72610b1b Filipe Manana 2017-08-10 5076 len == sctx->send_root->fs_info->sectorsize) 72610b1b Filipe Manana 2017-08-10 5077 return send_extent_data(sctx, offset, len); 72610b1b Filipe Manana 2017-08-10 5078 d906d49f Filipe Manana 2015-10-02 5079 path = alloc_path_for_send(); d906d49f Filipe Manana 2015-10-02 5080 if (!path) d906d49f Filipe Manana 2015-10-02 5081 return -ENOMEM; d906d49f Filipe Manana 2015-10-02 5082 d906d49f Filipe Manana 2015-10-02 5083 /* d906d49f Filipe Manana 2015-10-02 5084 * We can't send a clone operation for the entire range if we find d906d49f Filipe Manana 2015-10-02 5085 * extent items in the respective range in the source file that d906d49f Filipe Manana 2015-10-02 5086 * refer to different extents or if we find holes. d906d49f Filipe Manana 2015-10-02 5087 * So check for that and do a mix of clone and regular write/copy d906d49f Filipe Manana 2015-10-02 5088 * operations if needed. d906d49f Filipe Manana 2015-10-02 5089 * d906d49f Filipe Manana 2015-10-02 5090 * Example: d906d49f Filipe Manana 2015-10-02 5091 * d906d49f Filipe Manana 2015-10-02 5092 * mkfs.btrfs -f /dev/sda d906d49f Filipe Manana 2015-10-02 5093 * mount /dev/sda /mnt d906d49f Filipe Manana 2015-10-02 5094 * xfs_io -f -c "pwrite -S 0xaa 0K 100K" /mnt/foo d906d49f Filipe Manana 2015-10-02 5095 * cp --reflink=always /mnt/foo /mnt/bar d906d49f Filipe Manana 2015-10-02 5096 * xfs_io -c "pwrite -S 0xbb 50K 50K" /mnt/foo d906d49f Filipe Manana 2015-10-02 5097 * btrfs subvolume snapshot -r /mnt /mnt/snap d906d49f Filipe Manana 2015-10-02 5098 * d906d49f Filipe Manana 2015-10-02 5099 * If when we send the snapshot and we are processing file bar (which d906d49f Filipe Manana 2015-10-02 5100 * has a higher inode number than foo) we blindly send a clone operation d906d49f Filipe Manana 2015-10-02 5101 * for the [0, 100K[ range from foo to bar, the receiver ends up getting d906d49f Filipe Manana 2015-10-02 5102 * a file bar that matches the content of file foo - iow, doesn't match d906d49f Filipe Manana 2015-10-02 5103 * the content from bar in the original filesystem. d906d49f Filipe Manana 2015-10-02 5104 */ d906d49f Filipe Manana 2015-10-02 5105 key.objectid = clone_root->ino; d906d49f Filipe Manana 2015-10-02 5106 key.type = BTRFS_EXTENT_DATA_KEY; d906d49f Filipe Manana 2015-10-02 5107 key.offset = clone_root->offset; d906d49f Filipe Manana 2015-10-02 5108 ret = btrfs_search_slot(NULL, clone_root->root, &key, path, 0, 0); d906d49f Filipe Manana 2015-10-02 5109 if (ret < 0) d906d49f Filipe Manana 2015-10-02 5110 goto out; d906d49f Filipe Manana 2015-10-02 5111 if (ret > 0 && path->slots[0] > 0) { d906d49f Filipe Manana 2015-10-02 5112 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0] - 1); d906d49f Filipe Manana 2015-10-02 5113 if (key.objectid == clone_root->ino && d906d49f Filipe Manana 2015-10-02 5114 key.type == BTRFS_EXTENT_DATA_KEY) d906d49f Filipe Manana 2015-10-02 5115 path->slots[0]--; d906d49f Filipe Manana 2015-10-02 5116 } d906d49f Filipe Manana 2015-10-02 5117 d906d49f Filipe Manana 2015-10-02 5118 while (true) { d906d49f Filipe Manana 2015-10-02 5119 struct extent_buffer *leaf = path->nodes[0]; d906d49f Filipe Manana 2015-10-02 5120 int slot = path->slots[0]; d906d49f Filipe Manana 2015-10-02 5121 struct btrfs_file_extent_item *ei; d906d49f Filipe Manana 2015-10-02 5122 u8 type; d906d49f Filipe Manana 2015-10-02 5123 u64 ext_len; d906d49f Filipe Manana 2015-10-02 5124 u64 clone_len; c4b3268d Robbie Ko 2019-03-28 5125 u64 clone_data_offset; d906d49f Filipe Manana 2015-10-02 5126 d906d49f Filipe Manana 2015-10-02 5127 if (slot >= btrfs_header_nritems(leaf)) { d906d49f Filipe Manana 2015-10-02 5128 ret = btrfs_next_leaf(clone_root->root, path); d906d49f Filipe Manana 2015-10-02 5129 if (ret < 0) d906d49f Filipe Manana 2015-10-02 5130 goto out; d906d49f Filipe Manana 2015-10-02 5131 else if (ret > 0) d906d49f Filipe Manana 2015-10-02 5132 break; d906d49f Filipe Manana 2015-10-02 5133 continue; d906d49f Filipe Manana 2015-10-02 5134 } d906d49f Filipe Manana 2015-10-02 5135 d906d49f Filipe Manana 2015-10-02 5136 btrfs_item_key_to_cpu(leaf, &key, slot); d906d49f Filipe Manana 2015-10-02 5137 d906d49f Filipe Manana 2015-10-02 5138 /* d906d49f Filipe Manana 2015-10-02 5139 * We might have an implicit trailing hole (NO_HOLES feature d906d49f Filipe Manana 2015-10-02 5140 * enabled). We deal with it after leaving this loop. d906d49f Filipe Manana 2015-10-02 5141 */ d906d49f Filipe Manana 2015-10-02 5142 if (key.objectid != clone_root->ino || d906d49f Filipe Manana 2015-10-02 5143 key.type != BTRFS_EXTENT_DATA_KEY) d906d49f Filipe Manana 2015-10-02 5144 break; d906d49f Filipe Manana 2015-10-02 5145 d906d49f Filipe Manana 2015-10-02 5146 ei = btrfs_item_ptr(leaf, slot, struct btrfs_file_extent_item); d906d49f Filipe Manana 2015-10-02 5147 type = btrfs_file_extent_type(leaf, ei); d906d49f Filipe Manana 2015-10-02 5148 if (type == BTRFS_FILE_EXTENT_INLINE) { d906d49f Filipe Manana 2015-10-02 5149 ext_len = btrfs_file_extent_inline_len(leaf, slot, ei); 09cbfeaf Kirill A. Shutemov 2016-04-01 5150 ext_len = PAGE_ALIGN(ext_len); d906d49f Filipe Manana 2015-10-02 5151 } else { d906d49f Filipe Manana 2015-10-02 5152 ext_len = btrfs_file_extent_num_bytes(leaf, ei); d906d49f Filipe Manana 2015-10-02 5153 } d906d49f Filipe Manana 2015-10-02 5154 d906d49f Filipe Manana 2015-10-02 5155 if (key.offset + ext_len <= clone_root->offset) d906d49f Filipe Manana 2015-10-02 5156 goto next; d906d49f Filipe Manana 2015-10-02 5157 d906d49f Filipe Manana 2015-10-02 5158 if (key.offset > clone_root->offset) { d906d49f Filipe Manana 2015-10-02 5159 /* Implicit hole, NO_HOLES feature enabled. */ d906d49f Filipe Manana 2015-10-02 5160 u64 hole_len = key.offset - clone_root->offset; d906d49f Filipe Manana 2015-10-02 5161 d906d49f Filipe Manana 2015-10-02 5162 if (hole_len > len) d906d49f Filipe Manana 2015-10-02 5163 hole_len = len; d906d49f Filipe Manana 2015-10-02 5164 ret = send_extent_data(sctx, offset, hole_len); d906d49f Filipe Manana 2015-10-02 5165 if (ret < 0) d906d49f Filipe Manana 2015-10-02 5166 goto out; d906d49f Filipe Manana 2015-10-02 5167 d906d49f Filipe Manana 2015-10-02 5168 len -= hole_len; d906d49f Filipe Manana 2015-10-02 5169 if (len == 0) d906d49f Filipe Manana 2015-10-02 5170 break; d906d49f Filipe Manana 2015-10-02 5171 offset += hole_len; d906d49f Filipe Manana 2015-10-02 5172 clone_root->offset += hole_len; d906d49f Filipe Manana 2015-10-02 5173 data_offset += hole_len; d906d49f Filipe Manana 2015-10-02 5174 } d906d49f Filipe Manana 2015-10-02 5175 d906d49f Filipe Manana 2015-10-02 5176 if (key.offset >= clone_root->offset + len) d906d49f Filipe Manana 2015-10-02 5177 break; d906d49f Filipe Manana 2015-10-02 5178 c4b3268d Robbie Ko 2019-03-28 5179 if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte) { c4b3268d Robbie Ko 2019-03-28 5180 clone_root->offset = key.offset; c4b3268d Robbie Ko 2019-03-28 5181 clone_data_offset = btrfs_file_extent_offset(leaf, ei); c4b3268d Robbie Ko 2019-03-28 5182 if (clone_data_offset < data_offset && c4b3268d Robbie Ko 2019-03-28 5183 clone_data_offset + ext_len > data_offset) { c4b3268d Robbie Ko 2019-03-28 5184 u64 extent_offset; c4b3268d Robbie Ko 2019-03-28 5185 c4b3268d Robbie Ko 2019-03-28 5186 extent_offset = data_offset - clone_data_offset; c4b3268d Robbie Ko 2019-03-28 5187 ext_len -= extent_offset; c4b3268d Robbie Ko 2019-03-28 5188 clone_data_offset += extent_offset; c4b3268d Robbie Ko 2019-03-28 5189 clone_root->offset += extent_offset; c4b3268d Robbie Ko 2019-03-28 5190 } c4b3268d Robbie Ko 2019-03-28 5191 } c4b3268d Robbie Ko 2019-03-28 5192 d906d49f Filipe Manana 2015-10-02 5193 clone_len = min_t(u64, ext_len, len); d906d49f Filipe Manana 2015-10-02 5194 d906d49f Filipe Manana 2015-10-02 @5195 if (btrfs_file_extent_disk_bytenr(leaf, ei) == disk_byte && c4b3268d Robbie Ko 2019-03-28 5196 clone_data_offset == data_offset) d906d49f Filipe Manana 2015-10-02 5197 ret = send_clone(sctx, offset, clone_len, clone_root); d906d49f Filipe Manana 2015-10-02 5198 else d906d49f Filipe Manana 2015-10-02 5199 ret = send_extent_data(sctx, offset, clone_len); d906d49f Filipe Manana 2015-10-02 5200 d906d49f Filipe Manana 2015-10-02 5201 if (ret < 0) d906d49f Filipe Manana 2015-10-02 5202 goto out; d906d49f Filipe Manana 2015-10-02 5203 d906d49f Filipe Manana 2015-10-02 5204 len -= clone_len; d906d49f Filipe Manana 2015-10-02 5205 if (len == 0) d906d49f Filipe Manana 2015-10-02 5206 break; d906d49f Filipe Manana 2015-10-02 5207 offset += clone_len; d906d49f Filipe Manana 2015-10-02 5208 clone_root->offset += clone_len; d906d49f Filipe Manana 2015-10-02 5209 data_offset += clone_len; d906d49f Filipe Manana 2015-10-02 5210 next: d906d49f Filipe Manana 2015-10-02 5211 path->slots[0]++; d906d49f Filipe Manana 2015-10-02 5212 } d906d49f Filipe Manana 2015-10-02 5213 d906d49f Filipe Manana 2015-10-02 5214 if (len > 0) d906d49f Filipe Manana 2015-10-02 5215 ret = send_extent_data(sctx, offset, len); d906d49f Filipe Manana 2015-10-02 5216 else d906d49f Filipe Manana 2015-10-02 5217 ret = 0; d906d49f Filipe Manana 2015-10-02 5218 out: d906d49f Filipe Manana 2015-10-02 5219 btrfs_free_path(path); d906d49f Filipe Manana 2015-10-02 5220 return ret; d906d49f Filipe Manana 2015-10-02 5221 } d906d49f Filipe Manana 2015-10-02 5222 :::::: The code at line 5195 was first introduced by commit :::::: d906d49fc5f49a0129527e8fbc13312f36b9b9ce Btrfs: send, fix file corruption due to incorrect cloning operations :::::: TO: Filipe Manana <fdman...@suse.com> :::::: CC: Filipe Manana <fdman...@suse.com> --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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