18a98ec7cSDarrick J. Wong.. SPDX-License-Identifier: GPL-2.0 28a98ec7cSDarrick J. Wong 38a98ec7cSDarrick J. WongBlocks 48a98ec7cSDarrick J. Wong------ 58a98ec7cSDarrick J. Wong 68a98ec7cSDarrick J. Wongext4 allocates storage space in units of “blocks”. A block is a group of 78a98ec7cSDarrick J. Wongsectors between 1KiB and 64KiB, and the number of sectors must be an 88a98ec7cSDarrick J. Wongintegral power of 2. Blocks are in turn grouped into larger units called 98a98ec7cSDarrick J. Wongblock groups. Block size is specified at mkfs time and typically is 108a98ec7cSDarrick J. Wong4KiB. You may experience mounting problems if block size is greater than 118a98ec7cSDarrick J. Wongpage size (i.e. 64KiB blocks on a i386 which only has 4KiB memory 128a98ec7cSDarrick J. Wongpages). By default a filesystem can contain 2^32 blocks; if the '64bit' 13219db95bSAyush Ranjanfeature is enabled, then a filesystem can have 2^64 blocks. The location 14219db95bSAyush Ranjanof structures is stored in terms of the block number the structure lives 15219db95bSAyush Ranjanin and not the absolute offset on disk. 168a98ec7cSDarrick J. Wong 178a98ec7cSDarrick J. WongFor 32-bit filesystems, limits are as follows: 188a98ec7cSDarrick J. Wong 198a98ec7cSDarrick J. Wong.. list-table:: 208a98ec7cSDarrick J. Wong :widths: 1 1 1 1 1 218a98ec7cSDarrick J. Wong :header-rows: 1 228a98ec7cSDarrick J. Wong 238a98ec7cSDarrick J. Wong * - Item 248a98ec7cSDarrick J. Wong - 1KiB 258a98ec7cSDarrick J. Wong - 2KiB 268a98ec7cSDarrick J. Wong - 4KiB 278a98ec7cSDarrick J. Wong - 64KiB 288a98ec7cSDarrick J. Wong * - Blocks 298a98ec7cSDarrick J. Wong - 2^32 308a98ec7cSDarrick J. Wong - 2^32 318a98ec7cSDarrick J. Wong - 2^32 328a98ec7cSDarrick J. Wong - 2^32 338a98ec7cSDarrick J. Wong * - Inodes 348a98ec7cSDarrick J. Wong - 2^32 358a98ec7cSDarrick J. Wong - 2^32 368a98ec7cSDarrick J. Wong - 2^32 378a98ec7cSDarrick J. Wong - 2^32 388a98ec7cSDarrick J. Wong * - File System Size 398a98ec7cSDarrick J. Wong - 4TiB 408a98ec7cSDarrick J. Wong - 8TiB 418a98ec7cSDarrick J. Wong - 16TiB 42*688b0d85Slianzhi chang - 256TiB 438a98ec7cSDarrick J. Wong * - Blocks Per Block Group 448a98ec7cSDarrick J. Wong - 8,192 458a98ec7cSDarrick J. Wong - 16,384 468a98ec7cSDarrick J. Wong - 32,768 478a98ec7cSDarrick J. Wong - 524,288 488a98ec7cSDarrick J. Wong * - Inodes Per Block Group 498a98ec7cSDarrick J. Wong - 8,192 508a98ec7cSDarrick J. Wong - 16,384 518a98ec7cSDarrick J. Wong - 32,768 528a98ec7cSDarrick J. Wong - 524,288 538a98ec7cSDarrick J. Wong * - Block Group Size 548a98ec7cSDarrick J. Wong - 8MiB 558a98ec7cSDarrick J. Wong - 32MiB 568a98ec7cSDarrick J. Wong - 128MiB 578a98ec7cSDarrick J. Wong - 32GiB 588a98ec7cSDarrick J. Wong * - Blocks Per File, Extents 598a98ec7cSDarrick J. Wong - 2^32 608a98ec7cSDarrick J. Wong - 2^32 618a98ec7cSDarrick J. Wong - 2^32 628a98ec7cSDarrick J. Wong - 2^32 638a98ec7cSDarrick J. Wong * - Blocks Per File, Block Maps 648a98ec7cSDarrick J. Wong - 16,843,020 658a98ec7cSDarrick J. Wong - 134,480,396 668a98ec7cSDarrick J. Wong - 1,074,791,436 678a98ec7cSDarrick J. Wong - 4,398,314,962,956 (really 2^32 due to field size limitations) 688a98ec7cSDarrick J. Wong * - File Size, Extents 698a98ec7cSDarrick J. Wong - 4TiB 708a98ec7cSDarrick J. Wong - 8TiB 718a98ec7cSDarrick J. Wong - 16TiB 728a98ec7cSDarrick J. Wong - 256TiB 738a98ec7cSDarrick J. Wong * - File Size, Block Maps 748a98ec7cSDarrick J. Wong - 16GiB 758a98ec7cSDarrick J. Wong - 256GiB 768a98ec7cSDarrick J. Wong - 4TiB 778a98ec7cSDarrick J. Wong - 256TiB 788a98ec7cSDarrick J. Wong 798a98ec7cSDarrick J. WongFor 64-bit filesystems, limits are as follows: 808a98ec7cSDarrick J. Wong 818a98ec7cSDarrick J. Wong.. list-table:: 828a98ec7cSDarrick J. Wong :widths: 1 1 1 1 1 838a98ec7cSDarrick J. Wong :header-rows: 1 848a98ec7cSDarrick J. Wong 858a98ec7cSDarrick J. Wong * - Item 868a98ec7cSDarrick J. Wong - 1KiB 878a98ec7cSDarrick J. Wong - 2KiB 888a98ec7cSDarrick J. Wong - 4KiB 898a98ec7cSDarrick J. Wong - 64KiB 908a98ec7cSDarrick J. Wong * - Blocks 918a98ec7cSDarrick J. Wong - 2^64 928a98ec7cSDarrick J. Wong - 2^64 938a98ec7cSDarrick J. Wong - 2^64 948a98ec7cSDarrick J. Wong - 2^64 958a98ec7cSDarrick J. Wong * - Inodes 968a98ec7cSDarrick J. Wong - 2^32 978a98ec7cSDarrick J. Wong - 2^32 988a98ec7cSDarrick J. Wong - 2^32 998a98ec7cSDarrick J. Wong - 2^32 1008a98ec7cSDarrick J. Wong * - File System Size 1018a98ec7cSDarrick J. Wong - 16ZiB 1028a98ec7cSDarrick J. Wong - 32ZiB 1038a98ec7cSDarrick J. Wong - 64ZiB 1048a98ec7cSDarrick J. Wong - 1YiB 1058a98ec7cSDarrick J. Wong * - Blocks Per Block Group 1068a98ec7cSDarrick J. Wong - 8,192 1078a98ec7cSDarrick J. Wong - 16,384 1088a98ec7cSDarrick J. Wong - 32,768 1098a98ec7cSDarrick J. Wong - 524,288 1108a98ec7cSDarrick J. Wong * - Inodes Per Block Group 1118a98ec7cSDarrick J. Wong - 8,192 1128a98ec7cSDarrick J. Wong - 16,384 1138a98ec7cSDarrick J. Wong - 32,768 1148a98ec7cSDarrick J. Wong - 524,288 1158a98ec7cSDarrick J. Wong * - Block Group Size 1168a98ec7cSDarrick J. Wong - 8MiB 1178a98ec7cSDarrick J. Wong - 32MiB 1188a98ec7cSDarrick J. Wong - 128MiB 1198a98ec7cSDarrick J. Wong - 32GiB 1208a98ec7cSDarrick J. Wong * - Blocks Per File, Extents 1218a98ec7cSDarrick J. Wong - 2^32 1228a98ec7cSDarrick J. Wong - 2^32 1238a98ec7cSDarrick J. Wong - 2^32 1248a98ec7cSDarrick J. Wong - 2^32 1258a98ec7cSDarrick J. Wong * - Blocks Per File, Block Maps 1268a98ec7cSDarrick J. Wong - 16,843,020 1278a98ec7cSDarrick J. Wong - 134,480,396 1288a98ec7cSDarrick J. Wong - 1,074,791,436 1298a98ec7cSDarrick J. Wong - 4,398,314,962,956 (really 2^32 due to field size limitations) 1308a98ec7cSDarrick J. Wong * - File Size, Extents 1318a98ec7cSDarrick J. Wong - 4TiB 1328a98ec7cSDarrick J. Wong - 8TiB 1338a98ec7cSDarrick J. Wong - 16TiB 1348a98ec7cSDarrick J. Wong - 256TiB 1358a98ec7cSDarrick J. Wong * - File Size, Block Maps 1368a98ec7cSDarrick J. Wong - 16GiB 1378a98ec7cSDarrick J. Wong - 256GiB 1388a98ec7cSDarrick J. Wong - 4TiB 1398a98ec7cSDarrick J. Wong - 256TiB 1408a98ec7cSDarrick J. Wong 1418a98ec7cSDarrick J. WongNote: Files not using extents (i.e. files using block maps) must be 1428a98ec7cSDarrick J. Wongplaced within the first 2^32 blocks of a filesystem. Files with extents 1438a98ec7cSDarrick J. Wongmust be placed within the first 2^48 blocks of a filesystem. It's not 1448a98ec7cSDarrick J. Wongclear what happens with larger filesystems. 145