Kirk McKusick bc218d8920 Two bug fixes to UFS/FFS superblock integrity checks when reading a superblock. ... Two bugs have been reported with the UFS/FFS superblock integrity checks that were added in commit 076002f24d. The code checked that fs_sblockactualloc was properly set to the location of the superblock. The fs_sblockactualloc field was an addition to the superblock in commit dffce2150e on Jan 26 2018 and used a field that was zero in filesystems created before it was added. The integrity check had to be expanded to accept the fs_sblockactualloc field being zero so as not to reject filesystems created before Jan 26 2018. The integrity check set an upper bound on the value of fs_maxcontig based on the maximum transfer size supported by the kernel. It required that fs->fs_maxcontig <= maxphys / fs->fs_bsize. The kernel variable maxphys defines the maximum transfer size permitted by the controllers and/or buffering. The fs_maxcontig parameter controls the maximum number of blocks that the filesystem will read or write in a single transfer. It is calculated when the filesystem is created as maxphys / fs_bsize. The bug appeared in the loader because it uses a maxphys of 128K even when running on a system that supports larger values. If the filesystem was built on a system that supports a larger maxphys (1M is typical) it will have configured fs_maxcontig for that larger system so would fail the test when run with the smaller maxphys used by the loader. So we bound the upper allowable limit for fs_maxconfig to be able to at least work with a 1M maxphys on the smallest block size filesystem: 1M / 4096 == 256. We then use the limit for fs_maxcontig as fs_maxcontig <= MAX(256, maxphys / fs_bsize). There is no harm in allowing the mounting of filesystems that make larger than maxphys I/O requests because those (mostly 32-bit machines) can (very slowly) handle I/O requests that exceed maxphys. Thanks to everyone who helped sort out the problems and the fixes. Reported by: Cy Schubert, David Wolfskill Diagnosis by: Mark Johnston, John Baldwin Reviewed by: Warner Losh Tested by: Cy Schubert, David Wolfskill MFC after: 1 month (with 076002f24d) Differential Revision: https://reviews.freebsd.org/D35219		2022-05-31 19:58:37 -07:00
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ffs	Two bug fixes to UFS/FFS superblock integrity checks when reading a superblock.	2022-05-31 19:58:37 -07:00
ufs	ufs/acl.h: forward-declare struct inode	2022-04-10 00:43:53 +03:00