|| ||Andrea Arcangeli <firstname.lastname@example.org>|
|| ||Thu, 18 Jul 2002 00:55:04 +0200|
I would appreciate any feedback on the last patches for the i_size
atomic accesses on 32bit archs. Thanks,
diff between 2.4.19rc1aa2 and 2.4.19rc1aa2:
Only in 2.4.19rc1aa2: 000_e100-2.0.30-k1.gz
Only in 2.4.19rc2aa1: 000_e100-2.1.6.gz
Only in 2.4.19rc1aa2: 000_e1000-4.2.17-k1.gz
Only in 2.4.19rc2aa1: 000_e1000-4.3.2.gz
Upgrade to latest drivers to see if they fix the reports.
Only in 2.4.19rc1aa2: 00_free_pgtable-and-p4-tlb-race-fixes-1
Merged into mainline.
Only in 2.4.19rc1aa2: 00_nfs-bkl-2
Only in 2.4.19rc2aa1: 00_nfs-bkl-3
Only in 2.4.19rc1aa2: 00_rwsem-fair-29
Only in 2.4.19rc1aa2: 00_rwsem-fair-29-recursive-8
Only in 2.4.19rc2aa1: 00_rwsem-fair-30
Only in 2.4.19rc2aa1: 00_rwsem-fair-30-recursive-8
Only in 2.4.19rc1aa2: 00_sched-O1-rml-2.4.19-pre9-1.gz
Only in 2.4.19rc2aa1: 00_sched-O1-rml-2.4.19-pre9-2.gz
Only in 2.4.19rc2aa1: 10_rawio-vary-io-10
Only in 2.4.19rc1aa2: 10_rawio-vary-io-9
Only in 2.4.19rc1aa2: 70_xfs-1.1-3.gz
Only in 2.4.19rc2aa1: 70_xfs-1.1-4.gz
Only in 2.4.19rc1aa2: 90_init-survive-threaded-race-4
Only in 2.4.19rc2aa1: 90_init-survive-threaded-race-5
Only in 2.4.19rc1aa2: 91_zone_start_pfn-5
Only in 2.4.19rc2aa1: 91_zone_start_pfn-6
Only in 2.4.19rc1aa2: 20_pte-highmem-25
Only in 2.4.19rc2aa1: 20_pte-highmem-26
Only in 2.4.19rc1aa2: 00_readv-writev-1
Go in sync with mainline (alpha has some change now).
Only in 2.4.19rc2aa1: 00_set_64bit-atomic-1
I noticed set_64bit wasn't atomic due the lack of lock prefix. This
fixes the problem to be sure the cpu sees coherent values while
Only in 2.4.19rc1aa2: 00_setfl-race-fix-1
Only in 2.4.19rc2aa1: 00_setfl-race-fix-2
Merge ioctl part of the new ->fasync locking from Marcus Alanen.
BTW, it looks fasync callback can also be recalled w/o the
big kernel lock, the fasync_helper seems thread safe, but
I preferred not to risk in 2.4 in case some driver is relying on the
big kernel lock somehow.
Only in 2.4.19rc1aa2: 00_shm_destroy-deadlock-1
Only in 2.4.19rc2aa1: 00_shm_destroy-deadlock-2
Mainline changes shm_tot inside the shmid lock, which isn't
needed, the semaphore serializes the shm_tot instead.
Only in 2.4.19rc2aa1: 00_sock_fasync-memleak-1
Fix memleak if sock lookup fails, from Robert Love.
Only in 2.4.19rc2aa1: 00_wait_kio-cleanup-1
Drop pointless buffer_locked check, wait_on_buffer does
it internally (noticed by Jens).
Only in 2.4.19rc1aa2: 07_qlogicfc-1.gz
Only in 2.4.19rc2aa1: 07_qlogicfc-2.gz
Only in 2.4.19rc1aa2: 08_qlogicfc-template-aa-1
Only in 2.4.19rc2aa1: 08_qlogicfc-template-aa-2
Only in 2.4.19rc1aa2: 09_qlogic-link-1
Only in 2.4.19rc2aa1: 09_qlogic-link-2
Upgrade to 6.1b2 driver.
Only in 2.4.19rc2aa1: 50_uml-patch-2.4.18-40
New uml updates from Jeff (36->40).
Only in 2.4.19rc2aa1: 76_xfs-64bit-1
Only in 2.4.19rc1aa2: 80_x86_64-common-code-4
Only in 2.4.19rc2aa1: 80_x86_64-common-code-5
Only in 2.4.19rc2aa1: 81_x86_64-arch-2.4.19rc1-1.gz
Only in 2.4.19rc1aa2: 81_x86_64-arch-6.gz
Only in 2.4.19rc1aa2: 82_x86-64-compile-aa-6
Only in 2.4.19rc1aa2: 82_x86-64-pte-highmem-2
Only in 2.4.19rc2aa1: 82_x86_64-suse-2
Only in 2.4.19rc2aa1: 83_x86_64-cvs-020716-1
Only in 2.4.19rc1aa2: 83_x86_64-setup64-compile-1
Only in 2.4.19rc2aa1: 84_x86-64-mtrr-compile-1
Only in 2.4.19rc1aa2: 84_x86_64-io-compile-1
Only in 2.4.19rc1aa2: 85_x86_64-mmx-xmm-init-4
Only in 2.4.19rc1aa2: 86_x86_64-FIOQSIZE-1
Only in 2.4.19rc2aa1: 87_x86_64-o1sched-1
Only in 2.4.19rc2aa1: 88_x86_64-poll-1
Synchronize with CVS, code from SuSE Labs.
Only in 2.4.19rc2aa1: 90_proc-mapped-base-1
Allow the tasks to choose the start of the heap using
Only in 2.4.19rc1aa2: 94_numaq-tsc-3
Only in 2.4.19rc2aa1: 94_numaq-tsc-4
Don't disable the tsc feature anymore, unless the user
specifys notsc, the user needs to specify notsc anyways to be sure to
get a failure if userspace tries to read the tsc.
Only in 2.4.19rc2aa1: 95_fsync-corruption-fix-2
Do all the fsync in two passes, and avoid rolling the bh in the inode
list every time we write to it.
Only in 2.4.19rc2aa1: 96_inode_read_write-atomic-1
Only in 2.4.19rc2aa1: 97_i_size-corruption-fixes-1
While checking for another potential race, I found this race between
i_size writers and i_size readers. The i_size readers aren't taking
the i_sem, so they can read the i_size while only the upper 32bit
are updated, so any update of the i_size that changes both the high
32bits and low 32bits of the 64bit i_size, may lead the reader of the
i_size to get out of bounds results (the reader is also write page
that will go and ask the fs to allocate indirect blocks at weird
offsets behind the end of the i_size). This race can happen with SMP
only for example while growing the file size over 4G. Only the readers
inside the i_sem doesn't risk to get random i_size values. The patch
fixes this incrementally, by implementing two methods (i_size_read,
i_size_write) that ensure the lockless readers to get coherent i_size
values. The rules are: 1) i_size_write must be used for all i_size
updates (at least when there can be potential parallel readers outside
the i_sem), 2) i_size_read must be used for all lockless reads when
an i_size change can happen from under us.
The i_size_read/write on x86 are implemented with read_64bit and
set_64bit (see also the above fix to make set_64bit atomic
which should be needed also for the PAE pgd). The only idea
I had for read_64bit on x86 is been to use chmxchg8b for it too,
with the exchange values matching the compare values read off the
pointer. I think it should work fine, but I would appreciate if anybody
could check it or suggest any better way to do it. And now I also
realized this kernel will segfault on a 486/386 (cmpxchg8b appeared on
the pentium first), I will fix it tomorrow (not very high prio to fix
it) with a spinlock if the kernel is compiled for 386/486, scalability
of 486/386 SMP doesn't matter much :) In the meantime I'd appreciate
any feedback on this bugfix, thanks.
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