https://github.com/torvalds/linux
Revision 09bf4f5b6e6013f0ad6b090d4a8deebd4e56d878 authored by Al Viro on 15 June 2017, 04:17:30 UTC, committed by Al Viro on 15 June 2017, 04:41:18 UTC
tail unpacking is done in a wrong place; the deadlocks galore is best dealt with by doing that in ->write_iter() (and switching to iomap, while we are at it), but that's rather painful to backport. The trouble comes from grabbing pages that cover the beginning of tail from inside of ufs_new_fragments(); ongoing pageout of any of those is going to deadlock on ->truncate_mutex with process that got around to extending the tail holding that and waiting for page to get unlocked, while ->writepage() on that page is waiting on ->truncate_mutex. The thing is, we don't need ->truncate_mutex when the fragment we are trying to map is within the tail - the damn thing is allocated (tail can't contain holes). Let's do a plain lookup and if the fragment is present, we can just pretend that we'd won the race in almost all cases. The only exception is a fragment between the end of tail and the end of block containing tail. Protect ->i_lastfrag with ->meta_lock - read_seqlock_excl() is sufficient. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
1 parent 267309f
Tip revision: 09bf4f5b6e6013f0ad6b090d4a8deebd4e56d878 authored by Al Viro on 15 June 2017, 04:17:30 UTC
ufs: avoid grabbing ->truncate_mutex if possible
ufs: avoid grabbing ->truncate_mutex if possible
Tip revision: 09bf4f5
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| basic | ||
| coccinelle | ||
| dtc | ||
| gcc-plugins | ||
| gdb | ||
| genksyms | ||
| kconfig | ||
| ksymoops | ||
| mod | ||
| package | ||
| selinux | ||
| tracing | ||
| .gitignore | -rw-r--r-- | 170 bytes |
| Kbuild.include | -rw-r--r-- | 15.1 KB |
| Lindent | -rwxr-xr-x | 467 bytes |
| Makefile | -rw-r--r-- | 1.8 KB |
| Makefile.asm-generic | -rw-r--r-- | 1.1 KB |
| Makefile.build | -rw-r--r-- | 18.9 KB |
| Makefile.clean | -rw-r--r-- | 2.9 KB |
| Makefile.dtbinst | -rw-r--r-- | 1.1 KB |
| Makefile.extrawarn | -rw-r--r-- | 2.5 KB |
| Makefile.fwinst | -rw-r--r-- | 2.0 KB |
| Makefile.gcc-plugins | -rw-r--r-- | 3.2 KB |
| Makefile.headersinst | -rw-r--r-- | 4.4 KB |
| Makefile.help | -rw-r--r-- | 68 bytes |
| Makefile.host | -rw-r--r-- | 6.8 KB |
| Makefile.kasan | -rw-r--r-- | 1005 bytes |
| Makefile.lib | -rw-r--r-- | 15.6 KB |
| Makefile.modbuiltin | -rw-r--r-- | 1.8 KB |
| Makefile.modinst | -rw-r--r-- | 1.2 KB |
| Makefile.modpost | -rw-r--r-- | 5.5 KB |
| Makefile.modsign | -rw-r--r-- | 1005 bytes |
| Makefile.ubsan | -rw-r--r-- | 1.0 KB |
| adjust_autoksyms.sh | -rwxr-xr-x | 2.8 KB |
| asn1_compiler.c | -rw-r--r-- | 35.5 KB |
| bloat-o-meter | -rwxr-xr-x | 2.2 KB |
| bootgraph.pl | -rwxr-xr-x | 6.3 KB |
| check-lc_ctype.c | -rw-r--r-- | 201 bytes |
| check_00index.sh | -rwxr-xr-x | 1.3 KB |
| check_extable.sh | -rwxr-xr-x | 4.9 KB |
| checkincludes.pl | -rwxr-xr-x | 1.9 KB |
| checkkconfigsymbols.py | -rwxr-xr-x | 15.5 KB |
| checkpatch.pl | -rwxr-xr-x | 185.8 KB |
| checkstack.pl | -rwxr-xr-x | 5.4 KB |
| checksyscalls.sh | -rwxr-xr-x | 5.6 KB |
| checkversion.pl | -rwxr-xr-x | 1.9 KB |
| cleanfile | -rwxr-xr-x | 3.4 KB |
| cleanpatch | -rwxr-xr-x | 5.0 KB |
| coccicheck | -rwxr-xr-x | 7.1 KB |
| config | -rwxr-xr-x | 4.5 KB |
| conmakehash.c | -rw-r--r-- | 6.0 KB |
| const_structs.checkpatch | -rw-r--r-- | 964 bytes |
| decode_stacktrace.sh | -rwxr-xr-x | 3.7 KB |
| decodecode | -rwxr-xr-x | 2.1 KB |
| depmod.sh | -rwxr-xr-x | 1.7 KB |
| diffconfig | -rwxr-xr-x | 3.7 KB |
| docproc.c | -rw-r--r-- | 15.5 KB |
| export_report.pl | -rwxr-xr-x | 4.5 KB |
| extract-cert.c | -rw-r--r-- | 3.5 KB |
| extract-ikconfig | -rwxr-xr-x | 1.7 KB |
| extract-module-sig.pl | -rwxr-xr-x | 3.6 KB |
| extract-sys-certs.pl | -rwxr-xr-x | 3.7 KB |
| extract-vmlinux | -rwxr-xr-x | 1.6 KB |
| extract_xc3028.pl | -rwxr-xr-x | 44.6 KB |
| faddr2line | -rwxr-xr-x | 5.1 KB |
| gcc-goto.sh | -rwxr-xr-x | 495 bytes |
| gcc-ld | -rwxr-xr-x | 676 bytes |
| gcc-plugin.sh | -rwxr-xr-x | 1.0 KB |
| gcc-version.sh | -rwxr-xr-x | 822 bytes |
| gcc-x86_32-has-stack-protector.sh | -rwxr-xr-x | 184 bytes |
| gcc-x86_64-has-stack-protector.sh | -rwxr-xr-x | 209 bytes |
| gen_initramfs_list.sh | -rwxr-xr-x | 7.9 KB |
| get_dvb_firmware | -rwxr-xr-x | 25.2 KB |
| get_maintainer.pl | -rwxr-xr-x | 59.1 KB |
| gfp-translate | -rwxr-xr-x | 1.7 KB |
| headerdep.pl | -rwxr-xr-x | 3.5 KB |
| headers.sh | -rwxr-xr-x | 477 bytes |
| headers_check.pl | -rwxr-xr-x | 3.7 KB |
| headers_install.sh | -rwxr-xr-x | 1.3 KB |
| insert-sys-cert.c | -rw-r--r-- | 8.9 KB |
| kallsyms.c | -rw-r--r-- | 18.7 KB |
| kernel-doc | -rwxr-xr-x | 91.6 KB |
| kernel-doc-xml-ref | -rwxr-xr-x | 4.2 KB |
| ld-version.sh | -rwxr-xr-x | 234 bytes |
| link-vmlinux.sh | -rwxr-xr-x | 7.0 KB |
| makelst | -rwxr-xr-x | 773 bytes |
| markup_oops.pl | -rwxr-xr-x | 8.1 KB |
| mkcompile_h | -rwxr-xr-x | 2.5 KB |
| mkmakefile | -rwxr-xr-x | 1.2 KB |
| mksysmap | -rwxr-xr-x | 1.3 KB |
| mkuboot.sh | -rwxr-xr-x | 379 bytes |
| mkversion | -rw-r--r-- | 74 bytes |
| module-common.lds | -rw-r--r-- | 901 bytes |
| namespace.pl | -rwxr-xr-x | 13.1 KB |
| objdiff | -rwxr-xr-x | 2.8 KB |
| patch-kernel | -rwxr-xr-x | 9.9 KB |
| pnmtologo.c | -rw-r--r-- | 11.9 KB |
| profile2linkerlist.pl | -rwxr-xr-x | 375 bytes |
| prune-kernel | -rwxr-xr-x | 673 bytes |
| recordmcount.c | -rw-r--r-- | 17.2 KB |
| recordmcount.h | -rw-r--r-- | 16.4 KB |
| recordmcount.pl | -rwxr-xr-x | 18.0 KB |
| setlocalversion | -rwxr-xr-x | 3.9 KB |
| show_delta | -rwxr-xr-x | 3.0 KB |
| sign-file.c | -rw-r--r-- | 9.8 KB |
| sortextable.c | -rw-r--r-- | 8.4 KB |
| sortextable.h | -rw-r--r-- | 5.5 KB |
| spelling.txt | -rw-r--r-- | 23.6 KB |
| stackdelta | -rwxr-xr-x | 1.8 KB |
| stackusage | -rwxr-xr-x | 759 bytes |
| tags.sh | -rwxr-xr-x | 9.5 KB |
| unifdef.c | -rw-r--r-- | 34.8 KB |
| ver_linux | -rwxr-xr-x | 2.9 KB |
| xen-hypercalls.sh | -rw-r--r-- | 351 bytes |
| xz_wrap.sh | -rwxr-xr-x | 562 bytes |
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