path: root/share/mk/bsd.prog.mk
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authorMark Johnston <markj@FreeBSD.org>2020-05-20 18:29:23 +0000
committerMark Johnston <markj@FreeBSD.org>2020-05-20 18:29:23 +0000
commit66b415fb8f9a7bd9f01d063ecebc2c74cfcb10be (patch)
tree40a6d81513612f203242b1f00f646665fe5b25e4 /share/mk/bsd.prog.mk
parent9bf12bb91d729d827ca0dddf6885d4b3e94e07d3 (diff)
Don't block on the range lock in zfs_getpages().
After r358443 the vnode object lock no longer synchronizes concurrent zfs_getpages() and zfs_write() (which must update vnode pages to maintain coherence). This created a potential deadlock between ZFS range locks and VM page busy locks: a fault on a mapped file will cause the fault page to be busied, after which zfs_getpages() locks a range around the file offset in order to map adjacent, resident pages; zfs_write() locks the range first, and then must busy vnode pages when synchronizing. Solve this by adding a non-blocking mode for ZFS range locks, and using it in zfs_getpages(). If zfs_getpages() fails to acquire the range lock, only the fault page will be populated. Reported by: bdrewery Reviewed by: avg Tested by: pho Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D24839
Notes: svn path=/head/; revision=361287
Diffstat (limited to 'share/mk/bsd.prog.mk')
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