Style cleanup for O_DIRECT sysctl comment introduced in nfs_vnops.c:1.242.
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svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=140996
@ -216,14 +216,15 @@ SYSCTL_INT(_vfs_nfs, OID_AUTO, nfs_directio_enable, CTLFLAG_RW,
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&nfs_directio_enable, 0, "Enable NFS directio");
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/*
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* This sysctl allows other processes to mmap a file that has been opened O_DIRECT
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* by a process. In general, having processes mmap the file while Direct IO is in
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* progress can lead to Data Inconsistencies. But, we allow this by default to
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* prevent DoS attacks - to prevent a malicious user from opening up files O_DIRECT
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* preventing other users from mmap'ing these files. "Protected" environments where
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* stricter consistency guarantees are required can disable this knob.
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* The process that opened the file O_DIRECT cannot mmap() the file, because
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* mmap'ed IO on an O_DIRECT open() is not meaningful.
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* This sysctl allows other processes to mmap a file that has been opened
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* O_DIRECT by a process. In general, having processes mmap the file while
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* Direct IO is in progress can lead to Data Inconsistencies. But, we allow
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* this by default to prevent DoS attacks - to prevent a malicious user from
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* opening up files O_DIRECT preventing other users from mmap'ing these
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* files. "Protected" environments where stricter consistency guarantees are
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* required can disable this knob. The process that opened the file O_DIRECT
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* cannot mmap() the file, because mmap'ed IO on an O_DIRECT open() is not
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* meaningful.
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*/
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int nfs_directio_allow_mmap = 1;
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SYSCTL_INT(_vfs_nfs, OID_AUTO, nfs_directio_allow_mmap, CTLFLAG_RW,
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