Differential D45208

vfs_domount_update(): postpone setting MNT_UNION until VFS_MOUNT() is done
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Authored by kib on May 15 2024, 10:01 AM.

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mckusick
markj
olce

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rG21ccdb4119af: vfs_domount_update(): postpone setting MNT_UNION until VFS_MOUNT() is done

Summary

The file system that handles updating the mount point might do lookups
during the update, in which case it could find the flag MNT_UNION set on
the mp while mount point is still not updated.  In particular, the
rootvp->v_mount->mnt_vnodecovered is not yet set.

Delay setting MNT_UNION until the mount is performed.

PR:     265311
Reported by:    Robert Morris <rtm@lcs.mit.edu>

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rG FreeBSD src repository

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Event Timeline

kib created this revision.May 15 2024, 10:01 AM

Herald added subscribers: olce, imp. · View Herald TranscriptMay 15 2024, 10:01 AM

kib requested review of this revision.May 15 2024, 10:01 AM

This looks like the correct fix. One other unrelated nit.

sys/kern/vfs_mount.c
1526	Incorrect <tab> rather than <space> between &= and ~(MNT_UPDATE.

This revision is now accepted and ready to land.May 15 2024, 7:47 PM

olce accepted this revision.May 15 2024, 9:31 PM

Closed by commit rG21ccdb4119af: vfs_domount_update(): postpone setting MNT_UNION until VFS_MOUNT() is done (authored by kib). · Explain WhyMay 16 2024, 1:02 AM

This revision was automatically updated to reflect the committed changes.

kib added a commit: rG21ccdb4119af: vfs_domount_update(): postpone setting MNT_UNION until VFS_MOUNT() is done.

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sys/

kern/

9 lines

Diff 138592

sys/kern/vfs_mount.c

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