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- Fix an unlocked call to GETATTR by slightly shuffling the code in

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ffs_snapshot() around.
 - Acquire the interlock before releasing the mntvnode_mtx.  Use the
   interlock to protect v_usecount access.
This commit is contained in:
Jeff Roberson 2003-10-04 14:25:45 +00:00
parent f3c625e47a
commit 934914d2ef
1 changed files with 14 additions and 6 deletions
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20
sys/ufs/ffs/ffs_snapshot.c
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@ -415,22 +415,30 @@ ffs_snapshot(mp, snapfile)
if (xvp->v_mount != mp)
goto loop;
nvp = TAILQ_NEXT(xvp, v_nmntvnodes);
VI_LOCK(xvp);
mtx_unlock(&mntvnode_mtx);
mp_fixme("Unlocked GETATTR.");
if (vrefcnt(xvp) == 0 || xvp->v_type == VNON ||
(VTOI(xvp)->i_flags & SF_SNAPSHOT) ||
(VOP_GETATTR(xvp, &vat, td->td_ucred, td) == 0 &&
vat.va_nlink > 0)) {
if (xvp->v_usecount == 0 || xvp->v_type == VNON ||
(VTOI(xvp)->i_flags & SF_SNAPSHOT)) {
VI_UNLOCK(xvp);
mtx_lock(&mntvnode_mtx);
continue;
}
if (snapdebug)
vprint("ffs_snapshot: busy vnode", xvp);
if (vn_lock(xvp, LK_EXCLUSIVE, td) != 0)
if (vn_lock(xvp, LK_EXCLUSIVE | LK_INTERLOCK, td) != 0) {
mtx_lock(&mntvnode_mtx);
goto loop;
}
if (VOP_GETATTR(xvp, &vat, td->td_ucred, td) == 0 &&
vat.va_nlink > 0) {
VOP_UNLOCK(xvp, 0, td);
mtx_lock(&mntvnode_mtx);
continue;
}
xp = VTOI(xvp);
if (ffs_checkfreefile(copy_fs, vp, xp->i_number)) {
VOP_UNLOCK(xvp, 0, td);
mtx_lock(&mntvnode_mtx);
continue;
}
/*