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Drop the pseudofs vnode lock around call to pfs_read handler. The handler

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may need to lock arbitrary vnodes, causing either lock order reversal or
recursive vnode lock acquisition.

Tested by:	pho
Approved by:	des
MFC after:	2 weeks
This commit is contained in:
kib 2008-12-29 12:12:23 +00:00
parent c3f2d023e8
commit 7599f93972
1 changed files with 18 additions and 15 deletions
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33
sys/fs/pseudofs/pseudofs_vnops.c
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@ -476,7 +476,7 @@ pfs_read(struct vop_read_args *va)
struct uio *uio = va->a_uio;
struct proc *proc;
struct sbuf *sb = NULL;
int error;
int error, locked;
unsigned int buflen, offset, resid;
PFS_TRACE(("%s", pn->pn_name));
@ -502,13 +502,15 @@ pfs_read(struct vop_read_args *va)
PROC_UNLOCK(proc);
}
vhold(vn);
locked = VOP_ISLOCKED(vn);
VOP_UNLOCK(vn, 0);
if (pn->pn_flags & PFS_RAWRD) {
PFS_TRACE(("%lu resid", (unsigned long)uio->uio_resid));
error = pn_fill(curthread, proc, pn, NULL, uio);
PFS_TRACE(("%lu resid", (unsigned long)uio->uio_resid));
if (proc != NULL)
PRELE(proc);
PFS_RETURN (error);
goto ret;
}
/* beaucoup sanity checks so we don't ask for bogus allocation */
@ -518,34 +520,35 @@ pfs_read(struct vop_read_args *va)
(buflen = offset + resid + 1) < offset || buflen > INT_MAX) {
if (proc != NULL)
PRELE(proc);
PFS_RETURN (EINVAL);
error = EINVAL;
goto ret;
}
if (buflen > MAXPHYS + 1) {
if (proc != NULL)
PRELE(proc);
PFS_RETURN (EIO);
error = EIO;
goto ret;
}
sb = sbuf_new(sb, NULL, buflen, 0);
if (sb == NULL) {
if (proc != NULL)
PRELE(proc);
PFS_RETURN (EIO);
error = EIO;
goto ret;
}
error = pn_fill(curthread, proc, pn, sb, uio);
if (proc != NULL)
PRELE(proc);
if (error) {
sbuf_delete(sb);
PFS_RETURN (error);
goto ret;
}
sbuf_finish(sb);
error = uiomove_frombuf(sbuf_data(sb), sbuf_len(sb), uio);
sbuf_delete(sb);
ret:
vn_lock(vn, locked | LK_RETRY);
vdrop(vn);
if (proc != NULL)
PRELE(proc);
PFS_RETURN (error);
}