Author: jhb
Date: Wed Mar 11 22:13:12 2009
New Revision: 189709
URL: http://svn.freebsd.org/changeset/base/189709
Log:
MFC: Make cd9660 MPSAFE and able to use shared vnode locks for pathname
lookups. Also, disable operations on character device nodes.
Modified:
stable/7/sys/ (props changed)
stable/7/sys/contrib/pf/ (props changed)
stable/7/sys/dev/ath/ath_hal/ (props changed)
stable/7/sys/dev/cxgb/ (props changed)
stable/7/sys/fs/cd9660/cd9660_lookup.c
stable/7/sys/fs/cd9660/cd9660_node.c
stable/7/sys/fs/cd9660/cd9660_node.h
stable/7/sys/fs/cd9660/cd9660_vfsops.c
stable/7/sys/fs/cd9660/cd9660_vnops.c
Modified: stable/7/sys/fs/cd9660/cd9660_lookup.c
==============================================================================
--- stable/7/sys/fs/cd9660/cd9660_lookup.c Wed Mar 11 22:00:03 2009
(r189708)
+++ stable/7/sys/fs/cd9660/cd9660_lookup.c Wed Mar 11 22:13:12 2009
(r189709)
@@ -94,29 +94,34 @@ cd9660_lookup(ap)
struct iso_node *dp; /* inode for directory being searched */
struct iso_mnt *imp; /* filesystem that directory is in */
struct buf *bp; /* a buffer of directory entries */
- struct iso_directory_record *ep = 0;/* the current directory entry */
+ struct iso_directory_record *ep;/* the current directory entry */
+ struct iso_directory_record *ep2;/* copy of current directory entry */
int entryoffsetinblock; /* offset of ep in bp's buffer */
int saveoffset = 0; /* offset of last directory entry in
dir */
+ doff_t i_diroff; /* cached i_diroff value. */
+ doff_t i_offset; /* cached i_offset value. */
int numdirpasses; /* strategy for directory search */
doff_t endsearch; /* offset to end directory search */
struct vnode *pdp; /* saved dp during symlink work */
struct vnode *tdp; /* returned by cd9660_vget_internal */
u_long bmask; /* block offset mask */
int error;
- ino_t ino = 0, saved_ino;
- int reclen;
+ ino_t ino, i_ino;
+ int ltype, reclen;
u_short namelen;
int isoflags;
char altname[NAME_MAX];
int res;
int assoc, len;
char *name;
+ struct mount *mp;
struct vnode **vpp = ap->a_vpp;
struct componentname *cnp = ap->a_cnp;
int flags = cnp->cn_flags;
int nameiop = cnp->cn_nameiop;
struct thread *td = cnp->cn_thread;
+ ep2 = ep = NULL;
bp = NULL;
*vpp = NULL;
vdp = ap->a_dvp;
@@ -126,9 +131,11 @@ cd9660_lookup(ap)
/*
* We now have a segment name to search for, and a directory to search.
*/
-
+ ino = reclen = 0;
+ i_diroff = dp->i_diroff;
len = cnp->cn_namelen;
name = cnp->cn_nameptr;
+
/*
* A leading `=' means, we are looking for an associated file
*/
@@ -150,15 +157,14 @@ cd9660_lookup(ap)
* of simplicity.
*/
bmask = imp->im_bmask;
- if (nameiop != LOOKUP || dp->i_diroff == 0 ||
- dp->i_diroff > dp->i_size) {
+ if (nameiop != LOOKUP || i_diroff == 0 || i_diroff > dp->i_size) {
entryoffsetinblock = 0;
- dp->i_offset = 0;
+ i_offset = 0;
numdirpasses = 1;
} else {
- dp->i_offset = dp->i_diroff;
- if ((entryoffsetinblock = dp->i_offset & bmask) &&
- (error = cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL,
&bp)))
+ i_offset = i_diroff;
+ if ((entryoffsetinblock = i_offset & bmask) &&
+ (error = cd9660_blkatoff(vdp, (off_t)i_offset, NULL, &bp)))
return (error);
numdirpasses = 2;
nchstats.ncs_2passes++;
@@ -166,17 +172,17 @@ cd9660_lookup(ap)
endsearch = dp->i_size;
searchloop:
- while (dp->i_offset < endsearch) {
+ while (i_offset < endsearch) {
/*
* If offset is on a block boundary,
* read the next directory block.
* Release previous if it exists.
*/
- if ((dp->i_offset & bmask) == 0) {
+ if ((i_offset & bmask) == 0) {
if (bp != NULL)
brelse(bp);
if ((error =
- cd9660_blkatoff(vdp, (off_t)dp->i_offset, NULL,
&bp)) != 0)
+ cd9660_blkatoff(vdp, (off_t)i_offset, NULL, &bp))
!= 0)
return (error);
entryoffsetinblock = 0;
}
@@ -189,8 +195,8 @@ searchloop:
reclen = isonum_711(ep->length);
if (reclen == 0) {
/* skip to next block, if any */
- dp->i_offset =
- (dp->i_offset & ~bmask) + imp->logical_block_size;
+ i_offset =
+ (i_offset & ~bmask) + imp->logical_block_size;
continue;
}
@@ -225,7 +231,7 @@ searchloop:
* Save directory entry's inode
number and
* release directory buffer.
*/
- dp->i_ino = isodirino(ep, imp);
+ i_ino = isodirino(ep, imp);
goto found;
}
if (namelen != 1
@@ -242,7 +248,7 @@ searchloop:
else
ino = dbtob(bp->b_blkno)
+ entryoffsetinblock;
- saveoffset = dp->i_offset;
+ saveoffset = i_offset;
} else if (ino)
goto foundino;
#ifdef NOSORTBUG /* On some CDs directory entries are not sorted
correctly */
@@ -258,22 +264,22 @@ searchloop:
ino = isodirino(ep, imp);
else
ino = dbtob(bp->b_blkno) + entryoffsetinblock;
- dp->i_ino = ino;
- cd9660_rrip_getname(ep,altname,&namelen,&dp->i_ino,imp);
+ i_ino = ino;
+ cd9660_rrip_getname(ep, altname, &namelen, &i_ino, imp);
if (namelen == cnp->cn_namelen
&& !bcmp(name,altname,namelen))
goto found;
ino = 0;
break;
}
- dp->i_offset += reclen;
+ i_offset += reclen;
entryoffsetinblock += reclen;
}
if (ino) {
foundino:
- dp->i_ino = ino;
- if (saveoffset != dp->i_offset) {
- if (lblkno(imp, dp->i_offset) !=
+ i_ino = ino;
+ if (saveoffset != i_offset) {
+ if (lblkno(imp, i_offset) !=
lblkno(imp, saveoffset)) {
if (bp != NULL)
brelse(bp);
@@ -284,7 +290,8 @@ foundino:
entryoffsetinblock = saveoffset & bmask;
ep = (struct iso_directory_record *)
((char *)bp->b_data + entryoffsetinblock);
- dp->i_offset = saveoffset;
+ reclen = isonum_711(ep->length);
+ i_offset = saveoffset;
}
goto found;
}
@@ -295,8 +302,8 @@ notfound:
*/
if (numdirpasses == 2) {
numdirpasses--;
- dp->i_offset = 0;
- endsearch = dp->i_diroff;
+ i_offset = 0;
+ endsearch = i_diroff;
goto searchloop;
}
if (bp != NULL)
@@ -321,10 +328,10 @@ found:
* in the cache as to where the entry was found.
*/
if ((flags & ISLASTCN) && nameiop == LOOKUP)
- dp->i_diroff = dp->i_offset;
+ dp->i_diroff = i_offset;
/*
- * Step through the translation in the name. We do not `iput' the
+ * Step through the translation in the name. We do not `vput' the
* directory because we may need it again if a symbolic link
* is relative to the current directory. Instead we save it
* unlocked as "pdp". We must get the target inode before unlocking
@@ -334,7 +341,7 @@ found:
* when following backward pointers ".." we must unlock the
* parent directory before getting the requested directory.
* There is a potential race condition here if both the current
- * and parent directories are removed before the `iget' for the
+ * and parent directories are removed before the `vget' for the
* inode associated with ".." returns. We hope that this occurs
* infrequently since we cannot avoid this race condition without
* implementing a sophisticated deadlock detection algorithm.
@@ -343,30 +350,75 @@ found:
* that point backwards in the directory structure.
*/
pdp = vdp;
+
/*
- * If ino is different from dp->i_ino,
+ * Make a copy of the directory entry for non "." lookups so
+ * we can drop the buffer before calling vget() to avoid a
+ * lock order reversal between the vnode lock and the buffer
+ * lock.
+ */
+ if (dp->i_number != i_ino) {
+ ep2 = malloc(reclen, M_TEMP, M_WAITOK);
+ bcopy(ep, ep2, reclen);
+ ep = ep2;
+ }
+ brelse(bp);
+
+ /*
+ * If ino is different from i_ino,
* it's a relocated directory.
*/
if (flags & ISDOTDOT) {
- saved_ino = dp->i_ino;
- VOP_UNLOCK(pdp, 0, td); /* race to get the inode */
- error = cd9660_vget_internal(vdp->v_mount, saved_ino,
- LK_EXCLUSIVE, &tdp,
- saved_ino != ino, ep);
- brelse(bp);
- vn_lock(pdp, LK_EXCLUSIVE | LK_RETRY, td);
+ /*
+ * Expanded copy of vn_vget_ino() so that we can use
+ * cd9660_vget_internal().
+ */
+ mp = pdp->v_mount;
+ ltype = VOP_ISLOCKED(pdp, td);
+ for (;;) {
+ error = vfs_busy(mp, LK_NOWAIT, NULL, curthread);
+ if (error == 0)
+ break;
+ VOP_UNLOCK(pdp, 0, td);
+ pause("vn_vget", 1);
+ vn_lock(pdp, ltype | LK_RETRY, td);
+ if (pdp->v_iflag & VI_DOOMED)
+ return (ENOENT);
+ }
+ VOP_UNLOCK(pdp, 0, td);
+ error = cd9660_vget_internal(vdp->v_mount, i_ino,
+ cnp->cn_lkflags, &tdp,
+ i_ino != ino, ep);
+ free(ep2, M_TEMP);
+ vfs_unbusy(mp, td);
+ vn_lock(pdp, ltype | LK_RETRY, td);
+ if (pdp->v_iflag & VI_DOOMED) {
+ if (error == 0)
+ vput(tdp);
+ error = ENOENT;
+ }
if (error)
return (error);
*vpp = tdp;
- } else if (dp->i_number == dp->i_ino) {
- brelse(bp);
+ } else if (dp->i_number == i_ino) {
VREF(vdp); /* we want ourself, ie "." */
+ /*
+ * When we lookup "." we still can be asked to lock it
+ * differently.
+ */
+ ltype = cnp->cn_lkflags & LK_TYPE_MASK;
+ if (ltype != VOP_ISLOCKED(vdp, td)) {
+ if (ltype == LK_EXCLUSIVE)
+ vn_lock(vdp, LK_UPGRADE | LK_RETRY, td);
+ else /* if (ltype == LK_SHARED) */
+ vn_lock(vdp, LK_DOWNGRADE | LK_RETRY, td);
+ }
*vpp = vdp;
} else {
- error = cd9660_vget_internal(vdp->v_mount, dp->i_ino,
- LK_EXCLUSIVE, &tdp,
- dp->i_ino != ino, ep);
- brelse(bp);
+ error = cd9660_vget_internal(vdp->v_mount, i_ino,
+ cnp->cn_lkflags, &tdp,
+ i_ino != ino, ep);
+ free(ep2, M_TEMP);
if (error)
return (error);
*vpp = tdp;
Modified: stable/7/sys/fs/cd9660/cd9660_node.c
==============================================================================
--- stable/7/sys/fs/cd9660/cd9660_node.c Wed Mar 11 22:00:03 2009
(r189708)
+++ stable/7/sys/fs/cd9660/cd9660_node.c Wed Mar 11 22:13:12 2009
(r189709)
@@ -93,7 +93,6 @@ cd9660_reclaim(ap)
} */ *ap;
{
struct vnode *vp = ap->a_vp;
- struct iso_node *ip = VTOI(vp);
if (prtactive && vrefcnt(vp) != 0)
vprint("cd9660_reclaim: pushing active", vp);
@@ -109,8 +108,6 @@ cd9660_reclaim(ap)
/*
* Purge old data structures associated with the inode.
*/
- if (ip->i_mnt->im_devvp)
- vrele(ip->i_mnt->im_devvp);
FREE(vp->v_data, M_ISOFSNODE);
vp->v_data = NULL;
return (0);
Modified: stable/7/sys/fs/cd9660/cd9660_node.h
==============================================================================
--- stable/7/sys/fs/cd9660/cd9660_node.h Wed Mar 11 22:00:03 2009
(r189708)
+++ stable/7/sys/fs/cd9660/cd9660_node.h Wed Mar 11 22:13:12 2009
(r189709)
@@ -65,8 +65,6 @@ struct iso_node {
struct lockf *i_lockf; /* head of byte-level lock list */
doff_t i_endoff; /* end of useful stuff in directory */
doff_t i_diroff; /* offset in dir, where we found last entry */
- doff_t i_offset; /* offset of free space in directory */
- ino_t i_ino; /* inode number of found directory */
long iso_extent; /* extent of file */
unsigned long i_size;
Modified: stable/7/sys/fs/cd9660/cd9660_vfsops.c
==============================================================================
--- stable/7/sys/fs/cd9660/cd9660_vfsops.c Wed Mar 11 22:00:03 2009
(r189708)
+++ stable/7/sys/fs/cd9660/cd9660_vfsops.c Wed Mar 11 22:13:12 2009
(r189709)
@@ -381,6 +381,7 @@ iso_mountfs(devvp, mp, td)
mp->mnt_maxsymlinklen = 0;
MNT_ILOCK(mp);
mp->mnt_flag |= MNT_LOCAL;
+ mp->mnt_kern_flag |= MNTK_MPSAFE | MNTK_LOOKUP_SHARED;
MNT_IUNLOCK(mp);
isomp->im_mountp = mp;
isomp->im_dev = dev;
@@ -556,7 +557,7 @@ cd9660_root(mp, flags, vpp, td)
* With RRIP we must use the `.' entry of the root directory.
* Simply tell vget, that it's a relocated directory.
*/
- return (cd9660_vget_internal(mp, ino, LK_EXCLUSIVE, vpp,
+ return (cd9660_vget_internal(mp, ino, flags, vpp,
imp->iso_ftype == ISO_FTYPE_RRIP, dp));
}
@@ -670,6 +671,22 @@ cd9660_vget_internal(mp, ino, flags, vpp
if (error || *vpp != NULL)
return (error);
+ /*
+ * We must promote to an exclusive lock for vnode creation. This
+ * can happen if lookup is passed LOCKSHARED.
+ */
+ if ((flags & LK_TYPE_MASK) == LK_SHARED) {
+ flags &= ~LK_TYPE_MASK;
+ flags |= LK_EXCLUSIVE;
+ }
+
+ /*
+ * We do not lock vnode creation as it is believed to be too
+ * expensive for such rare case as simultaneous creation of vnode
+ * for same ino by different processes. We just allow them to race
+ * and check later to decide who wins. Let the race begin!
+ */
+
imp = VFSTOISOFS(mp);
dev = imp->im_dev;
@@ -750,7 +767,6 @@ cd9660_vget_internal(mp, ino, flags, vpp
bp = 0;
ip->i_mnt = imp;
- VREF(imp->im_devvp);
if (relocated) {
/*
@@ -808,6 +824,7 @@ cd9660_vget_internal(mp, ino, flags, vpp
vp->v_op = &cd9660_fifoops;
break;
default:
+ vp->v_vnlock->lk_flags &= ~LK_NOSHARE;
break;
}
Modified: stable/7/sys/fs/cd9660/cd9660_vnops.c
==============================================================================
--- stable/7/sys/fs/cd9660/cd9660_vnops.c Wed Mar 11 22:00:03 2009
(r189708)
+++ stable/7/sys/fs/cd9660/cd9660_vnops.c Wed Mar 11 22:13:12 2009
(r189709)
@@ -169,10 +169,14 @@ cd9660_open(ap)
int a_fdidx;
} */ *ap;
{
- struct iso_node *ip = VTOI(ap->a_vp);
+ struct vnode *vp = ap->a_vp;
+ struct iso_node *ip = VTOI(vp);
- vnode_create_vobject(ap->a_vp, ip->i_size, ap->a_td);
- return 0;
+ if (vp->v_type == VCHR || vp->v_type == VBLK)
+ return (EOPNOTSUPP);
+
+ vnode_create_vobject(vp, ip->i_size, ap->a_td);
+ return (0);
}
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