- Simplify the cache locking. The lock order relationship with the
vnode lock is much simpler than I originally thought it would be. Now, the cache lock is always acquired before the vnode lock. - Provide some gotos in __getcwd() to simplify the unlocking a bit. - Move Giant acquisition down into __getcwd(). Sponsored By: Isilon Systems, Inc.
This commit is contained in:
Jeff Roberson
parent
41bd6c15f2
commit
799cc2dcee
@ -168,7 +168,7 @@ SYSCTL_OPAQUE(_vfs_cache, OID_AUTO, nchstats, CTLFLAG_RD, &nchstats,
|
||||
|
||||
|
||||
|
||||
static void cache_zap(struct namecache *ncp, int locked);
|
||||
static void cache_zap(struct namecache *ncp);
|
||||
|
||||
static MALLOC_DEFINE(M_VFSCACHE, "vfscache", "VFS name cache entries");
|
||||
|
||||
@ -263,15 +263,13 @@ SYSCTL_PROC(_debug_hashstat, OID_AUTO, nchash, CTLTYPE_INT|CTLFLAG_RD,
|
||||
* pointer to a vnode or if it is just a negative cache entry.
|
||||
*/
|
||||
static void
|
||||
cache_zap(ncp, locked)
|
||||
cache_zap(ncp)
|
||||
struct namecache *ncp;
|
||||
int locked;
|
||||
{
|
||||
struct vnode *vp;
|
||||
|
||||
mtx_assert(&cache_lock, MA_OWNED);
|
||||
vp = NULL;
|
||||
if (!locked)
|
||||
CACHE_LOCK();
|
||||
LIST_REMOVE(ncp, nc_hash);
|
||||
LIST_REMOVE(ncp, nc_src);
|
||||
if (LIST_EMPTY(&ncp->nc_dvp->v_cache_src)) {
|
||||
@ -285,12 +283,9 @@ cache_zap(ncp, locked)
|
||||
numneg--;
|
||||
}
|
||||
numcache--;
|
||||
CACHE_UNLOCK();
|
||||
cache_free(ncp);
|
||||
if (vp)
|
||||
vdrop(vp);
|
||||
if (locked)
|
||||
CACHE_LOCK();
|
||||
}
|
||||
|
||||
/*
|
||||
@ -398,8 +393,8 @@ cache_lookup(dvp, vpp, cnp)
|
||||
if ((cnp->cn_flags & MAKEENTRY) == 0) {
|
||||
numposzaps++;
|
||||
nchstats.ncs_badhits++;
|
||||
cache_zap(ncp);
|
||||
CACHE_UNLOCK();
|
||||
cache_zap(ncp, 0);
|
||||
return (0);
|
||||
}
|
||||
|
||||
@ -416,8 +411,8 @@ cache_lookup(dvp, vpp, cnp)
|
||||
if (cnp->cn_nameiop == CREATE) {
|
||||
numnegzaps++;
|
||||
nchstats.ncs_badhits++;
|
||||
cache_zap(ncp);
|
||||
CACHE_UNLOCK();
|
||||
cache_zap(ncp, 0);
|
||||
return (0);
|
||||
}
|
||||
|
||||
@ -517,11 +512,11 @@ cache_enter(dvp, vp, cnp)
|
||||
ncp = TAILQ_FIRST(&ncneg);
|
||||
zap = 1;
|
||||
}
|
||||
CACHE_UNLOCK();
|
||||
if (hold)
|
||||
vhold(dvp);
|
||||
if (zap)
|
||||
cache_zap(ncp, 0);
|
||||
cache_zap(ncp);
|
||||
CACHE_UNLOCK();
|
||||
}
|
||||
|
||||
/*
|
||||
@ -571,9 +566,9 @@ cache_purge(vp)
|
||||
|
||||
CACHE_LOCK();
|
||||
while (!LIST_EMPTY(&vp->v_cache_src))
|
||||
cache_zap(LIST_FIRST(&vp->v_cache_src), 1);
|
||||
cache_zap(LIST_FIRST(&vp->v_cache_src));
|
||||
while (!TAILQ_EMPTY(&vp->v_cache_dst))
|
||||
cache_zap(TAILQ_FIRST(&vp->v_cache_dst), 1);
|
||||
cache_zap(TAILQ_FIRST(&vp->v_cache_dst));
|
||||
|
||||
do
|
||||
nextid++;
|
||||
@ -612,9 +607,9 @@ cache_purgevfs(mp)
|
||||
}
|
||||
}
|
||||
}
|
||||
CACHE_UNLOCK();
|
||||
while (!LIST_EMPTY(&mplist))
|
||||
cache_zap(LIST_FIRST(&mplist), 0);
|
||||
cache_zap(LIST_FIRST(&mplist));
|
||||
CACHE_UNLOCK();
|
||||
}
|
||||
|
||||
/*
|
||||
@ -819,6 +814,7 @@ kern___getcwd(struct thread *td, u_char *buf, enum uio_seg bufseg, u_int buflen)
|
||||
return (EINVAL);
|
||||
if (buflen > MAXPATHLEN)
|
||||
buflen = MAXPATHLEN;
|
||||
mtx_lock(&Giant);
|
||||
error = 0;
|
||||
tmpbuf = bp = malloc(buflen, M_TEMP, M_WAITOK);
|
||||
bp += buflen - 1;
|
||||
@ -829,66 +825,61 @@ kern___getcwd(struct thread *td, u_char *buf, enum uio_seg bufseg, u_int buflen)
|
||||
for (vp = fdp->fd_cdir; vp != fdp->fd_rdir && vp != rootvnode;) {
|
||||
if (vp->v_vflag & VV_ROOT) {
|
||||
if (vp->v_mount == NULL) { /* forced unmount */
|
||||
FILEDESC_UNLOCK(fdp);
|
||||
free(tmpbuf, M_TEMP);
|
||||
return (EBADF);
|
||||
error = EBADF;
|
||||
goto out;
|
||||
}
|
||||
vp = vp->v_mount->mnt_vnodecovered;
|
||||
continue;
|
||||
}
|
||||
if (vp->v_dd->v_id != vp->v_ddid) {
|
||||
FILEDESC_UNLOCK(fdp);
|
||||
numcwdfail1++;
|
||||
free(tmpbuf, M_TEMP);
|
||||
return (ENOTDIR);
|
||||
error = ENOTDIR;
|
||||
goto out;
|
||||
}
|
||||
CACHE_LOCK();
|
||||
ncp = TAILQ_FIRST(&vp->v_cache_dst);
|
||||
if (!ncp) {
|
||||
numcwdfail2++;
|
||||
CACHE_UNLOCK();
|
||||
FILEDESC_UNLOCK(fdp);
|
||||
free(tmpbuf, M_TEMP);
|
||||
return (ENOENT);
|
||||
error = ENOENT;
|
||||
goto out;
|
||||
}
|
||||
if (ncp->nc_dvp != vp->v_dd) {
|
||||
numcwdfail3++;
|
||||
CACHE_UNLOCK();
|
||||
FILEDESC_UNLOCK(fdp);
|
||||
free(tmpbuf, M_TEMP);
|
||||
return (EBADF);
|
||||
error = EBADF;
|
||||
goto out;
|
||||
}
|
||||
for (i = ncp->nc_nlen - 1; i >= 0; i--) {
|
||||
if (bp == tmpbuf) {
|
||||
numcwdfail4++;
|
||||
CACHE_UNLOCK();
|
||||
FILEDESC_UNLOCK(fdp);
|
||||
free(tmpbuf, M_TEMP);
|
||||
return (ENOMEM);
|
||||
error = ENOMEM;
|
||||
goto out;
|
||||
}
|
||||
*--bp = ncp->nc_name[i];
|
||||
}
|
||||
if (bp == tmpbuf) {
|
||||
numcwdfail4++;
|
||||
CACHE_UNLOCK();
|
||||
FILEDESC_UNLOCK(fdp);
|
||||
free(tmpbuf, M_TEMP);
|
||||
return (ENOMEM);
|
||||
error = ENOMEM;
|
||||
goto out;
|
||||
}
|
||||
*--bp = '/';
|
||||
slash_prefixed = 1;
|
||||
vp = vp->v_dd;
|
||||
CACHE_UNLOCK();
|
||||
}
|
||||
FILEDESC_UNLOCK(fdp);
|
||||
if (!slash_prefixed) {
|
||||
if (bp == tmpbuf) {
|
||||
numcwdfail4++;
|
||||
free(tmpbuf, M_TEMP);
|
||||
return (ENOMEM);
|
||||
error = ENOMEM;
|
||||
goto out;
|
||||
}
|
||||
*--bp = '/';
|
||||
}
|
||||
FILEDESC_UNLOCK(fdp);
|
||||
mtx_unlock(&Giant);
|
||||
numcwdfound++;
|
||||
if (bufseg == UIO_SYSSPACE)
|
||||
bcopy(bp, buf, strlen(bp) + 1);
|
||||
@ -896,6 +887,11 @@ kern___getcwd(struct thread *td, u_char *buf, enum uio_seg bufseg, u_int buflen)
|
||||
error = copyout(bp, buf, strlen(bp) + 1);
|
||||
free(tmpbuf, M_TEMP);
|
||||
return (error);
|
||||
out:
|
||||
FILEDESC_UNLOCK(fdp);
|
||||
mtx_unlock(&Giant);
|
||||
free(tmpbuf, M_TEMP);
|
||||
return (error);
|
||||
}
|
||||
|
||||
/*
|
||||
|
||||
Loading…
Reference in New Issue
Block a user