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-rw-r--r--usr/src/uts/common/fs/devfs/devfs_subr.c204
-rw-r--r--usr/src/uts/common/sys/fs/dv_node.h3
2 files changed, 107 insertions, 100 deletions
diff --git a/usr/src/uts/common/fs/devfs/devfs_subr.c b/usr/src/uts/common/fs/devfs/devfs_subr.c
index 7a4ab2bde1..21f31a43b2 100644
--- a/usr/src/uts/common/fs/devfs/devfs_subr.c
+++ b/usr/src/uts/common/fs/devfs/devfs_subr.c
@@ -508,6 +508,38 @@ dv_insert(struct dv_node *ddv, struct dv_node *dv)
}
/*
+ * Unlink a dv_node from a perent directory
+ */
+void
+dv_unlink(struct dv_node *ddv, struct dv_node *dv, struct dv_node **dv_pprev)
+{
+ /* verify linkage of arguments */
+ ASSERT(ddv && dv && dv_pprev);
+ ASSERT(dv->dv_dotdot == ddv);
+ ASSERT(*dv_pprev == dv);
+ ASSERT(RW_WRITE_HELD(&ddv->dv_contents));
+ ASSERT(DVTOV(ddv)->v_type == VDIR);
+
+ dcmn_err3(("dv_unlink: %s\n", dv->dv_name));
+
+ if (DVTOV(dv)->v_type == VDIR) {
+ ddv->dv_nlink--; /* .. to containing directory */
+ dv->dv_nlink -= 2; /* name + . */
+ } else {
+ dv->dv_nlink -= 1; /* name */
+ }
+ ASSERT(ddv->dv_nlink >= 2);
+ ASSERT(dv->dv_nlink == 0);
+
+ /* update ddv->dv_dot/dv_next */
+ *dv_pprev = dv->dv_next;
+
+ dv->dv_dotdot = NULL;
+ dv->dv_next = NULL;
+ dv->dv_dot = NULL;
+}
+
+/*
* Merge devfs node specific information into an attribute structure.
*
* NOTE: specfs provides ATIME,MTIME,CTIME,SIZE,BLKSIZE,NBLOCKS on leaf node.
@@ -1197,124 +1229,101 @@ dv_filldir(struct dv_node *ddv)
int
dv_cleandir(struct dv_node *ddv, char *devnm, uint_t flags)
{
- struct dv_node *dv, *prev = NULL, *next = NULL;
+ struct dv_node *dv;
+ struct dv_node **pprev, **npprev;
struct vnode *vp;
- int retval = 0, set_stale = 0;
+ int busy = 0;
dcmn_err3(("dv_cleandir: %s\n", ddv->dv_name));
- /*
- * If devnm is not NULL, we return immediately on busy.
- * Otherwise, we try our best to destroy all unused dv_node's
- */
- rw_enter(&ddv->dv_contents, RW_WRITER);
- for (dv = ddv->dv_dot; dv; prev = dv, dv = next) {
- int error = 0;
- next = dv->dv_next;
+ if (!(flags & DV_CLEANDIR_LCK))
+ rw_enter(&ddv->dv_contents, RW_WRITER);
+ for (pprev = &ddv->dv_dot, dv = *pprev; dv;
+ pprev = npprev, dv = *pprev) {
+ npprev = &dv->dv_next;
- if (devnm && (strncmp(devnm, dv->dv_name, strlen(devnm)) ||
+ /*
+ * If devnm is specified, the non-minor portion of the
+ * name must match devnm.
+ */
+ if (devnm &&
+ (strncmp(devnm, dv->dv_name, strlen(devnm)) ||
(dv->dv_name[strlen(devnm)] != ':' &&
dv->dv_name[strlen(devnm)] != '\0')))
- /*
- * If devnm is specified, the non-minor
- * portion of the name must match devnm
- */
continue;
+ /* check type of what we are cleaning */
vp = DVTOV(dv);
if (vp->v_type == VDIR) {
- if ((dv_cleandir(dv, NULL, flags) != 0) ||
- (dv->dv_nlink != 2)) {
- error = EBUSY;
- } else if (vp->v_count > 0) {
+ /* recurse on directories */
+ rw_enter(&dv->dv_contents, RW_WRITER);
+ if (dv_cleandir(dv, NULL,
+ flags | DV_CLEANDIR_LCK) == EBUSY) {
+ rw_exit(&dv->dv_contents);
+ goto set_busy;
+ }
+
+ /* A clean directory is an empty directory... */
+ ASSERT(dv->dv_nlink == 2);
+ mutex_enter(&vp->v_lock);
+ if (vp->v_count > 0) {
/*
- * The directory is empty but the directory
- * vnode is being held. If DV_CLEAN_FORCE is
- * specified, we force the directory to become
- * stale so that DR will succeed even if a
- * shell has /devices/xxx as current directory.
+ * ... but an empty directory can still have
+ * references to it. If we have dv_busy or
+ * DV_CLEAN_FORCE is *not* specified then a
+ * referenced directory is considered busy.
*/
- rw_enter(&dv->dv_contents, RW_WRITER);
- if (((flags & DV_CLEAN_FORCE) == 0) ||
- (dv->dv_busy != 0)) {
- error = EBUSY;
+ if (dv->dv_busy || !(flags & DV_CLEAN_FORCE)) {
+ mutex_exit(&vp->v_lock);
rw_exit(&dv->dv_contents);
- } else {
- /*
- * mark the node stale later,
- * after unlinking from tree.
- * Hold the dv_contents lock
- * to prevent further lookup
- * before we mark it stale.
- */
- set_stale = 1;
+ goto set_busy;
}
+
+ /*
+ * Mark referenced directory stale so that DR
+ * will succeed even if a shell has
+ * /devices/xxx as current directory (causing
+ * VN_HOLD reference to an empty directory).
+ */
+ ASSERT(!DV_STALE(dv));
+ ndi_rele_devi(dv->dv_devi);
+ dv->dv_devi = NULL; /* mark DV_STALE */
}
} else {
- ASSERT(vp->v_type == VCHR || vp->v_type == VBLK);
+ ASSERT((vp->v_type == VCHR) || (vp->v_type == VBLK));
+ ASSERT(dv->dv_nlink == 1); /* no hard links */
mutex_enter(&vp->v_lock);
if (vp->v_count > 0) {
- error = EBUSY;
+ mutex_exit(&vp->v_lock);
+ goto set_busy;
}
- mutex_exit(&vp->v_lock);
- }
-
- if (error != 0) {
- retval = error;
- if (devnm)
- break;
- continue;
}
/* unlink from directory */
- if (vp->v_type == VDIR) {
- ddv->dv_nlink--; /* .. to above */
- dv->dv_nlink--; /* . to self */
- }
- if (prev)
- prev->dv_next = dv->dv_next;
- else
- ddv->dv_dot = dv->dv_next;
- dv->dv_next = NULL;
- dv->dv_nlink--; /* name, back to zero */
+ dv_unlink(ddv, dv, pprev);
- if (set_stale) {
- /* only directories can be stale */
- ASSERT(vp->v_type == VDIR);
+ /* drop locks */
+ mutex_exit(&vp->v_lock);
+ if (vp->v_type == VDIR)
+ rw_exit(&dv->dv_contents);
- /*
- * If v_count != 0, someone else has a reference
- * to this node. We mark the node stale and let
- * devfs_inactive() free the node.
- *
- * If v_count is already zero, no one else has
- * a reference to this node, do nothing and
- * dv_destroy() will free the node.
- *
- * We hold the vp->v_lock to synchronize with
- * devfs_inactive() to prevent double free.
- */
- mutex_enter(&vp->v_lock);
- if (vp->v_count != 0) {
- ASSERT(!DV_STALE(dv));
- ndi_rele_devi(dv->dv_devi);
- dv->dv_devi = NULL;
- /* release dv_contents held in set_scale */
- rw_exit(&dv->dv_contents);
- mutex_exit(&vp->v_lock);
- /* don't touch dv after setting it stale */
- } else {
- /* release dv_contents held in set_scale */
- rw_exit(&dv->dv_contents);
- mutex_exit(&vp->v_lock);
- dv_destroy(dv, flags);
- }
- set_stale = 0;
- } else {
+ /* destroy vnode if ref count is zero */
+ if (vp->v_count == 0)
dv_destroy(dv, flags);
- }
- dv = prev; /* reset dv/prev for next loop */
+
+ /* pointer to previous stays unchanged */
+ npprev = pprev;
+ continue;
+
+ /*
+ * If devnm is not NULL we return immediately on busy,
+ * otherwise we continue destroying unused dv_node's.
+ */
+set_busy: busy++;
+ if (devnm)
+ break;
}
+
/*
* This code may be invoked to inform devfs that a new node has
* been created in the kernel device tree. So we always set
@@ -1323,9 +1332,10 @@ dv_cleandir(struct dv_node *ddv, char *devnm, uint_t flags)
*/
ddv->dv_flags |= DV_BUILD;
- rw_exit(&ddv->dv_contents);
+ if (!(flags & DV_CLEANDIR_LCK))
+ rw_exit(&ddv->dv_contents);
- return (retval);
+ return (busy ? EBUSY : 0);
}
/*
@@ -1711,6 +1721,7 @@ dv_walk(
struct vnode *dvp;
struct dv_node *dv;
struct dv_list *head, *tail, *next;
+ int len;
dcmn_err3(("dv_walk: ddv = %s, devnm = %s\n",
ddv->dv_name, devnm ? devnm : "<null>"));
@@ -1721,13 +1732,9 @@ dv_walk(
head = tail = next = NULL;
- mutex_enter(&dvp->v_lock);
-
rw_enter(&ddv->dv_contents, RW_READER);
+ mutex_enter(&dvp->v_lock);
for (dv = ddv->dv_dot; dv; dv = dv->dv_next) {
-
- int len;
-
/*
* If devnm is not NULL and is not the empty string,
* select only dv_nodes with matching non-minor name
@@ -1760,6 +1767,5 @@ dv_walk(
head = next;
}
rw_exit(&ddv->dv_contents);
-
mutex_exit(&dvp->v_lock);
}
diff --git a/usr/src/uts/common/sys/fs/dv_node.h b/usr/src/uts/common/sys/fs/dv_node.h
index 3b1feeacc6..94721eba50 100644
--- a/usr/src/uts/common/sys/fs/dv_node.h
+++ b/usr/src/uts/common/sys/fs/dv_node.h
@@ -20,7 +20,7 @@
* CDDL HEADER END
*/
/*
- * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
+ * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
@@ -105,6 +105,7 @@ typedef struct dv_node {
/* flags for devfs_clean() */
#define DV_CLEAN_FORCE 0x01 /* force clean of refed directories */
#define DV_RESET_PERM 0x02 /* force resetting of node permission */
+#define DV_CLEANDIR_LCK 0x04 /* dv_contents already held */
struct devfs_data {
struct dv_node *devfs_root;
generated by cgit v1.2.3 (git 2.39.1) at 2025-05-28 13:35:24 +0000