Add a pn_destroy field to pfs_node. This field points to a destructor

function which is called from pfs_destroy() before the node is reclaimed.

Modify pfs_create_{dir,file,link}() to accept a pointer to a destructor
function in addition to the usual attr / fill / vis pointers.

This breaks both the programming and binary interfaces between pseudofs
and its consumers.  It is believed that there are no pseudofs consumers
outside the source tree, so that the impact of this change is minimal.

Submitted by:	Aniruddha Bohra <bohra@cs.rutgers.edu>

5 files changed, 89 insertions, 67 deletions

diff --git a/sys/compat/linprocfs/linprocfs.c b/sys/compat/linprocfs/linprocfs.c
index f1640deba722..318689f57651 100644
--- a/sys/compat/linprocfs/linprocfs.c
+++ b/sys/compat/linprocfs/linprocfs.c
@@ -1172,83 +1172,83 @@ linprocfs_init(PFS_INIT_ARGS)
 
 	/* /proc/... */
 	pfs_create_file(root, "cmdline", &linprocfs_docmdline,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(root, "cpuinfo", &linprocfs_docpuinfo,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(root, "devices", &linprocfs_dodevices,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(root, "loadavg", &linprocfs_doloadavg,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(root, "meminfo", &linprocfs_domeminfo,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 #if 0
 	pfs_create_file(root, "modules", &linprocfs_domodules,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 #endif
 	pfs_create_file(root, "mounts", &linprocfs_domtab,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(root, "mtab", &linprocfs_domtab,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_link(root, "self", &procfs_docurproc,
-	    NULL, NULL, 0);
+	    NULL, NULL, NULL, 0);
 	pfs_create_file(root, "stat", &linprocfs_dostat,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(root, "uptime", &linprocfs_douptime,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(root, "version", &linprocfs_doversion,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 
 	/* /proc/net/... */
-	dir = pfs_create_dir(root, "net", NULL, NULL, 0);
+	dir = pfs_create_dir(root, "net", NULL, NULL, NULL, 0);
 	pfs_create_file(dir, "dev", &linprocfs_donetdev,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 
 	/* /proc/<pid>/... */
-	dir = pfs_create_dir(root, "pid", NULL, NULL, PFS_PROCDEP);
+	dir = pfs_create_dir(root, "pid", NULL, NULL, NULL, PFS_PROCDEP);
 	pfs_create_file(dir, "cmdline", &linprocfs_doproccmdline,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_link(dir, "cwd", &linprocfs_doproccwd,
-	    NULL, NULL, 0);
+	    NULL, NULL, NULL, 0);
 	pfs_create_file(dir, "environ", &linprocfs_doprocenviron,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_link(dir, "exe", &procfs_doprocfile,
-	    NULL, &procfs_notsystem, 0);
+	    NULL, &procfs_notsystem, NULL, 0);
 	pfs_create_file(dir, "maps", &linprocfs_doprocmaps,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(dir, "mem", &procfs_doprocmem,
-	    &procfs_attr, &procfs_candebug, PFS_RDWR|PFS_RAW);
+	    &procfs_attr, &procfs_candebug, NULL, PFS_RDWR|PFS_RAW);
 	pfs_create_link(dir, "root", &linprocfs_doprocroot,
-	    NULL, NULL, 0);
+	    NULL, NULL, NULL, 0);
 	pfs_create_file(dir, "stat", &linprocfs_doprocstat,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(dir, "statm", &linprocfs_doprocstatm,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(dir, "status", &linprocfs_doprocstatus,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 
 	/* /proc/scsi/... */
-	dir = pfs_create_dir(root, "scsi", NULL, NULL, 0);
+	dir = pfs_create_dir(root, "scsi", NULL, NULL, NULL, 0);
 	pfs_create_file(dir, "device_info", &linprocfs_doscsidevinfo,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(dir, "scsi", &linprocfs_doscsiscsi,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 
 	/* /proc/sys/... */
-	dir = pfs_create_dir(root, "sys", NULL, NULL, 0);
+	dir = pfs_create_dir(root, "sys", NULL, NULL, NULL, 0);
 	/* /proc/sys/kernel/... */
-	dir = pfs_create_dir(dir, "kernel", NULL, NULL, 0);
+	dir = pfs_create_dir(dir, "kernel", NULL, NULL, NULL, 0);
 	pfs_create_file(dir, "osrelease", &linprocfs_doosrelease,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(dir, "ostype", &linprocfs_doostype,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(dir, "version", &linprocfs_doosbuild,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(dir, "msgmni", &linprocfs_domsgmni,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(dir, "pid_max", &linprocfs_dopid_max,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(dir, "sem", &linprocfs_dosem,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 
 	return (0);
 }
diff --git a/sys/compat/linsysfs/linsysfs.c b/sys/compat/linsysfs/linsysfs.c
index cce49f795771..2247d29b73f7 100644
--- a/sys/compat/linsysfs/linsysfs.c
+++ b/sys/compat/linsysfs/linsysfs.c
@@ -175,7 +175,7 @@ linsysfs_run_bus(device_t dev, struct pfs_node *dir, struct pfs_node *scsi, char
 				strcat(new_path, "/");
 				strcat(new_path, device);
 				dir = pfs_create_dir(dir, device,
-				    NULL, NULL, 0);
+				    NULL, NULL, NULL, 0);
 
 				if (dinfo->cfg.baseclass == PCIC_STORAGE) {
 					/* DJA only make this if needed */
@@ -183,7 +183,7 @@ linsysfs_run_bus(device_t dev, struct pfs_node *dir, struct pfs_node *scsi, char
 					strcat(new_path, "/");
 					strcat(new_path, host);
 					sub_dir = pfs_create_dir(dir,
-					    host, NULL, NULL, 0);
+					    host, NULL, NULL, NULL, 0);
 					scsi_host = malloc(sizeof(
 					    struct scsi_host_queue),
 					    M_DEVBUF, M_NOWAIT);
@@ -196,13 +196,13 @@ linsysfs_run_bus(device_t dev, struct pfs_node *dir, struct pfs_node *scsi, char
 					scsi_host->name = "unknown";
 
 					sub_dir = pfs_create_dir(scsi, host,
-					    NULL, NULL, 0);
+					    NULL, NULL, NULL, 0);
 					pfs_create_link(sub_dir, "device",
 					    &linsysfs_link_scsi_host,
-					    NULL, NULL, 0);
+					    NULL, NULL, NULL, 0);
 					pfs_create_file(sub_dir, "proc_name",
 					    &linsysfs_scsiname,
-					    NULL, NULL, PFS_RD);
+					    NULL, NULL, NULL, PFS_RD);
 					scsi_host->name
 					    = linux_driver_get_name_dev(dev);
 					TAILQ_INSERT_TAIL(&scsi_host_q,
@@ -243,14 +243,14 @@ linsysfs_init(PFS_INIT_ARGS)
 	root = pi->pi_root;
 
 	/* /sys/class/... */
-	scsi = pfs_create_dir(root, "class", NULL, NULL, 0);
-	scsi = pfs_create_dir(scsi, "scsi_host", NULL, NULL, 0);
+	scsi = pfs_create_dir(root, "class", NULL, NULL, NULL, 0);
+	scsi = pfs_create_dir(scsi, "scsi_host", NULL, NULL, NULL, 0);
 
 	/* /sys/device */
-	dir = pfs_create_dir(root, "devices", NULL, NULL, 0);
+	dir = pfs_create_dir(root, "devices", NULL, NULL, NULL, 0);
 
 	/* /sys/device/pci0000:00 */
-	pci = pfs_create_dir(dir, "pci0000:00", NULL, NULL, 0);
+	pci = pfs_create_dir(dir, "pci0000:00", NULL, NULL, NULL, 0);
 
 	devclass = devclass_find("root");
 	if (devclass == NULL) {
diff --git a/sys/fs/procfs/procfs.c b/sys/fs/procfs/procfs.c
index d311a98a527e..56bc0cc03751 100644
--- a/sys/fs/procfs/procfs.c
+++ b/sys/fs/procfs/procfs.c
@@ -160,39 +160,39 @@ procfs_init(PFS_INIT_ARGS)
 	root = pi->pi_root;
 
 	pfs_create_link(root, "curproc", procfs_docurproc,
-	    NULL, NULL, 0);
+	    NULL, NULL, NULL, 0);
 
 	dir = pfs_create_dir(root, "pid",
-	    procfs_attr, NULL, PFS_PROCDEP);
+	    procfs_attr, NULL, NULL, PFS_PROCDEP);
 	pfs_create_file(dir, "cmdline", procfs_doproccmdline,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(dir, "ctl", procfs_doprocctl,
-	    procfs_attr, NULL, PFS_WR);
+	    procfs_attr, NULL, NULL, PFS_WR);
 	pfs_create_file(dir, "dbregs", procfs_doprocdbregs,
-	    procfs_attr, procfs_candebug, PFS_RDWR|PFS_RAW);
+	    procfs_attr, procfs_candebug, NULL, PFS_RDWR|PFS_RAW);
 	pfs_create_file(dir, "etype", procfs_doproctype,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(dir, "fpregs", procfs_doprocfpregs,
-	    procfs_attr, procfs_candebug, PFS_RDWR|PFS_RAW);
+	    procfs_attr, procfs_candebug, NULL, PFS_RDWR|PFS_RAW);
 	pfs_create_file(dir, "map", procfs_doprocmap,
-	    NULL, procfs_notsystem, PFS_RD);
+	    NULL, procfs_notsystem, NULL, PFS_RD);
 	node = pfs_create_file(dir, "mem", procfs_doprocmem,
-	    procfs_attr, procfs_candebug, PFS_RDWR|PFS_RAW);
+	    procfs_attr, procfs_candebug, NULL, PFS_RDWR|PFS_RAW);
 	node->pn_ioctl = procfs_ioctl;
 	node->pn_close = procfs_close;
 	pfs_create_file(dir, "note", procfs_doprocnote,
-	    procfs_attr, procfs_candebug, PFS_WR);
+	    procfs_attr, procfs_candebug, NULL, PFS_WR);
 	pfs_create_file(dir, "notepg", procfs_doprocnote,
-	    procfs_attr, procfs_candebug, PFS_WR);
+	    procfs_attr, procfs_candebug, NULL, PFS_WR);
 	pfs_create_file(dir, "regs", procfs_doprocregs,
-	    procfs_attr, procfs_candebug, PFS_RDWR|PFS_RAW);
+	    procfs_attr, procfs_candebug, NULL, PFS_RDWR|PFS_RAW);
 	pfs_create_file(dir, "rlimit", procfs_doprocrlimit,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 	pfs_create_file(dir, "status", procfs_doprocstatus,
-	    NULL, NULL, PFS_RD);
+	    NULL, NULL, NULL, PFS_RD);
 
 	pfs_create_link(dir, "file", procfs_doprocfile,
-	    NULL, procfs_notsystem, 0);
+	    NULL, procfs_notsystem, NULL, 0);
 
 	return (0);
 }
diff --git a/sys/fs/pseudofs/pseudofs.c b/sys/fs/pseudofs/pseudofs.c
index da1758b9303e..42c45bbd4908 100644
--- a/sys/fs/pseudofs/pseudofs.c
+++ b/sys/fs/pseudofs/pseudofs.c
@@ -122,7 +122,8 @@ _pfs_fixup_dir(struct pfs_node *parent)
  */
 struct pfs_node	*
 pfs_create_dir(struct pfs_node *parent, const char *name,
-	       pfs_attr_t attr, pfs_vis_t vis, int flags)
+	       pfs_attr_t attr, pfs_vis_t vis, pfs_destroy_t destroy,
+	       int flags)
 {
 	struct pfs_node *dir;
 
@@ -135,6 +136,7 @@ pfs_create_dir(struct pfs_node *parent, const char *name,
 	dir->pn_type = (flags & PFS_PROCDEP) ? pfstype_procdir : pfstype_dir;
 	dir->pn_attr = attr;
 	dir->pn_vis = vis;
+	dir->pn_destroy = destroy;
 	dir->pn_flags = flags;
 
 	if (_pfs_add_node(parent, dir) != 0) {
@@ -155,7 +157,8 @@ pfs_create_dir(struct pfs_node *parent, const char *name,
  */
 struct pfs_node	*
 pfs_create_file(struct pfs_node *parent, const char *name, pfs_fill_t fill,
-		pfs_attr_t attr, pfs_vis_t vis, int flags)
+		pfs_attr_t attr, pfs_vis_t vis, pfs_destroy_t destroy,
+		int flags)
 {
 	struct pfs_node *node;
 
@@ -169,6 +172,7 @@ pfs_create_file(struct pfs_node *parent, const char *name, pfs_fill_t fill,
 	node->pn_func = fill;
 	node->pn_attr = attr;
 	node->pn_vis = vis;
+	node->pn_destroy = destroy;
 	node->pn_flags = flags;
 
 	if (_pfs_add_node(parent, node) != 0) {
@@ -184,11 +188,12 @@ pfs_create_file(struct pfs_node *parent, const char *name, pfs_fill_t fill,
  */
 struct pfs_node	*
 pfs_create_link(struct pfs_node *parent, const char *name, pfs_fill_t fill,
-		pfs_attr_t attr, pfs_vis_t vis, int flags)
+		pfs_attr_t attr, pfs_vis_t vis, pfs_destroy_t destroy, 
+		int flags)
 {
 	struct pfs_node *node;
 
-	node = pfs_create_file(parent, name, fill, attr, vis, flags);
+	node = pfs_create_file(parent, name, fill, attr, vis, destroy, flags);
 	if (node == NULL)
 		return (NULL);
 	node->pn_type = pfstype_symlink;
@@ -249,6 +254,10 @@ pfs_destroy(struct pfs_node *node)
 		mtx_unlock(&node->pn_info->pi_mutex);
 	}
 
+	/* callback to free any private resources */
+	if(node->pn_destroy != NULL)
+		(node->pn_destroy)(node);
+	
 	/* revoke vnodes and release memory */
 	pfs_disable(node);
 	FREE(node, M_PFSNODES);
diff --git a/sys/fs/pseudofs/pseudofs.h b/sys/fs/pseudofs/pseudofs.h
index b9701bc09337..58eba44b714c 100644
--- a/sys/fs/pseudofs/pseudofs.h
+++ b/sys/fs/pseudofs/pseudofs.h
@@ -155,6 +155,15 @@ typedef int (*pfs_getextattr_t)(PFS_GETEXTATTR_ARGS);
 typedef int (*pfs_close_t)(PFS_CLOSE_ARGS);
 
 /*
+ * Destroy callback
+ */
+#define PFS_DESTROY_ARGS \
+	struct pfs_node *pn
+#define PFS_DESTROY_PROTO(name) \
+	int name(PFS_DESTROY_ARGS);
+typedef int (*pfs_destroy_t)(PFS_DESTROY_ARGS);
+
+/*
  * pfs_info: describes a pseudofs instance
  */
 struct pfs_info {
@@ -186,6 +195,7 @@ struct pfs_node {
 	pfs_attr_t		 pn_attr;
 	pfs_vis_t		 pn_vis;
 	pfs_getextattr_t	 pn_getextattr;
+	pfs_destroy_t		 pn_destroy;
 	void			*pn_data;
 	int			 pn_flags;
 
@@ -215,13 +225,16 @@ int		 pfs_uninit	(struct pfs_info *pi, struct vfsconf *vfc);
  * Directory structure construction and manipulation
  */
 struct pfs_node	*pfs_create_dir	(struct pfs_node *parent, const char *name,
-				 pfs_attr_t attr, pfs_vis_t vis, int flags);
+				 pfs_attr_t attr, pfs_vis_t vis, 
+				 pfs_destroy_t destroy, int flags);
 struct pfs_node	*pfs_create_file(struct pfs_node *parent, const char *name,
 				 pfs_fill_t fill, pfs_attr_t attr,
-				 pfs_vis_t vis, int flags);
+				 pfs_vis_t vis, pfs_destroy_t destroy,
+				 int flags);
 struct pfs_node	*pfs_create_link(struct pfs_node *parent, const char *name,
 				 pfs_fill_t fill, pfs_attr_t attr,
-				 pfs_vis_t vis, int flags);
+				 pfs_vis_t vis, pfs_destroy_t destroy,
+				 int flags);
 struct pfs_node	*pfs_find_node	(struct pfs_node *parent, const char *name);
 int		 pfs_disable	(struct pfs_node *pn);
 int		 pfs_enable	(struct pfs_node *pn);