[Libsysio-commit] HEAD: libsysio/drivers/native fs_native.c

[Ruth K. <rk...@us...>]

Update of /cvsroot/libsysio/libsysio/drivers/native
In directory sc8-pr-cvs1:/tmp/cvs-serv25000/drivers/native

Modified Files:
	fs_native.c 
Log Message:
Add capability of checking inode generation numbers,
if a field for it exists in the stat struct.

Bug fix for unlink/creat failure:
Changes allow re-use of an inode which is no longer in use, but
still exists in the inode cache. If the stat info for the new use
matches cached info, the inode is re-used. If not, the old inode is
marked 'zombie' and removed from the inode cache to make way for
the new inode.



Index: fs_native.c
===================================================================
RCS file: /cvsroot/libsysio/libsysio/drivers/native/fs_native.c,v
retrieving revision 1.11
retrieving revision 1.12
diff -u -w -b -B -p -r1.11 -r1.12
--- fs_native.c	23 Apr 2003 18:18:38 -0000	1.11
+++ fs_native.c	25 Jul 2003 14:45:34 -0000	1.12
@@ -151,6 +151,9 @@ do {                                    
 struct native_inode_identifier {
 	dev_t	dev;					/* device number */
 	ino_t	ino;					/* i-number */
+#ifdef HAVE_GENERATION
+	unsigned int gen;                               /* generation number */
+#endif
 };
 
 /*
@@ -310,8 +313,12 @@ native_i_new(struct filesys *fs, struct 
 	nino = malloc(sizeof(struct native_inode));
 	if (!nino)
 		return NULL;
+	bzero(&nino->ni_ident, sizeof(nino->ni_ident));
 	nino->ni_ident.dev = buf->st_dev;
 	nino->ni_ident.ino = buf->st_ino;
+#ifdef HAVE_GENERATION
+	nino->ni_ident.gen = buf->st_gen;
+#endif
 	nino->ni_fileid.fid_data = &nino->ni_ident;
 	nino->ni_fileid.fid_len = sizeof(nino->ni_ident);
 	nino->ni_fd = -1;
@@ -496,6 +503,27 @@ native_fsswop_mount(const char *source,
 	return err;
 }
 
+static int
+native_i_validate(struct inode *inop, struct intnl_stat stbuf)
+{
+	/*
+	 * Validate passed in inode against stat struct info
+	 */
+	struct native_inode *nino = I2NI(inop);
+	
+	if ((nino->ni_ident.dev == stbuf.st_dev &&
+	     nino->ni_ident.ino == stbuf.st_ino &&
+#ifdef HAVE_GENERATION
+	     nino->ni_ident.gen == stbuf.st_gen &&
+#endif
+	     ((inop)->i_mode & stbuf.st_mode) == (inop)->i_mode) &&
+	    ((!(S_ISCHR((inop)->i_mode) || S_ISBLK((inop)->i_mode)) ||
+	      (inop)->i_rdev == stbuf.st_rdev)))
+		return 0;
+
+	return 1;
+}
+
 /*
  * Find, and validate, or create i-node by host-relative path. Returned i-node
  * is referenced.
@@ -525,11 +553,7 @@ native_iget(struct filesys *fs,
 	 * Validate?
 	 */
 	if (*inop) {
-		struct native_inode *nino = I2NI(*inop);
-
-		if (nino->ni_ident.dev == stbuf.st_dev &&
-		    nino->ni_ident.ino == stbuf.st_ino &&
-		    ((*inop)->i_mode & stbuf.st_mode) == (*inop)->i_mode)
+		if (!native_i_validate(*inop, stbuf))
 			return 0;
 		/*
 		 * Invalidate.
@@ -540,23 +564,40 @@ native_iget(struct filesys *fs,
 	/*
 	 * I-node is not already known. Find or create it.
 	 */
+	bzero(&ident, sizeof(ident)); 
 	ident.dev = stbuf.st_dev;
 	ident.ino = stbuf.st_ino;
+#ifdef HAVE_GENERATION
+	ident.gen = stbuf.st_gen;
+#endif
 	fileid.fid_data = &ident;
 	fileid.fid_len = sizeof(ident);
 	ino = _sysio_i_find(fs, stbuf.st_ino, &fileid);
-	if (!ino) {
-		ino = native_i_new(fs, &stbuf);
-		if (!ino)
-			err = -ENOMEM;
-	} else if (forced) {
+	if (ino && forced) {
 		/*
 		 * Insertion was forced but it's already present!
 		 */
+		if (native_i_validate(ino, stbuf)) {
+			/* 
+			 * Cached inode has stale attrs
+			 * make way for the new one
+			 */
 		I_RELE(ino);
-		err = -EEXIST;
+			_sysio_i_undead(ino);
+			ino = NULL;
+		} else
+			/* 
+			 * OK to reuse cached inode
+			 */
+			goto out;
 	}
 
+	if (!ino) {
+		ino = native_i_new(fs, &stbuf);
+		if (!ino)
+			err = -ENOMEM;
+	}
+out:
 	if (!err)
 		*inop = ino;
 	return err;