Merge bk://cifs.bkbits.net/linux-2.5cifs

into smfhome.smfdom:/home/stevef/linux-2.5cifs

fs/cifs/dir.c

@@ -165,7 +165,9 @@ cifs_create(struct inode *inode, struct dentry *direntry, int mode,
 	cifs_sb = CIFS_SB(inode->i_sb);
 	pTcon = cifs_sb->tcon;
 
+	down(&direntry->d_sb->s_vfs_rename_sem);
 	full_path = build_path_from_dentry(direntry);
+	up(&direntry->d_sb->s_vfs_rename_sem);
 	if(full_path == NULL) {
 		FreeXid(xid);
 		return -ENOMEM;
@@ -304,7 +306,9 @@ int cifs_mknod(struct inode *inode, struct dentry *direntry, int mode, dev_t dev
 	cifs_sb = CIFS_SB(inode->i_sb);
 	pTcon = cifs_sb->tcon;
 
+	down(&direntry->d_sb->s_vfs_rename_sem);
 	full_path = build_path_from_dentry(direntry);
+	up(&direntry->d_sb->s_vfs_rename_sem);
 	if(full_path == NULL)
 		rc = -ENOMEM;
 	
@@ -355,6 +359,9 @@ cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry, struct name
 	cifs_sb = CIFS_SB(parent_dir_inode->i_sb);
 	pTcon = cifs_sb->tcon;
 
+	/* can not grab the rename sem here since it would
+	deadlock in the cases (beginning of sys_rename itself)
+	in which we already have the sb rename sem */
 	full_path = build_path_from_dentry(direntry);
 	if(full_path == NULL) {
 		FreeXid(xid);

fs/cifs/fcntl.c

@@ -39,7 +39,11 @@ int cifs_directory_notify(unsigned long arg, struct file * file)
 	xid = GetXid();
 	cifs_sb = CIFS_SB(file->f_dentry->d_sb);
 	pTcon = cifs_sb->tcon;
+
+	down(&file->f_dentry->d_sb->s_vfs_rename_sem);
 	full_path = build_path_from_dentry(file->f_dentry);
+	up(&file->f_dentry->d_sb->s_vfs_rename_sem);
+
 	if(full_path == NULL) {
 		rc = -ENOMEM;
 	} else {

fs/cifs/file.c

@@ -80,7 +80,9 @@ cifs_open(struct inode *inode, struct file *file)
 		}
 	}
 
+	down(&inode->i_sb->s_vfs_rename_sem);
 	full_path = build_path_from_dentry(file->f_dentry);
+	up(&inode->i_sb->s_vfs_rename_sem);
 	if(full_path == NULL) {
 		FreeXid(xid);
 		return -ENOMEM;
@@ -291,7 +293,10 @@ static int cifs_reopen_file(struct inode *inode, struct file *file)
 	}
 	cifs_sb = CIFS_SB(inode->i_sb);
 	pTcon = cifs_sb->tcon;
-
+/* can not grab rename sem here because various ops, including
+those that already have the rename sem can end up causing writepage
+to get called and if the server was down that means we end up here,
+and we can never tell if the caller already has the rename_sem */
 	full_path = build_path_from_dentry(file->f_dentry);
 	if(full_path == NULL) {
 		up(&pCifsFile->fh_sem);

fs/cifs/inode.c

@@ -345,7 +345,11 @@ cifs_unlink(struct inode *inode, struct dentry *direntry)
 	cifs_sb = CIFS_SB(inode->i_sb);
 	pTcon = cifs_sb->tcon;
 
+/* Unlink can be called from rename so we can not grab
+	the sem here since we deadlock otherwise */
+/*	down(&direntry->d_sb->s_vfs_rename_sem);*/
 	full_path = build_path_from_dentry(direntry);
+/*	up(&direntry->d_sb->s_vfs_rename_sem);*/
 	if(full_path == NULL) {
 		FreeXid(xid);
 		return -ENOMEM;
@@ -430,7 +434,9 @@ cifs_mkdir(struct inode *inode, struct dentry *direntry, int mode)
 	cifs_sb = CIFS_SB(inode->i_sb);
 	pTcon = cifs_sb->tcon;
 
+	down(&inode->i_sb->s_vfs_rename_sem);
 	full_path = build_path_from_dentry(direntry);
+	up(&inode->i_sb->s_vfs_rename_sem);
 	if(full_path == NULL) {
 		FreeXid(xid);
 		return -ENOMEM;
@@ -487,7 +493,9 @@ cifs_rmdir(struct inode *inode, struct dentry *direntry)
 	cifs_sb = CIFS_SB(inode->i_sb);
 	pTcon = cifs_sb->tcon;
 
+	down(&inode->i_sb->s_vfs_rename_sem);
 	full_path = build_path_from_dentry(direntry);
+	up(&inode->i_sb->s_vfs_rename_sem);
 	if(full_path == NULL) {
 		FreeXid(xid);
 		return -ENOMEM;
@@ -536,6 +544,8 @@ cifs_rename(struct inode *source_inode, struct dentry *source_direntry,
                      different share. Might eventually add support for this */
 	}
 
+	/* we already  have the rename sem so we do not need
+	to grab it again here to protect the path integrity */
 	fromName = build_path_from_dentry(source_direntry);
 	toName = build_path_from_dentry(target_direntry);
 	if((fromName == NULL) || (toName == NULL)) {
@@ -603,6 +613,8 @@ cifs_revalidate(struct dentry *direntry)
 
 	cifs_sb = CIFS_SB(direntry->d_sb);
 
+	/* can not safely grab the rename sem here if
+	rename calls revalidate since that would deadlock */
 	full_path = build_path_from_dentry(direntry);
 	if(full_path == NULL) {
 		FreeXid(xid);
@@ -751,7 +763,9 @@ cifs_setattr(struct dentry *direntry, struct iattr *attrs)
 	cifs_sb = CIFS_SB(direntry->d_inode->i_sb);
 	pTcon = cifs_sb->tcon;
 
+	down(&direntry->d_sb->s_vfs_rename_sem);
 	full_path = build_path_from_dentry(direntry);
+	up(&direntry->d_sb->s_vfs_rename_sem);
 	if(full_path == NULL) {
 		FreeXid(xid);
 		return -ENOMEM;

fs/cifs/link.c

@@ -44,10 +44,13 @@ cifs_hardlink(struct dentry *old_file, struct inode *inode,
 	cifs_sb_target = CIFS_SB(inode->i_sb);
 	pTcon = cifs_sb_target->tcon;
 
-/* No need to check for cross device links since server will do that - BB note DFS case in future though (when we may have to check) */
+/* No need to check for cross device links since server will do that
+   BB note DFS case in future though (when we may have to check) */
 
+	down(&inode->i_sb->s_vfs_rename_sem);
 	fromName = build_path_from_dentry(old_file);
 	toName = build_path_from_dentry(direntry);
+	up(&inode->i_sb->s_vfs_rename_sem);
 	if((fromName == NULL) || (toName == NULL)) {
 		rc = -ENOMEM;
 		goto cifs_hl_exit;
@@ -96,7 +99,11 @@ cifs_follow_link(struct dentry *direntry, struct nameidata *nd)
 	struct cifsTconInfo *pTcon;
 
 	xid = GetXid();
+
+	down(&direntry->d_sb->s_vfs_rename_sem);
 	full_path = build_path_from_dentry(direntry);
+	up(&direntry->d_sb->s_vfs_rename_sem);
+
 	if(full_path == NULL) {
 		FreeXid(xid);
 		return -ENOMEM;
@@ -159,7 +166,10 @@ cifs_symlink(struct inode *inode, struct dentry *direntry, const char *symname)
 	cifs_sb = CIFS_SB(inode->i_sb);
 	pTcon = cifs_sb->tcon;
 
+	down(&inode->i_sb->s_vfs_rename_sem);
 	full_path = build_path_from_dentry(direntry);
+	up(&inode->i_sb->s_vfs_rename_sem);
+
 	if(full_path == NULL) {
 		FreeXid(xid);
 		return -ENOMEM;
@@ -219,7 +229,13 @@ cifs_readlink(struct dentry *direntry, char *pBuffer, int buflen)
 	xid = GetXid();
 	cifs_sb = CIFS_SB(inode->i_sb);
 	pTcon = cifs_sb->tcon;
+
+/* BB would it be safe against deadlock to grab this sem 
+      even though rename itself grabs the sem and calls lookup? */
+/*       down(&inode->i_sb->s_vfs_rename_sem);*/
 	full_path = build_path_from_dentry(direntry);
+/*       up(&inode->i_sb->s_vfs_rename_sem);*/
+
 	if(full_path == NULL) {
 		FreeXid(xid);
 		return -ENOMEM;