s390utils/0067-cmsfs-fuse-Delete-old-file-if-renaming-to-an-existin.patch

From f6494a1210439d591a1319498026ffcdd91a2ebf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dan=20Hor=C3=A1k?= <dan@danny.cz>
Date: Tue, 29 Mar 2011 10:49:25 +0200
Subject: [PATCH 67/70] cmsfs-fuse: Delete old file if renaming to an existing file

Description: cmsfs-fuse: Delete old file if renaming to an existing file.
Symptom:     Stale old file if renaming a file to an existing file.
Problem:     In case rename is used to overwrite an existing file the old
             file entry was not deleted resulting in a duplicated file.
Solution:    If the target of a rename operation exists delete the target
             file before the rename operation.
---
 cmsfs-fuse/cmsfs-fuse.c |  248 ++++++++++++++++++++++++-----------------------
 1 files changed, 128 insertions(+), 120 deletions(-)

diff --git a/cmsfs-fuse/cmsfs-fuse.c b/cmsfs-fuse/cmsfs-fuse.c
index fd87774..9f1aa1a 100644
--- a/cmsfs-fuse/cmsfs-fuse.c
+++ b/cmsfs-fuse/cmsfs-fuse.c
@@ -2638,14 +2638,132 @@ static int cmsfs_utimens(const char *path, const struct timespec ts[2])
 	return 0;
 }
 
+/*
+ * Get the address of the last directory entry.
+ */
+off_t find_last_fdir_entry(off_t addr, int level)
+{
+	struct fst_entry fst;
+	int left, rc;
+	off_t ptr;
+
+	if (level > 0) {
+		level--;
+		left = PTRS_PER_BLOCK;
+		while (left--) {
+			ptr = get_fixed_pointer(addr + left * PTR_SIZE);
+			BUG(ptr < 0);
+			if (ptr)
+				return find_last_fdir_entry(ptr, level);
+		}
+		DIE("Directory entry not found\n");
+		return 0;
+	}
+
+	left = cmsfs.blksize / sizeof(struct fst_entry);
+	while (left--) {
+		rc = _read(&fst, sizeof(fst),
+			   addr + left * sizeof(struct fst_entry));
+		BUG(rc < 0);
+		if (is_file((unsigned long long *) fst.name,
+			    (unsigned long long *) fst.type))
+			return addr + left * sizeof(struct fst_entry);
+	}
+	DIE("Directory entry not found\n");
+}
+
+static int delete_file(const char *path)
+{
+	off_t fst_kill, fst_last;
+	struct walk_file walk;
+	struct file *f_moved;
+	char file[MAX_FNAME];
+	struct fst_entry fst;
+	struct file *f;
+	int rc = 0, i;
+
+	if (cmsfs.readonly)
+		return -EROFS;
+
+	fst_kill = lookup_file(path + 1, &fst, SHOW_UNLINKED);
+	if (!fst_kill)
+		return -ENOENT;
+	f = create_file_object(&fst, &rc);
+	if (f == NULL)
+		return rc;
+
+	/* delete all data blocks */
+	for (i = 0; i < f->fst->nr_blocks; i++)
+		free_block(f->blist[i].disk_addr);
+
+	if (f->fst->fop) {
+		rc = f->fops->delete_pointers(f, f->fst->levels, ABS(f->fst->fop));
+		if (rc < 0)
+			goto error;
+	}
+
+	if (cmsfs.dir_levels)
+		fst_last = find_last_fdir_entry(get_fop(cmsfs.fdir), cmsfs.dir_levels);
+	else
+		fst_last = find_last_fdir_entry(cmsfs.fdir, cmsfs.dir_levels);
+
+	/* remove unlinked file from fcache */
+	strncpy(file, path + 1, MAX_FNAME);
+	str_toupper(file);
+	invalidate_htab_entry(file);
+
+	if (fst_last == fst_kill)
+		goto skip_copy;
+
+	/* copy last entry over unlinked entry */
+	rc = _read(&fst, sizeof(struct fst_entry), fst_last);
+	BUG(rc < 0);
+	rc = _write(&fst, sizeof(struct fst_entry), fst_kill);
+	BUG(rc < 0);
+
+	/* update moved fcache entry */
+	memset(file, 0, sizeof(file));
+	decode_edf_name(file, fst.name, fst.type);
+	update_htab_entry(fst_kill, file);
+	/* update cached address of moved FST */
+	f_moved = file_open(file);
+	if (f_moved != NULL)
+		f->fst_addr = fst_kill;
+
+skip_copy:
+	/* delete last entry */
+	rc = _zero(fst_last, sizeof(struct fst_entry));
+	BUG(rc < 0);
+
+	/* if the deleted entry was the first of a block, free the block */
+	if (fst_last % cmsfs.blksize == 0) {
+		cache_dblocks(&walk);
+		/* delete the last block from dlist */
+		walk.dlist_used--;
+		free_block(fst_last);
+		purge_dblock_ptrs(cmsfs.dir_levels, get_fop(cmsfs.fdir));
+		rewrite_dblock_ptrs(&walk);
+		free_dblocks(&walk);
+	}
+
+	destroy_file_object(f);
+	decrease_file_count();
+	update_block_count();
+	return 0;
+
+error:
+	destroy_file_object(f);
+	return rc;
+}
+
 static int cmsfs_rename(const char *path, const char *new_path)
 {
+	struct fst_entry fst, fst_new;
+	off_t fst_addr, fst_addr_new;
 	char uc_old_name[MAX_FNAME];
 	char fname[8], ftype[8];
-	struct fst_entry fst;
 	char *uc_new_name;
 	struct file *f;
-	off_t fst_addr;
 	int rc;
 
 	if (cmsfs.readonly)
@@ -2655,6 +2773,14 @@ static int cmsfs_rename(const char *path, const char *new_path)
 	if (!fst_addr)
 		return -ENOENT;
 
+	/* if new file already exists it must be overwritten so delete it */
+	fst_addr_new = lookup_file(new_path + 1, &fst_new, HIDE_UNLINKED);
+	if (fst_addr_new) {
+		delete_file(new_path);
+		/* fst_addr may have changed due to copy-up */
+		fst_addr = lookup_file(path + 1, &fst, HIDE_UNLINKED);
+	}
+
 	rc = edf_name_valid(new_path + 1);
 	if (rc)
 		return rc;
@@ -4042,124 +4168,6 @@ static int cmsfs_write(const char *path, const char *buf, size_t size,
 	return rc;
 }
 
-/*
- * Get the address of the last directory entry.
- */
-off_t find_last_fdir_entry(off_t addr, int level)
-{
-	struct fst_entry fst;
-	int left, rc;
-	off_t ptr;
-
-	if (level > 0) {
-		level--;
-		left = PTRS_PER_BLOCK;
-		while (left--) {
-			ptr = get_fixed_pointer(addr + left * PTR_SIZE);
-			BUG(ptr < 0);
-			if (ptr)
-				return find_last_fdir_entry(ptr, level);
-		}
-		DIE("Directory entry not found\n");
-		return 0;
-	}
-
-	left = cmsfs.blksize / sizeof(struct fst_entry);
-	while (left--) {
-		rc = _read(&fst, sizeof(fst),
-			   addr + left * sizeof(struct fst_entry));
-		BUG(rc < 0);
-		if (is_file((unsigned long long *) fst.name,
-			    (unsigned long long *) fst.type))
-			return addr + left * sizeof(struct fst_entry);
-	}
-	DIE("Directory entry not found\n");
-}
-
-static int delete_file(const char *path)
-{
-	off_t fst_kill, fst_last;
-	struct walk_file walk;
-	struct file *f_moved;
-	char file[MAX_FNAME];
-	struct fst_entry fst;
-	struct file *f;
-	int rc = 0, i;
-
-	if (cmsfs.readonly)
-		return -EROFS;
-
-	fst_kill = lookup_file(path + 1, &fst, SHOW_UNLINKED);
-	if (!fst_kill)
-		return -ENOENT;
-	f = create_file_object(&fst, &rc);
-	if (f == NULL)
-		return rc;
-
-	/* delete all data blocks */
-	for (i = 0; i < f->fst->nr_blocks; i++)
-		free_block(f->blist[i].disk_addr);
-
-	if (f->fst->fop) {
-		rc = f->fops->delete_pointers(f, f->fst->levels, ABS(f->fst->fop));
-		if (rc < 0)
-			goto error;
-	}
-
-	if (cmsfs.dir_levels)
-		fst_last = find_last_fdir_entry(get_fop(cmsfs.fdir), cmsfs.dir_levels);
-	else
-		fst_last = find_last_fdir_entry(cmsfs.fdir, cmsfs.dir_levels);
-
-	/* remove unlinked file from fcache */
-	strncpy(file, path + 1, MAX_FNAME);
-	str_toupper(file);
-	invalidate_htab_entry(file);
-
-	if (fst_last == fst_kill)
-		goto skip_copy;
-
-	/* copy last entry over unlinked entry */
-	rc = _read(&fst, sizeof(struct fst_entry), fst_last);
-	BUG(rc < 0);
-	rc = _write(&fst, sizeof(struct fst_entry), fst_kill);
-	BUG(rc < 0);
-
-	/* update moved fcache entry */
-	memset(file, 0, sizeof(file));
-	decode_edf_name(file, fst.name, fst.type);
-	update_htab_entry(fst_kill, file);
-	/* update cached address of moved FST */
-	f_moved = file_open(file);
-	if (f_moved != NULL)
-		f->fst_addr = fst_kill;
-
-skip_copy:
-	/* delete last entry */
-	rc = _zero(fst_last, sizeof(struct fst_entry));
-	BUG(rc < 0);
-
-	/* if the deleted entry was the first of a block, free the block */
-	if (fst_last % cmsfs.blksize == 0) {
-		cache_dblocks(&walk);
-		/* delete the last block from dlist */
-		walk.dlist_used--;
-		free_block(fst_last);
-		purge_dblock_ptrs(cmsfs.dir_levels, get_fop(cmsfs.fdir));
-		rewrite_dblock_ptrs(&walk);
-		free_dblocks(&walk);
-	}
-
-	destroy_file_object(f);
-	decrease_file_count();
-	update_block_count();
-	return 0;
-
-error:
-	destroy_file_object(f);
-	return rc;
-}
-
 static int cmsfs_unlink(const char *path)
 {
 	struct fst_entry fst;
-- 
1.7.4