[v2,5/5] btrfs-progs: subvol: fix subvol del --commit-after

Commit Message

Misono Tomohiro Sept. 27, 2017, 2:03 a.m. UTC

Fix subvol del --commit-after to work properly:
 - SYNC ioctl will be issued even when last delete is failed
 - SYNC ioctl will be issued on each file system only once in the end

To achieve this, get_fsid() and add_seen_fsid() is called after each delete
to keep only one fd for each fs.

In the end, seen_fsid_hash will be traversed and SYNC is issued on each fs.

Signed-off-by: Tomohiro Misono <[e-mail]>
Reviewed-by: Qu Wenruo <[e-mail]>
---
 cmds-subvolume.c | 61 ++++++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 48 insertions(+), 13 deletions(-)

Patch

diff --git a/cmds-subvolume.c b/cmds-subvolume.c
index 9e561f3..0c8a75f 100644
--- a/cmds-subvolume.c
+++ b/cmds-subvolume.c
@@ -263,6 +263,9 @@  static int cmd_subvol_delete(int argc, char **argv)
 	DIR	*dirstream = NULL;
 	int verbose = 0;
 	int commit_mode = 0;
+	u8 fsid[BTRFS_FSID_SIZE];
+	char uuidbuf[BTRFS_UUID_UNPARSED_SIZE];
+	struct seen_fsid *seen_fsid_hash[SEEN_FSID_HASH_SIZE] = {NULL,};
 	enum { COMMIT_AFTER = 1, COMMIT_EACH = 2 };
 
 	while (1) {
@@ -358,31 +361,63 @@  again:
 				path, strerror(errno));
 			ret = 1;
 		}
+	} else if (commit_mode == COMMIT_AFTER) {
+		res = get_fsid(dname, fsid, 0);
+		if (res < 0) {
+			error("unable to get fsid for '%s': %s", path, strerror(-res));
+			error("delete suceeded but commit may not be done in the end");
+			ret = 1;
+			goto out;
+		}
+
+		if (add_seen_fsid(fsid, seen_fsid_hash, fd, dirstream) == 0) {
+			if (verbose > 0) {
+				uuid_unparse(fsid, uuidbuf);
+				printf("  new fs is found for '%s', fsid: %s\n", path, uuidbuf);
+			}
+			// this is the first time a subvolume on this filesystem is deleted
+			// keep fd in order to issue SYNC ioctl in the end
+			goto keep_fd;
+		}
 	}
 
 out:
+	close_file_or_dir(fd, dirstream);
+keep_fd:
+	fd = -1;
+	dirstream = NULL;
 	free(dupdname);
 	free(dupvname);
 	dupdname = NULL;
 	dupvname = NULL;
 	cnt++;
-	if (cnt < argc) {
-		close_file_or_dir(fd, dirstream);
-		/* avoid double free */
-		fd = -1;
-		dirstream = NULL;
+	if (cnt < argc)
 		goto again;
-	}
 
-	if (commit_mode == COMMIT_AFTER && fd != -1) {
-		res = wait_for_commit(fd);
-		if (res < 0) {
-			error("unable to do final sync after deletion: %s",
-				strerror(errno));
-			ret = 1;
+	if (commit_mode == COMMIT_AFTER) {
+		// traverse seen_fsid_hash and issue SYNC ioctl on each filesystem
+		int slot;
+		struct seen_fsid *seen;
+
+		for (slot = 0; slot < SEEN_FSID_HASH_SIZE; slot++) {
+			seen = seen_fsid_hash[slot];
+			while (seen) {
+				res = wait_for_commit(seen->fd);
+				if (res < 0) {
+					uuid_unparse(seen->fsid, uuidbuf);
+					error("unable to do final sync after deletion: %s, fsid: %s",
+						strerror(errno), uuidbuf);
+					ret = 1;
+				} else if (verbose > 0) {
+					uuid_unparse(seen->fsid, uuidbuf);
+					printf("final sync is done for fsid: %s\n", uuidbuf);
+				}
+				seen = seen->next;
+			}
 		}
+		// fd will also be closed in free_seen_fsid
+		free_seen_fsid(seen_fsid_hash);
 	}
-	close_file_or_dir(fd, dirstream);
 
 	return ret;
 }