btrfs-progs: open the devices exclusively for writes

Commit Message

Qu Wenruo Sept. 11, 2024, 9:20 a.m. UTC

There is an internal report that, during btrfs-convert to block-group
tree, by accident some systemd events triggered the mount of the target
fs.

This leads to double mount (one by kernel and one by the btrfs-progs),
which seems to cause quite some problems.

To avoid such accident, exclusively opens all devices if btrfs-progs is
doing write opeartions.

Reported-by: pandada8 <[e-mail]>
Signed-off-by: Qu Wenruo <[e-mail]>
---
 cmds/rescue.c             | 6 +++---
 common/filesystem-utils.c | 3 ++-
 convert/main.c            | 3 ++-
 image/image-restore.c     | 4 +++-
 mkfs/main.c               | 3 ++-
 tune/main.c               | 2 +-
 6 files changed, 13 insertions(+), 8 deletions(-)

Patch

diff --git a/cmds/rescue.c b/cmds/rescue.c
index 6d7d526df145..5bbd47e5c2e3 100644
--- a/cmds/rescue.c
+++ b/cmds/rescue.c
@@ -203,7 +203,7 @@  static int cmd_rescue_zero_log(const struct cmd_struct *cmd,
 	}
 
 	root = open_ctree(devname, 0, OPEN_CTREE_WRITES | OPEN_CTREE_PARTIAL |
-			  OPEN_CTREE_NO_BLOCK_GROUPS);
+			  OPEN_CTREE_NO_BLOCK_GROUPS | OPEN_CTREE_EXCLUSIVE);
 	if (!root) {
 		error("could not open ctree");
 		return 1;
@@ -258,7 +258,7 @@  static int cmd_rescue_fix_device_size(const struct cmd_struct *cmd,
 	}
 
 	oca.filename = devname;
-	oca.flags = OPEN_CTREE_WRITES | OPEN_CTREE_PARTIAL;
+	oca.flags = OPEN_CTREE_WRITES | OPEN_CTREE_PARTIAL | OPEN_CTREE_EXCLUSIVE;
 	fs_info = open_ctree_fs_info(&oca);
 	if (!fs_info) {
 		error("could not open btrfs");
@@ -437,7 +437,7 @@  static int cmd_rescue_clear_ino_cache(const struct cmd_struct *cmd,
 		goto out;
 	}
 	oca.filename = devname;
-	oca.flags = OPEN_CTREE_WRITES;
+	oca.flags = OPEN_CTREE_WRITES | OPEN_CTREE_EXCLUSIVE;
 	fs_info = open_ctree_fs_info(&oca);
 	if (!fs_info) {
 		error("could not open btrfs");
diff --git a/common/filesystem-utils.c b/common/filesystem-utils.c
index 7e898a3d193c..05451093a9fd 100644
--- a/common/filesystem-utils.c
+++ b/common/filesystem-utils.c
@@ -94,7 +94,8 @@  static int set_label_unmounted(const char *dev, const char *label)
 	/* Open the super_block at the default location
 	 * and as read-write.
 	 */
-	root = open_ctree(dev, 0, OPEN_CTREE_WRITES);
+	root = open_ctree(dev, 0, OPEN_CTREE_WRITES |
+				  OPEN_CTREE_EXCLUSIVE);
 	if (!root) /* errors are printed by open_ctree() */
 		return -1;
 
diff --git a/convert/main.c b/convert/main.c
index 1af47260cdf6..a227cc6fef84 100644
--- a/convert/main.c
+++ b/convert/main.c
@@ -1374,7 +1374,8 @@  static int do_convert(const char *devname, u32 convert_flags, u32 nodesize,
 	btrfs_sb_committed = true;
 
 	root = open_ctree_fd(fd, devname, 0,
-			     OPEN_CTREE_WRITES | OPEN_CTREE_TEMPORARY_SUPER);
+			     OPEN_CTREE_WRITES | OPEN_CTREE_TEMPORARY_SUPER |
+			     OPEN_CTREE_EXCLUSIVE);
 	if (!root) {
 		error("unable to open ctree for finalization");
 		goto fail;
diff --git a/image/image-restore.c b/image/image-restore.c
index bed5e78d227d..667b9811233d 100644
--- a/image/image-restore.c
+++ b/image/image-restore.c
@@ -1790,7 +1790,8 @@  int restore_metadump(const char *input, FILE *out, int old_restore,
 
 		oca.filename = target;
 		oca.flags = OPEN_CTREE_WRITES | OPEN_CTREE_RESTORE |
-			    OPEN_CTREE_PARTIAL | OPEN_CTREE_SKIP_LEAF_ITEM_CHECKS;
+			    OPEN_CTREE_PARTIAL | OPEN_CTREE_SKIP_LEAF_ITEM_CHECKS |
+			    OPEN_CTREE_EXCLUSIVE;
 		info = open_ctree_fs_info(&oca);
 		if (!info) {
 			error("open ctree failed");
@@ -1855,6 +1856,7 @@  int restore_metadump(const char *input, FILE *out, int old_restore,
 		root = open_ctree_fd(fileno(out), target, 0,
 					  OPEN_CTREE_PARTIAL |
 					  OPEN_CTREE_WRITES |
+					  OPEN_CTREE_EXCLUSIVE |
 					  OPEN_CTREE_NO_DEVICES |
 					  OPEN_CTREE_ALLOW_TRANSID_MISMATCH |
 					  OPEN_CTREE_SKIP_LEAF_ITEM_CHECKS);
diff --git a/mkfs/main.c b/mkfs/main.c
index 45c25df339ff..06cc2484e612 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -1846,7 +1846,8 @@  int BOX_MAIN(mkfs)(int argc, char **argv)
 	}
 
 	oca.filename = file;
-	oca.flags = OPEN_CTREE_WRITES | OPEN_CTREE_TEMPORARY_SUPER;
+	oca.flags = OPEN_CTREE_WRITES | OPEN_CTREE_TEMPORARY_SUPER |
+		    OPEN_CTREE_EXCLUSIVE;
 	fs_info = open_ctree_fs_info(&oca);
 	if (!fs_info) {
 		error("open ctree failed");
diff --git a/tune/main.c b/tune/main.c
index b0509cf131e6..d246b970e82e 100644
--- a/tune/main.c
+++ b/tune/main.c
@@ -185,7 +185,7 @@  int BOX_MAIN(btrfstune)(int argc, char *argv[])
 {
 	struct btrfs_root *root;
 	struct btrfs_fs_info *fs_info;
-	unsigned ctree_flags = OPEN_CTREE_WRITES;
+	unsigned ctree_flags = OPEN_CTREE_WRITES | OPEN_CTREE_EXCLUSIVE;
 	int seeding_flag = 0;
 	u64 seeding_value = 0;
 	int random_fsid = 0;