The old flag OPEN_CTREE_FS_PARTIAL is in fact quite easy to be confused
with OPEN_CTREE_PARTIAL, which allow btrfs-progs to open damaged
filesystem (like corrupted extent/csum tree).

However OPEN_CTREE_FS_PARTIAL, unlike its name, is just allowing
btrfs-progs to open fs with temporary superblocks (which only has 6
basic trees on SINGLE meta/sys chunks).

The usage of FS_PARTIAL is really confusing here.

So rename OPEN_CTREE_FS_PARTIAL to OPEN_CTREE_TEMPORARY_SUPER, and add
extra comment for its behavior.
Also rename BTRFS_MAGIC_PARTIAL to BTRFS_MAGIC_TEMPORARY to keep the
naming consistent.

And with above comment, the usage of FS_PARTIAL in dump-tree is
obviously incorrect, fix it.

Fixes: 8698a2b9ba89 ("btrfs-progs: Allow inspect dump-tree to show specified 
tree block even some tree roots are corrupted")
Signed-off-by: Qu Wenruo <w...@suse.com>
---
changelog:
v2:
  New patch
---
 cmds-inspect-dump-tree.c |  2 +-
 convert/main.c           |  4 ++--
 ctree.h                  |  8 +++++---
 disk-io.c                | 12 ++++++------
 disk-io.h                | 10 +++++++---
 mkfs/main.c              |  2 +-
 6 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/cmds-inspect-dump-tree.c b/cmds-inspect-dump-tree.c
index 0802b31e9596..e6510851e8f4 100644
--- a/cmds-inspect-dump-tree.c
+++ b/cmds-inspect-dump-tree.c
@@ -220,7 +220,7 @@ int cmd_inspect_dump_tree(int argc, char **argv)
        int uuid_tree_only = 0;
        int roots_only = 0;
        int root_backups = 0;
-       unsigned open_ctree_flags = OPEN_CTREE_FS_PARTIAL;
+       unsigned open_ctree_flags = OPEN_CTREE_PARTIAL;
        u64 block_only = 0;
        struct btrfs_root *tree_root_scan;
        u64 tree_id = 0;
diff --git a/convert/main.c b/convert/main.c
index 6bdfab40d0b0..80f3bed84c84 100644
--- a/convert/main.c
+++ b/convert/main.c
@@ -1140,7 +1140,7 @@ static int do_convert(const char *devname, u32 
convert_flags, u32 nodesize,
        }
 
        root = open_ctree_fd(fd, devname, mkfs_cfg.super_bytenr,
-                            OPEN_CTREE_WRITES | OPEN_CTREE_FS_PARTIAL);
+                            OPEN_CTREE_WRITES | OPEN_CTREE_TEMPORARY_SUPER);
        if (!root) {
                error("unable to open ctree");
                goto fail;
@@ -1230,7 +1230,7 @@ static int do_convert(const char *devname, u32 
convert_flags, u32 nodesize,
        }
 
        root = open_ctree_fd(fd, devname, 0,
-                       OPEN_CTREE_WRITES | OPEN_CTREE_FS_PARTIAL);
+                            OPEN_CTREE_WRITES | OPEN_CTREE_TEMPORARY_SUPER);
        if (!root) {
                error("unable to open ctree for finalization");
                goto fail;
diff --git a/ctree.h b/ctree.h
index fa861ba0b4c3..80d4e59a66ce 100644
--- a/ctree.h
+++ b/ctree.h
@@ -45,10 +45,12 @@ struct btrfs_free_space_ctl;
 #define BTRFS_MAGIC 0x4D5F53665248425FULL /* ascii _BHRfS_M, no null */
 
 /*
- * Fake signature for an unfinalized filesystem, structures might be partially
- * created or missing.
+ * Fake signature for an unfinalized filesystem, which only has barebone tree
+ * structures (normally 6 near empty trees, on SINGLE meta/sys temporary 
chunks)
+ *
+ * ascii !BHRfS_M, no null
  */
-#define BTRFS_MAGIC_PARTIAL 0x4D5F536652484221ULL /* ascii !BHRfS_M, no null */
+#define BTRFS_MAGIC_TEMPORARY 0x4D5F536652484221ULL
 
 #define BTRFS_MAX_MIRRORS 3
 
diff --git a/disk-io.c b/disk-io.c
index 58eae709e0e8..9e8b1e9d295c 100644
--- a/disk-io.c
+++ b/disk-io.c
@@ -1117,14 +1117,14 @@ static struct btrfs_fs_info *__open_ctree_fd(int fp, 
const char *path,
                fs_info->ignore_chunk_tree_error = 1;
 
        if ((flags & OPEN_CTREE_RECOVER_SUPER)
-            && (flags & OPEN_CTREE_FS_PARTIAL)) {
+            && (flags & OPEN_CTREE_TEMPORARY_SUPER)) {
                fprintf(stderr,
-                   "cannot open a partially created filesystem for recovery");
+       "cannot open a filesystem with temporary super block for recovery");
                goto out;
        }
 
-       if (flags & OPEN_CTREE_FS_PARTIAL)
-               sbflags = SBREAD_PARTIAL;
+       if (flags & OPEN_CTREE_TEMPORARY_SUPER)
+               sbflags = SBREAD_TEMPORARY;
 
        ret = btrfs_scan_fs_devices(fp, path, &fs_devices, sb_bytenr, sbflags,
                        (flags & OPEN_CTREE_NO_DEVICES));
@@ -1285,8 +1285,8 @@ static int check_super(struct btrfs_super_block *sb, 
unsigned sbflags)
        int csum_size;
 
        if (btrfs_super_magic(sb) != BTRFS_MAGIC) {
-               if (btrfs_super_magic(sb) == BTRFS_MAGIC_PARTIAL) {
-                       if (!(sbflags & SBREAD_PARTIAL)) {
+               if (btrfs_super_magic(sb) == BTRFS_MAGIC_TEMPORARY) {
+                       if (!(sbflags & SBREAD_TEMPORARY)) {
                                error("superblock magic doesn't match");
                                return -EIO;
                        }
diff --git a/disk-io.h b/disk-io.h
index f6a422f2a773..c4496155771f 100644
--- a/disk-io.h
+++ b/disk-io.h
@@ -73,8 +73,12 @@ enum btrfs_open_ctree_flags {
         */
        OPEN_CTREE_IGNORE_CHUNK_TREE_ERROR = (1U << 11),
 
-       /* Allow to open a partially created filesystem */
-       OPEN_CTREE_FS_PARTIAL = (1U << 12),
+       /*
+        * Allow to open fs with temporary superblock (BTRFS_MAGIC_PARTIAL),
+        * such fs contains very basic tree layout, just able to be opened.
+        * Such temporary super is used for mkfs or convert.
+        */
+       OPEN_CTREE_TEMPORARY_SUPER = (1U << 12),
 
        /*
         * Invalidate the free space tree (i.e., clear the FREE_SPACE_TREE_VALID
@@ -95,7 +99,7 @@ enum btrfs_read_sb_flags {
         * Read superblock with the fake signature, cannot be used with
         * SBREAD_RECOVER
         */
-       SBREAD_PARTIAL          = (1 << 1),
+       SBREAD_TEMPORARY = (1 << 1),
 };
 
 /*
diff --git a/mkfs/main.c b/mkfs/main.c
index b65b18ddf2f3..7ac587b77383 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -1099,7 +1099,7 @@ int main(int argc, char **argv)
        }
 
        fs_info = open_ctree_fs_info(file, 0, 0, 0,
-                       OPEN_CTREE_WRITES | OPEN_CTREE_FS_PARTIAL);
+                       OPEN_CTREE_WRITES | OPEN_CTREE_TEMPORARY_SUPER);
        if (!fs_info) {
                error("open ctree failed");
                goto error;
-- 
2.17.0

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