Btrfs: fix output of compression message in btrfs_parse_options()

The compression message might not be correctly output.
Fix it.

[[before fix]]

# mount -o compress /dev/sdb3 /test3
[  996.874264] BTRFS info (device sdb3): disk space caching is enabled
[  996.874268] BTRFS: has skinny extents
# mount | grep /test3
/dev/sdb3 on /test3 type btrfs (rw,relatime,compress=zlib,space_cache,subvolid=5,subvol=/)

# mount -o remount,compress-force /dev/sdb3 /test3
[ 1035.075017] BTRFS info (device sdb3): force zlib compression
[ 1035.075021] BTRFS info (device sdb3): disk space caching is enabled
# mount | grep /test3
/dev/sdb3 on /test3 type btrfs (rw,relatime,compress-force=zlib,space_cache,subvolid=5,subvol=/)

# mount -o remount,compress /dev/sdb3 /test3
[ 1053.679092] BTRFS info (device sdb3): disk space caching is enabled
# mount | grep /test3
/dev/sdb3 on /test3 type btrfs (rw,relatime,compress=zlib,space_cache,subvolid=5,subvol=/)

[[after fix]]

# mount -o compress /dev/sdb3 /test3
[  401.021753] BTRFS info (device sdb3): use zlib compression
[  401.021758] BTRFS info (device sdb3): disk space caching is enabled
[  401.021760] BTRFS: has skinny extents
# mount | grep /test3
/dev/sdb3 on /test3 type btrfs (rw,relatime,compress=zlib,space_cache,subvolid=5,subvol=/)

# mount -o remount,compress-force /dev/sdb3 /test3
[  439.824624] BTRFS info (device sdb3): force zlib compression
[  439.824629] BTRFS info (device sdb3): disk space caching is enabled
# mount | grep /test3
/dev/sdb3 on /test3 type btrfs (rw,relatime,compress-force=zlib,space_cache,subvolid=5,subvol=/)

# mount -o remount,compress /dev/sdb3 /test3
[  459.918430] BTRFS info (device sdb3): use zlib compression
[  459.918434] BTRFS info (device sdb3): disk space caching is enabled
# mount | grep /test3
/dev/sdb3 on /test3 type btrfs (rw,relatime,compress=zlib,space_cache,subvolid=5,subvol=/)

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

1 files changed, 22 insertions, 7 deletions

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 5099e4633e50..3225ac365408 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -381,6 +381,9 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
         int ret = 0;
         char *compress_type;
         bool compress_force = false;
+        enum btrfs_compression_type saved_compress_type;
+        bool saved_compress_force;
+        int no_compress = 0;
 
         cache_gen = btrfs_super_cache_generation(root->fs_info->super_copy);
         if (cache_gen)
@@ -458,6 +461,10 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                         /* Fallthrough */
                 case Opt_compress:
                 case Opt_compress_type:
+                        saved_compress_type = btrfs_test_opt(root, COMPRESS) ?
+                                info->compress_type : BTRFS_COMPRESS_NONE;
+                        saved_compress_force =
+                                btrfs_test_opt(root, FORCE_COMPRESS);
                         if (token == Opt_compress ||
                             token == Opt_compress_force ||
                             strcmp(args[0].from, "zlib") == 0) {
@@ -466,6 +473,7 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                                 btrfs_set_opt(info->mount_opt, COMPRESS);
                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
+                                no_compress = 0;
                         } else if (strcmp(args[0].from, "lzo") == 0) {
                                 compress_type = "lzo";
                                 info->compress_type = BTRFS_COMPRESS_LZO;
@@ -473,25 +481,21 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                                 btrfs_clear_opt(info->mount_opt, NODATACOW);
                                 btrfs_clear_opt(info->mount_opt, NODATASUM);
                                 btrfs_set_fs_incompat(info, COMPRESS_LZO);
+                                no_compress = 0;
                         } else if (strncmp(args[0].from, "no", 2) == 0) {
                                 compress_type = "no";
                                 btrfs_clear_opt(info->mount_opt, COMPRESS);
                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
                                 compress_force = false;
+                                no_compress++;
                         } else {
                                 ret = -EINVAL;
                                 goto out;
                         }
 
                         if (compress_force) {
-                                btrfs_set_and_info(root, FORCE_COMPRESS,
-                                                   "force %s compression",
-                                                   compress_type);
+                                btrfs_set_opt(info->mount_opt, FORCE_COMPRESS);
                         } else {
-                                if (!btrfs_test_opt(root, COMPRESS))
-                                        btrfs_info(root->fs_info,
-                                                   "btrfs: use %s compression",
-                                                   compress_type);
                                 /*
                                  * If we remount from compress-force=xxx to
                                  * compress=xxx, we need clear FORCE_COMPRESS
@@ -500,6 +504,17 @@ int btrfs_parse_options(struct btrfs_root *root, char *options)
                                  */
                                 btrfs_clear_opt(info->mount_opt, FORCE_COMPRESS);
                         }
+                        if ((btrfs_test_opt(root, COMPRESS) &&
+                             (info->compress_type != saved_compress_type ||
+                              compress_force != saved_compress_force)) ||
+                            (!btrfs_test_opt(root, COMPRESS) &&
+                             no_compress == 1)) {
+                                btrfs_info(root->fs_info,
+                                           "%s %s compression",
+                                           (compress_force) ? "force" : "use",
+                                           compress_type);
+                        }
+                        compress_force = false;
                         break;
                 case Opt_ssd:
                         btrfs_set_and_info(root, SSD,