[PATCH 2/2] exfat: allow to change some mount options for remount

[Hyunchul Lee]

Allow to change permission masks, allow_utime,
errors. But ignore other options.

Signed-off-by: Hyunchul Lee <hyc....@gmail.com>
---
 fs/exfat/super.c | 40 +++++++++++++++++++++++++++++-----------
 1 file changed, 29 insertions(+), 11 deletions(-)

diff --git a/fs/exfat/super.c b/fs/exfat/super.c
index 61c6cf240c19..3c1d47289ba2 100644
--- a/fs/exfat/super.c
+++ b/fs/exfat/super.c
@@ -696,9 +696,13 @@ static void exfat_free(struct fs_context *fc)
 static int exfat_reconfigure(struct fs_context *fc)
 {
        struct super_block *sb = fc->root->d_sb;
+       struct exfat_sb_info *sbi = EXFAT_SB(sb);
+       struct exfat_mount_options *new_opts;
        int ret;
        bool new_rdonly;
 
+       new_opts = &((struct exfat_sb_info *)fc->s_fs_info)->options;
+
        new_rdonly = fc->sb_flags & SB_RDONLY;
        if (new_rdonly != sb_rdonly(sb)) {
                if (new_rdonly) {
@@ -708,6 +712,12 @@ static int exfat_reconfigure(struct fs_context *fc)
                                return ret;
                }
        }
+
+       /* allow to change these options but ignore others */
+       sbi->options.fs_fmask = new_opts->fs_fmask;
+       sbi->options.fs_dmask = new_opts->fs_dmask;
+       sbi->options.allow_utime = new_opts->allow_utime;
+       sbi->options.errors = new_opts->errors;
        return 0;
 }
 
@@ -726,17 +736,25 @@ static int exfat_init_fs_context(struct fs_context *fc)
        if (!sbi)
                return -ENOMEM;
 
-       mutex_init(&sbi->s_lock);
-       ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
-                       DEFAULT_RATELIMIT_BURST);
-
-       sbi->options.fs_uid = current_uid();
-       sbi->options.fs_gid = current_gid();
-       sbi->options.fs_fmask = current->fs->umask;
-       sbi->options.fs_dmask = current->fs->umask;
-       sbi->options.allow_utime = -1;
-       sbi->options.iocharset = exfat_default_iocharset;
-       sbi->options.errors = EXFAT_ERRORS_RO;
+       if (fc->root) {
+               /* reconfiguration */
+               memcpy(&sbi->options, &EXFAT_SB(fc->root->d_sb)->options,
+                       sizeof(struct exfat_mount_options));
+               sbi->options.iocharset = exfat_default_iocharset;
+       } else {
+               mutex_init(&sbi->s_lock);
+               ratelimit_state_init(&sbi->ratelimit,
+                               DEFAULT_RATELIMIT_INTERVAL,
+                               DEFAULT_RATELIMIT_BURST);
+
+               sbi->options.fs_uid = current_uid();
+               sbi->options.fs_gid = current_gid();
+               sbi->options.fs_fmask = current->fs->umask;
+               sbi->options.fs_dmask = current->fs->umask;
+               sbi->options.allow_utime = -1;
+               sbi->options.iocharset = exfat_default_iocharset;
+               sbi->options.errors = EXFAT_ERRORS_RO;
+       }
 
        fc->s_fs_info = sbi;
        fc->ops = &exfat_context_ops;
-- 
2.17.1