diff options
| author | Jan Kara <jack@suse.cz> | 2023-06-20 13:28:32 +0200 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2023-06-20 13:48:01 +0200 |
| commit | d7439fb1f4338fffd0bc68bb62d78f7712725f26 (patch) | |
| tree | cfee9d8b47dbf428a1658be8be50b341305e08a7 /fs/super.c | |
| parent | fs: Protect reconfiguration of sb read-write from racing writes (diff) | |
| download | linux-d7439fb1f4338fffd0bc68bb62d78f7712725f26.tar.xz linux-d7439fb1f4338fffd0bc68bb62d78f7712725f26.zip | |
fs: Provide helpers for manipulating sb->s_readonly_remount
Provide helpers to set and clear sb->s_readonly_remount including
appropriate memory barriers. Also use this opportunity to document what
the barriers pair with and why they are needed.
Suggested-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Message-Id: <20230620112832.5158-1-jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs/super.c')
| -rw-r--r-- | fs/super.c | 17 |
1 files changed, 6 insertions, 11 deletions
diff --git a/fs/super.c b/fs/super.c index 5bf056087acc..5ee5da1fd498 100644 --- a/fs/super.c +++ b/fs/super.c @@ -944,8 +944,7 @@ int reconfigure_super(struct fs_context *fc) */ if (remount_ro) { if (force) { - sb->s_readonly_remount = 1; - smp_wmb(); + sb_start_ro_state_change(sb); } else { retval = sb_prepare_remount_readonly(sb); if (retval) @@ -953,12 +952,10 @@ int reconfigure_super(struct fs_context *fc) } } else if (remount_rw) { /* - * We set s_readonly_remount here to protect filesystem's - * reconfigure code from writes from userspace until - * reconfigure finishes. + * Protect filesystem's reconfigure code from writes from + * userspace until reconfigure finishes. */ - sb->s_readonly_remount = 1; - smp_wmb(); + sb_start_ro_state_change(sb); } if (fc->ops->reconfigure) { @@ -974,9 +971,7 @@ int reconfigure_super(struct fs_context *fc) WRITE_ONCE(sb->s_flags, ((sb->s_flags & ~fc->sb_flags_mask) | (fc->sb_flags & fc->sb_flags_mask))); - /* Needs to be ordered wrt mnt_is_readonly() */ - smp_wmb(); - sb->s_readonly_remount = 0; + sb_end_ro_state_change(sb); /* * Some filesystems modify their metadata via some other path than the @@ -991,7 +986,7 @@ int reconfigure_super(struct fs_context *fc) return 0; cancel_readonly: - sb->s_readonly_remount = 0; + sb_end_ro_state_change(sb); return retval; } |