Patch "gfs2: bypass signal_our_withdraw if no journal" has been added to the 5.11-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    gfs2: bypass signal_our_withdraw if no journal

to the 5.11-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     gfs2-bypass-signal_our_withdraw-if-no-journal.patch
and it can be found in the queue-5.11 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit cf0f4ecdb8efff3a6ce51555938dd737c02f2222
Author: Bob Peterson <rpeterso@xxxxxxxxxx>
Date:   Fri Mar 12 07:58:54 2021 -0500

    gfs2: bypass signal_our_withdraw if no journal
    
    [ Upstream commit d5bf630f355d8c532bef2347cf90e8ae60a5f1bd ]
    
    Before this patch, function signal_our_withdraw referenced the journal
    inode immediately. But corrupt file systems may have some invalid
    journals, in which case our attempt to read it in will withdraw and the
    resulting signal_our_withdraw would dereference the NULL value.
    
    This patch adds a check to signal_our_withdraw so that if the journal
    has not yet been initialized, it simply returns and does the old-style
    withdraw.
    
    Thanks, Andy Price, for his analysis.
    
    Reported-by: syzbot+50a8a9cf8127f2c6f5df@xxxxxxxxxxxxxxxxxxxxxxxxx
    Fixes: 601ef0d52e96 ("gfs2: Force withdraw to replay journals and wait for it to finish")
    Signed-off-by: Bob Peterson <rpeterso@xxxxxxxxxx>
    Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/gfs2/util.c b/fs/gfs2/util.c
index 8d3c670c990f..dc4985429cf2 100644
--- a/fs/gfs2/util.c
+++ b/fs/gfs2/util.c
@@ -119,17 +119,22 @@ void gfs2_freeze_unlock(struct gfs2_holder *freeze_gh)
 static void signal_our_withdraw(struct gfs2_sbd *sdp)
 {
 	struct gfs2_glock *live_gl = sdp->sd_live_gh.gh_gl;
-	struct inode *inode = sdp->sd_jdesc->jd_inode;
-	struct gfs2_inode *ip = GFS2_I(inode);
-	struct gfs2_glock *i_gl = ip->i_gl;
-	u64 no_formal_ino = ip->i_no_formal_ino;
+	struct inode *inode;
+	struct gfs2_inode *ip;
+	struct gfs2_glock *i_gl;
+	u64 no_formal_ino;
 	int log_write_allowed = test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);
 	int ret = 0;
 	int tries;
 
-	if (test_bit(SDF_NORECOVERY, &sdp->sd_flags))
+	if (test_bit(SDF_NORECOVERY, &sdp->sd_flags) || !sdp->sd_jdesc)
 		return;
 
+	inode = sdp->sd_jdesc->jd_inode;
+	ip = GFS2_I(inode);
+	i_gl = ip->i_gl;
+	no_formal_ino = ip->i_no_formal_ino;
+
 	/* Prevent any glock dq until withdraw recovery is complete */
 	set_bit(SDF_WITHDRAW_RECOVERY, &sdp->sd_flags);
 	/*