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authorOleg Kanatov <okanatov@gmail.com>2022-10-28 14:22:54 +0200
committerDave Kleikamp <dave.kleikamp@oracle.com>2022-11-10 22:22:23 +0100
commita60dca73a1a8079d867b2c2e9549440346c1ba83 (patch)
tree0dd5dbe6120024a988fd4b08217b57ae05b3f2c8
parentjfs: Fix a typo in function jfs_umount (diff)
downloadlinux-a60dca73a1a8079d867b2c2e9549440346c1ba83.tar.xz
linux-a60dca73a1a8079d867b2c2e9549440346c1ba83.zip
jfs: makes diUnmount/diMount in jfs_mount_rw atomic
jfs_mount_rw can call diUnmount and then diMount. These calls change the imap pointer. Between these two calls there may be calls of function jfs_lookup(). The jfs_lookup() function calls jfs_iget(), which, in turn calls diRead(). The latter references the imap pointer. That may cause diRead() to refer to a pointer freed in diUnmount(). This commit makes the calls to diUnmount()/diMount() atomic so that nothing will read the imap pointer until the whole remount is completed. Signed-off-by: Oleg Kanatov <okanatov@gmail.com> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
-rw-r--r--fs/jfs/jfs_imap.c2
-rw-r--r--fs/jfs/jfs_mount.c4
2 files changed, 5 insertions, 1 deletions
diff --git a/fs/jfs/jfs_imap.c b/fs/jfs/jfs_imap.c
index 799d3837e7c2..390cbfce391f 100644
--- a/fs/jfs/jfs_imap.c
+++ b/fs/jfs/jfs_imap.c
@@ -310,8 +310,8 @@ int diRead(struct inode *ip)
iagno = INOTOIAG(ip->i_ino);
/* read the iag */
- imap = JFS_IP(ipimap)->i_imap;
IREAD_LOCK(ipimap, RDWRLOCK_IMAP);
+ imap = JFS_IP(ipimap)->i_imap;
rc = diIAGRead(imap, iagno, &mp);
IREAD_UNLOCK(ipimap);
if (rc) {
diff --git a/fs/jfs/jfs_mount.c b/fs/jfs/jfs_mount.c
index 48d1f70f786c..b83aae56a1f2 100644
--- a/fs/jfs/jfs_mount.c
+++ b/fs/jfs/jfs_mount.c
@@ -234,11 +234,15 @@ int jfs_mount_rw(struct super_block *sb, int remount)
truncate_inode_pages(sbi->ipimap->i_mapping, 0);
truncate_inode_pages(sbi->ipbmap->i_mapping, 0);
+
+ IWRITE_LOCK(sbi->ipimap, RDWRLOCK_IMAP);
diUnmount(sbi->ipimap, 1);
if ((rc = diMount(sbi->ipimap))) {
+ IWRITE_UNLOCK(sbi->ipimap);
jfs_err("jfs_mount_rw: diMount failed!");
return rc;
}
+ IWRITE_UNLOCK(sbi->ipimap);
dbUnmount(sbi->ipbmap, 1);
if ((rc = dbMount(sbi->ipbmap))) {