ubifs: Do not update inode size in-place in authenticated mode

In authenticated mode we cannot fixup the inode sizes in-place
during recovery as this would invalidate the hashes and HMACs
we stored for this inode.

Instead, we just write the updated inodes to the journal. We can
only do this after ubifs_rcvry_gc_commit() is done though, so for
authenticated mode call ubifs_recover_size() after
ubifs_rcvry_gc_commit() and not vice versa as normally done.

Calling ubifs_recover_size() after ubifs_rcvry_gc_commit() has the
drawback that after a commit the size fixup information is gone, so
when a powercut happens while recovering from another powercut
we may lose some data written right before the first powercut.
This is why we only do this in authenticated mode and leave the
behaviour for unauthenticated mode untouched.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

1 files changed, 83 insertions, 28 deletions

diff --git a/fs/ubifs/recovery.c b/fs/ubifs/recovery.c
index 5c1334e6bc81..8526b7ec4707 100644
--- a/fs/ubifs/recovery.c
+++ b/fs/ubifs/recovery.c
@@ -1463,15 +1463,81 @@ out:
 }
 
 /**
+ * inode_fix_size - fix inode size
+ * @c: UBIFS file-system description object
+ * @e: inode size information for recovery
+ */
+static int inode_fix_size(struct ubifs_info *c, struct size_entry *e)
+{
+        struct inode *inode;
+        struct ubifs_inode *ui;
+        int err;
+
+        if (c->ro_mount)
+                ubifs_assert(c, !e->inode);
+
+        if (e->inode) {
+                /* Remounting rw, pick up inode we stored earlier */
+                inode = e->inode;
+        } else {
+                inode = ubifs_iget(c->vfs_sb, e->inum);
+                if (IS_ERR(inode))
+                        return PTR_ERR(inode);
+
+                if (inode->i_size >= e->d_size) {
+                        /*
+                         * The original inode in the index already has a size
+                         * big enough, nothing to do
+                         */
+                        iput(inode);
+                        return 0;
+                }
+
+                dbg_rcvry("ino %lu size %lld -> %lld",
+                          (unsigned long)e->inum,
+                          inode->i_size, e->d_size);
+
+                ui = ubifs_inode(inode);
+
+                inode->i_size = e->d_size;
+                ui->ui_size = e->d_size;
+                ui->synced_i_size = e->d_size;
+
+                e->inode = inode;
+        }
+
+        /*
+         * In readonly mode just keep the inode pinned in memory until we go
+         * readwrite. In readwrite mode write the inode to the journal with the
+         * fixed size.
+         */
+        if (c->ro_mount)
+                return 0;
+
+        err = ubifs_jnl_write_inode(c, inode);
+
+        iput(inode);
+
+        if (err)
+                return err;
+
+        rb_erase(&e->rb, &c->size_tree);
+        kfree(e);
+
+        return 0;
+}
+
+/**
  * ubifs_recover_size - recover inode size.
  * @c: UBIFS file-system description object
+ * @in_place: If true, do a in-place size fixup
  *
  * This function attempts to fix inode size discrepancies identified by the
  * 'ubifs_recover_size_accum()' function.
  *
  * This functions returns %0 on success and a negative error code on failure.
  */
-int ubifs_recover_size(struct ubifs_info *c)
+int ubifs_recover_size(struct ubifs_info *c, bool in_place)
 {
         struct rb_node *this = rb_first(&c->size_tree);
 
@@ -1480,6 +1546,9 @@ int ubifs_recover_size(struct ubifs_info *c)
                 int err;
 
                 e = rb_entry(this, struct size_entry, rb);
+
+                this = rb_next(this);
+
                 if (!e->exists) {
                         union ubifs_key key;
 
@@ -1503,40 +1572,26 @@ int ubifs_recover_size(struct ubifs_info *c)
                 }
 
                 if (e->exists && e->i_size < e->d_size) {
-                        if (c->ro_mount) {
-                                /* Fix the inode size and pin it in memory */
-                                struct inode *inode;
-                                struct ubifs_inode *ui;
-
-                                ubifs_assert(c, !e->inode);
-
-                                inode = ubifs_iget(c->vfs_sb, e->inum);
-                                if (IS_ERR(inode))
-                                        return PTR_ERR(inode);
-
-                                ui = ubifs_inode(inode);
-                                if (inode->i_size < e->d_size) {
-                                        dbg_rcvry("ino %lu size %lld -> %lld",
-                                                  (unsigned long)e->inum,
-                                                  inode->i_size, e->d_size);
-                                        inode->i_size = e->d_size;
-                                        ui->ui_size = e->d_size;
-                                        ui->synced_i_size = e->d_size;
-                                        e->inode = inode;
-                                        this = rb_next(this);
-                                        continue;
-                                }
-                                iput(inode);
-                        } else {
-                                /* Fix the size in place */
+                        ubifs_assert(c, !(c->ro_mount && in_place));
+
+                        /*
+                         * We found data that is outside the found inode size,
+                         * fixup the inode size
+                         */
+
+                        if (in_place) {
                                 err = fix_size_in_place(c, e);
                                 if (err)
                                         return err;
                                 iput(e->inode);
+                        } else {
+                                err = inode_fix_size(c, e);
+                                if (err)
+                                        return err;
+                                continue;
                         }
                 }
 
-                this = rb_next(this);
                 rb_erase(&e->rb, &c->size_tree);
                 kfree(e);
         }