UBIFS: allow mounting when short of space

It is fine if there is not free space - we should still allow mounting
this FS. This patch relaxes the free space requirements and adds info
dumps.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

1 files changed, 29 insertions, 11 deletions

diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 1c1bbe4135c6..2c91d6fa4e05 100644
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1074,6 +1074,30 @@ again:
 }
 
 /**
+ * check_free_space - check if there is enough free space to mount.
+ * @c: UBIFS file-system description object
+ *
+ * This function makes sure UBIFS has enough free space to be mounted in
+ * read/write mode. UBIFS must always have some free space to allow deletions.
+ */
+static int check_free_space(struct ubifs_info *c)
+{
+        ubifs_assert(c->dark_wm > 0);
+        if (c->lst.total_free + c->lst.total_dirty < c->dark_wm) {
+                ubifs_err("insufficient free space to mount in read/write mode");
+                dbg_dump_budg(c);
+                dbg_dump_lprops(c);
+                /*
+                 * We return %-EINVAL instead of %-ENOSPC because it seems to
+                 * be the closest error code mentioned in the mount function
+                 * documentation.
+                 */
+                return -EINVAL;
+        }
+        return 0;
+}
+
+/**
  * mount_ubifs - mount UBIFS file-system.
  * @c: UBIFS file-system description object
  *
@@ -1154,7 +1178,7 @@ static int mount_ubifs(struct ubifs_info *c)
 
         /*
          * Make sure the compressor which is set as default in the superblock
-         * or overriden by mount options is actually compiled in.
+         * or overridden by mount options is actually compiled in.
          */
         if (!ubifs_compr_present(c->default_compr)) {
                 ubifs_err("'compressor \"%s\" is not compiled in",
@@ -1236,12 +1260,9 @@ static int mount_ubifs(struct ubifs_info *c)
         if (!mounted_read_only) {
                 int lnum;
 
-                /* Check for enough free space */
-                if (ubifs_calc_available(c, c->min_idx_lebs) <= 0) {
-                        ubifs_err("insufficient available space");
-                        err = -EINVAL;
+                err = check_free_space(c);
+                if (err)
                         goto out_orphans;
-                }
 
                 /* Check for enough log space */
                 lnum = c->lhead_lnum + 1;
@@ -1442,12 +1463,9 @@ static int ubifs_remount_rw(struct ubifs_info *c)
         c->remounting_rw = 1;
         c->always_chk_crc = 1;
 
-        /* Check for enough free space */
-        if (ubifs_calc_available(c, c->min_idx_lebs) <= 0) {
-                ubifs_err("insufficient available space");
-                err = -EINVAL;
+        err = check_free_space(c);
+        if (err)
                 goto out;
-        }
 
         if (c->old_leb_cnt != c->leb_cnt) {
                 struct ubifs_sb_node *sup;