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>

diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c
index 1c1bbe4135c64dc606e8eb680fdaf6192f9491c9..2c91d6fa4e058e6b5136b2714da0f54cc61bfe6f 100644 (file)
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1073,6 +1073,30 @@ 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;