UBIFS: add a superblock flag for free space fix-up
The 'space_fixup' flag can be set in the superblock of a new filesystem by
mkfs.ubifs to indicate that any eraseblocks with free space remaining should be
fixed-up the first time it's mounted (after which the flag is un-set). This
means that the UBIFS image has been flashed by a "dumb" flasher and the free
space has been actually programmed (writing all 0xFFs), so this free space
cannot be used. UBIFS fixes the free space up by re-writing the contents of all
LEBs with free space using the atomic LEB change UBI operation.
Artem: improved commit message, add some more commentaries to the code.
Signed-off-by: Matthew L. Creech <mlcreech@gmail.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/fs/ubifs/debug.c b/fs/ubifs/debug.c
index b5ba2ea..f46d77e 100644
--- a/fs/ubifs/debug.c
+++ b/fs/ubifs/debug.c
@@ -316,6 +316,8 @@
printk(KERN_DEBUG "\tflags %#x\n", sup_flags);
printk(KERN_DEBUG "\t big_lpt %u\n",
!!(sup_flags & UBIFS_FLG_BIGLPT));
+ printk(KERN_DEBUG "\t space_fixup %u\n",
+ !!(sup_flags & UBIFS_FLG_SPACE_FIXUP));
printk(KERN_DEBUG "\tmin_io_size %u\n",
le32_to_cpu(sup->min_io_size));
printk(KERN_DEBUG "\tleb_size %u\n",
diff --git a/fs/ubifs/sb.c b/fs/ubifs/sb.c
index cad60b5..93d6928 100644
--- a/fs/ubifs/sb.c
+++ b/fs/ubifs/sb.c
@@ -617,6 +617,7 @@
c->vfs_sb->s_time_gran = le32_to_cpu(sup->time_gran);
memcpy(&c->uuid, &sup->uuid, 16);
c->big_lpt = !!(sup_flags & UBIFS_FLG_BIGLPT);
+ c->space_fixup = !!(sup_flags & UBIFS_FLG_SPACE_FIXUP);
/* Automatically increase file system size to the maximum size */
c->old_leb_cnt = c->leb_cnt;
diff --git a/fs/ubifs/ubifs-media.h b/fs/ubifs/ubifs-media.h
index b922f03..e24380c 100644
--- a/fs/ubifs/ubifs-media.h
+++ b/fs/ubifs/ubifs-media.h
@@ -408,9 +408,11 @@
* Superblock flags.
*
* UBIFS_FLG_BIGLPT: if "big" LPT model is used if set
+ * UBIFS_FLG_SPACE_FIXUP: first-mount "fixup" of free space within LEBs needed
*/
enum {
UBIFS_FLG_BIGLPT = 0x02,
+ UBIFS_FLG_SPACE_FIXUP = 0x04,
};
/**
diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h
index a2f9d4e..8e27553 100644
--- a/fs/ubifs/ubifs.h
+++ b/fs/ubifs/ubifs.h
@@ -1014,6 +1014,7 @@
* @cmt_wq: wait queue to sleep on if the log is full and a commit is running
*
* @big_lpt: flag that LPT is too big to write whole during commit
+ * @space_fixup: flag indicating that free space in LEBs needs to be cleaned up
* @no_chk_data_crc: do not check CRCs when reading data nodes (except during
* recovery)
* @bulk_read: enable bulk-reads
@@ -1253,6 +1254,7 @@
wait_queue_head_t cmt_wq;
unsigned int big_lpt:1;
+ unsigned int space_fixup:1;
unsigned int no_chk_data_crc:1;
unsigned int bulk_read:1;
unsigned int default_compr:2;