Commit 9f58d350 authored by Matthew L. Creech's avatar Matthew L. Creech Committed by Artem Bityutskiy

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: 's avatarMatthew L. Creech <>
Signed-off-by: 's avatarArtem Bityutskiy <>
parent e11602ea
......@@ -316,6 +316,8 @@ void dbg_dump_node(const struct ubifs_info *c, const void *node)
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",
printk(KERN_DEBUG "\tleb_size %u\n",
......@@ -617,6 +617,7 @@ int ubifs_read_superblock(struct ubifs_info *c)
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;
......@@ -408,9 +408,11 @@ enum {
* 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 {
......@@ -1014,6 +1014,7 @@ struct ubifs_debug_info;
* @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 @@ struct ubifs_info {
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;
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