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Commit 9f58d350 authored by Matthew L. Creech's avatar Matthew L. Creech Committed by Artem Bityutskiy
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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: default avatarMatthew L. Creech <mlcreech@gmail.com>
Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent e11602ea

fs/ubifs/debug.c

+2 −0
Original line number Diff line number Diff line
@@ -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",

		       le32_to_cpu(sup->min_io_size));

		printk(KERN_DEBUG "\tleb_size       %u\n",

fs/ubifs/sb.c

+1 −0
Original line number Diff line number Diff line
@@ -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;

fs/ubifs/ubifs-media.h

+2 −0
Original line number Diff line number Diff line
@@ -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 {

	UBIFS_FLG_BIGLPT = 0x02,

	UBIFS_FLG_SPACE_FIXUP = 0x04,

};



/**

fs/ubifs/ubifs.h

+2 −0
Original line number Diff line number Diff line
@@ -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;