提交 6554a657 编写于 作者: M Matthew L. Creech 提交者: Artem Bityutskiy

UBIFS: add the fixup function

This patch adds the 'ubifs_fixup_free_space()' function which scans all
LEBs in the filesystem for those that are in-use but have one or more
empty pages, then re-maps the LEBs in order to erase the empty portions.
Afterward it removes the "space_fixup" flag from the UBIFS superblock.

Artem: massaged the patch
Signed-off-by: NMatthew L. Creech <mlcreech@gmail.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
上级 9f58d350
......@@ -652,3 +652,152 @@ int ubifs_read_superblock(struct ubifs_info *c)
kfree(sup);
return err;
}
/**
* fixup_leb - fixup/unmap an LEB containing free space.
* @c: UBIFS file-system description object
* @lnum: the LEB number to fix up
* @len: number of used bytes in LEB (starting at offset 0)
*
* This function reads the contents of the given LEB number @lnum, then fixes
* it up, so that empty min. I/O units in the end of LEB are actually erased on
* flash (rather than being just all-0xff real data). If the LEB is completely
* empty, it is simply unmapped.
*/
static int fixup_leb(struct ubifs_info *c, int lnum, int len)
{
int err;
ubifs_assert(len >= 0);
ubifs_assert(len % c->min_io_size == 0);
ubifs_assert(len < c->leb_size);
if (len == 0) {
dbg_mnt("unmap empty LEB %d", lnum);
return ubi_leb_unmap(c->ubi, lnum);
}
dbg_mnt("fixup LEB %d, data len %d", lnum, len);
err = ubi_read(c->ubi, lnum, c->sbuf, 0, len);
if (err)
return err;
return ubi_leb_change(c->ubi, lnum, c->sbuf, len, UBI_UNKNOWN);
}
/**
* fixup_free_space - find & remap all LEBs containing free space.
* @c: UBIFS file-system description object
*
* This function walks through all LEBs in the filesystem and fiexes up those
* containing free/empty space.
*/
static int fixup_free_space(struct ubifs_info *c)
{
int lnum, err = 0;
struct ubifs_lprops *lprops;
ubifs_get_lprops(c);
/* Fixup LEBs in the master area */
for (lnum = UBIFS_MST_LNUM; lnum < UBIFS_LOG_LNUM; lnum++) {
err = fixup_leb(c, lnum, c->mst_offs + c->mst_node_alsz);
if (err)
goto out;
}
/* Unmap unused log LEBs */
lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
while (lnum != c->ltail_lnum) {
err = fixup_leb(c, lnum, 0);
if (err)
goto out;
lnum = ubifs_next_log_lnum(c, lnum);
}
/* Fixup the current log head */
err = fixup_leb(c, c->lhead_lnum, c->lhead_offs);
if (err)
goto out;
/* Fixup LEBs in the LPT area */
for (lnum = c->lpt_first; lnum <= c->lpt_last; lnum++) {
int free = c->ltab[lnum - c->lpt_first].free;
if (free > 0) {
err = fixup_leb(c, lnum, c->leb_size - free);
if (err)
goto out;
}
}
/* Unmap LEBs in the orphans area */
for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
err = fixup_leb(c, lnum, 0);
if (err)
goto out;
}
/* Fixup LEBs in the main area */
for (lnum = c->main_first; lnum < c->leb_cnt; lnum++) {
lprops = ubifs_lpt_lookup(c, lnum);
if (IS_ERR(lprops)) {
err = PTR_ERR(lprops);
goto out;
}
if (lprops->free > 0) {
err = fixup_leb(c, lnum, c->leb_size - lprops->free);
if (err)
goto out;
}
}
out:
ubifs_release_lprops(c);
return err;
}
/**
* ubifs_fixup_free_space - find & fix all LEBs with free space.
* @c: UBIFS file-system description object
*
* This function fixes up LEBs containing free space on first mount, if the
* appropriate flag was set when the FS was created. Each LEB with one or more
* empty min. I/O unit (i.e. free-space-count > 0) is re-written, to make sure
* the free space is actually erased. E.g., this is necessary for some NAND
* chips, since the free space may have been programmed like real "0xff" data
* (generating a non-0xff ECC), causing future writes to the not-really-erased
* NAND pages to behave badly. After the space is fixed up, the superblock flag
* is cleared, so that this is skipped for all future mounts.
*/
int ubifs_fixup_free_space(struct ubifs_info *c)
{
int err;
struct ubifs_sb_node *sup;
ubifs_assert(c->space_fixup);
ubifs_assert(!c->ro_mount);
ubifs_msg("start fixing up free space");
err = fixup_free_space(c);
if (err)
return err;
sup = ubifs_read_sb_node(c);
if (IS_ERR(sup))
return PTR_ERR(sup);
/* Free-space fixup is no longer required */
c->space_fixup = 0;
sup->flags &= cpu_to_le32(~UBIFS_FLG_SPACE_FIXUP);
err = ubifs_write_sb_node(c, sup);
kfree(sup);
if (err)
return err;
ubifs_msg("free space fixup complete");
return err;
}
......@@ -1633,6 +1633,7 @@ int ubifs_write_master(struct ubifs_info *c);
int ubifs_read_superblock(struct ubifs_info *c);
struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c);
int ubifs_write_sb_node(struct ubifs_info *c, struct ubifs_sb_node *sup);
int ubifs_fixup_free_space(struct ubifs_info *c);
/* replay.c */
int ubifs_validate_entry(struct ubifs_info *c,
......
Markdown is supported
0% .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑!
想要评论请 注册