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[LogFS] Fix bdev erases

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Erases for block devices were always just emulated by writing 0xff.
Some time back the write was removed and only the page cache was
changed to 0xff.  Superficialy a good idea with two problems:
1. Touching the page cache isn't necessary either.
2. However, writing out 0xff _is_ necessary for the journal.  As the
   journal is scanned linearly, an old non-overwritten commit entry
   can be used on next mount and cause havoc.

This should fix both aspects.
This commit is contained in:
Joern Engel
2010-03-04 21:30:58 +01:00
parent 5c564c2a04
commit 9421502b4f
6 changed files with 97 additions and 20 deletions
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12
fs/logfs/super.c
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@@ -317,6 +317,7 @@ static int logfs_make_writeable(struct super_block *sb)
static int logfs_get_sb_final(struct super_block *sb, struct vfsmount *mnt)
{
struct logfs_super *super = logfs_super(sb);
struct inode *rootdir;
int err;
@@ -329,15 +330,22 @@ static int logfs_get_sb_final(struct super_block *sb, struct vfsmount *mnt)
if (!sb->s_root)
goto fail;
super->s_erase_page = alloc_pages(GFP_KERNEL, 0);
if (!super->s_erase_page)
goto fail2;
memset(page_address(super->s_erase_page), 0xFF, PAGE_SIZE);
/* FIXME: check for read-only mounts */
err = logfs_make_writeable(sb);
if (err)
goto fail2;
goto fail3;
log_super("LogFS: Finished mounting\n");
simple_set_mnt(mnt, sb);
return 0;
fail3:
__free_page(super->s_erase_page);
fail2:
iput(rootdir);
fail:
@@ -498,6 +506,8 @@ static void logfs_kill_sb(struct super_block *sb)
logfs_cleanup_journal(sb);
logfs_cleanup_areas(sb);
logfs_cleanup_rw(sb);
if (super->s_erase_page)
__free_page(super->s_erase_page);
super->s_devops->put_device(sb);
mempool_destroy(super->s_btree_pool);
mempool_destroy(super->s_alias_pool);