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Fixed mkdir when inserting into a non-end block

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This was an oversight on my part when adding strict ordering to
directories. Unfortunately now we can't take advantage of the atomic
creation of tail+dir entries. Now we need to first create the tail, then
create the actually directory entry. If we lose power, the orphan is
cleaned up like orphans created during remove.

Note that we still take advantage of the atomic tail+dir entries if we
are an end block. This is actually because this corner case is
complicated to _not_ do atomically, needing to update the directory we
just committed to.
This commit is contained in:
Christopher Haster
2018-10-05 18:22:33 -05:00
parent 97a7191814
commit 795dd8c7ab
3 changed files with 39 additions and 10 deletions
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45
lfs.c
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@@ -1746,29 +1746,58 @@ int lfs_mkdir(lfs_t *lfs, const char *path) {
// build up new directory
lfs_alloc_ack(lfs);
lfs_mdir_t dir;
err = lfs_dir_alloc(lfs, &dir);
if (err) {
return err;
}
dir.tail[0] = cwd.tail[0];
dir.tail[1] = cwd.tail[1];
// find end of list
lfs_mdir_t pred = cwd;
while (pred.split) {
err = lfs_dir_fetch(lfs, &pred, pred.tail);
if (err) {
return err;
}
}
// setup dir
dir.tail[0] = pred.tail[0];
dir.tail[1] = pred.tail[1];
err = lfs_dir_commit(lfs, &dir, NULL);
if (err) {
return err;
}
// get next slot and commit
cwd.tail[0] = dir.pair[0];
cwd.tail[1] = dir.pair[1];
// current block end of list?
if (!cwd.split) {
// update atomically
cwd.tail[0] = dir.pair[0];
cwd.tail[1] = dir.pair[1];
} else {
// update tails, this creates a desync
pred.tail[0] = dir.pair[0];
pred.tail[1] = dir.pair[1];
lfs_global_orphans(lfs, +1);
err = lfs_dir_commit(lfs, &pred,
LFS_MKATTR(LFS_TYPE_SOFTTAIL, 0x1ff,
pred.tail, sizeof(pred.tail),
NULL));
if (err) {
return err;
}
lfs_global_orphans(lfs, -1);
}
// now insert into our parent block
lfs_pair_tole32(dir.pair);
err = lfs_dir_commit(lfs, &cwd,
LFS_MKATTR(LFS_TYPE_SOFTTAIL, 0x1ff, cwd.tail, sizeof(cwd.tail),
LFS_MKATTR(LFS_TYPE_DIRSTRUCT, id, dir.pair, sizeof(dir.pair),
LFS_MKATTR(LFS_TYPE_DIR, id, path, nlen,
NULL))));
(!cwd.split)
? LFS_MKATTR(LFS_TYPE_SOFTTAIL, 0x1ff,
cwd.tail, sizeof(cwd.tail), NULL)
: NULL)));
lfs_pair_fromle32(dir.pair);
if (err) {
return err;