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Removed file outlining on ENOSPC in lfs_file_sync

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This was initially added as protection against the case where a file
grew to no longer fit in a metadata-pair. While in most cases this
should be caught by the math in lfs_file_write, it doesn't handle a
problem that can happen if the files metadata is large enough that even
small inline files can't fit. This can happen if you combine a small
block size with large file names and many custom attributes.

But trying to outline on ENOSPC creates creates a lot of problems.

If we are actually low on space, this is one of the worst things we can
do. Inline files take up less space than CTZ skip-lists, but inline
files are rendered useless if we outline inline files as soon as we run
low on space.

On top of this, the outlining logic tries multiple mdir commits if it
gets ENOSPC, which can hide errors if ENOSPC is returned for other
reasons.

In a perfect world, we would be using a different error code for
no-room-in-metadata-pair, and no-blocks-on-disk.

For now I've removed the outlining logic and we will need to figure out
how to handle this situation more robustly.
This commit is contained in:
Christopher Haster
2020-01-29 22:05:58 -06:00
parent 44d7112794
commit f9c2fd93f2
1 changed files with 23 additions and 24 deletions
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47
lfs.c
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@@ -1631,33 +1631,17 @@ static int lfs_dir_compact(lfs_t *lfs,
// TODO huh?
LFS_ASSERT(commit.off % lfs->cfg->prog_size == 0);
// update gstate
lfs->gdelta = (lfs_gstate_t){0};
if (!relocated) {
lfs->gdisk = lfs->gstate;
}
// TODO here??
if (relocated) {
// update references if we relocated
LFS_DEBUG("Relocating %"PRIx32" %"PRIx32" -> %"PRIx32" %"PRIx32,
oldpair[0], oldpair[1], dir->pair[0], dir->pair[1]);
err = lfs_fs_relocate(lfs, oldpair, dir->pair);
if (err) {
// TODO make better
dir->pair[1] = oldpair[1]; //
return err;
}
LFS_DEBUG("Relocated %"PRIx32" %"PRIx32" -> %"PRIx32" %"PRIx32,
oldpair[0], oldpair[1], dir->pair[0], dir->pair[1]);
}
// successful compaction, swap dir pair to indicate most recent
lfs_pair_swap(dir->pair);
dir->rev = nrev;
dir->count = end - begin;
dir->off = commit.off;
dir->etag = commit.ptag;
// update gstate
lfs->gdelta = (lfs_gstate_t){0};
if (!relocated) {
lfs->gdisk = lfs->gstate;
}
}
break;
@@ -1685,6 +1669,21 @@ relocate:
continue;
}
// TODO here??
if (relocated) {
// update references if we relocated
LFS_DEBUG("Relocating %"PRIx32" %"PRIx32" -> %"PRIx32" %"PRIx32,
oldpair[0], oldpair[1], dir->pair[0], dir->pair[1]);
int err = lfs_fs_relocate(lfs, oldpair, dir->pair);
if (err) {
// TODO make better
//dir->pair[1] = oldpair[1]; //
return err;
}
LFS_DEBUG("Relocated %"PRIx32" %"PRIx32" -> %"PRIx32" %"PRIx32,
oldpair[0], oldpair[1], dir->pair[0], dir->pair[1]);
}
return 0;
}
@@ -2739,9 +2738,9 @@ int lfs_file_sync(lfs_t *lfs, lfs_file_t *file) {
{LFS_MKTAG(LFS_FROM_USERATTRS, file->id,
file->cfg->attr_count), file->cfg->attrs}));
if (err) {
if (err == LFS_ERR_NOSPC && (file->flags & LFS_F_INLINE)) {
goto relocate;
}
// if (err == LFS_ERR_NOSPC && (file->flags & LFS_F_INLINE)) {
// goto relocate;
// }
file->flags |= LFS_F_ERRED;
LFS_TRACE("lfs_file_sync -> %d", err);
return err;