| Message ID | 161076033640.3386689.11320451390779411930.stgit@magnolia (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | various: random fixes | expand |
On 16 Jan 2021 at 06:55, Darrick J. Wong wrote: > From: Darrick J. Wong <djwong@kernel.org> > > The name scanner in xfs_scrub cannot lock a namespace (dirent or xattr) > and the kernel does not provide a stable cursor interface, which means > that we can see the same byte sequence multiple times during a scan. > This isn't a confusing name error since the kernel enforces uniqueness > on the byte sequence, so all we need to do here is update the old entry. > Looks good to me. Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com> > Signed-off-by: Darrick J. Wong <djwong@kernel.org> > --- > scrub/unicrash.c | 16 +++++++++++++++- > 1 file changed, 15 insertions(+), 1 deletion(-) > > > diff --git a/scrub/unicrash.c b/scrub/unicrash.c > index de3217c2..cb0880c1 100644 > --- a/scrub/unicrash.c > +++ b/scrub/unicrash.c > @@ -68,7 +68,7 @@ struct name_entry { > > xfs_ino_t ino; > > - /* Raw UTF8 name */ > + /* Raw dirent name */ > size_t namelen; > char name[0]; > }; > @@ -627,6 +627,20 @@ unicrash_add( > uc->buckets[bucket] = new_entry; > > while (entry != NULL) { > + /* > + * If we see the same byte sequence then someone's modifying > + * the namespace while we're scanning it. Update the existing > + * entry's inode mapping and erase the new entry from existence. > + */ > + if (new_entry->namelen == entry->namelen && > + !memcmp(new_entry->name, entry->name, entry->namelen)) { > + entry->ino = new_entry->ino; > + uc->buckets[bucket] = new_entry->next; > + name_entry_free(new_entry); > + *badflags = 0; > + return; > + } > + > /* Same normalization? */ > if (new_entry->normstrlen == entry->normstrlen && > !u_strcmp(new_entry->normstr, entry->normstr) &&
diff --git a/scrub/unicrash.c b/scrub/unicrash.c index de3217c2..cb0880c1 100644 --- a/scrub/unicrash.c +++ b/scrub/unicrash.c @@ -68,7 +68,7 @@ struct name_entry { xfs_ino_t ino; - /* Raw UTF8 name */ + /* Raw dirent name */ size_t namelen; char name[0]; }; @@ -627,6 +627,20 @@ unicrash_add( uc->buckets[bucket] = new_entry; while (entry != NULL) { + /* + * If we see the same byte sequence then someone's modifying + * the namespace while we're scanning it. Update the existing + * entry's inode mapping and erase the new entry from existence. + */ + if (new_entry->namelen == entry->namelen && + !memcmp(new_entry->name, entry->name, entry->namelen)) { + entry->ino = new_entry->ino; + uc->buckets[bucket] = new_entry->next; + name_entry_free(new_entry); + *badflags = 0; + return; + } + /* Same normalization? */ if (new_entry->normstrlen == entry->normstrlen && !u_strcmp(new_entry->normstr, entry->normstr) &&