[BUG]
At least two users have already hit a bug in btrfs causing file
missing(Chromium config file).
The missing file's nlink is still 1 but its backref points to non-exist
parent inode.
This should be a kernel bug, but btrfsck fix is needed anyway.
[FIX]
For such nlink mismatch inode, we will delete all the invalid backref,
if there is no valid backref for it, create 'lost+found' under the root
of the subvolume and add link to the directory.
Reported-by: Mike Gavrilov <mikhail.v.gavrilov@xxxxxxxxx>
Reported-by: Ed Tomlinson <edt@xxxxxx>
Signed-off-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
---
cmds-check.c | 276 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 272 insertions(+), 4 deletions(-)
diff --git a/cmds-check.c b/cmds-check.c
index 6419caf..2b3263b 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -27,6 +27,7 @@
#include <unistd.h>
#include <getopt.h>
#include <uuid/uuid.h>
+#include <math.h>
#include "ctree.h"
#include "volumes.h"
#include "repair.h"
@@ -1777,6 +1778,73 @@ static int create_inode_item(struct btrfs_root *root,
return 0;
}
+/* Check the dir_item/index conflicts before insert */
+static int check_dir_conflict(struct btrfs_root *root,
+ char *name, int namelen,
+ u64 dir, u64 index)
+{
+ struct btrfs_path *path;
+ struct btrfs_key key;
+ struct btrfs_inode_item *inode_item;
+ struct btrfs_dir_item *dir_item;
+ int ret = 0;
+
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+
+ /* Given dir exists? */
+ key.objectid = dir;
+ key.type = BTRFS_INODE_ITEM_KEY;
+ key.offset = 0;
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+ if (ret > 0) {
+ ret = -ENOENT;
+ goto out;
+ }
+
+ /* Is it a dir? */
+ inode_item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_inode_item);
+ if (!(btrfs_inode_mode(path->nodes[0], inode_item) &
+ S_IFDIR)) {
+ ret = -ENOTDIR;
+ goto out;
+ }
+ btrfs_release_path(path);
+
+ /* Name conflicting? */
+ dir_item = btrfs_lookup_dir_item(NULL, root, path, dir, name,
+ namelen, 0);
+ if (IS_ERR(dir_item)) {
+ ret = PTR_ERR(dir_item);
+ goto out;
+ }
+ if (dir_item) {
+ ret = -EEXIST;
+ goto out;
+ }
+ btrfs_release_path(path);
+
+ /* Index conflicting? */
+ dir_item = btrfs_lookup_dir_index(NULL, root, path, dir, name,
+ namelen, index, 0);
+ if (IS_ERR(dir_item)) {
+ ret = PTR_ERR(dir_item);
+ goto out;
+ }
+ if (dir_item) {
+ ret = -EEXIST;
+ goto out;
+ }
+
+out:
+ btrfs_free_path(path);
+ return ret;
+}
+
static int repair_inode_backrefs(struct btrfs_root *root,
struct inode_record *rec,
struct cache_tree *inode_cache,
@@ -1837,6 +1905,18 @@ static int repair_inode_backrefs(struct btrfs_root *root,
struct btrfs_trans_handle *trans;
struct btrfs_key location;
+ ret = check_dir_conflict(root, backref->name,
+ backref->namelen,
+ backref->dir,
+ backref->index);
+ if (ret) {
+ /*
+ * let nlink fixing routine to handle it,
+ * which can do it better.
+ */
+ ret = 0;
+ break;
+ }
location.objectid = rec->ino;
location.type = BTRFS_INODE_ITEM_KEY;
location.offset = 0;
@@ -1874,20 +1954,206 @@ static int repair_inode_backrefs(struct btrfs_root *root,
return ret ? ret : repaired;
}
+/*
+ * Search for the inode_ref of given 'ino' to get the filename and
+ * btrfs type.
+ * This will only use the first inode_ref.
+ */
+static int find_file_name_type(struct btrfs_root *root,
+ struct btrfs_path *path,
+ u64 ino, char *buf,
+ int *namelen, u8 *type)
+{
+ struct btrfs_key key;
+ struct btrfs_key found_key;
+ struct btrfs_inode_ref *inode_ref;
+ struct btrfs_inode_item *inode_item;
+ struct extent_buffer *node;
+ u32 ret_namelen;
+ int slot;
+ int ret = 0;
+
+ /* Search for name in backref(Use the first one) */
+ key.objectid = ino;
+ key.type = BTRFS_INODE_REF_KEY;
+ key.offset = 0;
+
+ ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
+ if (ret < 0)
+ goto out;
+ node = path->nodes[0];
+ slot = path->slots[0];
+ btrfs_item_key_to_cpu(node, &found_key, slot);
+ if (found_key.objectid != ino ||
+ found_key.type != BTRFS_INODE_REF_KEY) {
+ ret = -ENOENT;
+ goto out;
+ }
+ inode_ref = btrfs_item_ptr(node, slot, struct btrfs_inode_ref);
+ ret_namelen = btrfs_inode_ref_name_len(node, inode_ref);
+ read_extent_buffer(node, buf, (unsigned long)(inode_ref + 1),
+ ret_namelen);
+ /* Search for inode type */
+ ret = btrfs_previous_item(root, path, ino, BTRFS_INODE_ITEM_KEY);
+ if (ret) {
+ if (ret > 0)
+ ret = -ENOENT;
+ goto out;
+ }
+ node = path->nodes[0];
+ slot = path->slots[0];
+ inode_item = btrfs_item_ptr(node, slot, struct btrfs_inode_item);
+
+ if (namelen)
+ *namelen = ret_namelen;
+ if (type)
+ *type = imode_to_type(btrfs_inode_mode(node, inode_item));
+out:
+ btrfs_release_path(path);
+ return ret;
+}
+
+
+static int remove_all_invalid_backref(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct inode_record *rec)
+{
+ struct inode_backref *backref;
+ struct inode_backref *tmp;
+ int ret = 0;
+
+ list_for_each_entry_safe(backref, tmp, &rec->backrefs, list) {
+ if (backref->found_dir_item &&
+ backref->found_inode_ref &&
+ backref->found_dir_index)
+ continue;
+
+ /*
+ * We can only handle case that has inode ref but points to
+ * invalid dir_index/dir_item.
+ */
+ if (!backref->found_inode_ref)
+ return -ENOENT;
+ ret = btrfs_unlink(trans, root, rec->ino, backref->dir,
+ backref->index, backref->name,
+ backref->namelen, 0);
+ if (ret < 0)
+ goto out;
+ list_del(&backref->list);
+ free(backref);
+ rec->nlink--;
+ }
+out:
+ return ret;
+}
+
+
+static int repair_inode_nlinks(struct btrfs_trans_handle *trans,
+ struct btrfs_root *root,
+ struct btrfs_path *path,
+ struct inode_record *rec)
+{
+ char *dir_name = "lost+found";
+ char namebuf[BTRFS_NAME_LEN] = {0};
+ u64 lost_found_ino;
+ u32 mode = 0700;
+ u8 type = 0;
+ int namelen = 0;
+ int ret = 0;
+
+ /*
+ * Get file name and type first before these invalid inode ref
+ * are deleted by remove_all_invalid_backref()
+ */
+ ret = find_file_name_type(root, path, rec->ino, namebuf,
+ &namelen, &type);
+ if (ret < 0) {
+ fprintf(stderr,
+ "Fail to get file name of inode %llu: %s\n",
+ rec->ino, strerror(-ret));
+ goto out;
+ }
+ ret = remove_all_invalid_backref(trans, root, rec);
+ if (ret < 0) {
+ fprintf(stderr,
+ "Fail to cleanup invalid backref for inode %llu: %s\n",
+ rec->ino, strerror(-ret));
+ goto out;
+ }
+
+ if (rec->found_link == 0) {
+ ret = btrfs_mkdir(trans, root, dir_name, strlen(dir_name),
+ BTRFS_FIRST_FREE_OBJECTID, &lost_found_ino,
+ mode);
+ if (ret < 0) {
+ fprintf(stderr, "Failed to create '%s' dir: %s",
+ dir_name, strerror(-ret));
+ goto out;
+ }
+ ret = btrfs_add_link(trans, root, rec->ino, lost_found_ino,
+ namebuf, namelen, type, NULL, 1);
+ if (ret == -EEXIST) {
+ /*
+ * Conflicting file name, add ".INO" as suffix
+ * +1 for '.' and +1 for log10
+ */
+ if (namelen + log10(rec->ino) + 2 > BTRFS_NAME_LEN) {
+ ret = -EFBIG;
+ goto out;
+ }
+ snprintf(namebuf + namelen, BTRFS_NAME_LEN - namelen,
+ ".%llu", rec->ino);
+ namelen += (log10(rec->ino) + 2);
+ ret = btrfs_add_link(trans, root, rec->ino,
+ lost_found_ino, namebuf,
+ namelen, type, NULL, 1);
+ }
+ if (ret < 0) {
+ fprintf(stderr,
+ "Fail to link the inode %llu to %s dir: %s",
+ rec->ino, dir_name, strerror(-ret));
+ goto out;
+ }
+ /*
+ * Just increase the found_link, don't actually add the
+ * backref. This will make things easiler and this inode
+ * record will be freed after the repair is done.
+ * So fsck will not report problem about this inode.
+ */
+ rec->found_link++;
+ printf("Moving file '%.*s' to '%s' dir due to its invalid backref\n",
+ namelen, namebuf, dir_name);
+ }
+ rec->errors &= ~I_ERR_LINK_COUNT_WRONG;
+ printf("Fixed the nlink of inode %llu\n", rec->ino);
+out:
+ btrfs_release_path(path);
+ return ret;
+}
+
static int try_repair_inode(struct btrfs_root *root, struct inode_record *rec)
{
struct btrfs_trans_handle *trans;
struct btrfs_path *path;
int ret = 0;
- if (!(rec->errors & (I_ERR_DIR_ISIZE_WRONG | I_ERR_NO_ORPHAN_ITEM)))
+ if (!(rec->errors & (I_ERR_DIR_ISIZE_WRONG |
+ I_ERR_NO_ORPHAN_ITEM |
+ I_ERR_LINK_COUNT_WRONG)))
return rec->errors;
path = btrfs_alloc_path();
if (!path)
return -ENOMEM;
- trans = btrfs_start_transaction(root, 1);
+ /*
+ * For nlink repair, it may create a dir and add link, so
+ * 2 for parent(256)'s dir_index and dir_item
+ * 2 for lost+found dir's inode_item and inode_ref
+ * 1 for the new inode_ref of the file
+ * 2 for lost+found dir's dir_index and dir_item for the file
+ */
+ trans = btrfs_start_transaction(root, 7);
if (IS_ERR(trans)) {
btrfs_free_path(path);
return PTR_ERR(trans);
@@ -1897,6 +2163,8 @@ static int try_repair_inode(struct btrfs_root *root, struct inode_record *rec)
ret = repair_inode_isize(trans, root, path, rec);
if (!ret && rec->errors & I_ERR_NO_ORPHAN_ITEM)
ret = repair_inode_orphan_item(trans, root, path, rec);
+ if (!ret && rec->errors & I_ERR_LINK_COUNT_WRONG)
+ ret = repair_inode_nlinks(trans, root, path, rec);
btrfs_commit_transaction(trans, root);
btrfs_free_path(path);
return ret;
@@ -2032,6 +2300,8 @@ static int check_inode_recs(struct btrfs_root *root,
}
}
+ if (rec->found_link != rec->nlink)
+ rec->errors |= I_ERR_LINK_COUNT_WRONG;
if (repair) {
ret = try_repair_inode(root, rec);
if (ret == 0 && can_free_inode_rec(rec)) {
@@ -2044,8 +2314,6 @@ static int check_inode_recs(struct btrfs_root *root,
error++;
if (!rec->found_inode_item)
rec->errors |= I_ERR_NO_INODE_ITEM;
- if (rec->found_link != rec->nlink)
- rec->errors |= I_ERR_LINK_COUNT_WRONG;
print_inode_error(root, rec);
list_for_each_entry(backref, &rec->backrefs, list) {
if (!backref->found_dir_item)
--
2.1.3
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