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ubifs: Check link count of inodes when killing orphans. 

O_TMPFILE files can change their link count back to non-zero.
This corner case needs to get addressed in the orphans subsystem
too.

Fixes: 474b93704f ("ubifs: Implement O_TMPFILE")
Reported-by: Lars Persson <lists@bofh.nu>
Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Richard Weinberger 2019-05-15 22:31:13 +02:00
parent eeabb9866e
commit ee1438ce5d
1 changed files with 35 additions and 9 deletions
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44
fs/ubifs/orphan.c
View File

@ -630,6 +630,7 @@ static int do_kill_orphans(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
{
struct ubifs_scan_node *snod;
struct ubifs_orph_node *orph;
struct ubifs_ino_node *ino = NULL;
unsigned long long cmt_no;
ino_t inum;
int i, n, err, first = 1;
@ -676,23 +677,40 @@ static int do_kill_orphans(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
if (first)
first = 0;
ino = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
if (!ino)
return -ENOMEM;
n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
for (i = 0; i < n; i++) {
union ubifs_key key1, key2;
inum = le64_to_cpu(orph->inos[i]);
dbg_rcvry("deleting orphaned inode %lu",
(unsigned long)inum);
lowest_ino_key(c, &key1, inum);
highest_ino_key(c, &key2, inum);
err = ubifs_tnc_remove_range(c, &key1, &key2);
ino_key_init(c, &key1, inum);
err = ubifs_tnc_lookup(c, &key1, ino);
if (err)
return err;
goto out_free;
/*
* Check whether an inode can really get deleted.
* linkat() with O_TMPFILE allows rebirth of an inode.
*/
if (ino->nlink == 0) {
dbg_rcvry("deleting orphaned inode %lu",
(unsigned long)inum);
lowest_ino_key(c, &key1, inum);
highest_ino_key(c, &key2, inum);
err = ubifs_tnc_remove_range(c, &key1, &key2);
if (err)
goto out_ro;
}
err = insert_dead_orphan(c, inum);
if (err)
return err;
goto out_free;
}
*last_cmt_no = cmt_no;
@ -704,7 +722,15 @@ static int do_kill_orphans(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
*last_flagged = 0;
}
return 0;
err = 0;
out_free:
kfree(ino);
return err;
out_ro:
ubifs_ro_mode(c, err);
kfree(ino);
return err;
}
/**