From c77cb993d9b8e2b788e97940a758721b2bf9b24c Mon Sep 17 00:00:00 2001 From: Erez_Zadok Date: Mon, 10 Sep 2007 20:19:29 -0400 Subject: [PATCH] Unionfs: cache coherency after lower objects are removed Prevent an oops if a lower file is deleted and then it is stat'ed from the upper layer. Ensure that we return a negative dentry so the user will get an ENOENT. Properly dput/mntput so we don't leak references at the lower file system. Signed-off-by: Erez Zadok --- fs/unionfs/lookup.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/fs/unionfs/lookup.c b/fs/unionfs/lookup.c index 8eb97494fdc..963d62225cd 100644 --- a/fs/unionfs/lookup.c +++ b/fs/unionfs/lookup.c @@ -92,7 +92,7 @@ struct dentry *unionfs_lookup_backend(struct dentry *dentry, struct dentry *lower_dir_dentry = NULL; struct dentry *parent_dentry = NULL; struct dentry *d_interposed = NULL; - int bindex, bstart, bend, bopaque; + int bindex, bstart = -1, bend, bopaque; int dentry_count = 0; /* Number of positive dentries. */ int first_dentry_offset = -1; /* -1 is uninitialized */ struct dentry *first_dentry = NULL; @@ -413,7 +413,14 @@ out: if (!err && UNIONFS_D(dentry)) { BUG_ON(dbend(dentry) > UNIONFS_D(dentry)->bcount); BUG_ON(dbend(dentry) > sbmax(dentry->d_sb)); - BUG_ON(dbstart(dentry) < 0); + if (dbstart(dentry) < 0 && + dentry->d_inode && bstart >= 0 && + (!UNIONFS_I(dentry->d_inode) || + !UNIONFS_I(dentry->d_inode)->lower_inodes)) { + unionfs_mntput(dentry->d_sb->s_root, bstart); + dput(first_lower_dentry); + UNIONFS_I(dentry->d_inode)->stale = 1; + } } kfree(whname); if (locked_parent) @@ -423,6 +430,9 @@ out: unionfs_unlock_dentry(dentry); if (!err && d_interposed) return d_interposed; + if (dentry->d_inode && UNIONFS_I(dentry->d_inode)->stale && + first_dentry_offset >= 0) + unionfs_mntput(dentry->d_sb->s_root, first_dentry_offset); return ERR_PTR(err); } -- 2.43.0