From aa3ff3c152ff94ef045ed802db7535167f8a21ab Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Sun, 15 Oct 2017 18:00:20 +0300 Subject: ovl: copy up of disconnected dentries With NFS export, some operations on decoded file handles (e.g. open, link, setattr, xattr_set) may call copy up with a disconnected non-dir. In this case, we will copy up lower inode to index dir without linking it to upper dir. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi --- fs/overlayfs/copy_up.c | 56 ++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 41 insertions(+), 15 deletions(-) (limited to 'fs/overlayfs/copy_up.c') diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c index 8ef25d8c3cfe..d855f508fa20 100644 --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -450,7 +450,10 @@ static int ovl_link_up(struct ovl_copy_up_ctx *c) } } inode_unlock(udir); - ovl_set_nlink_upper(c->dentry); + if (err) + return err; + + err = ovl_set_nlink_upper(c->dentry); return err; } @@ -655,6 +658,9 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) err = ovl_get_index_name(c->lowerpath.dentry, &c->destname); if (err) return err; + } else if (WARN_ON(!c->parent)) { + /* Disconnected dentry must be copied up to index dir */ + return -EIO; } else { /* * Mark parent "impure" because it may now contain non-pure @@ -677,12 +683,17 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) } } - if (!err && c->indexed) + + if (err) + goto out; + + if (c->indexed) ovl_set_flag(OVL_INDEX, d_inode(c->dentry)); if (to_index) { - kfree(c->destname.name); - } else if (!err) { + /* Initialize nlink for copy up of disconnected dentry */ + err = ovl_set_nlink_upper(c->dentry); + } else { struct inode *udir = d_inode(c->destdir); /* Restore timestamps on parent (best effort) */ @@ -693,6 +704,9 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c) ovl_dentry_set_upper_alias(c->dentry); } +out: + if (to_index) + kfree(c->destname.name); return err; } @@ -717,14 +731,17 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, if (err) return err; - ovl_path_upper(parent, &parentpath); - ctx.destdir = parentpath.dentry; - ctx.destname = dentry->d_name; + if (parent) { + ovl_path_upper(parent, &parentpath); + ctx.destdir = parentpath.dentry; + ctx.destname = dentry->d_name; - err = vfs_getattr(&parentpath, &ctx.pstat, - STATX_ATIME | STATX_MTIME, AT_STATX_SYNC_AS_STAT); - if (err) - return err; + err = vfs_getattr(&parentpath, &ctx.pstat, + STATX_ATIME | STATX_MTIME, + AT_STATX_SYNC_AS_STAT); + if (err) + return err; + } /* maybe truncate regular file. this has no effect on dirs */ if (flags & O_TRUNC) @@ -745,7 +762,7 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry, } else { if (!ovl_dentry_upper(dentry)) err = ovl_do_copy_up(&ctx); - if (!err && !ovl_dentry_has_upper_alias(dentry)) + if (!err && parent && !ovl_dentry_has_upper_alias(dentry)) err = ovl_link_up(&ctx); ovl_copy_up_end(dentry); } @@ -758,10 +775,19 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags) { int err = 0; const struct cred *old_cred = ovl_override_creds(dentry->d_sb); + bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED); + + /* + * With NFS export, copy up can get called for a disconnected non-dir. + * In this case, we will copy up lower inode to index dir without + * linking it to upper dir. + */ + if (WARN_ON(disconnected && d_is_dir(dentry))) + return -EIO; while (!err) { struct dentry *next; - struct dentry *parent; + struct dentry *parent = NULL; /* * Check if copy-up has happened as well as for upper alias (in @@ -777,12 +803,12 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags) * with rename. */ if (ovl_dentry_upper(dentry) && - ovl_dentry_has_upper_alias(dentry)) + (ovl_dentry_has_upper_alias(dentry) || disconnected)) break; next = dget(dentry); /* find the topmost dentry not yet copied up */ - for (;;) { + for (; !disconnected;) { parent = dget_parent(next); if (ovl_dentry_upper(parent)) -- cgit v1.2.3