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authorAmir Goldstein <amir73il@gmail.com>2018-01-03 18:54:42 +0200
committerMiklos Szeredi <mszeredi@redhat.com>2018-01-19 17:43:24 +0100
commita5a927a7c82e28ea76599dee4019c41e372c911f (patch)
treebafff47b89c2e07707dc6f4764d50f7292883989
parent2ba9d57e65044859f7ff133bcb0a902769bf3bc6 (diff)
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ovl: take mnt_want_write() for removing impure xattr
The optimization in ovl_cache_get_impure() that tries to remove an unneeded "impure" xattr needs to take mnt_want_write() on upper fs. Fixes: 4edb83bb1041 ("ovl: constant d_ino for non-merge dirs") Cc: <stable@vger.kernel.org> #v4.14 Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
-rw-r--r--fs/overlayfs/readdir.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 7dfe381c2cd8..1a8c39887992 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -593,8 +593,15 @@ static struct ovl_dir_cache *ovl_cache_get_impure(struct path *path)
return ERR_PTR(res);
}
if (list_empty(&cache->entries)) {
- /* Good oportunity to get rid of an unnecessary "impure" flag */
- ovl_do_removexattr(ovl_dentry_upper(dentry), OVL_XATTR_IMPURE);
+ /*
+ * A good opportunity to get rid of an unneeded "impure" flag.
+ * Removing the "impure" xattr is best effort.
+ */
+ if (!ovl_want_write(dentry)) {
+ ovl_do_removexattr(ovl_dentry_upper(dentry),
+ OVL_XATTR_IMPURE);
+ ovl_drop_write(dentry);
+ }
ovl_clear_flag(OVL_IMPURE, d_inode(dentry));
kfree(cache);
return NULL;