From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Simmons Date: Thu, 27 Feb 2020 16:09:02 -0500 Subject: [lustre-devel] [PATCH 074/622] lustre: llite: handle zero length xattr values correctly In-Reply-To: <1582838290-17243-1-git-send-email-jsimmons@infradead.org> References: <1582838290-17243-1-git-send-email-jsimmons@infradead.org> Message-ID: <1582838290-17243-75-git-send-email-jsimmons@infradead.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lustre-devel@lists.lustre.org From: "John L. Hammond" In mdt_getxattr(), set OBD_MD_FLXATTR in mbo_valid of the reply's MDT body so that the client can distinguish between nonexistent extended attributes and zero length values. In ll_xattr_list() and ll_getxattr_common() test for OBD_MD_FLXATTR and return 0 rather than -ENODATA in the appropriate cases. Add sanity test_102t() to test that zero length values are handled correctly. Lustre-commit: 1e4164a1254d ("LU-11109 mdt: handle zero length xattr values correctly") Signed-off-by: John L. Hammond Reviewed-on: https://review.whamcloud.com/32755 Reviewed-by: Andreas Dilger Reviewed-by: Mikhail Pershin Reviewed-by: James Simmons Signed-off-by: James Simmons --- fs/lustre/llite/xattr.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/fs/lustre/llite/xattr.c b/fs/lustre/llite/xattr.c index f25ae59..636334e 100644 --- a/fs/lustre/llite/xattr.c +++ b/fs/lustre/llite/xattr.c @@ -363,6 +363,11 @@ int ll_xattr_list(struct inode *inode, const char *name, int type, void *buffer, /* only detect the xattr size */ if (size == 0) { + /* LU-11109: Older MDTs do not distinguish + * between nonexistent xattrs and zero length + * values in this case. Newer MDTs will return + * -ENODATA or set OBD_MD_FLXATTR. + */ rc = body->mbo_eadatasize; goto out; } @@ -375,7 +380,22 @@ int ll_xattr_list(struct inode *inode, const char *name, int type, void *buffer, } if (body->mbo_eadatasize == 0) { - rc = -ENODATA; + /* LU-11109: Newer MDTs set OBD_MD_FLXATTR on + * success so that we can distinguish between + * zero length value and nonexistent xattr. + * + * If OBD_MD_FLXATTR is not set then we keep + * the old behavior and return -ENODATA for + * getxattr() when mbo_eadatasize is 0. But + * -ENODATA only makes sense for getxattr() + * and not for listxattr(). + */ + if (body->mbo_valid & OBD_MD_FLXATTR) + rc = 0; + else if (valid == OBD_MD_FLXATTR) + rc = -ENODATA; + else + rc = 0; goto out; } -- 1.8.3.1