From 05aaec645a6262d431486eb5ac7cd702646cfcfb Mon Sep 17 00:00:00 2001
From: Anand Avati <avati@redhat.com>
Date: Thu, 2 May 2013 08:00:22 -0700
Subject: dht,posix: support for case discovery

This is support for discovering a filename in a given directory
which has a case insensitive match of a given name. It is implemented
as a virtual extended attribute on the directory where the required
filename is specified in the key.

E.g:

  sh# getfattr -e "text" -n user.glusterfs.get_real_filename:FiLe-B /mnt/samba/patchy
  getfattr: Removing leading '/' from absolute path names
  # file: mnt/samba/patchy
  user.glusterfs.get_real_filename:FiLe-B="file-b"

In reality, there can be multiple "answers" as the backend filesystem is
case sensitive and there can be multiple files which can strcasecamp()
successfully. In this case we pick the first matched file from the first
responding server.

If a matching file does not exist, we return ENOENT (and NOT ENODATA).
This way the caller can differentiate between "unsupported" glusterfs
API and file not existing.

This API is used by Samba VFS to perform efficient discovery of the real
filename without doing a full scan at the Samba level.

Change-Id: I53054c4067cba69e585fd0bbce004495bc6e39e8
BUG: 953694
Signed-off-by: Anand Avati <avati@redhat.com>
Reviewed-on: http://review.gluster.org/4941
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
---
 xlators/storage/posix/src/posix.c | 66 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)

(limited to 'xlators/storage')

diff --git a/xlators/storage/posix/src/posix.c b/xlators/storage/posix/src/posix.c
index 5e014f8e9..93577cf54 100644
--- a/xlators/storage/posix/src/posix.c
+++ b/xlators/storage/posix/src/posix.c
@@ -2439,6 +2439,53 @@ out:
         return 0;
 }
 
+
+int
+posix_xattr_get_real_filename (call_frame_t *frame, xlator_t *this, loc_t *loc,
+			       const char *key, dict_t *dict, dict_t *xdata)
+{
+	char *real_path = NULL;
+	struct dirent *dirent = NULL;
+	DIR *fd = NULL;
+	const char *fname = NULL;
+	char *found = NULL;
+	int ret = -1;
+	int op_ret = -1;
+
+        MAKE_INODE_HANDLE (real_path, this, loc, NULL);
+
+	fd = opendir (real_path);
+	if (!fd)
+		return -errno;
+
+	fname = key + strlen (GF_XATTR_GET_REAL_FILENAME_KEY);
+
+	while ((dirent = readdir (fd))) {
+		if (strcasecmp (dirent->d_name, fname) == 0) {
+			found = gf_strdup (dirent->d_name);
+			if (!found) {
+				closedir (fd);
+				return -ENOMEM;
+			}
+			break;
+		}
+	}
+
+	closedir (fd);
+
+	if (!found)
+		return -ENOENT;
+
+	ret = dict_set_dynstr (dict, (char *)key, found);
+	if (ret) {
+		GF_FREE (found);
+		return -ENOMEM;
+	}
+	ret = strlen (found) + 1;
+
+	return ret;
+}
+
 /**
  * posix_getxattr - this function returns a dictionary with all the
  *                  key:value pair present as xattr. used for
@@ -2493,9 +2540,28 @@ posix_getxattr (call_frame_t *frame, xlator_t *this,
 
         dict = dict_new ();
         if (!dict) {
+		op_errno = ENOMEM;
                 goto out;
         }
 
+	if (loc->inode && name &&
+	    (strncmp (name, GF_XATTR_GET_REAL_FILENAME_KEY,
+		      strlen (GF_XATTR_GET_REAL_FILENAME_KEY)) == 0)) {
+		ret = posix_xattr_get_real_filename (frame, this, loc,
+						     name, dict, xdata);
+		if (ret < 0) {
+			op_ret = -1;
+			op_errno = -ret;
+			gf_log (this->name, GF_LOG_WARNING,
+				"Failed to get rea filename (%s, %s): %s",
+				loc->path, name, strerror (op_errno));
+			goto out;
+		}
+
+		size = ret;
+		goto done;
+	}
+
         if (loc->inode && name && !strcmp (name, GLUSTERFS_OPEN_FD_COUNT)) {
                 if (!list_empty (&loc->inode->fd_list)) {
                         ret = dict_set_uint32 (dict, (char *)name, 1);
-- 
cgit