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authorjiffin <jthottan@redhat.com>2014-11-04 20:33:01 +0530
committerNiels de Vos <ndevos@redhat.com>2014-11-14 06:40:30 -0800
commitfdef42e82d66011a3a92c9c96db4ada2fa8d4814 (patch)
tree47deaab1135b7acc2fd1d9973d582074f27817dd /xlators/nfs/server/src/mount3.c
parentc3dc90b53558316904985932490584402aaef48d (diff)
gNFS : make it possible to mount a subdir that actually is a symlink
We are using the function to export all sub-directories in a gluster volume via nfs. For real directories it works fine but if we have a symbolic link which points to the directory, it is not possible to mount that directory via nfs and the nameof the link. Kernel nfs resolves symlink handle to directoryhandle , similar gluster nfs should resolve the symbolic link handle into directory handle. Change-Id: I8bd07534ba9474f0b863f2335b2fd222ab625dba BUG: 1157223 Signed-off-by: jiffin tony thottan <jthottan@redhat.com> Reviewed-on: http://review.gluster.org/9052 Reviewed-by: soumya k <skoduri@redhat.com> Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Jeff Darcy <jdarcy@redhat.com> Reviewed-by: Niels de Vos <ndevos@redhat.com>
Diffstat (limited to 'xlators/nfs/server/src/mount3.c')
-rw-r--r--xlators/nfs/server/src/mount3.c144
1 files changed, 143 insertions, 1 deletions
diff --git a/xlators/nfs/server/src/mount3.c b/xlators/nfs/server/src/mount3.c
index 6be856ba92a..f76c1c41ff2 100644
--- a/xlators/nfs/server/src/mount3.c
+++ b/xlators/nfs/server/src/mount3.c
@@ -845,6 +845,15 @@ mnt3_resolve_subdir_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
struct iatt *buf, dict_t *xattr,
struct iatt *postparent);
+int
+mnt3_parse_dir_exports (rpcsvc_request_t *req, struct mount3_state *ms,
+ char *subdir);
+
+int32_t
+mnt3_readlink_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+ int32_t op_ret, int32_t op_errno, const char *path,
+ struct iatt *buf, dict_t *xdata);
+
/* There are multiple components in the directory export path and each one
* needs to be looked up one after the other.
*/
@@ -880,6 +889,13 @@ __mnt3_resolve_export_subdir_comp (mnt3_resolve_t *mres)
}
nfs_request_user_init (&nfu, mres->req);
+ if (IA_ISLNK (mres->resolveloc.inode->ia_type)) {
+ ret = nfs_readlink (mres->mstate->nfsx, mres->exp->vol, &nfu,
+ &mres->resolveloc, mnt3_readlink_cbk, mres);
+ gf_log (GF_MNT, GF_LOG_DEBUG, "Symlink found , need to resolve"
+ " into directory handle");
+ goto err;
+ }
ret = nfs_lookup (mres->mstate->nfsx, mres->exp->vol, &nfu,
&mres->resolveloc, mnt3_resolve_subdir_cbk, mres);
@@ -954,7 +970,124 @@ err:
return 0;
}
+/* This function resolves symbolic link into directory path from
+ * the mount and restart the parsing process from the begining
+ *
+ * Note : Path specified in the symlink should be relative to the
+ * symlink, because that is the one which is consistent throught
+ * out the file system.
+ * If the symlink resolves into another symlink ,then same process
+ * will be repeated.
+ * If symbolic links points outside the file system are not considered
+ * here.
+ *
+ * TODO : 1.) This function cannot handle symlinks points to path which
+ * goes out of the filesystem and comes backs again to same.
+ * For example, consider vol is exported volume.It contains
+ * dir,
+ * symlink1 which points to ../vol/dir,
+ * symlink2 which points to ../mnt/../vol/dir,
+ * symlink1 and symlink2 are not handled right now.
+ *
+ * 2.) udp mount routine is much simpler from tcp routine and resolves
+ * symlink directly.May be ,its better we change this routine
+ * similar to udp
+ */
+int32_t
+mnt3_readlink_cbk (call_frame_t *frame, void *cookie, xlator_t *this,
+ int32_t op_ret, int32_t op_errno, const char *path,
+ struct iatt *buf, dict_t *xdata)
+{
+ mnt3_resolve_t *mres = NULL;
+ int ret = -EFAULT;
+ char *real_loc = NULL;
+ size_t path_len = 0;
+ size_t parent_path_len = 0;
+ char *parent_path = NULL;
+ char *absolute_path = NULL;
+ char *relative_path = NULL;
+ int mntstat = 0;
+
+ GF_ASSERT (frame);
+
+ mres = frame->local;
+ if (!mres || !path || (path[0] == '/') || (op_ret < 0))
+ goto mnterr;
+ /* Finding current location of symlink */
+ parent_path_len = strlen (mres->resolveloc.path) - strlen (mres->resolveloc.name);
+ parent_path = gf_strndup (mres->resolveloc.path, parent_path_len);
+ if (!parent_path) {
+ ret = -ENOMEM;
+ goto mnterr;
+ }
+
+ relative_path = gf_strdup (path);
+ if (!relative_path) {
+ ret = -ENOMEM;
+ goto mnterr;
+ }
+ /* Resolving into absolute path */
+ ret = gf_build_absolute_path (parent_path, relative_path, &absolute_path);
+ if (ret < 0) {
+ gf_log (GF_MNT, GF_LOG_ERROR, "Cannot resolve symlink, path"
+ "is out of boundary from current location %s"
+ "and with relative path %s pointed by symlink",
+ parent_path, relative_path);
+
+ goto mnterr;
+ }
+
+ /* Building the actual mount path to be mounted */
+ path_len = strlen (mres->exp->vol->name) + strlen (absolute_path)
+ + strlen (mres->remainingdir) + 1;
+ real_loc = GF_CALLOC (1, path_len, gf_nfs_mt_char);
+ if (!real_loc) {
+ ret = -ENOMEM;
+ goto mnterr;
+ }
+ sprintf (real_loc , "%s%s", mres->exp->vol->name, absolute_path);
+ gf_path_strip_trailing_slashes (real_loc);
+
+ /* There may entries after symlink in the mount path,
+ * we should include remaining entries too */
+ if (strlen (mres->remainingdir) > 0)
+ strcat (real_loc, mres->remainingdir);
+
+ gf_log (GF_MNT, GF_LOG_DEBUG, "Resolved path is : %s%s "
+ "and actual mount path is %s",
+ absolute_path, mres->remainingdir, real_loc);
+
+ /* After the resolving the symlink , parsing should be done
+ * for the populated mount path
+ */
+ ret = mnt3_parse_dir_exports (mres->req, mres->mstate, real_loc);
+
+ if (ret) {
+ gf_log (GF_MNT, GF_LOG_ERROR,
+ "Resolved into an unknown path %s%s "
+ "from the current location of symlink %s",
+ absolute_path, mres->remainingdir, parent_path);
+ }
+
+ GF_FREE (real_loc);
+ GF_FREE (absolute_path);
+ GF_FREE (parent_path);
+ GF_FREE (relative_path);
+
+ return ret;
+
+mnterr:
+ mntstat = mnt3svc_errno_to_mnterr (-ret);
+ mnt3svc_mnt_error_reply (mres->req, mntstat);
+ if (absolute_path)
+ GF_FREE (absolute_path);
+ if (parent_path)
+ GF_FREE (parent_path);
+ if (relative_path)
+ GF_FREE (relative_path);
+ return ret;
+}
/* We will always have to perform a hard lookup on all the components of a
* directory export for a mount request because in the mount reply we need the
@@ -996,6 +1129,13 @@ __mnt3_resolve_subdir (mnt3_resolve_t *mres)
}
nfs_request_user_init (&nfu, mres->req);
+ if (IA_ISLNK (mres->resolveloc.inode->ia_type)) {
+ ret = nfs_readlink (mres->mstate->nfsx, mres->exp->vol, &nfu,
+ &mres->resolveloc, mnt3_readlink_cbk, mres);
+ gf_log (GF_MNT, GF_LOG_DEBUG, "Symlink found , need to resolve "
+ "into directory handle");
+ goto err;
+ }
ret = nfs_lookup (mres->mstate->nfsx, mres->exp->vol, &nfu,
&mres->resolveloc, mnt3_resolve_subdir_cbk, mres);
@@ -2054,13 +2194,15 @@ __mnt3udp_get_export_subdir_inode (struct svc_req *req, char *subdir,
* TODO: Instead of linking against libgfapi.so, just for one API
* i.e. glfs_resolve_at(), It would be cleaner if PATH name to
* inode resolution code can be moved to libglusterfs.so or so.
+ * refer bugzilla for more details :
+ * https://bugzilla.redhat.com/show_bug.cgi?id=1161573
*/
fs = glfs_new_from_ctx (exp->vol->ctx);
if (!fs)
return NULL;
ret = glfs_resolve_at (fs, exp->vol, NULL, subdir,
- &loc, &buf, 0 /* Follow link */,
+ &loc, &buf, 1 /* Follow link */,
0 /* Hard lookup */);
glfs_free_from_ctx (fs);