LU-17173 utils: cleanup lfs flushctx

[fs/lustre-release.git] / lustre / utils / liblustreapi_fid.c

diff --git a/lustre/utils/liblustreapi_fid.c b/lustre/utils/liblustreapi_fid.c
index 8d3f268..bf326bc 100644 (file)
--- a/lustre/utils/liblustreapi_fid.c
+++ b/lustre/utils/liblustreapi_fid.c
@@ -30,7 +30,7 @@
  * Copyright (c) 2018, 2019, Data Direct Networks
  */
 
-/* for O_DIRECTORY */
+/* for O_DIRECTORY and struct file_handle */
 #ifndef _GNU_SOURCE
 #define _GNU_SOURCE
 #endif
@@ -43,8 +43,10 @@
 #include <sys/ioctl.h>
 #include <sys/xattr.h>
 #include <unistd.h>
+#include <sched.h>
 
 #include <libcfs/util/ioctl.h>
+#include <libcfs/util/hash.h>
 #include <lustre/lustreapi.h>
 #include <linux/lustre/lustre_fid.h>
 #include "lustreapi_internal.h"
@@ -222,16 +224,6 @@ int llapi_fid2path(const char *path_or_device, const char *fidstr, char *path,
                goto out;
        }
 
-       if (*path_or_device == '/')
-               rc = get_root_path(WANT_FD, NULL, &mnt_fd,
-                                  (char *)path_or_device, -1, NULL);
-       else
-               rc = get_root_path(WANT_FD, (char *)path_or_device,
-                                  &mnt_fd, NULL, -1, NULL);
-
-       if (rc < 0)
-               goto out;
-
        rc = llapi_fid_parse(fidstr, &fid, NULL);
        if (rc < 0) {
                llapi_err_noerrno(LLAPI_MSG_ERROR,
@@ -241,11 +233,15 @@ int llapi_fid2path(const char *path_or_device, const char *fidstr, char *path,
                goto out;
        }
 
+       rc = llapi_root_path_open(path_or_device, &mnt_fd);
+       if (rc < 0)
+               goto out;
+
+       /* mnt_fd is cached internally, no need to close it */
        rc = llapi_fid2path_at(mnt_fd, &fid, path, pathlen, recno, linkno);
-out:
-       if (!(mnt_fd < 0))
-               close(mnt_fd);
+       close(mnt_fd);
 
+out:
        return rc;
 }
 
@@ -398,6 +394,69 @@ int llapi_path2parent(const char *path, unsigned int linkno,
 }
 
 /**
+ * Convert a struct lu_fid into a struct file_handle
+ *
+ * \param[out] _handle a newly allocated struct file_handle on success
+ * \param[in]  fid     a Lustre File IDentifier
+ *
+ * \retval             0 on success
+ * \retval             negative errno if an error occured
+ *
+ * On success, the caller is responsible for freeing \p handle.
+ */
+int llapi_fid_to_handle(struct file_handle **_handle, const struct lu_fid *fid)
+{
+       struct lustre_file_handle *lfh;
+       struct file_handle *handle;
+
+       if (!_handle || !fid)
+               return -EINVAL;
+
+       handle = calloc(1, sizeof(*handle) + sizeof(*lfh));
+       if (handle == NULL)
+               return -errno;
+
+       handle->handle_bytes = sizeof(*lfh);
+       handle->handle_type = FILEID_LUSTRE;
+       lfh = (struct lustre_file_handle *)handle->f_handle;
+       /* Only lfh->lfh_child needs to be set */
+       lfh->lfh_child = *fid;
+
+       *_handle = handle;
+       return 0;
+}
+
+/**
+ * Attempt to open a file with a Lustre File IDentifier
+ *
+ * \param[in] lustre_fd                an open file descriptor for an object in lustre
+ * \param[in] fid              a Lustre File IDentifier of the file to open
+ * \param[in] flags            open(2) flags
+ *
+ * \retval                     non-negative file descriptor on success
+ * \retval                     negative errno if an error occured
+ */
+int llapi_open_by_fid_at(int lustre_fd, const struct lu_fid *fid, int flags)
+{
+       struct file_handle *handle = NULL;
+       int fd;
+       int rc;
+
+       rc = llapi_fid_to_handle(&handle, fid);
+       if (rc < 0)
+               return rc;
+
+       /* Sadly open_by_handle_at() only works for root, but this is also the
+        * case for the original approach of opening $MOUNT/.lustre/FID.
+        */
+       fd = open_by_handle_at(lustre_fd, handle, flags);
+       rc = -errno;
+       free(handle);
+
+       return fd < 0 ? rc : fd;
+}
+
+/**
  * Attempt to open a file with Lustre file identifier \a fid
  * and return an open file descriptor.
  *
@@ -411,18 +470,19 @@ int llapi_path2parent(const char *path, unsigned int linkno,
 int llapi_open_by_fid(const char *lustre_dir, const struct lu_fid *fid,
                      int flags)
 {
-       char mntdir[PATH_MAX];
-       char path[PATH_MAX + 64];
-       int rc;
+       int mnt_fd, rc;
 
-       rc = llapi_search_mounts(lustre_dir, 0, mntdir, NULL);
+       rc = llapi_root_path_open(lustre_dir, &mnt_fd);
        if (rc)
-               return rc;
-
-       snprintf(path, sizeof(path), "%s/.lustre/fid/"DFID, mntdir, PFID(fid));
-       rc = open(path, flags);
-       if (rc < 0)
-               rc = -errno;
+               goto out;
 
+       rc = llapi_open_by_fid_at(mnt_fd, fid, flags);
+       close(mnt_fd);
+out:
        return rc;
 }
+
+unsigned long llapi_fid_hash(const struct lu_fid *f, unsigned int shift)
+{
+       return hash_long(fid_flatten_long(f), shift);
+}