From: Henri Doreau <henri.dor...@cea.fr>

Added LL_IOC_GETPARENT to retrieve the <parent_fid>/name(s) of a given
entry, based on its link EA. This saves multiple calls to
path2fid/fid2path.

Merged with second later patch that does various cleanups.
Avoid unneeded allocation. Get read-only attributes from the user
getparent structure and write the modified attributes only, instead
of populating a whole structure in kernel and copying it back.

Signed-off-by: Thomas Leibovici <thomas.leibov...@cea.fr>
Signed-off-by: Henri Doreau <henri.dor...@cea.fr>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3613
Reviewed-on: http://review.whamcloud.com/7069
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5837
Reviewed-on: http://review.whamcloud.com/12527
Reviewed-by: Ned Bass <ba...@llnl.gov>
Reviewed-by: frank zago <fz...@cray.com>
Reviewed-by: John L. Hammond <john.hamm...@intel.com>
Reviewed-by: Oleg Drokin <oleg.dro...@intel.com>
Signed-off-by: James Simmons <jsimm...@infradead.org>
---
 .../lustre/lustre/include/lustre/lustre_idl.h      |    8 ++
 .../lustre/lustre/include/lustre/lustre_user.h     |    1 +
 drivers/staging/lustre/lustre/llite/dir.c          |    2 +
 drivers/staging/lustre/lustre/llite/file.c         |    2 +
 .../staging/lustre/lustre/llite/llite_internal.h   |   13 ++
 drivers/staging/lustre/lustre/llite/llite_lib.c    |  125 ++++++++++++++++++++
 drivers/staging/lustre/lustre/llite/xattr.c        |   10 +--
 7 files changed, 152 insertions(+), 9 deletions(-)

diff --git a/drivers/staging/lustre/lustre/include/lustre/lustre_idl.h 
b/drivers/staging/lustre/lustre/include/lustre/lustre_idl.h
index 2dc550a..0cc47bc 100644
--- a/drivers/staging/lustre/lustre/include/lustre/lustre_idl.h
+++ b/drivers/staging/lustre/lustre/include/lustre/lustre_idl.h
@@ -3468,6 +3468,14 @@ struct getinfo_fid2path {
 
 void lustre_swab_fid2path(struct getinfo_fid2path *gf);
 
+/** path2parent request/reply structures */
+struct getparent {
+       struct lu_fid   gp_fid;         /**< parent FID */
+       __u32           gp_linkno;      /**< hardlink number */
+       __u32           gp_name_size;   /**< size of the name field */
+       char            gp_name[0];     /**< zero-terminated link name */
+} __packed;
+
 enum {
        LAYOUT_INTENT_ACCESS    = 0,
        LAYOUT_INTENT_READ      = 1,
diff --git a/drivers/staging/lustre/lustre/include/lustre/lustre_user.h 
b/drivers/staging/lustre/lustre/include/lustre/lustre_user.h
index cc0a786..08ac6e4 100644
--- a/drivers/staging/lustre/lustre/include/lustre/lustre_user.h
+++ b/drivers/staging/lustre/lustre/include/lustre/lustre_user.h
@@ -245,6 +245,7 @@ struct ost_id {
 #define LL_IOC_LMV_SET_DEFAULT_STRIPE  _IOWR('f', 246, struct lmv_user_md)
 #define LL_IOC_MIGRATE                 _IOR('f', 247, int)
 #define LL_IOC_FID2MDTIDX              _IOWR('f', 248, struct lu_fid)
+#define LL_IOC_GETPARENT               _IOWR('f', 249, struct getparent)
 
 /* Lease types for use as arg and return of LL_IOC_{GET,SET}_LEASE ioctl. */
 enum ll_lease_type {
diff --git a/drivers/staging/lustre/lustre/llite/dir.c 
b/drivers/staging/lustre/lustre/llite/dir.c
index 234095e..705de1c 100644
--- a/drivers/staging/lustre/lustre/llite/dir.c
+++ b/drivers/staging/lustre/lustre/llite/dir.c
@@ -1562,6 +1562,8 @@ out_quotactl:
                return rc;
        case OBD_IOC_FID2PATH:
                return ll_fid2path(inode, (void __user *)arg);
+       case LL_IOC_GETPARENT:
+               return ll_getparent(file, (void __user *)arg);
        case LL_IOC_FID2MDTIDX: {
                struct obd_export *exp = ll_i2mdexp(inode);
                struct lu_fid fid;
diff --git a/drivers/staging/lustre/lustre/llite/file.c 
b/drivers/staging/lustre/lustre/llite/file.c
index 127d0e0..45acc5d 100644
--- a/drivers/staging/lustre/lustre/llite/file.c
+++ b/drivers/staging/lustre/lustre/llite/file.c
@@ -2362,6 +2362,8 @@ ll_file_ioctl(struct file *file, unsigned int cmd, 
unsigned long arg)
 
                return 0;
        }
+       case LL_IOC_GETPARENT:
+               return ll_getparent(file, (struct getparent __user *)arg);
        case OBD_IOC_FID2PATH:
                return ll_fid2path(inode, (void __user *)arg);
        case LL_IOC_DATA_VERSION: {
diff --git a/drivers/staging/lustre/lustre/llite/llite_internal.h 
b/drivers/staging/lustre/lustre/llite/llite_internal.h
index fc707c2..1cc427c 100644
--- a/drivers/staging/lustre/lustre/llite/llite_internal.h
+++ b/drivers/staging/lustre/lustre/llite/llite_internal.h
@@ -36,6 +36,7 @@
 #include "../include/lustre_ver.h"
 #include "../include/lustre_disk.h"    /* for s2sbi */
 #include "../include/lustre_eacl.h"
+#include "../include/lustre_linkea.h"
 
 /* for struct cl_lock_descr and struct cl_io */
 #include "../include/cl_object.h"
@@ -1038,7 +1039,17 @@ static inline __u64 ll_file_maxbytes(struct inode *inode)
 /* llite/xattr.c */
 extern const struct xattr_handler *ll_xattr_handlers[];
 
+#define XATTR_USER_T           1
+#define XATTR_TRUSTED_T                2
+#define XATTR_SECURITY_T       3
+#define XATTR_ACL_ACCESS_T     4
+#define XATTR_ACL_DEFAULT_T    5
+#define XATTR_LUSTRE_T         6
+#define XATTR_OTHER_T          7
+
 ssize_t ll_listxattr(struct dentry *dentry, char *buffer, size_t size);
+int ll_xattr_list(struct inode *inode, const char *name, int type,
+                 void *buffer, size_t size, __u64 valid);
 
 /**
  * Common IO arguments for various VFS I/O interfaces.
@@ -1399,6 +1410,8 @@ void ll_xattr_fini(void);
 int ll_page_sync_io(const struct lu_env *env, struct cl_io *io,
                    struct cl_page *page, enum cl_req_type crt);
 
+int ll_getparent(struct file *file, struct getparent __user *arg);
+
 /* lcommon_cl.c */
 int cl_setattr_ost(struct inode *inode, const struct iattr *attr);
 
diff --git a/drivers/staging/lustre/lustre/llite/llite_lib.c 
b/drivers/staging/lustre/lustre/llite/llite_lib.c
index 5792354..5cbce1b 100644
--- a/drivers/staging/lustre/lustre/llite/llite_lib.c
+++ b/drivers/staging/lustre/lustre/llite/llite_lib.c
@@ -2545,3 +2545,128 @@ void ll_compute_rootsquash_state(struct ll_sb_info *sbi)
        }
        up_write(&squash->rsi_sem);
 }
+
+/**
+ * Parse linkea content to extract information about a given hardlink
+ *
+ * \param[in]  ldata           - Initialized linkea data
+ * \param[in]  linkno          - Link identifier
+ * \param[out] parent_fid      - The entry's parent FID
+ * \param[in]  size            - Entry name destination buffer
+ *
+ * \retval 0 on success
+ * \retval Appropriate negative error code on failure
+ */
+static int ll_linkea_decode(struct linkea_data *ldata, unsigned int linkno,
+                           struct lu_fid *parent_fid, struct lu_name *ln)
+{
+       unsigned int idx;
+       int rc;
+
+       rc = linkea_init(ldata);
+       if (rc < 0)
+               return rc;
+
+       if (linkno >= ldata->ld_leh->leh_reccount)
+               /* beyond last link */
+               return -ENODATA;
+
+       linkea_first_entry(ldata);
+       for (idx = 0; ldata->ld_lee; idx++) {
+               linkea_entry_unpack(ldata->ld_lee, &ldata->ld_reclen, ln,
+                                   parent_fid);
+               if (idx == linkno)
+                       break;
+
+               linkea_next_entry(ldata);
+       }
+
+       if (idx < linkno)
+               return -ENODATA;
+
+       return 0;
+}
+
+/**
+ * Get parent FID and name of an identified link. Operation is performed for
+ * a given link number, letting the caller iterate over linkno to list one or
+ * all links of an entry.
+ *
+ * \param[in]    file  - File descriptor against which to perform the operation
+ * \param[in,out] arg  - User-filled structure containing the linkno to operate
+ *                       on and the available size. It is eventually filled 
with
+ *                       the requested information or left untouched on error
+ *
+ * \retval - 0 on success
+ * \retval - Appropriate negative error code on failure
+ */
+int ll_getparent(struct file *file, struct getparent __user *arg)
+{
+       struct inode *inode = file_inode(file);
+       struct linkea_data *ldata;
+       struct lu_fid parent_fid;
+       struct lu_buf buf = {
+               .lb_buf = NULL,
+               .lb_len = 0
+       };
+       struct lu_name ln;
+       u32 name_size;
+       u32 linkno;
+       int rc;
+
+       if (!capable(CFS_CAP_DAC_READ_SEARCH) &&
+           !(ll_i2sbi(inode)->ll_flags & LL_SBI_USER_FID2PATH))
+               return -EPERM;
+
+       if (get_user(name_size, &arg->gp_name_size))
+               return -EFAULT;
+
+       if (get_user(linkno, &arg->gp_linkno))
+               return -EFAULT;
+
+       if (name_size > PATH_MAX)
+               return -EINVAL;
+
+       ldata = kzalloc(sizeof(*ldata), GFP_NOFS);
+       if (!ldata)
+               return -ENOMEM;
+
+       rc = linkea_data_new(ldata, &buf);
+       if (rc < 0)
+               goto ldata_free;
+
+       rc = ll_xattr_list(inode, XATTR_NAME_LINK, XATTR_TRUSTED_T, buf.lb_buf,
+                          buf.lb_len, OBD_MD_FLXATTR);
+       if (rc < 0)
+               goto lb_free;
+
+       rc = ll_linkea_decode(ldata, linkno, &parent_fid, &ln);
+       if (rc < 0)
+               goto lb_free;
+
+       if (ln.ln_namelen >= name_size) {
+               rc = -EOVERFLOW;
+               goto lb_free;
+       }
+
+       if (copy_to_user(&arg->gp_fid, &parent_fid, sizeof(arg->gp_fid))) {
+               rc = -EFAULT;
+               goto lb_free;
+       }
+
+       if (copy_to_user(&arg->gp_name, ln.ln_name, ln.ln_namelen)) {
+               rc = -EFAULT;
+               goto lb_free;
+       }
+
+       if (put_user('\0', arg->gp_name + ln.ln_namelen)) {
+               rc = -EFAULT;
+               goto lb_free;
+       }
+
+lb_free:
+       lu_buf_free(&buf);
+ldata_free:
+       kfree(ldata);
+       return rc;
+}
diff --git a/drivers/staging/lustre/lustre/llite/xattr.c 
b/drivers/staging/lustre/lustre/llite/xattr.c
index 17ad04f..0e6a559 100644
--- a/drivers/staging/lustre/lustre/llite/xattr.c
+++ b/drivers/staging/lustre/lustre/llite/xattr.c
@@ -44,14 +44,6 @@
 
 #include "llite_internal.h"
 
-#define XATTR_USER_T       (1)
-#define XATTR_TRUSTED_T         (2)
-#define XATTR_SECURITY_T       (3)
-#define XATTR_ACL_ACCESS_T      (4)
-#define XATTR_ACL_DEFAULT_T     (5)
-#define XATTR_LUSTRE_T   (6)
-#define XATTR_OTHER_T     (7)
-
 static
 int get_xattr_type(const char *name)
 {
@@ -219,7 +211,7 @@ static int ll_xattr_set(const struct xattr_handler *handler,
                                   flags);
 }
 
-static int
+int
 ll_xattr_list(struct inode *inode, const char *name, int type, void *buffer,
              size_t size, __u64 valid)
 {
-- 
1.7.1

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