storage/posix: removing deleting entries in case of creation failures

The code is not atomic enough to not to delete a dentry created by a
prallel dentry creation operation.

Change-Id: I9bd6d2aa9e7a1c0688c0a937b02a4b4f56d7aa2e
BUG: 1138387
Signed-off-by: Raghavendra G <rgowdapp@redhat.com>
Reviewed-on-master: http://review.gluster.org/8327
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Reviewed-on: http://review.gluster.org/8693
Tested-by: Vijay Bellur <vbellur@redhat.com>

4 files changed, 91 insertions, 41 deletions

diff --git a/xlators/storage/posix/src/posix-handle.c b/xlators/storage/posix/src/posix-handle.c
index 46ef5ada1f1..9439b295cb9 100644
--- a/xlators/storage/posix/src/posix-handle.c
+++ b/xlators/storage/posix/src/posix-handle.c
@@ -801,7 +801,7 @@ posix_handle_soft (xlator_t *this, const char *real_path, loc_t *loc,
 }
 
 
-static int
+int
 posix_handle_unset_gfid (xlator_t *this, uuid_t gfid)
 {
         char        *path = NULL;
diff --git a/xlators/storage/posix/src/posix-helpers.c b/xlators/storage/posix/src/posix-helpers.c
index 9ba95bc4941..5f8984cc8a7 100644
--- a/xlators/storage/posix/src/posix-helpers.c
+++ b/xlators/storage/posix/src/posix-helpers.c
@@ -654,6 +654,24 @@ out:
         return xattr;
 }
 
+void
+posix_gfid_unset (xlator_t *this, dict_t *xdata)
+{
+        uuid_t uuid = {0, };
+        int    ret  = 0;
+
+        if (xdata == NULL)
+                goto out;
+
+        ret = dict_get_ptr (xdata, "gfid-req", (void **)&uuid);
+        if (ret) {
+                goto out;
+        }
+
+        posix_handle_unset (this, uuid, NULL);
+out:
+        return;
+}
 
 int
 posix_gfid_set (xlator_t *this, const char *path, loc_t *loc, dict_t *xattr_req)
diff --git a/xlators/storage/posix/src/posix.c b/xlators/storage/posix/src/posix.c
index 90bc5de444e..0c84b554cda 100644
--- a/xlators/storage/posix/src/posix.c
+++ b/xlators/storage/posix/src/posix.c
@@ -1042,7 +1042,6 @@ posix_mknod (call_frame_t *frame, xlator_t *this,
         char                 *real_path       = 0;
         char                 *par_path        = 0;
         struct iatt           stbuf           = { 0, };
-        char                  was_present     = 1;
         struct posix_private *priv            = NULL;
         gid_t                 gid             = 0;
         struct iatt           preparent       = {0,};
@@ -1050,6 +1049,7 @@ posix_mknod (call_frame_t *frame, xlator_t *this,
         void *                uuid_req        = NULL;
         int32_t               nlink_samepgfid = 0;
         char                 *pgfid_xattr_key = NULL;
+        gf_boolean_t          entry_created   = _gf_false, gfid_set = _gf_false;
 
         DECLARE_OLD_FS_ID_VAR;
 
@@ -1127,10 +1127,14 @@ real_op:
                 }
         }
 
+        entry_created = _gf_true;
+
         op_ret = posix_gfid_set (this, real_path, loc, xdata);
         if (op_ret) {
                 gf_log (this->name, GF_LOG_ERROR,
                         "setting gfid on %s failed", real_path);
+        } else {
+                gfid_set = _gf_true;
         }
 
 #ifndef HAVE_SET_FSID
@@ -1196,28 +1200,35 @@ out:
                              (loc)?loc->inode:NULL, &stbuf, &preparent,
                              &postparent, NULL);
 
-        if ((op_ret == -1) && (!was_present)) {
-                unlink (real_path);
+        if (op_ret < 0) {
+                if (entry_created) {
+                        if (S_ISREG (mode))
+                                sys_unlink (real_path);
+                        else
+                                sys_rmdir (real_path);
+                }
+
+                if (gfid_set)
+                        posix_gfid_unset (this, xdata);
         }
 
         return 0;
 }
 
-
 int
 posix_mkdir (call_frame_t *frame, xlator_t *this,
              loc_t *loc, mode_t mode, mode_t umask, dict_t *xdata)
 {
-        int32_t               op_ret      = -1;
-        int32_t               op_errno    = 0;
-        char                 *real_path   = NULL;
-        char                 *par_path   = NULL;
-        struct iatt           stbuf       = {0, };
-        char                  was_present = 1;
-        struct posix_private *priv        = NULL;
-        gid_t                 gid         = 0;
-        struct iatt           preparent = {0,};
-        struct iatt           postparent = {0,};
+        int32_t               op_ret        = -1;
+        int32_t               op_errno      = 0;
+        char                 *real_path     = NULL;
+        char                 *par_path      = NULL;
+        struct iatt           stbuf         = {0, };
+        struct posix_private *priv          = NULL;
+        gid_t                 gid           = 0;
+        struct iatt           preparent     = {0,};
+        struct iatt           postparent    = {0,};
+        gf_boolean_t          entry_created = _gf_false, gfid_set = _gf_false;
 
         DECLARE_OLD_FS_ID_VAR;
 
@@ -1245,9 +1256,6 @@ posix_mkdir (call_frame_t *frame, xlator_t *this,
         gid = frame->root->gid;
 
         op_ret = posix_pstat (this, NULL, real_path, &stbuf);
-        if ((op_ret == -1) && (errno == ENOENT)) {
-                was_present = 0;
-        }
 
         SET_FS_ID (frame->root->uid, gid);
 
@@ -1274,10 +1282,14 @@ posix_mkdir (call_frame_t *frame, xlator_t *this,
                 goto out;
         }
 
+        entry_created = _gf_true;
+
         op_ret = posix_gfid_set (this, real_path, loc, xdata);
         if (op_ret) {
                 gf_log (this->name, GF_LOG_ERROR,
                         "setting gfid on %s failed", real_path);
+        } else {
+                gfid_set = _gf_true;
         }
 
 #ifndef HAVE_SET_FSID
@@ -1331,8 +1343,12 @@ out:
                              (loc)?loc->inode:NULL, &stbuf, &preparent,
                              &postparent, NULL);
 
-        if ((op_ret == -1) && (!was_present)) {
-                unlink (real_path);
+        if (op_ret < 0) {
+                if (entry_created)
+                        sys_rmdir (real_path);
+
+                if (gfid_set)
+                        posix_gfid_unset (this, xdata);
         }
 
         return 0;
@@ -1619,11 +1635,11 @@ posix_symlink (call_frame_t *frame, xlator_t *this,
         struct iatt           stbuf           = { 0, };
         struct posix_private *priv            = NULL;
         gid_t                 gid             = 0;
-        char                  was_present     = 1;
         struct iatt           preparent       = {0,};
         struct iatt           postparent      = {0,};
         char                 *pgfid_xattr_key = NULL;
         int32_t               nlink_samepgfid = 0;
+        gf_boolean_t          entry_created   = _gf_false, gfid_set = _gf_false;
 
         DECLARE_OLD_FS_ID_VAR;
 
@@ -1637,10 +1653,6 @@ posix_symlink (call_frame_t *frame, xlator_t *this,
 
         MAKE_ENTRY_HANDLE (real_path, par_path, this, loc, &stbuf);
 
-        if ((op_ret == -1) && (errno == ENOENT)){
-                was_present = 0;
-        }
-
         SET_FS_ID (frame->root->uid, gid);
 
         gid = frame->root->gid;
@@ -1668,10 +1680,14 @@ posix_symlink (call_frame_t *frame, xlator_t *this,
                 goto out;
         }
 
+        entry_created = _gf_true;
+
         op_ret = posix_gfid_set (this, real_path, loc, xdata);
         if (op_ret) {
                 gf_log (this->name, GF_LOG_ERROR,
                         "setting gfid on %s failed", real_path);
+        } else {
+                gfid_set = _gf_true;
         }
 
 #ifndef HAVE_SET_FSID
@@ -1733,8 +1749,12 @@ out:
                              (loc)?loc->inode:NULL, &stbuf, &preparent,
                              &postparent, NULL);
 
-        if ((op_ret == -1) && (!was_present)) {
-                unlink (real_path);
+        if (op_ret < 0) {
+                if (entry_created)
+                        sys_unlink (real_path);
+
+                if (gfid_set)
+                        posix_gfid_unset (this, xdata);
         }
 
         return 0;
@@ -1938,10 +1958,6 @@ out:
                              &preoldparent, &postoldparent,
                              &prenewparent, &postnewparent, NULL);
 
-        if ((op_ret == -1) && !was_present) {
-                unlink (real_newpath);
-        }
-
         return 0;
 }
 
@@ -1957,11 +1973,11 @@ posix_link (call_frame_t *frame, xlator_t *this,
         char                 *par_newpath     = 0;
         struct iatt           stbuf           = {0, };
         struct posix_private *priv            = NULL;
-        char                  was_present     = 1;
         struct iatt           preparent       = {0,};
         struct iatt           postparent      = {0,};
         int32_t               nlink_samepgfid = 0;
         char                 *pgfid_xattr_key = NULL;
+        gf_boolean_t          entry_created   = _gf_false;
 
         DECLARE_OLD_FS_ID_VAR;
 
@@ -1977,9 +1993,6 @@ posix_link (call_frame_t *frame, xlator_t *this,
         MAKE_INODE_HANDLE (real_oldpath, this, oldloc, &stbuf);
 
         MAKE_ENTRY_HANDLE (real_newpath, par_newpath, this, newloc, &stbuf);
-        if ((op_ret == -1) && (errno == ENOENT)) {
-                was_present = 0;
-        }
 
         op_ret = posix_pstat (this, newloc->pargfid, par_newpath, &preparent);
         if (op_ret == -1) {
@@ -2000,6 +2013,8 @@ posix_link (call_frame_t *frame, xlator_t *this,
                 goto out;
         }
 
+        entry_created = _gf_true;
+
         op_ret = posix_pstat (this, NULL, real_newpath, &stbuf);
         if (op_ret == -1) {
                 op_errno = errno;
@@ -2047,8 +2062,9 @@ out:
                              (oldloc)?oldloc->inode:NULL, &stbuf, &preparent,
                              &postparent, NULL);
 
-        if ((op_ret == -1) && (!was_present)) {
-                unlink (real_newpath);
+        if (op_ret < 0) {
+                if (entry_created)
+                        sys_unlink (real_newpath);
         }
 
         return 0;
@@ -2136,6 +2152,7 @@ posix_create (call_frame_t *frame, xlator_t *this,
 
         int                    nlink_samepgfid = 0;
         char *                 pgfid_xattr_key = NULL;
+        gf_boolean_t           entry_created   = _gf_false, gfid_set = _gf_false;
 
         DECLARE_OLD_FS_ID_VAR;
 
@@ -2193,6 +2210,11 @@ posix_create (call_frame_t *frame, xlator_t *this,
                 goto out;
         }
 
+        if ((_flags & O_CREAT) && (_flags & O_EXCL)) {
+                entry_created = _gf_true;
+        }
+
+
         if (was_present)
                 goto fill_stat;
 
@@ -2200,6 +2222,8 @@ posix_create (call_frame_t *frame, xlator_t *this,
         if (op_ret) {
                 gf_log (this->name, GF_LOG_ERROR,
                         "setting gfid on %s failed", real_path);
+        } else {
+                gfid_set = _gf_true;
         }
 
 #ifndef HAVE_SET_FSID
@@ -2280,16 +2304,20 @@ out:
 
         if ((-1 == op_ret) && (_fd != -1)) {
                 close (_fd);
-
-                if (!was_present) {
-                        unlink (real_path);
-                }
         }
 
         STACK_UNWIND_STRICT (create, frame, op_ret, op_errno,
                              fd, (loc)?loc->inode:NULL, &stbuf, &preparent,
                              &postparent, xdata);
 
+        if (op_ret < 0) {
+                if (entry_created)
+                        sys_unlink (real_path);
+
+                if (gfid_set)
+                        posix_gfid_unset (this, xdata);
+        }
+
         return 0;
 }
 
diff --git a/xlators/storage/posix/src/posix.h b/xlators/storage/posix/src/posix.h
index aa4a66c3051..efd52f00b18 100644
--- a/xlators/storage/posix/src/posix.h
+++ b/xlators/storage/posix/src/posix.h
@@ -228,4 +228,8 @@ int
 posix_get_ancestry (xlator_t *this, inode_t *leaf_inode,
                     gf_dirent_t *head, char **path, int type, int32_t *op_errno,
                     dict_t *xdata);
+
+void
+posix_gfid_unset (xlator_t *this, dict_t *xdata);
+
 #endif /* _POSIX_H */