libgfapi : anonymous fd support

      backport of http://review.gluster.org/#/c/9971/

Anonymous fd's are floating fd assigned to a glusterfs client
without a explicit file open. Here either it will create a new
anonymous fd or existing anonymous fd in the client stack for
requested file.The anonymous fd's are mainly used for IO's.
This patch introduces two api's glfs_h_anonymous_read and
glfs_h_anonymous_write which performs read and write respectively

cherry-picked as fa0ad231745846918b2625d0e1a89c0a5c3c24dc
>Change-Id: Id646f2220e8387b2f8bb244c848dc1db6761444f
>BUG: 1204651
>Signed-off-by: Jiffin Tony Thottan <jthottan@redhat.com>
>Reviewed-by: Niels de Vos <ndevos@redhat.com>
>Reviewed-on: http://review.gluster.org/9971
>Tested-by: Gluster Build System <jenkins@build.gluster.com>
>Signed-off-by: Jiffin Tony Thottan <jthottan@redhat.com>

Change-Id: I6b01d88f92ad045e48debee23aa79f4517c6bdc2
BUG: 1218857
Signed-off-by: Jiffin Tony Thottan <jthottan@redhat.com>
Reviewed-on: http://review.gluster.org/10635
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>

6 files changed, 227 insertions, 0 deletions

diff --git a/api/src/gfapi.aliases b/api/src/gfapi.aliases
index 6d48ecdf2c9..9776c87fdcb 100644
--- a/api/src/gfapi.aliases
+++ b/api/src/gfapi.aliases
@@ -131,6 +131,9 @@ _pub_glfs_h_acl_set _glfs_h_acl_set$GFAPI_3.7.0
 _pub_glfs_h_acl_get _glfs_h_acl_get$GFAPI_3.7.0
 _pub_glfs_h_statfs _glfs_h_statfs$GFAPI_3.7.0
 
+_pub_glfs_h_anonymous_read _glfs_h_anonymous_read$GFAPI_3.7.0
+_pub_glfs_h_anonymous_write _glfs_h_anonymous_write$GFAPI_3.7.0
+
 _priv_glfs_free_from_ctx _glfs_free_from_ctx$GFAPI_PRIVATE_3.7.0
 _priv_glfs_new_from_ctx _glfs_new_from_ctx$GFAPI_PRIVATE_3.7.0
 _priv_glfs_resolve _glfs_resolve$GFAPI_PRIVATE_3.7.0
diff --git a/api/src/gfapi.map b/api/src/gfapi.map
index 24209d666dc..48863985135 100644
--- a/api/src/gfapi.map
+++ b/api/src/gfapi.map
@@ -152,6 +152,8 @@ GFAPI_3.7.0 {
 		glfs_h_acl_set;
 		glfs_h_acl_get;
 		glfs_h_statfs;
+		glfs_h_anonymous_read;
+		glfs_h_anonymous_write;
 } GFAPI_3.6.0;
 
 GFAPI_PRIVATE_3.7.0 {
diff --git a/api/src/glfs-fops.c b/api/src/glfs-fops.c
index 944868effc6..56fc4098375 100644
--- a/api/src/glfs-fops.c
+++ b/api/src/glfs-fops.c
@@ -3624,3 +3624,158 @@ out:
 }
 
 GFAPI_SYMVER_PRIVATE_DEFAULT(glfs_process_upcall_event, 3.7.0);
+
+ssize_t
+glfs_anonymous_pwritev (struct glfs *fs, struct glfs_object *object,
+                        const struct iovec *iovec, int iovcnt,
+                        off_t offset, int flags)
+{
+        xlator_t        *subvol = NULL;
+        struct iobref   *iobref = NULL;
+        struct iobuf    *iobuf  = NULL;
+        struct iovec    iov     = {0, };
+        inode_t         *inode  = NULL;
+        fd_t            *fd     = NULL;
+        int             ret     = -1;
+        size_t          size    = -1;
+
+        __glfs_entry_fs (fs);
+
+        subvol = glfs_active_subvol (fs);
+        if (!subvol) {
+                ret = -1;
+                errno = EIO;
+                goto out;
+        }
+
+        /* get/refresh the in arg objects inode in correlation to the xlator */
+        inode = glfs_resolve_inode (fs, subvol, object);
+        if (!inode) {
+                ret = -1;
+                errno = ESTALE;
+                goto out;
+        }
+
+        fd = fd_anonymous (inode);
+        if (!fd) {
+                ret = -1;
+                gf_msg ("gfapi", GF_LOG_ERROR, ENOMEM, API_MSG_FDCREATE_FAILED,
+                        "Allocating anonymous fd failed");
+                errno = ENOMEM;
+                goto out;
+        }
+
+        size = iov_length (iovec, iovcnt);
+
+        iobuf = iobuf_get2 (subvol->ctx->iobuf_pool, size);
+        if (!iobuf) {
+                ret = -1;
+                errno = ENOMEM;
+                goto out;
+        }
+
+        iobref = iobref_new ();
+        if (!iobref) {
+                iobuf_unref (iobuf);
+                errno = ENOMEM;
+                ret = -1;
+                goto out;
+        }
+
+        ret = iobref_add (iobref, iobuf);
+        if (ret) {
+                iobuf_unref (iobuf);
+                iobref_unref (iobref);
+                errno = ENOMEM;
+                ret = -1;
+                goto out;
+        }
+
+        iov_unload (iobuf_ptr (iobuf), iovec, iovcnt);
+
+        iov.iov_base = iobuf_ptr (iobuf);
+        iov.iov_len = size;
+
+        ret = syncop_writev (subvol, fd, &iov, 1, offset, iobref, flags,
+                             NULL, NULL);
+        DECODE_SYNCOP_ERR (ret);
+
+        iobuf_unref (iobuf);
+        iobref_unref (iobref);
+
+        if (ret <= 0)
+                goto out;
+
+out:
+
+        if (fd)
+                fd_unref(fd);
+
+        glfs_subvol_done (fs, subvol);
+
+        return ret;
+}
+
+ssize_t
+glfs_anonymous_preadv (struct glfs *fs,  struct glfs_object *object,
+                       const struct iovec *iovec, int iovcnt,
+                       off_t offset, int flags)
+{
+        xlator_t        *subvol = NULL;
+        struct iovec    *iov    = NULL;
+        struct iobref   *iobref = NULL;
+        inode_t         *inode  = NULL;
+        fd_t            *fd     = NULL;
+        int             cnt     = 0;
+        ssize_t         ret     = -1;
+        ssize_t         size    = -1;
+
+        __glfs_entry_fs (fs);
+
+        subvol = glfs_active_subvol (fs);
+        if (!subvol) {
+                ret = -1;
+                errno = EIO;
+                goto out;
+        }
+
+        /* get/refresh the in arg objects inode in correlation to the xlator */
+        inode = glfs_resolve_inode (fs, subvol, object);
+        if (!inode) {
+                ret = -1;
+                errno = ESTALE;
+                goto out;
+        }
+
+        fd = fd_anonymous (inode);
+        if (!fd) {
+                ret = -1;
+                gf_msg ("gfapi", GF_LOG_ERROR, ENOMEM, API_MSG_FDCREATE_FAILED,
+                        "Allocating anonymous fd failed");
+                errno = ENOMEM;
+                goto out;
+        }
+
+        size = iov_length (iovec, iovcnt);
+
+	ret = syncop_readv (subvol, fd, size, offset, flags, &iov, &cnt,
+                            &iobref, NULL, NULL);
+        DECODE_SYNCOP_ERR (ret);
+        if (ret <= 0)
+                goto out;
+
+        size = iov_copy (iovec, iovcnt, iov, cnt);
+
+        ret = size;
+out:
+        if (iov)
+                GF_FREE (iov);
+        if (iobref)
+                iobref_unref (iobref);
+        if (fd)
+                fd_unref(fd);
+
+        glfs_subvol_done (fs, subvol);
+
+        return ret;
+}
diff --git a/api/src/glfs-handleops.c b/api/src/glfs-handleops.c
index 4a544f7c905..2793e1cb118 100644
--- a/api/src/glfs-handleops.c
+++ b/api/src/glfs-handleops.c
@@ -1962,3 +1962,51 @@ pub_glfs_h_acl_set (struct glfs *fs, struct glfs_object *object,
 #endif
 GFAPI_SYMVER_PUBLIC_DEFAULT(glfs_h_acl_set, 3.7.0);
 GFAPI_SYMVER_PUBLIC_DEFAULT(glfs_h_acl_get, 3.7.0);
+
+/* The API to perform read using anonymous fd */
+ssize_t
+pub_glfs_h_anonymous_read (struct glfs *fs, struct glfs_object *object,
+                           const void *buf, size_t count, off_t offset)
+{
+        struct iovec    iov     = {0, };
+        ssize_t         ret     = 0;
+
+        /* validate in args */
+        if ((fs == NULL) || (object == NULL)) {
+                errno = EINVAL;
+                return -1;
+        }
+
+        iov.iov_base = (void *) buf;
+        iov.iov_len = count;
+
+        ret = glfs_anonymous_preadv (fs, object, &iov, 1, offset, 0);
+
+        return ret;
+}
+
+GFAPI_SYMVER_PUBLIC_DEFAULT(glfs_h_anonymous_read, 3.7.0);
+
+/* The API to perform write using anonymous fd */
+ssize_t
+pub_glfs_h_anonymous_write (struct glfs *fs, struct glfs_object *object,
+                            const void *buf, size_t count, off_t offset)
+{
+        struct iovec iov        = {0, };
+        ssize_t      ret        = 0;
+
+        /* validate in args */
+        if ((fs == NULL) || (object == NULL)) {
+                errno = EINVAL;
+                return -1;
+        }
+
+        iov.iov_base = (void *) buf;
+        iov.iov_len = count;
+
+        ret = glfs_anonymous_pwritev (fs, object, &iov, 1, offset, 0);
+
+        return ret;
+}
+
+GFAPI_SYMVER_PUBLIC_DEFAULT(glfs_h_anonymous_write, 3.7.0);
diff --git a/api/src/glfs-handles.h b/api/src/glfs-handles.h
index 28e9e79b9a3..19c4e8f7a62 100644
--- a/api/src/glfs-handles.h
+++ b/api/src/glfs-handles.h
@@ -310,6 +310,16 @@ glfs_h_acl_get (struct glfs *fs, struct glfs_object *object,
                 const acl_type_t type) __THROW;
         GFAPI_PUBLIC(glfs_h_acl_get, 3.7.0);
 
+size_t
+glfs_h_anonymous_write (struct glfs *fs, struct glfs_object *object,
+                        const void *buf, size_t count, off_t offset) __THROW
+        GFAPI_PUBLIC(glfs_h_anonymous_write, 3.7.0);
+
+ssize_t
+glfs_h_anonymous_read (struct glfs *fs, struct glfs_object *object,
+                      const void *buf, size_t count, off_t offset) __THROW
+        GFAPI_PUBLIC(glfs_h_anonymous_read, 3.7.0);
+
 __END_DECLS
 
 #endif /* !_GLFS_HANDLES_H */
diff --git a/api/src/glfs-internal.h b/api/src/glfs-internal.h
index 972f2e4cf49..3c83fe848ff 100644
--- a/api/src/glfs-internal.h
+++ b/api/src/glfs-internal.h
@@ -342,4 +342,13 @@ glfs_h_poll_cache_invalidation (struct glfs *fs,
                                 struct callback_arg *up_arg,
                                 struct gf_upcall *upcall_data);
 
+ssize_t
+glfs_anonymous_preadv (struct glfs *fs, struct glfs_object *object,
+                       const struct iovec *iovec, int iovcnt,
+                       off_t offset, int flags);
+ssize_t
+glfs_anonymous_pwritev (struct glfs *fs, struct glfs_object *object,
+                        const struct iovec *iovec, int iovcnt,
+                        off_t offset, int flags);
+
 #endif /* !_GLFS_INTERNAL_H */