[PATCH 30/49] xfs: split out the remote symlink handling

Dave Chinner
2013-07-19T06:45:38Z

From: Dave Chinner <dchinner@redhat.com>

The remote symlink format definition and manipulation needs to be
shared with userspace, but the in-kernel interfaces do not. Split
the remote symlink format handling out into xfs_symlink_remote.[ch]
fo it can easily be shared with userspace.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
include/Makefile | 1 -
include/libxfs.h | 1 -
include/xfs_format.h | 42 ++++++++++
include/xfs_symlink.h | 47 -----------
libxfs/Makefile | 2 +-
libxfs/xfs_symlink.c | 176 -----------------------------------------
libxfs/xfs_symlink_remote.c | 185 ++++++++++++++++++++++++++++++++++++++++++++
7 files changed, 228 insertions(+), 226 deletions(-)
delete mode 100644 include/xfs_symlink.h
delete mode 100644 libxfs/xfs_symlink.c
create mode 100644 libxfs/xfs_symlink_remote.c

diff --git a/include/Makefile b/include/Makefile
index 2b121e5..70720e5 100644
--- a/include/Makefile
+++ b/include/Makefile
@@ -39,7 +39,6 @@ QAHFILES = libxfs.h libxlog.h \
xfs_mount.h \
xfs_quota_defs.h \
xfs_sb.h \
- xfs_symlink.h \
xfs_trace.h \
xfs_trans.h \
xfs_trans_resv.h \
diff --git a/include/libxfs.h b/include/libxfs.h
index f84b816..37e9e15 100644
--- a/include/libxfs.h
+++ b/include/libxfs.h
@@ -61,7 +61,6 @@
#include <xfs/xfs_btree_trace.h>
#include <xfs/xfs_bmap.h>
#include <xfs/xfs_trace.h>
-#include <xfs/xfs_symlink.h>

#ifndef ARRAY_SIZE
diff --git a/include/xfs_format.h b/include/xfs_format.h
index 6205374..35c08ff 100644
--- a/include/xfs_format.h
+++ b/include/xfs_format.h
@@ -27,6 +27,12 @@
* xfs_log_format.h. Everything else goes here.
*/

+struct xfs_mount;
+struct xfs_trans;
+struct xfs_inode;
+struct xfs_buf;
+struct xfs_ifork;
+
/*
* RealTime Device format definitions
*/
@@ -123,5 +129,41 @@ typedef struct xfs_dqblk {

#define XFS_DQUOT_CRC_OFF offsetof(struct xfs_dqblk, dd_crc)

+/*
+ * Remote symlink format and access functions.
+ */
+#define XFS_SYMLINK_MAGIC 0x58534c4d /* XSLM */
+
+struct xfs_dsymlink_hdr {
+ __be32 sl_magic;
+ __be32 sl_offset;
+ __be32 sl_bytes;
+ __be32 sl_crc;
+ uuid_t sl_uuid;
+ __be64 sl_owner;
+ __be64 sl_blkno;
+ __be64 sl_lsn;
+};
+
+/*
+ * The maximum pathlen is 1024 bytes. Since the minimum file system
+ * blocksize is 512 bytes, we can get a max of 3 extents back from
+ * bmapi when crc headers are taken into account.
+ */
+#define XFS_SYMLINK_MAPS 3
+
+#define XFS_SYMLINK_BUF_SPACE(mp, bufsize) \
+ ((bufsize) - (xfs_sb_version_hascrc(&(mp)->m_sb) ? \
+ sizeof(struct xfs_dsymlink_hdr) : 0))
+
+int xfs_symlink_blocks(struct xfs_mount *mp, int pathlen);
+int xfs_symlink_hdr_set(struct xfs_mount *mp, xfs_ino_t ino, uint32_t offset,
+ uint32_t size, struct xfs_buf *bp);
+bool xfs_symlink_hdr_ok(struct xfs_mount *mp, xfs_ino_t ino, uint32_t offset,
+ uint32_t size, struct xfs_buf *bp);
+void xfs_symlink_local_to_remote(struct xfs_trans *tp, struct xfs_buf *bp,
+ struct xfs_inode *ip, struct xfs_ifork *ifp);
+
+extern const struct xfs_buf_ops xfs_symlink_buf_ops;

#endif /* __XFS_FORMAT_H__ */
diff --git a/include/xfs_symlink.h b/include/xfs_symlink.h
deleted file mode 100644
index e85dfd1..0000000
--- a/include/xfs_symlink.h
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
- * Copyright (c) 2012 Red Hat, Inc. All rights reserved.
- */
-#ifndef __XFS_SYMLINK_H
-#define __XFS_SYMLINK_H 1
-
-#define XFS_SYMLINK_MAGIC 0x58534c4d /* XSLM */
-
-struct xfs_dsymlink_hdr {
- __be32 sl_magic;
- __be32 sl_offset;
- __be32 sl_bytes;
- __be32 sl_crc;
- uuid_t sl_uuid;
- __be64 sl_owner;
- __be64 sl_blkno;
- __be64 sl_lsn;
-};
-
-/*
- * The maximum pathlen is 1024 bytes. Since the minimum file system
- * blocksize is 512 bytes, we can get a max of 3 extents back from
- * bmapi when crc headers are taken into account.
- */
-#define XFS_SYMLINK_MAPS 3
-
-#define XFS_SYMLINK_BUF_SPACE(mp, bufsize) \
- ((bufsize) - (xfs_sb_version_hascrc(&(mp)->m_sb) ? \
- sizeof(struct xfs_dsymlink_hdr) : 0))
-
-int xfs_symlink_blocks(struct xfs_mount *mp, int pathlen);
-bool xfs_symlink_hdr_ok(struct xfs_mount *mp, xfs_ino_t ino, uint32_t offset,
- uint32_t size, struct xfs_buf *bp);
-void xfs_symlink_local_to_remote(struct xfs_trans *tp, struct xfs_buf *bp,
- struct xfs_inode *ip, struct xfs_ifork *ifp);
-
-extern const struct xfs_buf_ops xfs_symlink_buf_ops;
-
-#ifdef __KERNEL__
-
-int xfs_symlink(struct xfs_inode *dp, struct xfs_name *link_name,
- const char *target_path, umode_t mode, struct xfs_inode **ipp);
-int xfs_readlink(struct xfs_inode *ip, char *link);
-int xfs_inactive_symlink_rmt(struct xfs_inode *ip, struct xfs_trans **tpp);
-
-#endif /* __KERNEL__ */
-#endif /* __XFS_SYMLINK_H */
diff --git a/libxfs/Makefile b/libxfs/Makefile
index b7df144..6ba38f9 100644
--- a/libxfs/Makefile
+++ b/libxfs/Makefile
@@ -23,7 +23,7 @@ CFILES = cache.c init.c kmem.c logitem.c radix-tree.c rdwr.c trans.c util.c \
xfs_dir2_node.c xfs_dir2_data.c xfs_dir2_sf.c xfs_bmap.c \
xfs_mount.c xfs_rtalloc.c xfs_attr.c xfs_attr_remote.c \
crc32.c \
- xfs_symlink.c \
+ xfs_symlink_remote.c \
xfs_trans_resv.c

CFILES += $(PKG_PLATFORM).c
diff --git a/libxfs/xfs_symlink.c b/libxfs/xfs_symlink.c
deleted file mode 100644
index f2e69f9..0000000
--- a/libxfs/xfs_symlink.c
+++ /dev/null
@@ -1,176 +0,0 @@
-/*
- * Copyright 2013 Red Hat, Inc.
- * All rights reserved.
- */
-
-#include "xfs.h"
-
-/*
- * Each contiguous block has a header, so it is not just a simple pathlen
- * to FSB conversion.
- */
-int
-xfs_symlink_blocks(
- struct xfs_mount *mp,
- int pathlen)
-{
- int buflen = XFS_SYMLINK_BUF_SPACE(mp, mp->m_sb.sb_blocksize);
-
- return (pathlen + buflen - 1) / buflen;
-}
-
-/*
- * This is used by mkfs/proto.c to create symlinks.
- */
-int
-xfs_symlink_hdr_set(
- struct xfs_mount *mp,
- xfs_ino_t ino,
- uint32_t offset,
- uint32_t size,
- struct xfs_buf *bp)
-{
- struct xfs_dsymlink_hdr *dsl = bp->b_addr;
-
- if (!xfs_sb_version_hascrc(&mp->m_sb))
- return 0;
-
- dsl->sl_magic = cpu_to_be32(XFS_SYMLINK_MAGIC);
- dsl->sl_offset = cpu_to_be32(offset);
- dsl->sl_bytes = cpu_to_be32(size);
- uuid_copy(&dsl->sl_uuid, &mp->m_sb.sb_uuid);
- dsl->sl_owner = cpu_to_be64(ino);
- dsl->sl_blkno = cpu_to_be64(bp->b_bn);
- bp->b_ops = &xfs_symlink_buf_ops;
-
- return sizeof(struct xfs_dsymlink_hdr);
-}
-
-/*
- * Checking of the symlink header is split into two parts. the verifier does
- * CRC, location and bounds checking, the unpacking function checks the path
- * parameters and owner.
- */
-bool
-xfs_symlink_hdr_ok(
- struct xfs_mount *mp,
- xfs_ino_t ino,
- uint32_t offset,
- uint32_t size,
- struct xfs_buf *bp)
-{
- struct xfs_dsymlink_hdr *dsl = bp->b_addr;
-
- if (offset != be32_to_cpu(dsl->sl_offset))
- return false;
- if (size != be32_to_cpu(dsl->sl_bytes))
- return false;
- if (ino != be64_to_cpu(dsl->sl_owner))
- return false;
-
- /* ok */
- return true;
-
-}
-
-static bool
-xfs_symlink_verify(
- struct xfs_buf *bp)
-{
- struct xfs_mount *mp = bp->b_target->bt_mount;
- struct xfs_dsymlink_hdr *dsl = bp->b_addr;
-
- if (!xfs_sb_version_hascrc(&mp->m_sb))
- return false;
- if (dsl->sl_magic != cpu_to_be32(XFS_SYMLINK_MAGIC))
- return false;
- if (!uuid_equal(&dsl->sl_uuid, &mp->m_sb.sb_uuid))
- return false;
- if (bp->b_bn != be64_to_cpu(dsl->sl_blkno))
- return false;
- if (be32_to_cpu(dsl->sl_offset) +
- be32_to_cpu(dsl->sl_bytes) >= MAXPATHLEN)
- return false;
- if (dsl->sl_owner == 0)
- return false;
-
- return true;
-}
-
-static void
-xfs_symlink_read_verify(
- struct xfs_buf *bp)
-{
- struct xfs_mount *mp = bp->b_target->bt_mount;
-
- /* no verification of non-crc buffers */
- if (!xfs_sb_version_hascrc(&mp->m_sb))
- return;
-
- if (!xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
- offsetof(struct xfs_dsymlink_hdr, sl_crc)) ||
- !xfs_symlink_verify(bp)) {
- XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
- xfs_buf_ioerror(bp, EFSCORRUPTED);
- }
-}
-
-static void
-xfs_symlink_write_verify(
- struct xfs_buf *bp)
-{
- struct xfs_mount *mp = bp->b_target->bt_mount;
- struct xfs_buf_log_item *bip = bp->b_fspriv;
-
- /* no verification of non-crc buffers */
- if (!xfs_sb_version_hascrc(&mp->m_sb))
- return;
-
- if (!xfs_symlink_verify(bp)) {
- XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
- xfs_buf_ioerror(bp, EFSCORRUPTED);
- return;
- }
-
- if (bip) {
- struct xfs_dsymlink_hdr *dsl = bp->b_addr;
- dsl->sl_lsn = cpu_to_be64(bip->bli_item.li_lsn);
- }
- xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
- offsetof(struct xfs_dsymlink_hdr, sl_crc));
-}
-
-const struct xfs_buf_ops xfs_symlink_buf_ops = {
- .verify_read = xfs_symlink_read_verify,
- .verify_write = xfs_symlink_write_verify,
-};
-
-void
-xfs_symlink_local_to_remote(
- struct xfs_trans *tp,
- struct xfs_buf *bp,
- struct xfs_inode *ip,
- struct xfs_ifork *ifp)
-{
- struct xfs_mount *mp = ip->i_mount;
- char *buf;
-
- if (!xfs_sb_version_hascrc(&mp->m_sb)) {
- bp->b_ops = NULL;
- memcpy(bp->b_addr, ifp->if_u1.if_data, ifp->if_bytes);
- return;
- }
-
- /*
- * As this symlink fits in an inode literal area, it must also fit in
- * the smallest buffer the filesystem supports.
- */
- ASSERT(BBTOB(bp->b_length) >=
- ifp->if_bytes + sizeof(struct xfs_dsymlink_hdr));
-
- bp->b_ops = &xfs_symlink_buf_ops;
-
- buf = bp->b_addr;
- buf += xfs_symlink_hdr_set(mp, ip->i_ino, 0, ifp->if_bytes, bp);
- memcpy(buf, ifp->if_u1.if_data, ifp->if_bytes);
-}
diff --git a/libxfs/xfs_symlink_remote.c b/libxfs/xfs_symlink_remote.c
new file mode 100644
index 0000000..539db0c
--- /dev/null
+++ b/libxfs/xfs_symlink_remote.c
@@ -0,0 +1,185 @@
+/*
+ * Copyright (c) 2000-2006 Silicon Graphics, Inc.
+ * Copyright (c) 2012-2013 Red Hat, Inc.
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include <xfs.h>
+
+/*
+ * Each contiguous block has a header, so it is not just a simple pathlen
+ * to FSB conversion.
+ */
+int
+xfs_symlink_blocks(
+ struct xfs_mount *mp,
+ int pathlen)
+{
+ int buflen = XFS_SYMLINK_BUF_SPACE(mp, mp->m_sb.sb_blocksize);
+
+ return (pathlen + buflen - 1) / buflen;
+}
+
+int
+xfs_symlink_hdr_set(
+ struct xfs_mount *mp,
+ xfs_ino_t ino,
+ uint32_t offset,
+ uint32_t size,
+ struct xfs_buf *bp)
+{
+ struct xfs_dsymlink_hdr *dsl = bp->b_addr;
+
+ if (!xfs_sb_version_hascrc(&mp->m_sb))
+ return 0;
+
+ dsl->sl_magic = cpu_to_be32(XFS_SYMLINK_MAGIC);
+ dsl->sl_offset = cpu_to_be32(offset);
+ dsl->sl_bytes = cpu_to_be32(size);
+ uuid_copy(&dsl->sl_uuid, &mp->m_sb.sb_uuid);
+ dsl->sl_owner = cpu_to_be64(ino);
+ dsl->sl_blkno = cpu_to_be64(bp->b_bn);
+ bp->b_ops = &xfs_symlink_buf_ops;
+
+ return sizeof(struct xfs_dsymlink_hdr);
+}
+
+/*
+ * Checking of the symlink header is split into two parts. the verifier does
+ * CRC, location and bounds checking, the unpacking function checks the path
+ * parameters and owner.
+ */
+bool
+xfs_symlink_hdr_ok(
+ struct xfs_mount *mp,
+ xfs_ino_t ino,
+ uint32_t offset,
+ uint32_t size,
+ struct xfs_buf *bp)
+{
+ struct xfs_dsymlink_hdr *dsl = bp->b_addr;
+
+ if (offset != be32_to_cpu(dsl->sl_offset))
+ return false;
+ if (size != be32_to_cpu(dsl->sl_bytes))
+ return false;
+ if (ino != be64_to_cpu(dsl->sl_owner))
+ return false;
+
+ /* ok */
+ return true;
+}
+
+static bool
+xfs_symlink_verify(
+ struct xfs_buf *bp)
+{
+ struct xfs_mount *mp = bp->b_target->bt_mount;
+ struct xfs_dsymlink_hdr *dsl = bp->b_addr;
+
+ if (!xfs_sb_version_hascrc(&mp->m_sb))
+ return false;
+ if (dsl->sl_magic != cpu_to_be32(XFS_SYMLINK_MAGIC))
+ return false;
+ if (!uuid_equal(&dsl->sl_uuid, &mp->m_sb.sb_uuid))
+ return false;
+ if (bp->b_bn != be64_to_cpu(dsl->sl_blkno))
+ return false;
+ if (be32_to_cpu(dsl->sl_offset) +
+ be32_to_cpu(dsl->sl_bytes) >= MAXPATHLEN)
+ return false;
+ if (dsl->sl_owner == 0)
+ return false;
+
+ return true;
+}
+
+static void
+xfs_symlink_read_verify(
+ struct xfs_buf *bp)
+{
+ struct xfs_mount *mp = bp->b_target->bt_mount;
+
+ /* no verification of non-crc buffers */
+ if (!xfs_sb_version_hascrc(&mp->m_sb))
+ return;
+
+ if (!xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
+ offsetof(struct xfs_dsymlink_hdr, sl_crc)) ||
+ !xfs_symlink_verify(bp)) {
+ XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
+ xfs_buf_ioerror(bp, EFSCORRUPTED);
+ }
+}
+
+static void
+xfs_symlink_write_verify(
+ struct xfs_buf *bp)
+{
+ struct xfs_mount *mp = bp->b_target->bt_mount;
+ struct xfs_buf_log_item *bip = bp->b_fspriv;
+
+ /* no verification of non-crc buffers */
+ if (!xfs_sb_version_hascrc(&mp->m_sb))
+ return;
+
+ if (!xfs_symlink_verify(bp)) {
+ XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
+ xfs_buf_ioerror(bp, EFSCORRUPTED);
+ return;
+ }
+
+ if (bip) {
+ struct xfs_dsymlink_hdr *dsl = bp->b_addr;
+ dsl->sl_lsn = cpu_to_be64(bip->bli_item.li_lsn);
+ }
+ xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
+ offsetof(struct xfs_dsymlink_hdr, sl_crc));
+}
+
+const struct xfs_buf_ops xfs_symlink_buf_ops = {
+ .verify_read = xfs_symlink_read_verify,
+ .verify_write = xfs_symlink_write_verify,
+};
+
+void
+xfs_symlink_local_to_remote(
+ struct xfs_trans *tp,
+ struct xfs_buf *bp,
+ struct xfs_inode *ip,
+ struct xfs_ifork *ifp)
+{
+ struct xfs_mount *mp = ip->i_mount;
+ char *buf;
+
+ if (!xfs_sb_version_hascrc(&mp->m_sb)) {
+ bp->b_ops = NULL;
+ memcpy(bp->b_addr, ifp->if_u1.if_data, ifp->if_bytes);
+ return;
+ }
+
+ /*
+ * As this symlink fits in an inode literal area, it must also fit in
+ * the smallest buffer the filesystem supports.
+ */
+ ASSERT(BBTOB(bp->b_length) >=
+ ifp->if_bytes + sizeof(struct xfs_dsymlink_hdr));
+
+ bp->b_ops = &xfs_symlink_buf_ops;
+
+ buf = bp->b_addr;
+ buf += xfs_symlink_hdr_set(mp, ip->i_ino, 0, ifp->if_bytes, bp);
+ memcpy(buf, ifp->if_u1.if_data, ifp->if_bytes);
+}
--
1.8.3.2