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[PATCH 30/55] xfs: split out the remote symlink handling

To: xfs@xxxxxxxxxxx
Subject: [PATCH 30/55] xfs: split out the remote symlink handling
From: Dave Chinner <david@xxxxxxxxxxxxx>
Date: Thu, 5 Sep 2013 08:05:34 +1000
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <1378332359-14737-1-git-send-email-david@xxxxxxxxxxxxx>
References: <1378332359-14737-1-git-send-email-david@xxxxxxxxxxxxx>
From: Dave Chinner <dchinner@xxxxxxxxxx>

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@xxxxxxxxxx>
---
 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 c86d2ce..6a4e521 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_resv.h \
        xfs_trans_space.h \
diff --git a/include/libxfs.h b/include/libxfs.h
index 8ab832d..51a2442 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

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