From: Dave Chinner <dchinner@xxxxxxxxxx>
Signed-off-by: Dave Chinner <dchinner@xxxxxxxxxx>
---
include/Makefile | 4 +-
include/libxfs.h | 1 +
include/xfs_buf_item.h | 4 +-
include/xfs_symlink.h | 43 ++++++++++++++
libxfs/Makefile | 2 +-
libxfs/xfs_symlink.c | 154 ++++++++++++++++++++++++++++++++++++++++++++++++
6 files changed, 204 insertions(+), 4 deletions(-)
create mode 100644 include/xfs_symlink.h
create mode 100644 libxfs/xfs_symlink.c
diff --git a/include/Makefile b/include/Makefile
index 9ed5077..54241bd 100644
--- a/include/Makefile
+++ b/include/Makefile
@@ -28,8 +28,8 @@ QAHFILES = libxfs.h libxlog.h \
xfs_dir_sf.h xfs_extfree_item.h xfs_ialloc.h xfs_ialloc_btree.h \
xfs_inode.h xfs_inode_item.h xfs_inum.h \
xfs_log.h xfs_log_priv.h xfs_log_recover.h xfs_metadump.h \
- xfs_mount.h xfs_quota.h xfs_rtalloc.h xfs_sb.h xfs_trace.h \
- xfs_trans.h xfs_trans_space.h xfs_types.h xfs_dfrag.h
+ xfs_mount.h xfs_quota.h xfs_rtalloc.h xfs_sb.h xfs_symlink.h \
+ xfs_trace.h xfs_trans.h xfs_trans_space.h xfs_types.h xfs_dfrag.h
HFILES = handle.h jdm.h xqm.h xfs.h xfs_fs.h
HFILES += $(PKG_PLATFORM).h
diff --git a/include/libxfs.h b/include/libxfs.h
index f66da03..29767ef 100644
--- a/include/libxfs.h
+++ b/include/libxfs.h
@@ -56,6 +56,7 @@
#include <xfs/xfs_btree_trace.h>
#include <xfs/xfs_bmap.h>
#include <xfs/xfs_trace.h>
+#include <xfs/xfs_symlink.h>
#ifndef ARRAY_SIZE
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
diff --git a/include/xfs_buf_item.h b/include/xfs_buf_item.h
index d1eeeab..298438f 100644
--- a/include/xfs_buf_item.h
+++ b/include/xfs_buf_item.h
@@ -50,6 +50,7 @@ extern kmem_zone_t *xfs_buf_item_zone;
#define XFS_BLF_AGI_BUF (1<<8)
#define XFS_BLF_DINO_BUF (1<<9)
#define XFS_BLF_SB_BUF (1<<10)
+#define XFS_BLF_SYMLINK_BUF (1<<11)
#define XFS_BLF_TYPE_MASK \
(XFS_BLF_UDQUOT_BUF | \
@@ -60,7 +61,8 @@ extern kmem_zone_t *xfs_buf_item_zone;
XFS_BLF_AGFL_BUF | \
XFS_BLF_AGI_BUF | \
XFS_BLF_DINO_BUF | \
- XFS_BLF_SB_BUF)
+ XFS_BLF_SB_BUF | \
+ XFS_BLF_SYMLINK_BUF)
#define XFS_BLF_CHUNK 128
#define XFS_BLF_SHIFT 7
diff --git a/include/xfs_symlink.h b/include/xfs_symlink.h
new file mode 100644
index 0000000..bb21e6a
--- /dev/null
+++ b/include/xfs_symlink.h
@@ -0,0 +1,43 @@
+/*
+ * 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);
+
+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 28f71c8..75f365c 100644
--- a/libxfs/Makefile
+++ b/libxfs/Makefile
@@ -17,7 +17,7 @@ CFILES = cache.c init.c kmem.c logitem.c radix-tree.c rdwr.c trans.c util.c \
xfs_dir2.c xfs_dir2_leaf.c xfs_attr_leaf.c xfs_dir2_block.c \
xfs_dir2_node.c xfs_dir2_data.c xfs_dir2_sf.c xfs_bmap.c \
xfs_mount.c xfs_rtalloc.c xfs_trans.c xfs_attr.c \
- crc32.c
+ crc32.c xfs_symlink.c
CFILES += $(PKG_PLATFORM).c
PCFILES = darwin.c freebsd.c irix.c linux.c
diff --git a/libxfs/xfs_symlink.c b/libxfs/xfs_symlink.c
new file mode 100644
index 0000000..e018abc
--- /dev/null
+++ b/libxfs/xfs_symlink.c
@@ -0,0 +1,154 @@
+/*
+ * 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 fsblocks = 0;
+ int len = pathlen;
+
+ do {
+ fsblocks++;
+ len -= XFS_SYMLINK_BUF_SPACE(mp, mp->m_sb.sb_blocksize);
+ } while (len > 0);
+
+ ASSERT(fsblocks <= XFS_SYMLINK_MAPS);
+ return fsblocks;
+}
+
+/*
+ * XXX: this need to be used by mkfs/proto.c to create symlinks.
+ */
+static 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,
+};
+
--
1.7.10
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