[PATCH 4.9 41/51] xfs: replace xfs_mode_to_ftype table with switch statement

From: Greg Kroah-Hartman
Date: Thu Feb 02 2017 - 13:45:10 EST


4.9-stable review patch. If anyone has any objections, please let me know.

------------------


From: Amir Goldstein <amir73il@xxxxxxxxx>

commit 1fc4d33fed124fb182e8e6c214e973a29389ae83.

The size of the xfs_mode_to_ftype[] conversion table
was too small to handle an invalid value of mode=S_IFMT.

Instead of fixing the table size, replace the conversion table
with a conversion helper that uses a switch statement.

Suggested-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/xfs/libxfs/xfs_dir2.c | 36 ++++++++++++++++++++++--------------
fs/xfs/libxfs/xfs_dir2.h | 5 ++---
fs/xfs/xfs_iops.c | 2 +-
3 files changed, 25 insertions(+), 18 deletions(-)

--- a/fs/xfs/libxfs/xfs_dir2.c
+++ b/fs/xfs/libxfs/xfs_dir2.c
@@ -36,21 +36,29 @@
struct xfs_name xfs_name_dotdot = { (unsigned char *)"..", 2, XFS_DIR3_FT_DIR };

/*
- * @mode, if set, indicates that the type field needs to be set up.
- * This uses the transformation from file mode to DT_* as defined in linux/fs.h
- * for file type specification. This will be propagated into the directory
- * structure if appropriate for the given operation and filesystem config.
+ * Convert inode mode to directory entry filetype
*/
-const unsigned char xfs_mode_to_ftype[S_IFMT >> S_SHIFT] = {
- [0] = XFS_DIR3_FT_UNKNOWN,
- [S_IFREG >> S_SHIFT] = XFS_DIR3_FT_REG_FILE,
- [S_IFDIR >> S_SHIFT] = XFS_DIR3_FT_DIR,
- [S_IFCHR >> S_SHIFT] = XFS_DIR3_FT_CHRDEV,
- [S_IFBLK >> S_SHIFT] = XFS_DIR3_FT_BLKDEV,
- [S_IFIFO >> S_SHIFT] = XFS_DIR3_FT_FIFO,
- [S_IFSOCK >> S_SHIFT] = XFS_DIR3_FT_SOCK,
- [S_IFLNK >> S_SHIFT] = XFS_DIR3_FT_SYMLINK,
-};
+const unsigned char xfs_mode_to_ftype(int mode)
+{
+ switch (mode & S_IFMT) {
+ case S_IFREG:
+ return XFS_DIR3_FT_REG_FILE;
+ case S_IFDIR:
+ return XFS_DIR3_FT_DIR;
+ case S_IFCHR:
+ return XFS_DIR3_FT_CHRDEV;
+ case S_IFBLK:
+ return XFS_DIR3_FT_BLKDEV;
+ case S_IFIFO:
+ return XFS_DIR3_FT_FIFO;
+ case S_IFSOCK:
+ return XFS_DIR3_FT_SOCK;
+ case S_IFLNK:
+ return XFS_DIR3_FT_SYMLINK;
+ default:
+ return XFS_DIR3_FT_UNKNOWN;
+ }
+}

/*
* ASCII case-insensitive (ie. A-Z) support for directories that was
--- a/fs/xfs/libxfs/xfs_dir2.h
+++ b/fs/xfs/libxfs/xfs_dir2.h
@@ -35,10 +35,9 @@ struct xfs_dir2_data_unused;
extern struct xfs_name xfs_name_dotdot;

/*
- * directory filetype conversion tables.
+ * Convert inode mode to directory entry filetype
*/
-#define S_SHIFT 12
-extern const unsigned char xfs_mode_to_ftype[];
+extern const unsigned char xfs_mode_to_ftype(int mode);

/*
* directory operations vector for encode/decode routines
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -103,7 +103,7 @@ xfs_dentry_to_name(
{
namep->name = dentry->d_name.name;
namep->len = dentry->d_name.len;
- namep->type = xfs_mode_to_ftype[(mode & S_IFMT) >> S_SHIFT];
+ namep->type = xfs_mode_to_ftype(mode);
}

STATIC void