GFS2: Support for FIEMAP ioctl

This patch implements the FIEMAP ioctl for GFS2. We can use the generic
code (aside from a lock order issue, solved as per Ted Tso's suggestion)
for which I've introduced a new variant of the generic function. We also
have one exception to deal with, namely stuffed files, so we do that
"by hand", setting all the required flags.

This has been tested with a modified (I could only find an old version) of
Eric's test program, and appears to work correctly.

This patch does not currently support FIEMAP of xattrs, but the plan is to add
that feature at some future point.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Theodore Tso <tytso@mit.edu>
Cc: Eric Sandeen <sandeen@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index f2a3010140e..e34bc6925fd 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2059,6 +2059,9 @@ extern int vfs_fstat(unsigned int, struct kstat *);
 
 extern int do_vfs_ioctl(struct file *filp, unsigned int fd, unsigned int cmd,
                     unsigned long arg);
+extern int __generic_block_fiemap(struct inode *inode,
+                                  struct fiemap_extent_info *fieinfo, u64 start,
+                                  u64 len, get_block_t *get_block);
 extern int generic_block_fiemap(struct inode *inode,
                                 struct fiemap_extent_info *fieinfo, u64 start,
                                 u64 len, get_block_t *get_block);