From: Christoph Hellwig <hch@lst.de>
Date: Tue, 16 Aug 2016 22:45:30 +0000 (+1000)
Subject: xfs: (re-)implement FIEMAP_FLAG_XATTR
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=1d4795e7bde075588c90df2175349bb2251802d5;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

xfs: (re-)implement FIEMAP_FLAG_XATTR

Use a special read-only iomap_ops implementation to support fiemap on
the attr fork.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
---

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 1cce760399a2..697c8fd4200f 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1106,3 +1106,48 @@ struct iomap_ops xfs_iomap_ops = {
 	.iomap_begin		= xfs_file_iomap_begin,
 	.iomap_end		= xfs_file_iomap_end,
 };
+
+static int
+xfs_xattr_iomap_begin(
+	struct inode		*inode,
+	loff_t			offset,
+	loff_t			length,
+	unsigned		flags,
+	struct iomap		*iomap)
+{
+	struct xfs_inode	*ip = XFS_I(inode);
+	struct xfs_mount	*mp = ip->i_mount;
+	xfs_fileoff_t		offset_fsb = XFS_B_TO_FSBT(mp, offset);
+	xfs_fileoff_t		end_fsb = XFS_B_TO_FSB(mp, offset + length);
+	struct xfs_bmbt_irec	imap;
+	int			nimaps = 1, error = 0;
+	unsigned		lockmode;
+
+	if (XFS_FORCED_SHUTDOWN(mp))
+		return -EIO;
+
+	lockmode = xfs_ilock_data_map_shared(ip);
+
+	/* if there are no attribute fork or extents, return ENOENT */
+	if (XFS_IFORK_Q(ip) || !ip->i_d.di_anextents) {
+		error = -ENOENT;
+		goto out_unlock;
+	}
+
+	ASSERT(ip->i_d.di_aformat != XFS_DINODE_FMT_LOCAL);
+	error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
+			       &nimaps, XFS_BMAPI_ENTIRE | XFS_BMAPI_ATTRFORK);
+out_unlock:
+	xfs_iunlock(ip, lockmode);
+
+	if (!error) {
+		ASSERT(nimaps);
+		xfs_bmbt_to_iomap(ip, iomap, &imap);
+	}
+
+	return error;
+}
+
+struct iomap_ops xfs_xattr_iomap_ops = {
+	.iomap_begin		= xfs_xattr_iomap_begin,
+};
diff --git a/fs/xfs/xfs_iomap.h b/fs/xfs/xfs_iomap.h
index e066d045e2ff..fb8aca3d69ab 100644
--- a/fs/xfs/xfs_iomap.h
+++ b/fs/xfs/xfs_iomap.h
@@ -35,5 +35,6 @@ void xfs_bmbt_to_iomap(struct xfs_inode *, struct iomap *,
 		struct xfs_bmbt_irec *);
 
 extern struct iomap_ops xfs_iomap_ops;
+extern struct iomap_ops xfs_xattr_iomap_ops;
 
 #endif /* __XFS_IOMAP_H__*/
diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
index ab820f84ed50..b24c3102fa93 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -1009,7 +1009,14 @@ xfs_vn_fiemap(
 	int			error;
 
 	xfs_ilock(XFS_I(inode), XFS_IOLOCK_SHARED);
-	error = iomap_fiemap(inode, fieinfo, start, length, &xfs_iomap_ops);
+	if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) {
+		fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR;
+		error = iomap_fiemap(inode, fieinfo, start, length,
+				&xfs_xattr_iomap_ops);
+	} else {
+		error = iomap_fiemap(inode, fieinfo, start, length,
+				&xfs_iomap_ops);
+	}
 	xfs_iunlock(XFS_I(inode), XFS_IOLOCK_SHARED);
 
 	return error;