Patchwork libext2fs: ext2fs_dup_handle should deep copy MMP buffers

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Submitter Darrick J. Wong
Date July 23, 2013, 5:27 a.m.
Message ID <20130723052737.GG5785@blackbox.djwong.org>
Download mbox | patch
Permalink /patch/260965/
State Superseded
Headers show

Comments

Darrick J. Wong - July 23, 2013, 5:27 a.m.
It turns out that resize2fs uses ext2fs_dup_handle to duplicate fs handles.  If
MMP is enabled, this causes both handles to share MMP buffers, which is bad
news when it comes time to free both fs handles.  Change the code to provide
each handle with its own separate copy of the MMP buffer.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 lib/ext2fs/dupfs.c |   25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

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Patch

diff --git a/lib/ext2fs/dupfs.c b/lib/ext2fs/dupfs.c
index 64d3124..02721e1 100644
--- a/lib/ext2fs/dupfs.c
+++ b/lib/ext2fs/dupfs.c
@@ -40,6 +40,9 @@  errcode_t ext2fs_dup_handle(ext2_filsys src, ext2_filsys *dest)
 	fs->block_map = 0;
 	fs->badblocks = 0;
 	fs->dblist = 0;
+	fs->mmp_buf = 0;
+	fs->mmp_cmp = 0;
+	fs->mmp_fd = -1;
 
 	io_channel_bumpcount(fs->io);
 	if (fs->icache)
@@ -87,6 +90,28 @@  errcode_t ext2fs_dup_handle(ext2_filsys src, ext2_filsys *dest)
 		if (retval)
 			goto errout;
 	}
+	if (src->mmp_buf) {
+		retval = ext2fs_get_mem(src->blocksize, &fs->mmp_buf);
+		if (retval)
+			goto errout;
+		memcpy(fs->mmp_buf, src->mmp_buf, src->blocksize);
+	}
+	if (src->mmp_fd >= 0) {
+		fs->mmp_fd = dup(src->mmp_fd);
+		if (fs->mmp_fd < 0) {
+			retval = EXT2_ET_MMP_OPEN_DIRECT;
+			goto errout;
+		}
+	}
+	if (src->mmp_cmp) {
+		int align = ext2fs_get_dio_alignment(src->mmp_fd);
+
+		retval = ext2fs_get_memalign(src->blocksize, align,
+					     &fs->mmp_cmp);
+		if (retval)
+			goto errout;
+		memcpy(fs->mmp_cmp, src->mmp_cmp, src->blocksize);
+	}
 	*dest = fs;
 	return 0;
 errout: