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authorDarrick J. Wong <darrick.wong@oracle.com>2018-04-16 23:07:36 -0700
committerDarrick J. Wong <darrick.wong@oracle.com>2018-05-02 09:21:33 -0700
commit021ba8e98fe5c6691b3cc3669faafa02403aa211 (patch)
tree9b4b92b15794cb1e2c7a70f7dae329b3923679b2
parent7b38460dc8e4eafba06c78f8e37099d3b34d473c (diff)
downloadlinux-021ba8e98fe5c6691b3cc3669faafa02403aa211.tar.bz2
xfs: cap the length of deduplication requests
Since deduplication potentially has to read in all the pages in both files in order to compare the contents, cap the deduplication request length at MAX_RW_COUNT/2 (roughly 1GB) so that we have /some/ upper bound on the request length and can't just lock up the kernel forever. Found by running generic/304 after commit 1ddae54555b62 ("common/rc: add missing 'local' keywords"). Reported-by: matorola@gmail.com Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
-rw-r--r--fs/xfs/xfs_file.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index eed073cc4778..e70fb8ccecea 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -880,8 +880,18 @@ xfs_file_dedupe_range(
struct file *dst_file,
u64 dst_loff)
{
+ struct inode *srci = file_inode(src_file);
+ u64 max_dedupe;
int error;
+ /*
+ * Since we have to read all these pages in to compare them, cut
+ * it off at MAX_RW_COUNT/2 rounded down to the nearest block.
+ * That means we won't do more than MAX_RW_COUNT IO per request.
+ */
+ max_dedupe = (MAX_RW_COUNT >> 1) & ~(i_blocksize(srci) - 1);
+ if (len > max_dedupe)
+ len = max_dedupe;
error = xfs_reflink_remap_range(src_file, loff, dst_file, dst_loff,
len, true);
if (error)