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authorLinus Torvalds <torvalds@linux-foundation.org>2018-05-04 20:36:50 -1000
committerLinus Torvalds <torvalds@linux-foundation.org>2018-05-04 20:36:50 -1000
commit2e171ffcdf62a90ea7a0192728f81c1ac288de50 (patch)
treed337070832c1666ed28fc0fc2cfda70b76426739 /fs
parent4148d3884a4c842a5b3ee2976c2ebbdb7bbd0559 (diff)
parent021ba8e98fe5c6691b3cc3669faafa02403aa211 (diff)
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Merge tag 'xfs-4.17-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull xfs fixes from Darrick Wong: "I've got one more bug fix for xfs for 4.17-rc4, which caps the amount of data we try to handle in one dedupe request so that userspace can't livelock the kernel. This series has been run through a full xfstests run during the week and through a quick xfstests run against this morning's master, with no ajor failures reported. Summary: - Cap the maximum length of a deduplication request at MAX_RW_COUNT/2 to avoid kernel livelock due to excessively large IO requests" * tag 'xfs-4.17-fixes-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux: xfs: cap the length of deduplication requests
Diffstat (limited to 'fs')
-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)