Ceph » CephFS

Here's a simplified reproducer:

import os

file = "test_file" 
fd = os.open(file, os.O_CREAT | os.O_RDWR, 0o644)

os.lseek(fd, 46374912, os.SEEK_SET)
os.write(fd, b"bar")
os.lseek(fd, 4190203, os.SEEK_SET)
os.write(fd, b"foo!!")
os.close(fd)

with open(file, 'r') as f:
    print(f.read())

Author: Christopher Hoffman <choffman@redhat.com>
Date:   Tue Jun 17 16:44:08 2025 +0000

    client: Fix logic in fscrypt hole optimization

    In fscrypt decryption code path, ensure if a data block
    is hit when there are holes present in adjacent blocks,
    that we exit hole traversal and continue on to decrypt the block.

    Fixes: https://tracker.ceph.com/issues/71602
    Signed-off-by: Christopher Hoffman <choffman@redhat.com>

diff --git a/src/client/FSCrypt.cc b/src/client/FSCrypt.cc
index d3f162c8af2..edb38898aff 100644
--- a/src/client/FSCrypt.cc
+++ b/src/client/FSCrypt.cc
@@ -898,11 +898,25 @@ int FSCryptFDataDenc::decrypt_bl(uint64_t off, uint64_t len, uint64_t pos, const
   while (pos < target_end) {
     bool has_hole = false;

+    /*
+     * Check to see if cur_block is part of a
+     * hole. We expect holes to ordered by offset.
+     *
+     * There is four states it can be in
+     * 1. If position is before hole offset, it cannot be part of a hole
+     * 2. If hole end is less than position, hole occurs completely before
+     * 3. If hole starts after target_end, hole occurs completely after
+     * 4. No conditionals are met, is a hole
+     */
+
     while (hiter != holes.end()) {
       uint64_t hofs = hiter->first;
       uint64_t hlen = hiter->second;
       uint64_t hend = hofs + hlen - 1;

+      if (pos < hofs)
+       break;
+
       if (hend < pos) {
         ++hiter;
         continue;