In the Linux kernel, the following vulnerability has been resolved: btrfs: zoned: do not flag ZEROOUT on non-dirty extent buffer Btrfs clears the content of an extent buffer marked as EXTENT_BUFFER_ZONED_ZEROOUT before the bio submission. This mechanism is introduced to prevent a write hole of an extent buffer, which is once allocated, marked dirty, but turns out unnecessary and cleaned up within one transaction operation. Currently, btrfs_clear_buffer_dirty() marks the extent buffer as EXTENT_BUFFER_ZONED_ZEROOUT, and skips the entry function. If this call happens while the buffer is under IO (with the WRITEBACK flag set, without the DIRTY flag), we can add the ZEROOUT flag and clear the buffer's content just before a bio submission. As a result: 1) it can lead to adding faulty delayed reference item which leads to a FS corrupted (EUCLEAN) error, and 2) it writes out cleared tree node on disk The former issue is previously discussed in [1]. The corruption happens when it run…