https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=89a1e4a573d40b233011402f42630b970ff71291
commit 89a1e4a573d40b233011402f42630b970ff71291 Author: Corinna Vinschen <[email protected]> AuthorDate: Mon Nov 27 21:14:49 2023 +0100 Commit: Corinna Vinschen <[email protected]> CommitDate: Tue Nov 28 10:55:52 2023 +0100 Cygwin: open(2): reset sparseness on O_TRUNCated files open(2) implements O_TRUNC by just reducing the size of the file to 0, to make sure EAs stay available. Turns out, file sparseness is not removed this way either, so add code to do just that. Fixes: 603ef545bdbd ("* fhandler.cc (fhandler_base::open): Never open files with FILE_OVERWITE/FILE_OVERWRITE_IF.") Signed-off-by: Corinna Vinschen <[email protected]> Diff: --- winsup/cygwin/fhandler/base.cc | 9 +++++++++ winsup/cygwin/release/3.4.10 | 3 +++ 2 files changed, 12 insertions(+) diff --git a/winsup/cygwin/fhandler/base.cc b/winsup/cygwin/fhandler/base.cc index 58b63da8de88..05e51536ff64 100644 --- a/winsup/cygwin/fhandler/base.cc +++ b/winsup/cygwin/fhandler/base.cc @@ -773,6 +773,15 @@ fhandler_base::open (int flags, mode_t mode) NtClose (fh); goto done; } + /* Drop sparseness */ + if (pc.file_attributes () & FILE_ATTRIBUTE_SPARSE_FILE) + { + FILE_SET_SPARSE_BUFFER fssb = { SetSparse: FALSE }; + status = NtFsControlFile (fh, NULL, NULL, NULL, &io, + FSCTL_SET_SPARSE, &fssb, sizeof fssb, NULL, 0); + if (NT_SUCCESS (status)) + pc.file_attributes (pc.file_attributes () & ~FILE_ATTRIBUTE_SPARSE_FILE); + } } set_handle (fh); diff --git a/winsup/cygwin/release/3.4.10 b/winsup/cygwin/release/3.4.10 index 02f6885837b4..632ffcd39493 100644 --- a/winsup/cygwin/release/3.4.10 +++ b/winsup/cygwin/release/3.4.10 @@ -21,3 +21,6 @@ Bug Fixes - Fix posix_fallocate(3) return value in case of being called on other than regular files. + +- Reset sparseness in case open(2) has been called with O_CREAT|O_TRUNC on + sparse files.
