https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=a7f392686b5b2091e8f555ff2a2d63443e1fcb1c
commit a7f392686b5b2091e8f555ff2a2d63443e1fcb1c Author: Corinna Vinschen <[email protected]> Date: Sun Dec 23 21:36:42 2018 +0100 Cygwin: utilize FILE_DISPOSITION_POSIX_SEMANTICS - short-circuit most code in unlink_nt since it's not necessary anymore if FILE_DISPOSITION_POSIX_SEMANTICS is supported. - Immediately remove O_TMPFILE from filesystem after creation. Disable code for now because we have to implement /proc/self/fd opening by handle first, lest linkat fails. Signed-off-by: Corinna Vinschen <[email protected]> Diff: --- winsup/cygwin/syscalls.cc | 79 +++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 76 insertions(+), 3 deletions(-) diff --git a/winsup/cygwin/syscalls.cc b/winsup/cygwin/syscalls.cc index 6d10855..c1a3ed4 100644 --- a/winsup/cygwin/syscalls.cc +++ b/winsup/cygwin/syscalls.cc @@ -658,23 +658,64 @@ unlink_nt (path_conv &pc) HANDLE fh, fh_ro = NULL; OBJECT_ATTRIBUTES attr; IO_STATUS_BLOCK io; + ACCESS_MASK access = DELETE; + ULONG flags = FILE_OPEN_FOR_BACKUP_INTENT; HANDLE old_trans = NULL, trans = NULL; ULONG num_links = 1; FILE_DISPOSITION_INFORMATION disp = { TRUE }; int reopened = 0; - bin_status bin_stat = dont_move; syscall_printf ("Trying to delete %S, isdir = %d", pc.get_nt_native_path (), pc.isdir ()); - ACCESS_MASK access = DELETE; - ULONG flags = FILE_OPEN_FOR_BACKUP_INTENT; + /* Add the reparse point flag to known reparse points, otherwise we remove the target, not the reparse point. */ if (pc.is_known_reparse_point ()) flags |= FILE_OPEN_REPARSE_POINT; pc.get_object_attr (attr, sec_none_nih); + + /* First check if we can use POSIX unlink semantics: W10 1709++, local NTFS. + With POSIX unlink semantics the entire job gets MUCH easier and faster. + Just try to do it and if it fails, it fails. */ + if (wincap.has_posix_file_info () && !pc.isremote () && pc.fs_is_ntfs ()) + { + FILE_DISPOSITION_INFORMATION_EX fdie; + + if (pc.file_attributes () & FILE_ATTRIBUTE_READONLY) + access |= FILE_WRITE_ATTRIBUTES; + status = NtOpenFile (&fh, access, &attr, &io, FILE_SHARE_VALID_FLAGS, + flags); + if (!NT_SUCCESS (status)) + goto out; + /* Why didn't the devs add a FILE_DELETE_IGNORE_READONLY_ATTRIBUTE + flag just like they did with FILE_LINK_IGNORE_READONLY_ATTRIBUTE + and FILE_LINK_IGNORE_READONLY_ATTRIBUTE??? + + POSIX unlink semantics are nice, but they still fail if the file + has the R/O attribute set. Removing the file is very much a safe + bet afterwards, so, no transaction. */ + if (pc.file_attributes () & FILE_ATTRIBUTE_READONLY) + { + status = NtSetAttributesFile (fh, pc.file_attributes () + & ~FILE_ATTRIBUTE_READONLY); + if (!NT_SUCCESS (status)) + { + NtClose (fh); + goto out; + } + } + fdie.Flags = FILE_DISPOSITION_DELETE | FILE_DISPOSITION_POSIX_SEMANTICS; + status = NtSetInformationFile (fh, &io, &fdie, sizeof fdie, + FileDispositionInformationEx); + /* Restore R/O attribute in case we have multiple hardlinks. */ + if (pc.file_attributes () & FILE_ATTRIBUTE_READONLY) + NtSetAttributesFile (fh, pc.file_attributes ()); + NtClose (fh); + goto out; + } + /* If the R/O attribute is set, we have to open the file with FILE_WRITE_ATTRIBUTES to be able to remove this flags before trying to delete it. We do this separately because there are filesystems @@ -1426,7 +1467,39 @@ open (const char *unix_path, int flags, ...) if ((fh->is_fs_special () && fh->device_access_denied (flags)) || !fh->open_with_arch (flags, mode & 07777)) __leave; /* errno already set */ +#if 0 + /* W10 1709 POSIX unlink semantics: + TODO: Works nicely for O_TEMPFILE but using linkat requires that + we first fix /proc/self/fd handling to allow opening by handle + rather than by symlinked filename only. */ + if ((flags & O_TMPFILE) && wincap.has_posix_file_info () + && fh->pc.fs_is_ntfs ()) + { + HANDLE del_h; + OBJECT_ATTRIBUTES attr; + NTSTATUS status; + IO_STATUS_BLOCK io; + FILE_DISPOSITION_INFORMATION_EX fdie; + + status = NtOpenFile (&del_h, DELETE, + fh->pc.init_reopen_attr (attr, fh->get_handle ()), &io, + FILE_SHARE_VALID_FLAGS, FILE_OPEN_FOR_BACKUP_INTENT); + if (!NT_SUCCESS (status)) + debug_printf ("reopening tmpfile handle failed, status %y", status); + else + { + fdie.Flags = FILE_DISPOSITION_DELETE + | FILE_DISPOSITION_POSIX_SEMANTICS; + status = NtSetInformationFile (del_h, &io, &fdie, sizeof fdie, + FileDispositionInformationEx); + if (!NT_SUCCESS (status)) + debug_printf ("Setting POSIX delete disposition on tmpfile " + "failed, status = %y", status); + NtClose (del_h); + } + } +#endif fd = fh; if (fd <= 2) set_std_handle (fd);
