* syscalls.cc (check_dir_not_empty): Check surplus directory entries
by calling NtQueryAttributesFile. Make STATUS_DIRECTORY_NOT_EMPTY return value dependent on its status code. Add long comment to explain. (unlink_nt): Add comment to explain flaw in checking the sharing mode. Set status to STATUS_SUCCESS instead of 0. Add a retry loop to setting the delete disposition and trying to move a directory to bin to workaround rare cases of lingering, already deleted subdirectory entries. Add long comment to explain. (rename): Set status to STATUS_SUCCESS instead of 0.
This commit is contained in:
Corinna Vinschen
parent
f6ba9446ed
commit
28fa2a72f8
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@ -1,3 +1,15 @@
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2011-11-07 Corinna Vinschen <corinna@vinschen.de>
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* syscalls.cc (check_dir_not_empty): Check surplus directory entries
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by calling NtQueryAttributesFile. Make STATUS_DIRECTORY_NOT_EMPTY
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return value dependent on its status code. Add long comment to explain.
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(unlink_nt): Add comment to explain flaw in checking the sharing mode.
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Set status to STATUS_SUCCESS instead of 0. Add a retry loop to setting
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the delete disposition and trying to move a directory to bin to
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workaround rare cases of lingering, already deleted subdirectory
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entries. Add long comment to explain.
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(rename): Set status to STATUS_SUCCESS instead of 0.
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2011-11-05 Christopher Faylor <me.cygwin2011@cgf.cx>
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* pinfo.cc (status_exit): Recognize STATUS_ILLEGAL_INSTRUCTION.
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@ -516,25 +516,57 @@ check_dir_not_empty (HANDLE dir, path_conv &pc)
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return status;
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}
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int cnt = 1;
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do
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{
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while (pfni->NextEntryOffset)
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{
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if (++cnt > 2)
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{
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if (strace.active ())
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{
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UNICODE_STRING fname;
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OBJECT_ATTRIBUTES attr;
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FILE_BASIC_INFORMATION fbi;
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pfni = (PFILE_NAMES_INFORMATION)
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((caddr_t) pfni + pfni->NextEntryOffset);
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RtlInitCountedUnicodeString(&fname, pfni->FileName,
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pfni->FileNameLength);
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debug_printf ("Directory %S not empty, found file <%S>",
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pc.get_nt_native_path (), &fname);
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}
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InitializeObjectAttributes (&attr, &fname, 0, dir, NULL);
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status = NtQueryAttributesFile (&attr, &fbi);
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/* Intensive testing shows that sometimes directories, for which
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the delete disposition has already been set, and the deleting
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handle is already closed, can linger in the parent dir for a
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couple of ms for no apparent reason (Windows Defender or other
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real-time scanners are suspect).
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A fast rm -r is capable to exploit this problem. Setting the
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delete disposition of the parent dir then fails with
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STATUS_DIRECTORY_NOT_EMPTY. Examining the content of the
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affected dir can then show either that the dir is empty, or it
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can contain a lingering subdir. Calling NtQueryAttributesFile
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on that subdir returns with STATUS_DELETE_PENDING, or it
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disappeared before that call.
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That's what we do here. If NtQueryAttributesFile succeeded,
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or if the error code does not indicate an already deleted
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entry, STATUS_DIRECTORY_NOT_EMPTY is returned.
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Otherwise STATUS_SUCCESS is returned. Read on in unlink_nt. */
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if (status != STATUS_DELETE_PENDING
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&& status != STATUS_OBJECT_NAME_NOT_FOUND
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&& status != STATUS_OBJECT_PATH_NOT_FOUND)
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{
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debug_printf ("Directory %S not empty, found file <%S>, "
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"query status = %p",
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pc.get_nt_native_path (), &fname, status);
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return STATUS_DIRECTORY_NOT_EMPTY;
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}
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}
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pfni = (PFILE_NAMES_INFORMATION) ((caddr_t) pfni + pfni->NextEntryOffset);
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}
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}
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while (NT_SUCCESS (NtQueryDirectoryFile (dir, NULL, NULL, 0, &io, pfni,
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bufsiz, FileNamesInformation,
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FALSE, NULL, FALSE)));
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return STATUS_SUCCESS;
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}
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@ -548,6 +580,7 @@ unlink_nt (path_conv &pc)
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HANDLE old_trans = NULL, trans = NULL;
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ULONG num_links = 1;
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FILE_DISPOSITION_INFORMATION disp = { TRUE };
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int reopened = 0;
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bin_status bin_stat = dont_move;
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@ -608,7 +641,16 @@ unlink_nt (path_conv &pc)
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will fail. That indicates that the file has to be moved to the recycle
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bin so that it actually disappears from its directory even though its
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in use. Otherwise, if opening doesn't fail, the file is not in use and
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we can go straight to setting the delete disposition flag. */
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we can go straight to setting the delete disposition flag.
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NOTE: The missing sharing modes FILE_SHARE_READ and FILE_SHARE_WRITE do
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NOT result in a STATUS_SHARING_VIOLATION, if another handle is
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opened for reading/writing metadata only. In other words, if
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another handle is open, but does not have the file open with
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FILE_READ_DATA or FILE_WRITE_DATA, the following NtOpenFile call
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will succeed. So, apparently there is no reliable way to find out
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if a file is already open elsewhere for other purposes than
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reading and writing data. */
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status = NtOpenFile (&fh, access, &attr, &io, FILE_SHARE_DELETE, flags);
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if (status == STATUS_SHARING_VIOLATION || status == STATUS_LOCK_NOT_GRANTED)
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{
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@ -673,7 +715,7 @@ unlink_nt (path_conv &pc)
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if (status == STATUS_DELETE_PENDING)
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{
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debug_printf ("Delete %S already pending", pc.get_nt_native_path ());
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status = 0;
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status = STATUS_SUCCESS;
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goto out;
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}
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debug_printf ("Opening %S for delete failed, status = %p",
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@ -685,9 +727,11 @@ unlink_nt (path_conv &pc)
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if (bin_stat == move_to_bin
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&& (bin_stat = try_to_bin (pc, fh, access)) == has_been_moved)
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{
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status = 0;
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status = STATUS_SUCCESS;
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goto out;
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}
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try_again:
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/* Try to set delete disposition. */
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status = NtSetInformationFile (fh, &io, &disp, sizeof disp,
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FileDispositionInformation);
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@ -695,17 +739,70 @@ unlink_nt (path_conv &pc)
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{
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debug_printf ("Setting delete disposition on %S failed, status = %p",
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pc.get_nt_native_path (), status);
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if (strace.active () && status == STATUS_DIRECTORY_NOT_EMPTY)
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if (status == STATUS_DIRECTORY_NOT_EMPTY)
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{
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NTSTATUS status2;
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NTSTATUS status2 = STATUS_SUCCESS;
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if (!reopened)
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{
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/* Have to close and reopen the file from scratch, otherwise
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we collide with the delete-only sharing mode. */
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pc.get_object_attr (attr, sec_none_nih);
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NtClose (fh);
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status2 = NtOpenFile (&fh, access | FILE_LIST_DIRECTORY | SYNCHRONIZE,
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status2 = NtOpenFile (&fh, access | FILE_LIST_DIRECTORY
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| SYNCHRONIZE,
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&attr, &io, FILE_SHARE_VALID_FLAGS,
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flags | FILE_SYNCHRONOUS_IO_NONALERT);
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if (NT_SUCCESS (status2))
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check_dir_not_empty (fh, pc);
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}
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if (NT_SUCCESS (status2) && reopened < 20)
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{
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/* Workaround rm -r problem:
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Sometimes a deleted directory lingers in its parent dir
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after the deleting handle has already been closed. This
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can break deleting the parent dir. See the comment in
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check_dir_not_empty for more information.
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What we do here is this: If check_dir_not_empty returns
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STATUS_SUCCESS, the dir is either empty, or only inhabited
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by already deleted entries. If so, we try to move the dir
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into the bin. This usually works.
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However, if we're on a filesystem which doesn't support
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the try_to_bin method, or if moving to the bin doesn't work
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for some reason, just try to delete the directory again,
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with a very short grace period to free the CPU for a while.
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This gives the OS time to clean up. 5ms is enough in my
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testing to make sure that we don't have to try more than
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once in practically all cases.
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While this is an extrem bordercase, we don't want to hang
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infinitely in case a file in the directory is in the "delete
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pending" state but an application holds an open handle to it
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for a longer time. So we don't try this more than 20 times,
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which means a process time of 100-120ms. */
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if (check_dir_not_empty (fh, pc) == STATUS_SUCCESS)
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{
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if (bin_stat == dont_move)
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{
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bin_stat = move_to_bin;
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if (!pc.fs_is_nfs () && !pc.fs_is_netapp ())
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{
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debug_printf ("Try-to-bin %S",
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pc.get_nt_native_path ());
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bin_stat = try_to_bin (pc, fh, access);
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}
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}
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if (bin_stat == has_been_moved)
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status = STATUS_SUCCESS;
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else
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{
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debug_printf ("Try %S again", pc.get_nt_native_path ());
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++reopened;
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Sleep (5L);
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goto try_again;
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}
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}
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}
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else
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{
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fh = NULL;
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@ -725,7 +822,7 @@ unlink_nt (path_conv &pc)
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error 59, ERROR_UNEXP_NET_ERR when trying to access the file.
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Microsoft KB 837665 describes this problem as a bug in 2K3, but
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I have reproduced it on other systems. */
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if (status == STATUS_CANNOT_DELETE
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else if (status == STATUS_CANNOT_DELETE
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&& (!pc.isremote () || pc.fs_is_ncfsd ()))
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{
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HANDLE fh2;
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@ -1835,7 +1932,7 @@ rename (const char *oldpath, const char *newpath)
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bool old_explicit_suffix = false, new_explicit_suffix = false;
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size_t olen, nlen;
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bool equal_path;
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NTSTATUS status = 0;
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NTSTATUS status = STATUS_SUCCESS;
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HANDLE fh = NULL, nfh;
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HANDLE old_trans = NULL, trans = NULL;
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OBJECT_ATTRIBUTES attr;
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