diff options
Diffstat (limited to 'src/fileio.c')
| -rw-r--r-- | src/fileio.c | 74 |
1 files changed, 29 insertions, 45 deletions
diff --git a/src/fileio.c b/src/fileio.c index f00c389a520..c672e0f7baf 100644 --- a/src/fileio.c +++ b/src/fileio.c @@ -134,6 +134,7 @@ static dev_t timestamp_file_system; is added here. */ static Lisp_Object Vwrite_region_annotation_buffers; +static Lisp_Object emacs_readlinkat (int, char const *); static Lisp_Object file_name_directory (Lisp_Object); static bool a_write (int, Lisp_Object, ptrdiff_t, ptrdiff_t, Lisp_Object *, struct coding_system *); @@ -2219,7 +2220,7 @@ permissions. */) report_file_error ("Copying permissions to", newname); } #else /* not WINDOWSNT */ - ifd = emacs_open (SSDATA (encoded_file), O_RDONLY, 0); + ifd = emacs_open (SSDATA (encoded_file), O_RDONLY | O_NONBLOCK, 0); if (ifd < 0) report_file_error ("Opening input file", file); @@ -2705,31 +2706,19 @@ This is what happens in interactive use with M-x. */) } if (dirp) call4 (Qcopy_directory, file, newname, Qt, Qnil); - else - { - Lisp_Object symlink_target - = (S_ISLNK (file_st.st_mode) - ? check_emacs_readlinkat (AT_FDCWD, file, SSDATA (encoded_file)) - : Qnil); - if (!NILP (symlink_target)) - Fmake_symbolic_link (symlink_target, newname, ok_if_already_exists); - else if (S_ISFIFO (file_st.st_mode)) - { - /* If it's a FIFO, calling `copy-file' will hang if it's a - inter-file system move, so do it here. (It will signal - an error in that case, but it won't hang in any case.) */ - if (!NILP (ok_if_already_exists)) - barf_or_query_if_file_exists (newname, false, - "rename to it", - FIXNUMP (ok_if_already_exists), - false); - if (rename (SSDATA (encoded_file), SSDATA (encoded_newname)) != 0) - report_file_errno ("Renaming", list2 (file, newname), errno); - return Qnil; - } + else if (S_ISREG (file_st.st_mode)) + Fcopy_file (file, newname, ok_if_already_exists, Qt, Qt, Qt); + else if (S_ISLNK (file_st.st_mode)) + { + Lisp_Object target = emacs_readlinkat (AT_FDCWD, + SSDATA (encoded_file)); + if (!NILP (target)) + Fmake_symbolic_link (target, newname, ok_if_already_exists); else - Fcopy_file (file, newname, ok_if_already_exists, Qt, Qt, Qt); + report_file_error ("Renaming", list2 (file, newname)); } + else + report_file_errno ("Renaming", list2 (file, newname), rename_errno); specpdl_ref count = SPECPDL_INDEX (); specbind (Qdelete_by_moving_to_trash, Qnil); @@ -6345,24 +6334,6 @@ init_fileio (void) umask (realmask); valid_timestamp_file_system = 0; - - /* fsync can be a significant performance hit. Often it doesn't - suffice to make the file-save operation survive a crash. For - batch scripts, which are typically part of larger shell commands - that don't fsync other files, its effect on performance can be - significant so its utility is particularly questionable. - Hence, for now by default fsync is used only when interactive. - - For more on why fsync often fails to work on today's hardware, see: - Zheng M et al. Understanding the robustness of SSDs under power fault. - 11th USENIX Conf. on File and Storage Technologies, 2013 (FAST '13), 271-84 - https://www.usenix.org/system/files/conference/fast13/fast13-final80.pdf - - For more on why fsync does not suffice even if it works properly, see: - Roche X. Necessary step(s) to synchronize filename operations on disk. - Austin Group Defect 672, 2013-03-19 - https://austingroupbugs.net/view.php?id=672 */ - write_region_inhibit_fsync = noninteractive; } void @@ -6620,9 +6591,22 @@ file is usually more useful if it contains the deleted text. */); DEFVAR_BOOL ("write-region-inhibit-fsync", write_region_inhibit_fsync, doc: /* Non-nil means don't call fsync in `write-region'. This variable affects calls to `write-region' as well as save commands. -Setting this to nil may avoid data loss if the system loses power or -the operating system crashes. By default, it is non-nil in batch mode. */); - write_region_inhibit_fsync = 0; /* See also `init_fileio' above. */ +By default, it is non-nil. + +Although setting this to nil may avoid data loss if the system loses power, +it can be a significant performance hit in the usual case, and it doesn't +necessarily cause file-save operations to actually survive a crash. */); + + /* For more on why fsync often fails to work on today's hardware, see: + Zheng M et al. Understanding the robustness of SSDs under power fault. + 11th USENIX Conf. on File and Storage Technologies, 2013 (FAST '13), 271-84 + https://www.usenix.org/system/files/conference/fast13/fast13-final80.pdf + + For more on why fsync does not suffice even if it works properly, see: + Roche X. Necessary step(s) to synchronize filename operations on disk. + Austin Group Defect 672, 2013-03-19 + https://austingroupbugs.net/view.php?id=672 */ + write_region_inhibit_fsync = true; DEFVAR_BOOL ("delete-by-moving-to-trash", delete_by_moving_to_trash, doc: /* Specifies whether to use the system's trash can. |