diff options
| -rw-r--r-- | NEWS | 4 | ||||
| -rw-r--r-- | doc/coreutils.texi | 9 | ||||
| -rw-r--r-- | src/copy.c | 16 | ||||
| -rw-r--r-- | src/copy.h | 3 | ||||
| -rw-r--r-- | src/cp.c | 14 | ||||
| -rw-r--r-- | src/install.c | 1 | ||||
| -rw-r--r-- | src/mv.c | 1 | ||||
| -rwxr-xr-x | tests/cp/sparse | 4 |
8 files changed, 46 insertions, 6 deletions
@@ -41,6 +41,10 @@ GNU coreutils NEWS -*- outline -*- chroot now accepts the options --userspec and --groups. + cp accepts a new option, --reflink: create a lightweight copy + using copy-on-write (COW). This is currently supported only on + btrfs file systems. + cp now preserves time stamps on symbolic links, when possible cp, install, mv: take advantage of btrfs' O(1) copy-on-write feature diff --git a/doc/coreutils.texi b/doc/coreutils.texi index 90a54b268..bb1d87a87 100644 --- a/doc/coreutils.texi +++ b/doc/coreutils.texi @@ -7543,6 +7543,15 @@ Also, it is not portable to use @option{-R} to copy symbolic links unless you also specify @option{-P}, as @acronym{POSIX} allows implementations that dereference symbolic links by default. +@item --reflink +@opindex --reflink +Perform a lightweight, copy-on-write (COW) copy. +Copying with this option can succeed only on some relatively new file systems. +Once it has succeeded, beware that the source and destination files +share the same disk data blocks as long as they remain unmodified. +Thus, if a disk I/O error affects data blocks of one of the files, +the other suffers the exact same fate. + @item --remove-destination @opindex --remove-destination Remove each existing destination file before attempting to open it diff --git a/src/copy.c b/src/copy.c index 24b5f6b46..bed90c459 100644 --- a/src/copy.c +++ b/src/copy.c @@ -624,13 +624,16 @@ copy_reg (char const *src_name, char const *dst_name, goto close_src_and_dst_desc; } - /* If --sparse=auto is in effect, attempt a btrfs clone operation. - If the operation is not supported or it fails then copy the file - in the usual way. */ - bool copied = (x->sparse_mode == SPARSE_AUTO - && clone_file (dest_desc, source_desc) == 0); + if (x->reflink) + { + if (clone_file (dest_desc, source_desc)) + { + error (0, errno, _("failed to clone %s"), quote (dst_name)); + return_val = false; + } + goto close_src_and_dst_desc; + } - if (!copied) { typedef uintptr_t word; off_t n_read_total = 0; @@ -2232,6 +2235,7 @@ valid_options (const struct cp_options *co) assert (VALID_BACKUP_TYPE (co->backup_type)); assert (VALID_SPARSE_MODE (co->sparse_mode)); assert (!(co->hard_link && co->symbolic_link)); + assert (!(co->reflink && co->sparse_mode != SPARSE_AUTO)); return true; } diff --git a/src/copy.h b/src/copy.h index 8e0b4080e..ddf4f4e2c 100644 --- a/src/copy.h +++ b/src/copy.h @@ -219,6 +219,9 @@ struct cp_options such a symlink) and returns false. */ bool open_dangling_dest_symlink; + /* If true, attempt to clone the file instead of copying it. */ + bool reflink; + /* This is a set of destination name/inode/dev triples. Each such triple represents a file we have created corresponding to a source file name that was specified on the command line. Use it to avoid clobbering @@ -76,6 +76,7 @@ enum NO_PRESERVE_ATTRIBUTES_OPTION, PARENTS_OPTION, PRESERVE_ATTRIBUTES_OPTION, + REFLINK_OPTION, SPARSE_OPTION, STRIP_TRAILING_SLASHES_OPTION, UNLINK_DEST_BEFORE_OPENING @@ -121,6 +122,7 @@ static struct option const long_opts[] = {"recursive", no_argument, NULL, 'R'}, {"remove-destination", no_argument, NULL, UNLINK_DEST_BEFORE_OPENING}, {"sparse", required_argument, NULL, SPARSE_OPTION}, + {"reflink", no_argument, NULL, REFLINK_OPTION}, {"strip-trailing-slashes", no_argument, NULL, STRIP_TRAILING_SLASHES_OPTION}, {"suffix", required_argument, NULL, 'S'}, {"symbolic-link", no_argument, NULL, 's'}, @@ -190,6 +192,7 @@ Mandatory arguments to long options are mandatory for short options too.\n\ "), stdout); fputs (_("\ -R, -r, --recursive copy directories recursively\n\ + --reflink perform a lightweight (CoW/clone) copy\n\ --remove-destination remove each existing destination file before\n\ attempting to open it (contrast with --force)\n\ "), stdout); @@ -752,6 +755,7 @@ cp_option_init (struct cp_options *x) x->interactive = I_UNSPECIFIED; x->move_mode = false; x->one_file_system = false; + x->reflink = false; x->preserve_ownership = false; x->preserve_links = false; @@ -916,6 +920,10 @@ main (int argc, char **argv) sparse_type_string, sparse_type); break; + case REFLINK_OPTION: + x.reflink = true; + break; + case 'a': /* Like -dR --preserve=all with reduced failure diagnostics. */ x.dereference = DEREF_NEVER; x.preserve_links = true; @@ -1076,6 +1084,12 @@ main (int argc, char **argv) usage (EXIT_FAILURE); } + if (x.reflink && x.sparse_mode != SPARSE_AUTO) + { + error (0, 0, _("--reflink can be used only with --sparse=auto")); + usage (EXIT_FAILURE); + } + if (backup_suffix_string) simple_backup_suffix = xstrdup (backup_suffix_string); diff --git a/src/install.c b/src/install.c index fd8f71ef3..73b3981ef 100644 --- a/src/install.c +++ b/src/install.c @@ -269,6 +269,7 @@ cp_option_init (struct cp_options *x) { cp_options_default (x); x->copy_as_regular = true; + x->reflink = false; x->dereference = DEREF_ALWAYS; x->unlink_dest_before_opening = true; x->unlink_dest_after_failed_open = false; @@ -105,6 +105,7 @@ cp_option_init (struct cp_options *x) cp_options_default (x); x->copy_as_regular = false; /* FIXME: maybe make this an option */ + x->reflink = false; x->dereference = DEREF_NEVER; x->unlink_dest_before_opening = false; x->unlink_dest_after_failed_open = false; diff --git a/tests/cp/sparse b/tests/cp/sparse index bd1a84f40..9683a9e33 100755 --- a/tests/cp/sparse +++ b/tests/cp/sparse @@ -38,4 +38,8 @@ cp --sparse=always sparse copy || fail=1 # Ensure that the copy has the same block count as the original. test `stat --printf %b copy` -le `stat --printf %b sparse` || fail=1 +# Ensure that --sparse={always,never} with --reflink fail. +cp --sparse=always --reflink sparse copy && fail=1 +cp --sparse=never --reflink sparse copy && fail=1 + Exit $fail |