This email is follow up to <https://bugs.gnu.org/8601> dated 2011-05-01. Jeff,
thanks for reporting the problem. (There's a good chance this email will bounce
but I'll send it to your 2011 email address anyway.)
I recently ran into the same issue and derived the attached patches
independently. I then found your bug report, made sure the attached patches
fixed every problem that your proposal did, and installed the attached patches
into Savannah.
The attached patches 1-3 merely fix typos and refactor.
Patch 4 corresponds to your proposal; however, it differs in that its basic idea
is to use the FIEMAP code only as a fallback if SEEK_DATA doesn't work, rather
than try to add to the already-too-complicated code that fiddles with FIEMAPs.
(I don't observe any significant performance advantage to the FIEMAP stuff, but
maybe that's just me.)
Patch 5 adds opportunistic use of the copy_file_range syscall introduced in
Linux kernel 4.5 (2016) and reworked in 5.3 (2019). This should improve 'cp'
performance on kernels and file systems that support copy_file_range.
>From 4fe5259ab6c9e459a6db5938d143a9c65be113d9 Mon Sep 17 00:00:00 2001
From: Paul Eggert <egg...@cs.ucla.edu>
Date: Thu, 25 Jun 2020 18:10:49 -0700
Subject: [PATCH 1/5] maint: typo fix
* NEWS: Fix typo.
---
NEWS | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/NEWS b/NEWS
index d36259641..d713fa724 100644
--- a/NEWS
+++ b/NEWS
@@ -17,7 +17,7 @@ GNU coreutils NEWS -*- outline -*-
cp and install now default to copy-on-write (COW) if available.
- On GNU/Linux systems, ls no longer issues an error message on
+ On GNU/Linux systems, ls no longer issues an error message on a
directory merely because it was removed. This reverts a change
that was made in release 8.32.
--
2.25.4
>From 51981008f9892d44231c432535deac4f9b3cbe5e Mon Sep 17 00:00:00 2001
From: Paul Eggert <egg...@cs.ucla.edu>
Date: Tue, 23 Jun 2020 19:18:04 -0700
Subject: [PATCH 2/5] cp: refactor extent_copy
* src/copy.c (extent_copy): New arg SCAN, replacing
REQUIRE_NORMAL_COPY. All callers changed.
(enum scantype): New type.
(infer_scantype): Rename from is_probably_sparse and return
the new type. Add args FD and SCAN. All callers changed.
---
src/copy.c | 119 +++++++++++++++++++++++++----------------------------
1 file changed, 55 insertions(+), 64 deletions(-)
diff --git a/src/copy.c b/src/copy.c
index 54601ce07..f694f913f 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -422,9 +422,8 @@ extent_copy (int src_fd, int dest_fd, char *buf, size_t buf_size,
size_t hole_size, off_t src_total_size,
enum Sparse_type sparse_mode,
char const *src_name, char const *dst_name,
- bool *require_normal_copy)
+ struct extent_scan *scan)
{
- struct extent_scan scan;
off_t last_ext_start = 0;
off_t last_ext_len = 0;
@@ -432,45 +431,25 @@ extent_copy (int src_fd, int dest_fd, char *buf, size_t buf_size,
We may need this at the end, for a final ftruncate. */
off_t dest_pos = 0;
- extent_scan_init (src_fd, &scan);
-
- *require_normal_copy = false;
bool wrote_hole_at_eof = true;
- do
+ while (true)
{
- bool ok = extent_scan_read (&scan);
- if (! ok)
- {
- if (scan.hit_final_extent)
- break;
-
- if (scan.initial_scan_failed)
- {
- *require_normal_copy = true;
- return false;
- }
-
- error (0, errno, _("%s: failed to get extents info"),
- quotef (src_name));
- return false;
- }
-
bool empty_extent = false;
- for (unsigned int i = 0; i < scan.ei_count || empty_extent; i++)
+ for (unsigned int i = 0; i < scan->ei_count || empty_extent; i++)
{
off_t ext_start;
off_t ext_len;
off_t ext_hole_size;
- if (i < scan.ei_count)
+ if (i < scan->ei_count)
{
- ext_start = scan.ext_info[i].ext_logical;
- ext_len = scan.ext_info[i].ext_length;
+ ext_start = scan->ext_info[i].ext_logical;
+ ext_len = scan->ext_info[i].ext_length;
}
else /* empty extent at EOF. */
{
i--;
- ext_start = last_ext_start + scan.ext_info[i].ext_length;
+ ext_start = last_ext_start + scan->ext_info[i].ext_length;
ext_len = 0;
}
@@ -498,7 +477,7 @@ extent_copy (int src_fd, int dest_fd, char *buf, size_t buf_size,
{
error (0, errno, _("cannot lseek %s"), quoteaf (src_name));
fail:
- extent_scan_free (&scan);
+ extent_scan_free (scan);
return false;
}
@@ -539,7 +518,7 @@ extent_copy (int src_fd, int dest_fd, char *buf, size_t buf_size,
/* For now, do not treat FIEMAP_EXTENT_UNWRITTEN specially,
because that (in combination with no sync) would lead to data
loss at least on XFS and ext4 when using 2.6.39-rc3 kernels. */
- if (0 && (scan.ext_info[i].ext_flags & FIEMAP_EXTENT_UNWRITTEN))
+ if (0 && (scan->ext_info[i].ext_flags & FIEMAP_EXTENT_UNWRITTEN))
{
empty_extent = true;
last_ext_len = 0;
@@ -571,16 +550,23 @@ extent_copy (int src_fd, int dest_fd, char *buf, size_t buf_size,
extents beyond the apparent size. */
if (dest_pos == src_total_size)
{
- scan.hit_final_extent = true;
+ scan->hit_final_extent = true;
break;
}
}
/* Release the space allocated to scan->ext_info. */
- extent_scan_free (&scan);
+ extent_scan_free (scan);
+ if (scan->hit_final_extent)
+ break;
+ if (! extent_scan_read (scan) && ! scan->hit_final_extent)
+ {
+ error (0, errno, _("%s: failed to get extents info"),
+ quotef (src_name));
+ return false;
+ }
}
- while (! scan.hit_final_extent);
/* When the source file ends with a hole, we have to do a little more work,
since the above copied only up to and including the final extent.
@@ -1021,16 +1007,35 @@ fchmod_or_lchmod (int desc, char const *name, mode_t mode)
# define HAVE_STRUCT_STAT_ST_BLOCKS 0
#endif
+/* Type of scan being done on the input when looking for sparseness. */
+enum scantype
+ {
+ /* No fancy scanning; just read and write. */
+ PLAIN_SCANTYPE,
+
+ /* Read and examine data looking for zero blocks; useful when
+ attempting to create sparse output. */
+ ZERO_SCANTYPE,
+
+ /* Extent information is available. */
+ EXTENT_SCANTYPE
+ };
+
/* Use a heuristic to determine whether stat buffer SB comes from a file
with sparse blocks. If the file has fewer blocks than would normally
be needed for a file of its size, then at least one of the blocks in
the file is a hole. In that case, return true. */
-static bool
-is_probably_sparse (struct stat const *sb)
+static enum scantype
+infer_scantype (int fd, struct stat const *sb, struct extent_scan *scan)
{
- return (HAVE_STRUCT_STAT_ST_BLOCKS
- && S_ISREG (sb->st_mode)
- && ST_NBLOCKS (*sb) < sb->st_size / ST_NBLOCKSIZE);
+ if (! (HAVE_STRUCT_STAT_ST_BLOCKS
+ && S_ISREG (sb->st_mode)
+ && ST_NBLOCKS (*sb) < sb->st_size / ST_NBLOCKSIZE))
+ return PLAIN_SCANTYPE;
+
+ extent_scan_init (fd, scan);
+ extent_scan_read (scan);
+ return scan->initial_scan_failed ? ZERO_SCANTYPE : EXTENT_SCANTYPE;
}
@@ -1061,6 +1066,7 @@ copy_reg (char const *src_name, char const *dst_name,
mode_t src_mode = src_sb->st_mode;
struct stat sb;
struct stat src_open_sb;
+ struct extent_scan scan;
bool return_val = true;
bool data_copy_required = x->data_copy_required;
@@ -1260,23 +1266,13 @@ copy_reg (char const *src_name, char const *dst_name,
fdadvise (source_desc, 0, 0, FADVISE_SEQUENTIAL);
/* Deal with sparse files. */
- bool make_holes = false;
- bool sparse_src = is_probably_sparse (&src_open_sb);
-
- if (S_ISREG (sb.st_mode))
- {
- /* Even with --sparse=always, try to create holes only
- if the destination is a regular file. */
- if (x->sparse_mode == SPARSE_ALWAYS)
- make_holes = true;
-
- /* Use a heuristic to determine whether SRC_NAME contains any sparse
- blocks. If the file has fewer blocks than would normally be
- needed for a file of its size, then at least one of the blocks in
- the file is a hole. */
- if (x->sparse_mode == SPARSE_AUTO && sparse_src)
- make_holes = true;
- }
+ enum scantype scantype = infer_scantype (source_desc, &src_open_sb,
+ &scan);
+ bool make_holes
+ = (S_ISREG (sb.st_mode)
+ && (x->sparse_mode == SPARSE_ALWAYS
+ || (x->sparse_mode == SPARSE_AUTO
+ && scantype != PLAIN_SCANTYPE)));
/* If not making a sparse file, try to use a more-efficient
buffer size. */
@@ -1305,10 +1301,8 @@ copy_reg (char const *src_name, char const *dst_name,
buf_alloc = xmalloc (buf_size + buf_alignment);
buf = ptr_align (buf_alloc, buf_alignment);
- if (sparse_src)
+ if (scantype == EXTENT_SCANTYPE)
{
- bool normal_copy_required;
-
/* Perform an efficient extent-based copy, falling back to the
standard copy only if the initial extent scan fails. If the
'--sparse=never' option is specified, write all data but use
@@ -1316,14 +1310,11 @@ copy_reg (char const *src_name, char const *dst_name,
if (extent_copy (source_desc, dest_desc, buf, buf_size, hole_size,
src_open_sb.st_size,
make_holes ? x->sparse_mode : SPARSE_NEVER,
- src_name, dst_name, &normal_copy_required))
+ src_name, dst_name, &scan))
goto preserve_metadata;
- if (! normal_copy_required)
- {
- return_val = false;
- goto close_src_and_dst_desc;
- }
+ return_val = false;
+ goto close_src_and_dst_desc;
}
off_t n_read;
--
2.25.4
>From 35a55effa81c5f4f8fe7414e8aede0acccee470f Mon Sep 17 00:00:00 2001
From: Paul Eggert <egg...@cs.ucla.edu>
Date: Wed, 24 Jun 2020 17:05:20 -0700
Subject: [PATCH 3/5] cp: avoid copy_reg goto
* src/copy.c (copy_reg): Redo to avoid label and goto.
---
src/copy.c | 34 +++++++++++-----------------------
1 file changed, 11 insertions(+), 23 deletions(-)
diff --git a/src/copy.c b/src/copy.c
index f694f913f..b382cfa4d 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -1301,29 +1301,18 @@ copy_reg (char const *src_name, char const *dst_name,
buf_alloc = xmalloc (buf_size + buf_alignment);
buf = ptr_align (buf_alloc, buf_alignment);
- if (scantype == EXTENT_SCANTYPE)
- {
- /* Perform an efficient extent-based copy, falling back to the
- standard copy only if the initial extent scan fails. If the
- '--sparse=never' option is specified, write all data but use
- any extents to read more efficiently. */
- if (extent_copy (source_desc, dest_desc, buf, buf_size, hole_size,
- src_open_sb.st_size,
- make_holes ? x->sparse_mode : SPARSE_NEVER,
- src_name, dst_name, &scan))
- goto preserve_metadata;
-
- return_val = false;
- goto close_src_and_dst_desc;
- }
-
off_t n_read;
- bool wrote_hole_at_eof;
- if (! sparse_copy (source_desc, dest_desc, buf, buf_size,
- make_holes ? hole_size : 0,
- x->sparse_mode == SPARSE_ALWAYS, src_name, dst_name,
- UINTMAX_MAX, &n_read,
- &wrote_hole_at_eof))
+ bool wrote_hole_at_eof = false;
+ if (! (scantype == EXTENT_SCANTYPE
+ ? extent_copy (source_desc, dest_desc, buf, buf_size, hole_size,
+ src_open_sb.st_size,
+ make_holes ? x->sparse_mode : SPARSE_NEVER,
+ src_name, dst_name, &scan)
+ : sparse_copy (source_desc, dest_desc, buf, buf_size,
+ make_holes ? hole_size : 0,
+ x->sparse_mode == SPARSE_ALWAYS,
+ src_name, dst_name, UINTMAX_MAX, &n_read,
+ &wrote_hole_at_eof)))
{
return_val = false;
goto close_src_and_dst_desc;
@@ -1336,7 +1325,6 @@ copy_reg (char const *src_name, char const *dst_name,
}
}
-preserve_metadata:
if (x->preserve_timestamps)
{
struct timespec timespec[2];
--
2.25.4
>From 6fc41029fff6e955a87312d8f5f967f0d01e390c Mon Sep 17 00:00:00 2001
From: Paul Eggert <egg...@cs.ucla.edu>
Date: Thu, 25 Jun 2020 16:31:44 -0700
Subject: [PATCH 4/5] cp: use SEEK_DATA/SEEK_HOLE if available
If it works, prefer lseek with SEEK_DATA and SEEK_HOLE to FIEMAP,
as lseek is simpler and more portable (will be in next POSIX).
Problem reported in 2011 by Jeff Liu (Bug#8061).
* NEWS: Mention this.
* src/copy.c (lseek_copy) [SEEK_HOLE]: New function.
(enum scantype): New constants ERROR_SCANTYPE, LSEEK_SCANTYPE.
(union scan_inference): New type.
(infer_scantype): Last arg is now union scan_inference *,
not struct extent_scan *. All callers changed.
Prefer SEEK_HOLE to FIEMAP if both work, since
SEEK_HOLE is simpler and more portable.
(copy_reg): Do the fdadvise after initial scan, in case the scan
fails. Report an error if the initial scan fails.
(copy_reg) [SEEK_HOLE]: Use lseek_copy if scantype says so.
---
NEWS | 3 +
src/copy.c | 209 ++++++++++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 201 insertions(+), 11 deletions(-)
diff --git a/NEWS b/NEWS
index d713fa724..63cb47d10 100644
--- a/NEWS
+++ b/NEWS
@@ -17,6 +17,9 @@ GNU coreutils NEWS -*- outline -*-
cp and install now default to copy-on-write (COW) if available.
+ cp, install and mv now prefer lseek+SEEK_HOLE to ioctl+FS_IOC_FIEMAP
+ on sparse files, as lseek is simpler and more portable.
+
On GNU/Linux systems, ls no longer issues an error message on a
directory merely because it was removed. This reverts a change
that was made in release 8.32.
diff --git a/src/copy.c b/src/copy.c
index b382cfa4d..d88f8cf93 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -416,7 +416,12 @@ write_zeros (int fd, off_t n_bytes)
Upon a successful copy, return true. If the initial extent scan
fails, set *NORMAL_COPY_REQUIRED to true and return false.
Upon any other failure, set *NORMAL_COPY_REQUIRED to false and
- return false. */
+ return false.
+
+ FIXME: Once we no longer need to support Linux kernel versions
+ before 3.1 (2011), this function can be retired as it is superseded
+ by lseek_copy. That is, we no longer need extent-scan.h and can
+ remove any of the code that uses it. */
static bool
extent_copy (int src_fd, int dest_fd, char *buf, size_t buf_size,
size_t hole_size, off_t src_total_size,
@@ -595,6 +600,150 @@ extent_copy (int src_fd, int dest_fd, char *buf, size_t buf_size,
return true;
}
+#ifdef SEEK_HOLE
+/* Perform an efficient extent copy, if possible. This avoids
+ the overhead of detecting holes in hole-introducing/preserving
+ copy, and thus makes copying sparse files much more efficient.
+ Copy from SRC_FD to DEST_FD, using BUF (of size BUF_SIZE) for a buffer.
+ Look for holes of size HOLE_SIZE in the input.
+ The input file is of size SRC_TOTAL_SIZE.
+ Use SPARSE_MODE to determine whether to create holes in the output.
+ SRC_NAME and DST_NAME are the input and output file names.
+ Return true if successful, false (with a diagnostic) otherwise. */
+
+static bool
+lseek_copy (int src_fd, int dest_fd, char *buf, size_t buf_size,
+ size_t hole_size, off_t ext_start, off_t src_total_size,
+ enum Sparse_type sparse_mode,
+ char const *src_name, char const *dst_name)
+{
+ off_t last_ext_start = 0;
+ off_t last_ext_len = 0;
+ off_t dest_pos = 0;
+ bool wrote_hole_at_eof = true;
+
+ while (0 <= ext_start)
+ {
+ off_t ext_end = lseek (src_fd, ext_start, SEEK_HOLE);
+ if (ext_end < 0)
+ {
+ if (errno != ENXIO)
+ goto cannot_lseek;
+ ext_end = src_total_size;
+ if (ext_end <= ext_start)
+ {
+ /* The input file grew; get its current size. */
+ src_total_size = lseek (src_fd, 0, SEEK_END);
+ if (src_total_size < 0)
+ goto cannot_lseek;
+
+ /* If the input file shrank after growing, stop copying. */
+ if (src_total_size <= ext_start)
+ break;
+
+ ext_end = src_total_size;
+ }
+ }
+ /* If the input file must have grown, increase its measured size. */
+ if (src_total_size < ext_end)
+ src_total_size = ext_end;
+
+ if (lseek (src_fd, ext_start, SEEK_SET) < 0)
+ goto cannot_lseek;
+
+ wrote_hole_at_eof = false;
+ off_t ext_hole_size = ext_start - last_ext_start - last_ext_len;
+
+ if (ext_hole_size)
+ {
+ if (sparse_mode != SPARSE_NEVER)
+ {
+ if (! create_hole (dest_fd, dst_name,
+ sparse_mode == SPARSE_ALWAYS,
+ ext_hole_size))
+ return false;
+ wrote_hole_at_eof = true;
+ }
+ else
+ {
+ /* When not inducing holes and when there is a hole between
+ the end of the previous extent and the beginning of the
+ current one, write zeros to the destination file. */
+ if (! write_zeros (dest_fd, ext_hole_size))
+ {
+ error (0, errno, _("%s: write failed"),
+ quotef (dst_name));
+ return false;
+ }
+ }
+ }
+
+ off_t ext_len = ext_end - ext_start;
+ last_ext_start = ext_start;
+ last_ext_len = ext_len;
+
+ /* Copy this extent, looking for further opportunities to not
+ bother to write zeros unless --sparse=never, since SEEK_HOLE
+ is conservative and may miss some holes. */
+ off_t n_read;
+ bool read_hole;
+ if ( ! sparse_copy (src_fd, dest_fd, buf, buf_size,
+ sparse_mode == SPARSE_NEVER ? 0 : hole_size,
+ true, src_name, dst_name, ext_len, &n_read,
+ &read_hole))
+ return false;
+
+ dest_pos = ext_start + n_read;
+ if (n_read)
+ wrote_hole_at_eof = read_hole;
+ if (n_read < ext_len)
+ {
+ /* The input file shrank. */
+ src_total_size = dest_pos;
+ break;
+ }
+
+ ext_start = lseek (src_fd, dest_pos, SEEK_DATA);
+ if (ext_start < 0)
+ {
+ if (errno != ENXIO)
+ goto cannot_lseek;
+ break;
+ }
+ }
+
+ /* When the source file ends with a hole, we have to do a little more work,
+ since the above copied only up to and including the final extent.
+ In order to complete the copy, we may have to insert a hole or write
+ zeros in the destination corresponding to the source file's hole-at-EOF.
+
+ In addition, if the final extent was a block of zeros at EOF and we've
+ just converted them to a hole in the destination, we must call ftruncate
+ here in order to record the proper length in the destination. */
+ if ((dest_pos < src_total_size || wrote_hole_at_eof)
+ && ! (sparse_mode == SPARSE_NEVER
+ ? write_zeros (dest_fd, src_total_size - dest_pos)
+ : ftruncate (dest_fd, src_total_size) == 0))
+ {
+ error (0, errno, _("failed to extend %s"), quoteaf (dst_name));
+ return false;
+ }
+
+ if (sparse_mode == SPARSE_ALWAYS && dest_pos < src_total_size
+ && punch_hole (dest_fd, dest_pos, src_total_size - dest_pos) < 0)
+ {
+ error (0, errno, _("error deallocating %s"), quoteaf (dst_name));
+ return false;
+ }
+
+ return true;
+
+ cannot_lseek:
+ error (0, errno, _("cannot lseek %s"), quoteaf (src_name));
+ return false;
+}
+#endif
+
/* FIXME: describe */
/* FIXME: rewrite this to use a hash table so we avoid the quadratic
performance hit that's probably noticeable only on trees deeper
@@ -1010,6 +1159,9 @@ fchmod_or_lchmod (int desc, char const *name, mode_t mode)
/* Type of scan being done on the input when looking for sparseness. */
enum scantype
{
+ /* An error was found when determining scantype. */
+ ERROR_SCANTYPE,
+
/* No fancy scanning; just read and write. */
PLAIN_SCANTYPE,
@@ -1017,22 +1169,44 @@ enum scantype
attempting to create sparse output. */
ZERO_SCANTYPE,
+ /* lseek information is available. */
+ LSEEK_SCANTYPE,
+
/* Extent information is available. */
EXTENT_SCANTYPE
};
-/* Use a heuristic to determine whether stat buffer SB comes from a file
- with sparse blocks. If the file has fewer blocks than would normally
- be needed for a file of its size, then at least one of the blocks in
- the file is a hole. In that case, return true. */
+/* Result of infer_scantype. */
+union scan_inference
+{
+ /* Used if infer_scantype returns LSEEK_SCANTYPE. This is the
+ offset of the first data block, or -1 if the file has no data. */
+ off_t ext_start;
+
+ /* Used if infer_scantype returns EXTENT_SCANTYPE. */
+ struct extent_scan extent_scan;
+};
+
+/* Return how to scan a file with descriptor FD and stat buffer SB.
+ Store any information gathered into *SCAN. */
static enum scantype
-infer_scantype (int fd, struct stat const *sb, struct extent_scan *scan)
+infer_scantype (int fd, struct stat const *sb,
+ union scan_inference *scan_inference)
{
if (! (HAVE_STRUCT_STAT_ST_BLOCKS
&& S_ISREG (sb->st_mode)
&& ST_NBLOCKS (*sb) < sb->st_size / ST_NBLOCKSIZE))
return PLAIN_SCANTYPE;
+#ifdef SEEK_HOLE
+ scan_inference->ext_start = lseek (fd, 0, SEEK_DATA);
+ if (0 <= scan_inference->ext_start)
+ return LSEEK_SCANTYPE;
+ else if (errno != EINVAL && errno != ENOTSUP)
+ return errno == ENXIO ? LSEEK_SCANTYPE : ERROR_SCANTYPE;
+#endif
+
+ struct extent_scan *scan = &scan_inference->extent_scan;
extent_scan_init (fd, scan);
extent_scan_read (scan);
return scan->initial_scan_failed ? ZERO_SCANTYPE : EXTENT_SCANTYPE;
@@ -1066,7 +1240,7 @@ copy_reg (char const *src_name, char const *dst_name,
mode_t src_mode = src_sb->st_mode;
struct stat sb;
struct stat src_open_sb;
- struct extent_scan scan;
+ union scan_inference scan_inference;
bool return_val = true;
bool data_copy_required = x->data_copy_required;
@@ -1263,17 +1437,23 @@ copy_reg (char const *src_name, char const *dst_name,
size_t buf_size = io_blksize (sb);
size_t hole_size = ST_BLKSIZE (sb);
- fdadvise (source_desc, 0, 0, FADVISE_SEQUENTIAL);
-
/* Deal with sparse files. */
enum scantype scantype = infer_scantype (source_desc, &src_open_sb,
- &scan);
+ &scan_inference);
+ if (scantype == ERROR_SCANTYPE)
+ {
+ error (0, errno, _("cannot lseek %s"), quoteaf (src_name));
+ return_val = false;
+ goto close_src_and_dst_desc;
+ }
bool make_holes
= (S_ISREG (sb.st_mode)
&& (x->sparse_mode == SPARSE_ALWAYS
|| (x->sparse_mode == SPARSE_AUTO
&& scantype != PLAIN_SCANTYPE)));
+ fdadvise (source_desc, 0, 0, FADVISE_SEQUENTIAL);
+
/* If not making a sparse file, try to use a more-efficient
buffer size. */
if (! make_holes)
@@ -1307,7 +1487,14 @@ copy_reg (char const *src_name, char const *dst_name,
? extent_copy (source_desc, dest_desc, buf, buf_size, hole_size,
src_open_sb.st_size,
make_holes ? x->sparse_mode : SPARSE_NEVER,
- src_name, dst_name, &scan)
+ src_name, dst_name, &scan_inference.extent_scan)
+#ifdef SEEK_HOLE
+ : scantype == LSEEK_SCANTYPE
+ ? lseek_copy (source_desc, dest_desc, buf, buf_size, hole_size,
+ scan_inference.ext_start, src_open_sb.st_size,
+ make_holes ? x->sparse_mode : SPARSE_NEVER,
+ src_name, dst_name)
+#endif
: sparse_copy (source_desc, dest_desc, buf, buf_size,
make_holes ? hole_size : 0,
x->sparse_mode == SPARSE_ALWAYS,
--
2.25.4
>From 81849f05b94068f873299bd9fc01b4eebdb31f64 Mon Sep 17 00:00:00 2001
From: Paul Eggert <egg...@cs.ucla.edu>
Date: Thu, 25 Jun 2020 17:34:23 -0700
Subject: [PATCH 5/5] cp: use copy_file_range if available
* NEWS: Mention this.
* bootstrap.conf (gnulib_modules): Add copy-file-range.
* src/copy.c (sparse_copy): Try copy_file_range if not
looking for holes.
---
NEWS | 5 +++--
bootstrap.conf | 1 +
src/copy.c | 40 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 44 insertions(+), 2 deletions(-)
diff --git a/NEWS b/NEWS
index 63cb47d10..1c3f6378d 100644
--- a/NEWS
+++ b/NEWS
@@ -17,8 +17,9 @@ GNU coreutils NEWS -*- outline -*-
cp and install now default to copy-on-write (COW) if available.
- cp, install and mv now prefer lseek+SEEK_HOLE to ioctl+FS_IOC_FIEMAP
- on sparse files, as lseek is simpler and more portable.
+ cp, install and mv now use the copy_file_range syscall if available.
+ Also, they prefer lseek+SEEK_HOLE to ioctl+FS_IOC_FIEMAP on sparse
+ files, as lseek is simpler and more portable.
On GNU/Linux systems, ls no longer issues an error message on a
directory merely because it was removed. This reverts a change
diff --git a/bootstrap.conf b/bootstrap.conf
index 12e2d831a..2506f0db4 100644
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -54,6 +54,7 @@ gnulib_modules="
closeout
config-h
configmake
+ copy-file-range
crypto/md5
crypto/sha1
crypto/sha256
diff --git a/src/copy.c b/src/copy.c
index d88f8cf93..4050f6953 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -265,6 +265,46 @@ sparse_copy (int src_fd, int dest_fd, char *buf, size_t buf_size,
{
*last_write_made_hole = false;
*total_n_read = 0;
+
+ /* If not looking for holes, use copy_file_range if available. */
+ if (!hole_size)
+ while (max_n_read)
+ {
+ /* Copy at most COPY_MAX bytes at a time; this is min
+ (PTRDIFF_MAX, SIZE_MAX) truncated to a value that is
+ surely aligned well. */
+ ssize_t ssize_max = TYPE_MAXIMUM (ssize_t);
+ ptrdiff_t copy_max = MIN (ssize_max, SIZE_MAX) >> 30 << 30;
+ ssize_t n_copied = copy_file_range (src_fd, NULL, dest_fd, NULL,
+ MIN (max_n_read, copy_max), 0);
+ if (n_copied == 0)
+ {
+ /* copy_file_range incorrectly returns 0 when reading from
+ the proc file system on the Linux kernel through at
+ least 5.6.19 (2020), so fall back on 'read' if the
+ input file seems empty. */
+ if (*total_n_read == 0)
+ break;
+ return true;
+ }
+ if (n_copied < 0)
+ {
+ if (errno == ENOSYS || errno == EINVAL
+ || errno == EBADF || errno == EXDEV)
+ break;
+ if (errno == EINTR)
+ n_copied = 0;
+ else
+ {
+ error (0, errno, _("error copying %s to %s"),
+ quoteaf_n (0, src_name), quoteaf_n (1, dst_name));
+ return false;
+ }
+ }
+ max_n_read -= n_copied;
+ *total_n_read += n_copied;
+ }
+
bool make_hole = false;
off_t psize = 0;
--
2.25.4
