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From 5f2dac18054d9d9b3d84e7fba8c2a6e750d2c245 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
Date: Wed, 1 Apr 2020 12:51:34 +0100
Subject: [PATCH 01/12] cp: ensure --attributes-only doesn't remove files
* src/copy.c (copy_internal): Ensure we don't unlink the destination
unless explicitly requested.
* tests/cp/attr-existing.sh: Add test cases.
* NEWS: Mention the bug fix.
Fixes https://bugs.gnu.org/40352
Upstream-commit: 7b5f0fa47cd04c84975250d5b5da7c98e097e99f
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
src/copy.c | 9 +++++----
tests/cp/attr-existing.sh | 21 ++++++++++++++++++---
2 files changed, 23 insertions(+), 7 deletions(-)
diff --git a/src/copy.c b/src/copy.c
index 6e5efc7..54601ce 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -2211,10 +2211,11 @@ copy_internal (char const *src_name, char const *dst_name,
/* Never unlink dst_name when in move mode. */
&& ! x->move_mode
&& (x->unlink_dest_before_opening
- || (x->preserve_links && 1 < dst_sb.st_nlink)
- || (x->dereference == DEREF_NEVER
- && ! S_ISREG (src_sb.st_mode))
- ))
+ || (x->data_copy_required
+ && ((x->preserve_links && 1 < dst_sb.st_nlink)
+ || (x->dereference == DEREF_NEVER
+ && ! S_ISREG (src_sb.st_mode))))
+ ))
{
if (unlink (dst_name) != 0 && errno != ENOENT)
{
diff --git a/tests/cp/attr-existing.sh b/tests/cp/attr-existing.sh
index 59ce641..14fc844 100755
--- a/tests/cp/attr-existing.sh
+++ b/tests/cp/attr-existing.sh
@@ -19,11 +19,26 @@
. "${srcdir=.}/tests/init.sh"; path_prepend_ ./src
print_ver_ cp
-printf '1' > file1
-printf '2' > file2
-printf '2' > file2.exp
+printf '1' > file1 || framework_failure_
+printf '2' > file2 || framework_failure_
+printf '2' > file2.exp || framework_failure_
cp --attributes-only file1 file2 || fail=1
cmp file2 file2.exp || fail=1
+# coreutils v8.32 and before would remove destination files
+# if hardlinked or the source was not a regular file.
+ln file2 link2 || framework_failure_
+cp -a --attributes-only file1 file2 || fail=1
+cmp file2 file2.exp || fail=1
+
+ln -s file1 sym1 || framework_failure_
+returns_ 1 cp -a --attributes-only sym1 file2 || fail=1
+cmp file2 file2.exp || fail=1
+
+# One can still force removal though
+cp -a --remove-destination --attributes-only sym1 file2 || fail=1
+test -L file2 || fail=1
+cmp file1 file2 || fail=1
+
Exit $fail
--
2.26.3
From c728747b06e71894c96d1f27434f2484af992c75 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Tue, 23 Jun 2020 19:18:04 -0700
Subject: [PATCH 02/12] 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.
Upstream-commit: 761ba28400a04ee24eefe9cd4973ec8850cd7a52
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
src/copy.c | 119 +++++++++++++++++++++++++----------------------------
1 file changed, 55 insertions(+), 64 deletions(-)
diff --git a/src/copy.c b/src/copy.c
index 54601ce..f694f91 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;
--
2.26.3
From ed7ff81de507bef46991f4caac550f41ab65e3ed Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed, 24 Jun 2020 17:05:20 -0700
Subject: [PATCH 03/12] cp: avoid copy_reg goto
* src/copy.c (copy_reg): Redo to avoid label and goto.
Upstream-commit: 2fcd0f3328f5181a2986905fa5469a0152c67279
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
src/copy.c | 34 +++++++++++-----------------------
1 file changed, 11 insertions(+), 23 deletions(-)
diff --git a/src/copy.c b/src/copy.c
index f694f91..b382cfa 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];
--
2.26.3
From 5631bded3a385ca0bbd77456b50767fe5580240c Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Thu, 25 Jun 2020 16:31:44 -0700
Subject: [PATCH 04/12] 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.
Upstream-commit: a6eaee501f6ec0c152abe88640203a64c390993e
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
src/copy.c | 209 ++++++++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 198 insertions(+), 11 deletions(-)
diff --git a/src/copy.c b/src/copy.c
index b382cfa..d88f8cf 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,
--
2.26.3
From be7466be92d779cfbece418d4de33191ae52ab4a Mon Sep 17 00:00:00 2001
From: Kamil Dudka <kdudka@redhat.com>
Date: Wed, 24 Mar 2021 16:06:53 +0100
Subject: [PATCH 05/12] import the copy-file-range module from gnulib
---
aclocal.m4 | 1 +
lib/config.hin | 3 +++
lib/copy-file-range.c | 33 +++++++++++++++++++++++++++++++++
lib/gnulib.mk | 10 ++++++++++
m4/copy-file-range.m4 | 36 ++++++++++++++++++++++++++++++++++++
m4/gnulib-comp.m4 | 8 ++++++++
6 files changed, 91 insertions(+)
create mode 100644 lib/copy-file-range.c
create mode 100644 m4/copy-file-range.m4
diff --git a/aclocal.m4 b/aclocal.m4
index 713f7c5..09a7ea8 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1165,6 +1165,7 @@ m4_include([m4/closedir.m4])
m4_include([m4/codeset.m4])
m4_include([m4/config-h.m4])
m4_include([m4/configmake.m4])
+m4_include([m4/copy-file-range.m4])
m4_include([m4/ctype.m4])
m4_include([m4/cycle-check.m4])
m4_include([m4/d-ino.m4])
diff --git a/lib/config.hin b/lib/config.hin
index 9769c39..bf9f9f8 100644
--- a/lib/config.hin
+++ b/lib/config.hin
@@ -370,6 +370,9 @@
/* Define to 1 when the gnulib module connect should be tested. */
#undef GNULIB_TEST_CONNECT
+/* Define to 1 when the gnulib module copy-file-range should be tested. */
+#undef GNULIB_TEST_COPY_FILE_RANGE
+
/* Define to 1 when the gnulib module dirfd should be tested. */
#undef GNULIB_TEST_DIRFD
diff --git a/lib/copy-file-range.c b/lib/copy-file-range.c
new file mode 100644
index 0000000..069f144
--- /dev/null
+++ b/lib/copy-file-range.c
@@ -0,0 +1,33 @@
+/* Stub for copy_file_range
+ Copyright 2019-2020 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+#include <config.h>
+
+#include <unistd.h>
+
+#include <errno.h>
+
+ssize_t
+copy_file_range (int infd, off_t *pinoff,
+ int outfd, off_t *poutoff,
+ size_t length, unsigned int flags)
+{
+ /* There is little need to emulate copy_file_range with read+write,
+ since programs that use copy_file_range must fall back on
+ read+write anyway. */
+ errno = ENOSYS;
+ return -1;
+}
diff --git a/lib/gnulib.mk b/lib/gnulib.mk
index b3633b8..86829f3 100644
--- a/lib/gnulib.mk
+++ b/lib/gnulib.mk
@@ -65,6 +65,7 @@
# closeout \
# config-h \
# configmake \
+# copy-file-range \
# crypto/md5 \
# crypto/sha1 \
# crypto/sha256 \
@@ -800,6 +801,15 @@ CLEANFILES += lib/configmake.h lib/configmake.h-t
## end gnulib module configmake
+## begin gnulib module copy-file-range
+
+
+EXTRA_DIST += lib/copy-file-range.c
+
+EXTRA_lib_libcoreutils_a_SOURCES += lib/copy-file-range.c
+
+## end gnulib module copy-file-range
+
## begin gnulib module count-leading-zeros
lib_libcoreutils_a_SOURCES += lib/count-leading-zeros.c
diff --git a/m4/copy-file-range.m4 b/m4/copy-file-range.m4
new file mode 100644
index 0000000..5c5a274
--- /dev/null
+++ b/m4/copy-file-range.m4
@@ -0,0 +1,36 @@
+# copy-file-range.m4
+dnl Copyright 2019-2020 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+AC_DEFUN([gl_FUNC_COPY_FILE_RANGE],
+[
+ AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
+
+ dnl Persuade glibc <unistd.h> to declare copy_file_range.
+ AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
+
+ dnl Use AC_LINK_IFELSE, rather than AC_CHECK_FUNCS or a variant,
+ dnl since we don't want AC_CHECK_FUNCS's checks for glibc stubs.
+ dnl Programs that use copy_file_range must fall back on read+write
+ dnl anyway, and there's little point to substituting the Gnulib stub
+ dnl for a glibc stub.
+ AC_CACHE_CHECK([for copy_file_range], [gl_cv_func_copy_file_range],
+ [AC_LINK_IFELSE(
+ [AC_LANG_PROGRAM(
+ [[#include <unistd.h>
+ ]],
+ [[ssize_t (*func) (int, off_t *, int, off_t, size_t, unsigned)
+ = copy_file_range;
+ return func (0, 0, 0, 0, 0, 0) & 127;
+ ]])
+ ],
+ [gl_cv_func_copy_file_range=yes],
+ [gl_cv_func_copy_file_range=no])
+ ])
+
+ if test "$gl_cv_func_copy_file_range" != yes; then
+ HAVE_COPY_FILE_RANGE=0
+ fi
+])
diff --git a/m4/gnulib-comp.m4 b/m4/gnulib-comp.m4
index dead90e..953e7f0 100644
--- a/m4/gnulib-comp.m4
+++ b/m4/gnulib-comp.m4
@@ -129,6 +129,7 @@ AC_DEFUN([gl_EARLY],
# Code from module configmake:
# Code from module connect:
# Code from module connect-tests:
+ # Code from module copy-file-range:
# Code from module count-leading-zeros:
# Code from module count-leading-zeros-tests:
# Code from module crypto/af_alg:
@@ -977,6 +978,11 @@ AC_DEFUN([gl_INIT],
gl_DIRENT_MODULE_INDICATOR([closedir])
gl_CONFIG_H
gl_CONFIGMAKE_PREP
+ gl_FUNC_COPY_FILE_RANGE
+ if test $HAVE_COPY_FILE_RANGE = 0; then
+ AC_LIBOBJ([copy-file-range])
+ fi
+ gl_UNISTD_MODULE_INDICATOR([copy-file-range])
gl_AF_ALG
AC_DEFINE([GL_COMPILE_CRYPTO_STREAM], 1, [Compile Gnulib crypto stream ops.])
AC_REQUIRE([AC_C_RESTRICT])
@@ -2746,6 +2752,7 @@ AC_DEFUN([gl_FILE_LIST], [
lib/closeout.c
lib/closeout.h
lib/copy-acl.c
+ lib/copy-file-range.c
lib/count-leading-zeros.c
lib/count-leading-zeros.h
lib/creat-safer.c
@@ -3438,6 +3445,7 @@ AC_DEFUN([gl_FILE_LIST], [
m4/codeset.m4
m4/config-h.m4
m4/configmake.m4
+ m4/copy-file-range.m4
m4/ctype.m4
m4/cycle-check.m4
m4/d-ino.m4
--
2.26.3
From 48370c95bcf7c25ce021fbd2145062d3d29ae6d5 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Thu, 25 Jun 2020 17:34:23 -0700
Subject: [PATCH 06/12] 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.
Upstream-commit: 4b04a0c3b792d27909670a81d21f2a3b3e0ea563
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
bootstrap.conf | 1 +
src/copy.c | 40 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 41 insertions(+)
diff --git a/bootstrap.conf b/bootstrap.conf
index 2a342c1..7d53e28 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 d88f8cf..4050f69 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;
--
2.26.3
From 23ea1ba463d33e268f35847059e637a5935e4581 Mon Sep 17 00:00:00 2001
From: Zorro Lang <zlang@redhat.com>
Date: Mon, 26 Apr 2021 17:25:18 +0200
Subject: [PATCH 07/12] copy: do not refuse to copy a swap file
* src/copy.c (sparse_copy): Fallback to read() if copy_file_range()
fails with ETXTBSY. Otherwise it would be impossible to copy files
that are being used as swap. This used to work before introducing
the support for copy_file_range() in coreutils. (Bug#48036)
Upstream-commit: 785478013b416cde50794be35475c0c4fdbb48b4
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
src/copy.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/copy.c b/src/copy.c
index 4050f69..1798bb7 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -290,7 +290,7 @@ sparse_copy (int src_fd, int dest_fd, char *buf, size_t buf_size,
if (n_copied < 0)
{
if (errno == ENOSYS || errno == EINVAL
- || errno == EBADF || errno == EXDEV)
+ || errno == EBADF || errno == EXDEV || errno == ETXTBSY)
break;
if (errno == EINTR)
n_copied = 0;
--
2.31.1
From cd7c7a6b5ad89ef0a61722552d532901fc1bed05 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
Date: Sun, 2 May 2021 21:27:17 +0100
Subject: [PATCH 08/12] copy: ensure we enforce --reflink=never
* src/copy.c (sparse_copy): Don't use copy_file_range()
with --reflink=never as copy_file_range() may implicitly
use acceleration techniques like reflinking.
(extent_copy): Pass through whether we allow reflinking.
(lseek_copy): Likewise.
Fixes https://bugs.gnu.org/48164
Upstream-commit: ea9af99234031ab8d5169c8a669434e2a6b4f864
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
src/copy.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)
diff --git a/src/copy.c b/src/copy.c
index 4050f69..0337538 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -258,7 +258,7 @@ create_hole (int fd, char const *name, bool punch_holes, off_t size)
bytes read. */
static bool
sparse_copy (int src_fd, int dest_fd, char *buf, size_t buf_size,
- size_t hole_size, bool punch_holes,
+ size_t hole_size, bool punch_holes, bool allow_reflink,
char const *src_name, char const *dst_name,
uintmax_t max_n_read, off_t *total_n_read,
bool *last_write_made_hole)
@@ -266,8 +266,9 @@ 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)
+ /* If not looking for holes, use copy_file_range if available,
+ but don't use if reflink disallowed as that may be implicit. */
+ if ((! hole_size) && allow_reflink)
while (max_n_read)
{
/* Copy at most COPY_MAX bytes at a time; this is min
@@ -466,6 +467,7 @@ 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,
enum Sparse_type sparse_mode,
+ bool allow_reflink,
char const *src_name, char const *dst_name,
struct extent_scan *scan)
{
@@ -579,8 +581,8 @@ extent_copy (int src_fd, int dest_fd, char *buf, size_t buf_size,
if ( ! sparse_copy (src_fd, dest_fd, buf, buf_size,
sparse_mode == SPARSE_ALWAYS ? hole_size: 0,
- true, src_name, dst_name, ext_len, &n_read,
- &read_hole))
+ true, allow_reflink, src_name, dst_name,
+ ext_len, &n_read, &read_hole))
goto fail;
dest_pos = ext_start + n_read;
@@ -655,6 +657,7 @@ 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,
+ bool allow_reflink,
char const *src_name, char const *dst_name)
{
off_t last_ext_start = 0;
@@ -729,8 +732,8 @@ lseek_copy (int src_fd, int dest_fd, char *buf, size_t buf_size,
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))
+ true, allow_reflink, src_name, dst_name,
+ ext_len, &n_read, &read_hole))
return false;
dest_pos = ext_start + n_read;
@@ -1527,17 +1530,20 @@ 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,
+ x->reflink_mode != REFLINK_NEVER,
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,
+ x->reflink_mode != REFLINK_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,
+ x->reflink_mode != REFLINK_NEVER,
src_name, dst_name, UINTMAX_MAX, &n_read,
&wrote_hole_at_eof)))
{
--
2.30.2
From 7978f1de88dcdb17b67db9268038930e9c71154f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
Date: Sat, 8 May 2021 17:18:54 +0100
Subject: [PATCH 09/12] copy: handle ENOTSUP from copy_file_range()
* src/copy.c (sparse_copy): Ensure we fall back to
a standard copy if copy_file_range() returns ENOTSUP.
This generally is best checked when checking ENOSYS,
but it also seems to be a practical concern on Centos 7,
as a quick search gave https://bugzilla.redhat.com/1840284
Upstream-commit: 8ec0d1799e19a079b8a661c6bb69f6c58e52f1aa
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
src/copy.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/src/copy.c b/src/copy.c
index 9977193..e3977cd 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -290,8 +290,9 @@ sparse_copy (int src_fd, int dest_fd, char *buf, size_t buf_size,
}
if (n_copied < 0)
{
- if (errno == ENOSYS || errno == EINVAL
- || errno == EBADF || errno == EXDEV || errno == ETXTBSY)
+ if (errno == ENOSYS || is_ENOTSUP (errno)
+ || errno == EINVAL || errno == EBADF
+ || errno == EXDEV || errno == ETXTBSY)
break;
if (errno == EINTR)
n_copied = 0;
--
2.31.1
From d8d3edbfc13ff13c185f23436209b788f906aa41 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
Date: Sun, 9 May 2021 21:55:22 +0100
Subject: [PATCH 10/12] copy: handle EOPNOTSUPP from SEEK_DATA
* src/copy.c (infer_scantype): Ensure we don't error out
if SEEK_DATA returns EOPNOTSUPP, on systems where this value
is distinct from ENOTSUP. Generally both of these should be checked.
Upstream-commit: 017877bd088284d515753d78b81ca6e6a88c1350
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
src/copy.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/copy.c b/src/copy.c
index e3977cd..de8030d 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -1246,7 +1246,7 @@ infer_scantype (int fd, struct stat const *sb,
scan_inference->ext_start = lseek (fd, 0, SEEK_DATA);
if (0 <= scan_inference->ext_start)
return LSEEK_SCANTYPE;
- else if (errno != EINVAL && errno != ENOTSUP)
+ else if (errno != EINVAL && !is_ENOTSUP (errno))
return errno == ENXIO ? LSEEK_SCANTYPE : ERROR_SCANTYPE;
#endif
--
2.31.1
From 1daf8c0fc9a5766c22b7ea84bea8c88c86a0c495 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
Date: Sat, 8 May 2021 19:23:20 +0100
Subject: [PATCH 11/12] copy: handle system security config issues with
copy_file_range()
* src/copy.c (sparse_copy): Upon EPERM from copy_file_range(),
fall back to a standard copy, which will give a more accurate
error as to whether the issue is with the source or destination.
Also this will avoid the issue where seccomp or apparmor are
not configured to handle copy_file_range(), in which case
the fall back standard copy would succeed without issue.
This specific issue with seccomp was noticed for example in:
https://github.com/golang/go/issues/40900
Upstream-commit: 2e66e1732fced7af20fa76c60e636d39a1767d48
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
src/copy.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/src/copy.c b/src/copy.c
index de8030d..62eec7b 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -294,6 +294,15 @@ sparse_copy (int src_fd, int dest_fd, char *buf, size_t buf_size,
|| errno == EINVAL || errno == EBADF
|| errno == EXDEV || errno == ETXTBSY)
break;
+
+ /* copy_file_range might not be enabled in seccomp filters,
+ so retry with a standard copy. EPERM can also occur
+ for immutable files, but that would only be in the edge case
+ where the file is made immutable after creating/truncating,
+ in which case the (more accurate) error is still shown. */
+ if (errno == EPERM && *total_n_read == 0)
+ break;
+
if (errno == EINTR)
n_copied = 0;
else
--
2.31.1
From 42c9e598f61ba6bc27a615e39e40023a676a523b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
Date: Wed, 12 May 2021 23:47:38 +0100
Subject: [PATCH 12/12] copy: disallow copy_file_range() on Linux kernels
before 5.3
copy_file_range() before Linux kernel release 5.3 had many issues,
as described at https://lwn.net/Articles/789527/, which was
referenced from https://lwn.net/Articles/846403/; a more general
article discussing the generality of copy_file_range().
Linux kernel 5.3 was released in September 2019, which is new enough
that we need to actively avoid older kernels.
* src/copy.c (functional_copy_file_range): A new function
that returns false for Linux kernels before version 5.3.
(sparse_copy): Call this new function to gate use of
copy_file_range().
Upstream-commit: ba5e6885d2c255648cddb87b4e795659c1990374
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
src/copy.c | 47 +++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 45 insertions(+), 2 deletions(-)
diff --git a/src/copy.c b/src/copy.c
index 62eec7b..2e1699b 100644
--- a/src/copy.c
+++ b/src/copy.c
@@ -21,6 +21,7 @@
#include <assert.h>
#include <sys/ioctl.h>
#include <sys/types.h>
+#include <sys/utsname.h>
#include <selinux/selinux.h>
#if HAVE_HURD_H
@@ -64,6 +65,7 @@
#include "write-any-file.h"
#include "areadlink.h"
#include "yesno.h"
+#include "xstrtol.h"
#include "selinux.h"
#if USE_XATTR
@@ -244,6 +246,47 @@ create_hole (int fd, char const *name, bool punch_holes, off_t size)
return true;
}
+/* copy_file_range() before Linux kernel release 5.3 had many issues,
+ as described at https://lwn.net/Articles/789527/,
+ so return FALSE for Linux kernels earlier than that.
+ This function can be removed when such kernels (released before Sep 2019)
+ are no longer a consideration. */
+
+static bool
+functional_copy_file_range (void)
+{
+#ifdef __linux__
+ static int version_allowed = -1;
+
+ if (version_allowed == -1)
+ version_allowed = 0;
+ else
+ return version_allowed;
+
+ struct utsname name;
+ if (uname (&name) == -1)
+ return version_allowed;
+
+ char *p = name.release;
+ uintmax_t ver[2] = {0, 0};
+ size_t iver = 0;
+
+ do
+ {
+ strtol_error err = xstrtoumax (p, &p, 10, &ver[iver], NULL);
+ if (err != LONGINT_OK || *p++ != '.')
+ break;
+ }
+ while (++iver < ARRAY_CARDINALITY (ver));
+
+ version_allowed = (ver[0] > 5 || (ver[0] == 5 && ver[1] >= 3));
+
+ return version_allowed;
+#else
+ return true;
+#endif
+
+}
/* Copy the regular file open on SRC_FD/SRC_NAME to DST_FD/DST_NAME,
honoring the MAKE_HOLES setting and using the BUF_SIZE-byte buffer
@@ -266,9 +309,9 @@ 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 not looking for holes, use copy_file_range if functional,
but don't use if reflink disallowed as that may be implicit. */
- if ((! hole_size) && allow_reflink)
+ if ((! hole_size) && allow_reflink && functional_copy_file_range ())
while (max_n_read)
{
/* Copy at most COPY_MAX bytes at a time; this is min
--
2.31.1
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