--- /dev/null
+From 093a8b4bfaba60005f14493ce7ef11ed665a0176 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
+Date: Thu, 23 Mar 2023 13:19:04 +0000
+Subject: [PATCH] copy: fix --reflink=auto to fallback in more cases
+
+On restricted systems like android or some containers,
+FICLONE could return EPERM, EACCES, or ENOTTY,
+which would have induced the command to fail to copy
+rather than falling back to a more standard copy.
+
+* src/copy.c (is_terminal_failure): A new function refactored
+from handle_clone_fail().
+(is_CLONENOTSUP): Merge in the handling of EACCES, ENOTTY, EPERM
+as they also pertain to determination of whether cloning is supported
+if we ever use this function in that context.
+(handle_clone_fail): Use is_terminal_failure() in all cases,
+so that we assume a terminal failure in less errno cases.
+* NEWS: Mention the bug fix.
+Addresses https://bugs.gnu.org/62404
+---
+--- a/src/copy.c
++++ b/src/copy.c
+@@ -278,15 +278,27 @@ create_hole (int fd, char const *name, b
+ }
+
+
+-/* Whether the errno from FICLONE, or copy_file_range
+- indicates operation is not supported for this file or file system. */
++/* Whether the errno indicates the operation is a transient failure.
++ I.e., a failure that would indicate the operation _is_ supported,
++ but has failed in a terminal way. */
++
++static bool
++is_terminal_error (int err)
++{
++ return err == EIO || err == ENOMEM || err == ENOSPC || err == EDQUOT;
++}
++
++
++/* Whether the errno from FICLONE, or copy_file_range indicates
++ the operation is not supported/allowed for this file or process. */
+
+ static bool
+ is_CLONENOTSUP (int err)
+ {
+- return err == ENOSYS || is_ENOTSUP (err)
++ return err == ENOSYS || err == ENOTTY || is_ENOTSUP (err)
+ || err == EINVAL || err == EBADF
+- || err == EXDEV || err == ETXTBSY;
++ || err == EXDEV || err == ETXTBSY
++ || err == EPERM || err == EACCES;
+ }
+
+
+@@ -339,20 +351,18 @@ sparse_copy (int src_fd, int dest_fd, ch
+ {
+ copy_debug.offload = COPY_DEBUG_UNSUPPORTED;
+
+- if (is_CLONENOTSUP (errno))
+- 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,
++ /* Consider operation unsupported only if no data copied.
++ For example, EPERM could occur if copy_file_range not 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,
+ in which case the (more accurate) error is still shown. */
+- if (errno == EPERM && *total_n_read == 0)
++ if (*total_n_read == 0 && is_CLONENOTSUP (errno))
+ break;
+
+ /* ENOENT was seen sometimes across CIFS shares, resulting in
+ no data being copied, but subsequent standard copies succeed. */
+- if (errno == ENOENT && *total_n_read == 0)
++ if (*total_n_read == 0 && errno == ENOENT)
+ break;
+
+ if (errno == EINTR)
+@@ -1172,17 +1182,15 @@ handle_clone_fail (int dst_dirfd, char c
+ char const* src_name, char const* dst_name,
+ int dest_desc, bool new_dst, enum Reflink_type reflink_mode)
+ {
+- /* If the clone operation is creating the destination,
+- then don't try and cater for all non transient file system errors,
+- and instead only cater for specific transient errors. */
+- bool transient_failure;
+- if (dest_desc < 0) /* currently for fclonefileat(). */
+- transient_failure = errno == EIO || errno == ENOMEM
+- || errno == ENOSPC || errno == EDQUOT;
+- else /* currently for FICLONE. */
+- transient_failure = ! is_CLONENOTSUP (errno);
++ /* When the clone operation fails, report failure only with errno values
++ known to mean trouble when the clone is supported and called properly.
++ Do not report failure merely because !is_CLONENOTSUP (errno),
++ as systems may yield oddball errno values here with FICLONE.
++ Also is_CLONENOTSUP() is not appropriate for the range of errnos
++ possible from fclonefileat(), so it's more consistent to avoid. */
++ bool report_failure = is_terminal_error (errno);
+
+- if (reflink_mode == REFLINK_ALWAYS || transient_failure)
++ if (reflink_mode == REFLINK_ALWAYS || report_failure)
+ error (0, errno, _("failed to clone %s from %s"),
+ quoteaf_n (0, dst_name), quoteaf_n (1, src_name));
+
+@@ -1190,14 +1198,14 @@ handle_clone_fail (int dst_dirfd, char c
+ but cloned no data. */
+ if (new_dst /* currently not for fclonefileat(). */
+ && reflink_mode == REFLINK_ALWAYS
+- && ((! transient_failure) || lseek (dest_desc, 0, SEEK_END) == 0)
++ && ((! report_failure) || lseek (dest_desc, 0, SEEK_END) == 0)
+ && unlinkat (dst_dirfd, dst_relname, 0) != 0 && errno != ENOENT)
+ error (0, errno, _("cannot remove %s"), quoteaf (dst_name));
+
+- if (! transient_failure)
++ if (! report_failure)
+ copy_debug.reflink = COPY_DEBUG_UNSUPPORTED;
+
+- if (reflink_mode == REFLINK_ALWAYS || transient_failure)
++ if (reflink_mode == REFLINK_ALWAYS || report_failure)
+ return false;
+
+ return true;
projects / openwrt / staging / stintel.git / blobdiff