137 lines
5.7 KiB
Diff
137 lines
5.7 KiB
Diff
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From 093a8b4bfaba60005f14493ce7ef11ed665a0176 Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?P=C3=A1draig=20Brady?= <P@draigBrady.com>
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Date: Thu, 23 Mar 2023 13:19:04 +0000
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Subject: copy: fix --reflink=auto to fallback in more cases
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On restricted systems like android or some containers,
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FICLONE could return EPERM, EACCES, or ENOTTY,
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which would have induced the command to fail to copy
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rather than falling back to a more standard copy.
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* src/copy.c (is_terminal_failure): A new function refactored
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from handle_clone_fail().
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(is_CLONENOTSUP): Merge in the handling of EACCES, ENOTTY, EPERM
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as they also pertain to determination of whether cloning is supported
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if we ever use this function in that context.
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(handle_clone_fail): Use is_terminal_failure() in all cases,
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so that we assume a terminal failure in less errno cases.
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* NEWS: Mention the bug fix.
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Addresses https://bugs.gnu.org/62404
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---
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NEWS | 8 ++++++++
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src/copy.c | 62 +++++++++++++++++++++++++++++++++++---------------------------
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2 files changed, 43 insertions(+), 27 deletions(-)
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diff --git a/src/copy.c b/src/copy.c
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index 3919787..f8ba058 100644
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--- a/src/copy.c
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+++ b/src/copy.c
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@@ -278,15 +278,27 @@ create_hole (int fd, char const *name, bool punch_holes, off_t size)
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}
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-/* Whether the errno from FICLONE, or copy_file_range
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- indicates operation is not supported for this file or file system. */
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+/* Whether the errno indicates the operation is a transient failure.
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+ I.e., a failure that would indicate the operation _is_ supported,
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+ but has failed in a terminal way. */
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+
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+static bool
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+is_terminal_error (int err)
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+{
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+ return err == EIO || err == ENOMEM || err == ENOSPC || err == EDQUOT;
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+}
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+
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+
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+/* Whether the errno from FICLONE, or copy_file_range indicates
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+ the operation is not supported/allowed for this file or process. */
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static bool
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is_CLONENOTSUP (int err)
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{
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- return err == ENOSYS || is_ENOTSUP (err)
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+ return err == ENOSYS || err == ENOTTY || is_ENOTSUP (err)
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|| err == EINVAL || err == EBADF
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- || err == EXDEV || err == ETXTBSY;
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+ || err == EXDEV || err == ETXTBSY
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+ || err == EPERM || err == EACCES;
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}
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@@ -339,20 +351,18 @@ sparse_copy (int src_fd, int dest_fd, char **abuf, size_t buf_size,
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{
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copy_debug.offload = COPY_DEBUG_UNSUPPORTED;
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- if (is_CLONENOTSUP (errno))
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- break;
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-
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- /* copy_file_range might not be enabled in seccomp filters,
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- so retry with a standard copy. EPERM can also occur
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- for immutable files, but that would only be in the edge case
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- where the file is made immutable after creating/truncating,
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+ /* Consider operation unsupported only if no data copied.
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+ For example, EPERM could occur if copy_file_range not enabled
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+ in seccomp filters, so retry with a standard copy. EPERM can
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+ also occur for immutable files, but that would only be in the
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+ edge case where the file is made immutable after creating,
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in which case the (more accurate) error is still shown. */
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- if (errno == EPERM && *total_n_read == 0)
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+ if (*total_n_read == 0 && is_CLONENOTSUP (errno))
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break;
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/* ENOENT was seen sometimes across CIFS shares, resulting in
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no data being copied, but subsequent standard copies succeed. */
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- if (errno == ENOENT && *total_n_read == 0)
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+ if (*total_n_read == 0 && errno == ENOENT)
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break;
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if (errno == EINTR)
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@@ -1172,17 +1182,15 @@ handle_clone_fail (int dst_dirfd, char const* dst_relname,
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char const* src_name, char const* dst_name,
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int dest_desc, bool new_dst, enum Reflink_type reflink_mode)
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{
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- /* If the clone operation is creating the destination,
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- then don't try and cater for all non transient file system errors,
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- and instead only cater for specific transient errors. */
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- bool transient_failure;
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- if (dest_desc < 0) /* currently for fclonefileat(). */
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- transient_failure = errno == EIO || errno == ENOMEM
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- || errno == ENOSPC || errno == EDQUOT;
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- else /* currently for FICLONE. */
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- transient_failure = ! is_CLONENOTSUP (errno);
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-
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- if (reflink_mode == REFLINK_ALWAYS || transient_failure)
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+ /* When the clone operation fails, report failure only with errno values
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+ known to mean trouble when the clone is supported and called properly.
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+ Do not report failure merely because !is_CLONENOTSUP (errno),
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+ as systems may yield oddball errno values here with FICLONE.
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+ Also is_CLONENOTSUP() is not appropriate for the range of errnos
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+ possible from fclonefileat(), so it's more consistent to avoid. */
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+ bool report_failure = is_terminal_error (errno);
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+
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+ if (reflink_mode == REFLINK_ALWAYS || report_failure)
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error (0, errno, _("failed to clone %s from %s"),
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quoteaf_n (0, dst_name), quoteaf_n (1, src_name));
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@@ -1190,14 +1198,14 @@ handle_clone_fail (int dst_dirfd, char const* dst_relname,
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but cloned no data. */
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if (new_dst /* currently not for fclonefileat(). */
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&& reflink_mode == REFLINK_ALWAYS
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- && ((! transient_failure) || lseek (dest_desc, 0, SEEK_END) == 0)
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+ && ((! report_failure) || lseek (dest_desc, 0, SEEK_END) == 0)
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&& unlinkat (dst_dirfd, dst_relname, 0) != 0 && errno != ENOENT)
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error (0, errno, _("cannot remove %s"), quoteaf (dst_name));
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- if (! transient_failure)
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+ if (! report_failure)
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copy_debug.reflink = COPY_DEBUG_UNSUPPORTED;
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- if (reflink_mode == REFLINK_ALWAYS || transient_failure)
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+ if (reflink_mode == REFLINK_ALWAYS || report_failure)
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return false;
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return true;
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--
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cgit v1.1
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