fsmonitor-settings: remote repos on macOS are incompatible
Teach Git to detect remote working directories on macOS and mark them as incompatible with FSMonitor. With this, `git fsmonitor--daemon run` will error out with a message like it does for bare repos. Client commands, like `git status`, will not attempt to start the daemon. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Jeff Hostetler committed
May 26, 2022 at 21:47 UTC
1e7be10de0d493f471bf102a7eed32da8247c825
3 files changed
+80
compat/fsmonitor/fsm-settings-darwin.c
+66
@@ -2,8 +2,74 @@
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#include "config.h"
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#include "repository.h"
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#include "fsmonitor-settings.h"
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+#include "fsmonitor.h"
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+#include <sys/param.h>
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+#include <sys/mount.h>
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+
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+/*
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+ * Remote working directories are problematic for FSMonitor.
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+ *
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+ * The underlying file system on the server machine and/or the remote
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+ * mount type (NFS, SAMBA, etc.) dictates whether notification events
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+ * are available at all to remote client machines.
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+ *
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+ * Kernel differences between the server and client machines also
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+ * dictate the how (buffering, frequency, de-dup) the events are
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+ * delivered to client machine processes.
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+ *
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+ * A client machine (such as a laptop) may choose to suspend/resume
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+ * and it is unclear (without lots of testing) whether the watcher can
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+ * resync after a resume. We might be able to treat this as a normal
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+ * "events were dropped by the kernel" event and do our normal "flush
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+ * and resync" --or-- we might need to close the existing (zombie?)
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+ * notification fd and create a new one.
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+ *
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+ * In theory, the above issues need to be addressed whether we are
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+ * using the Hook or IPC API.
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+ *
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+ * For the builtin FSMonitor, we create the Unix domain socket for the
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+ * IPC in the .git directory. If the working directory is remote,
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+ * then the socket will be created on the remote file system. This
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+ * can fail if the remote file system does not support UDS file types
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+ * (e.g. smbfs to a Windows server) or if the remote kernel does not
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+ * allow a non-local process to bind() the socket. (These problems
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+ * could be fixed by moving the UDS out of the .git directory and to a
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+ * well-known local directory on the client machine, but care should
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+ * be taken to ensure that $HOME is actually local and not a managed
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+ * file share.)
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+ *
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+ * So (for now at least), mark remote working directories as
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+ * incompatible.
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+ */
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+static enum fsmonitor_reason check_remote(struct repository *r)
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+{
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+ struct statfs fs;
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+
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+ if (statfs(r->worktree, &fs) == -1) {
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+ int saved_errno = errno;
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+ trace_printf_key(&trace_fsmonitor, "statfs('%s') failed: %s",
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+ r->worktree, strerror(saved_errno));
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+ errno = saved_errno;
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+ return FSMONITOR_REASON_ERROR;
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+ }
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+
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+ trace_printf_key(&trace_fsmonitor,
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+ "statfs('%s') [type 0x%08x][flags 0x%08x] '%s'",
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+ r->worktree, fs.f_type, fs.f_flags, fs.f_fstypename);
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+
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+ if (!(fs.f_flags & MNT_LOCAL))
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+ return FSMONITOR_REASON_REMOTE;
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+
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+ return FSMONITOR_REASON_OK;
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+}
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enum fsmonitor_reason fsm_os__incompatible(struct repository *r)
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{
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+ enum fsmonitor_reason reason;
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+
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+ reason = check_remote(r);
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+ if (reason != FSMONITOR_REASON_OK)
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+ return reason;
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+
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return FSMONITOR_REASON_OK;
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}
fsmonitor-settings.c
+12
@@ -208,6 +208,18 @@ char *fsm_settings__get_incompatible_msg(const struct repository *r,
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xgetcwd());
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goto done;
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+ case FSMONITOR_REASON_ERROR:
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+ strbuf_addf(&msg,
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+ _("repository '%s' is incompatible with fsmonitor due to errors"),
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+ r->worktree);
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+ goto done;
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+
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+ case FSMONITOR_REASON_REMOTE:
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+ strbuf_addf(&msg,
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+ _("remote repository '%s' is incompatible with fsmonitor"),
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+ r->worktree);
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+ goto done;
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+
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case FSMONITOR_REASON_VFS4GIT:
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strbuf_addf(&msg,
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_("virtual repository '%s' is incompatible with fsmonitor"),
fsmonitor-settings.h
+2
@@ -17,6 +17,8 @@ enum fsmonitor_reason {
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FSMONITOR_REASON_UNTESTED = 0,
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FSMONITOR_REASON_OK, /* no incompatibility or when disabled */
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FSMONITOR_REASON_BARE,
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+ FSMONITOR_REASON_ERROR, /* FS error probing for compatibility */
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+ FSMONITOR_REASON_REMOTE,
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FSMONITOR_REASON_VFS4GIT, /* VFS for Git virtualization */
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};
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