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fsmonitor: support case-insensitive events 

Teach fsmonitor_refresh_callback() to handle case-insensitive
lookups if case-sensitive lookups fail on case-insensitive systems.
This can cause 'git status' to report stale status for files if there
are case issues/errors in the worktree.

The FSMonitor daemon sends FSEvents using the observed spelling
of each pathname.  On case-insensitive file systems this may be
different than the expected case spelling.

The existing code uses index_name_pos() to find the cache-entry for
the pathname in the FSEvent and clear the CE_FSMONITOR_VALID bit so
that the worktree scan/index refresh will revisit and revalidate the
path.

On a case-insensitive file system, the exact match lookup may fail
to find the associated cache-entry. This causes status to think that
the cached CE flags are correct and skip over the file.

Update event handling to optionally use the name-hash and dir-name-hash
if necessary.

Also update t7527 to convert the "test_expect_failure" to "_success"
now that we have fixed the bug.

Signed-off-by: Jeff Hostetler <jeffhostetler@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jeff Hostetler 2024-02-26 21:39:25 +00:00 committed by Junio C Hamano
parent b0dba507fe
commit 29c139ce78
2 changed files with 137 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

121
fsmonitor.c
View File

@ -5,6 +5,7 @@
#include "ewah/ewok.h"
#include "fsmonitor.h"
#include "fsmonitor-ipc.h"
#include "name-hash.h"
#include "run-command.h"
#include "strbuf.h"
#include "trace2.h"
@ -202,6 +203,113 @@ static void invalidate_ce_fsm(struct cache_entry *ce)
static size_t handle_path_with_trailing_slash(
struct index_state *istate, const char *name, int pos);
/*
* Use the name-hash to do a case-insensitive cache-entry lookup with
* the pathname and invalidate the cache-entry.
*
* Returns the number of cache-entries that we invalidated.
*/
static size_t handle_using_name_hash_icase(
struct index_state *istate, const char *name)
{
struct cache_entry *ce = NULL;
ce = index_file_exists(istate, name, strlen(name), 1);
if (!ce)
return 0;
/*
* A case-insensitive search in the name-hash using the
* observed pathname found a cache-entry, so the observed path
* is case-incorrect. Invalidate the cache-entry and use the
* correct spelling from the cache-entry to invalidate the
* untracked-cache. Since we now have sparse-directories in
* the index, the observed pathname may represent a regular
* file or a sparse-index directory.
*
* Note that we should not have seen FSEvents for a
* sparse-index directory, but we handle it just in case.
*
* Either way, we know that there are not any cache-entries for
* children inside the cone of the directory, so we don't need to
* do the usual scan.
*/
trace_printf_key(&trace_fsmonitor,
"fsmonitor_refresh_callback MAP: '%s' '%s'",
name, ce->name);
/*
* NEEDSWORK: We used the name-hash to find the correct
* case-spelling of the pathname in the cache-entry[], so
* technically this is a tracked file or a sparse-directory.
* It should not have any entries in the untracked-cache, so
* we should not need to use the case-corrected spelling to
* invalidate the the untracked-cache. So we may not need to
* do this. For now, I'm going to be conservative and always
* do it; we can revisit this later.
*/
untracked_cache_invalidate_trimmed_path(istate, ce->name, 0);
invalidate_ce_fsm(ce);
return 1;
}
/*
* Use the dir-name-hash to find the correct-case spelling of the
* directory. Use the canonical spelling to invalidate all of the
* cache-entries within the matching cone.
*
* Returns the number of cache-entries that we invalidated.
*/
static size_t handle_using_dir_name_hash_icase(
struct index_state *istate, const char *name)
{
struct strbuf canonical_path = STRBUF_INIT;
int pos;
size_t len = strlen(name);
size_t nr_in_cone;
if (name[len - 1] == '/')
len--;
if (!index_dir_find(istate, name, len, &canonical_path))
return 0; /* name is untracked */
if (!memcmp(name, canonical_path.buf, canonical_path.len)) {
strbuf_release(&canonical_path);
/*
* NEEDSWORK: Our caller already tried an exact match
* and failed to find one. They called us to do an
* ICASE match, so we should never get an exact match,
* so we could promote this to a BUG() here if we
* wanted to. It doesn't hurt anything to just return
* 0 and go on because we should never get here. Or we
* could just get rid of the memcmp() and this "if"
* clause completely.
*/
BUG("handle_using_dir_name_hash_icase(%s) did not exact match",
name);
}
trace_printf_key(&trace_fsmonitor,
"fsmonitor_refresh_callback MAP: '%s' '%s'",
name, canonical_path.buf);
/*
* The dir-name-hash only tells us the corrected spelling of
* the prefix. We have to use this canonical path to do a
* lookup in the cache-entry array so that we repeat the
* original search using the case-corrected spelling.
*/
strbuf_addch(&canonical_path, '/');
pos = index_name_pos(istate, canonical_path.buf,
canonical_path.len);
nr_in_cone = handle_path_with_trailing_slash(
istate, canonical_path.buf, pos);
strbuf_release(&canonical_path);
return nr_in_cone;
}
/*
* The daemon sent an observed pathname without a trailing slash.
* (This is the normal case.) We do not know if it is a tracked or
@ -335,6 +443,19 @@ static void fsmonitor_refresh_callback(struct index_state *istate, char *name)
else
nr_in_cone = handle_path_without_trailing_slash(istate, name, pos);
/*
* If we did not find an exact match for this pathname or any
* cache-entries with this directory prefix and we're on a
* case-insensitive file system, try again using the name-hash
* and dir-name-hash.
*/
if (!nr_in_cone && ignore_case) {
nr_in_cone = handle_using_name_hash_icase(istate, name);
if (!nr_in_cone)
nr_in_cone = handle_using_dir_name_hash_icase(
istate, name);
}
if (nr_in_cone)
trace_printf_key(&trace_fsmonitor,
"fsmonitor_refresh_callback CNT: %d",

26
t/t7527-builtin-fsmonitor.sh
View File

@ -1051,7 +1051,7 @@ test_expect_success 'split-index and FSMonitor work well together' '
#
# The setup is a little contrived.
#
test_expect_failure CASE_INSENSITIVE_FS 'fsmonitor subdir case wrong on disk' '
test_expect_success CASE_INSENSITIVE_FS 'fsmonitor subdir case wrong on disk' '
test_when_finished "stop_daemon_delete_repo subdir_case_wrong" &&
git init subdir_case_wrong &&
@ -1116,19 +1116,19 @@ test_expect_failure CASE_INSENSITIVE_FS 'fsmonitor subdir case wrong on disk' '
grep -q "dir1/DIR2/dir3/file3.*pos -3" "$PWD/subdir_case_wrong.log1" &&
# Verify that we get a mapping event to correct the case.
grep -q "MAP:.*dir1/DIR2/dir3/file3.*dir1/dir2/dir3/file3" \
"$PWD/subdir_case_wrong.log1" &&
# The refresh-callbacks should have caused "git status" to clear
# the CE_FSMONITOR_VALID bit on each of those files and caused
# the worktree scan to visit them and mark them as modified.
grep -q " M AAA" "$PWD/subdir_case_wrong.out" &&
grep -q " M zzz" "$PWD/subdir_case_wrong.out" &&
# Expect Breakage: with the case confusion, the "(pos -3)" causes
# the client to not clear the CE_FSMONITOR_VALID bit and therefore
# status will not rescan the file and therefore not report it as dirty.
grep -q " M dir1/dir2/dir3/file3" "$PWD/subdir_case_wrong.out"
'
test_expect_failure CASE_INSENSITIVE_FS 'fsmonitor file case wrong on disk' '
test_expect_success CASE_INSENSITIVE_FS 'fsmonitor file case wrong on disk' '
test_when_finished "stop_daemon_delete_repo file_case_wrong" &&
git init file_case_wrong &&
@ -1242,14 +1242,20 @@ test_expect_failure CASE_INSENSITIVE_FS 'fsmonitor file case wrong on disk' '
GIT_TRACE_FSMONITOR="$PWD/file_case_wrong-try3.log" \
git -C file_case_wrong --no-optional-locks status --short \
>"$PWD/file_case_wrong-try3.out" &&
# Verify that we get a mapping event to correct the case.
grep -q "fsmonitor_refresh_callback MAP:.*dir1/dir2/dir3/FILE-3-A.*dir1/dir2/dir3/file-3-a" \
"$PWD/file_case_wrong-try3.log" &&
grep -q "fsmonitor_refresh_callback MAP:.*dir1/dir2/dir4/file-4-a.*dir1/dir2/dir4/FILE-4-A" \
"$PWD/file_case_wrong-try3.log" &&
# FSEvents are in observed case.
grep -q "fsmonitor_refresh_callback.*FILE-3-A.*pos -3" "$PWD/file_case_wrong-try3.log" &&
grep -q "fsmonitor_refresh_callback.*file-4-a.*pos -9" "$PWD/file_case_wrong-try3.log" &&
# Expect Breakage: with the case confusion, the "(pos-3)" and
# "(pos -9)" causes the client to not clear the CE_FSMONITOR_VALID
# bit and therefore status will not rescan the files and therefore
# not report them as dirty.
# The refresh-callbacks should have caused "git status" to clear
# the CE_FSMONITOR_VALID bit on each of those files and caused
# the worktree scan to visit them and mark them as modified.
grep -q " M dir1/dir2/dir3/file-3-a" "$PWD/file_case_wrong-try3.out" &&
grep -q " M dir1/dir2/dir4/FILE-4-A" "$PWD/file_case_wrong-try3.out"
'