git/fsmonitor.h
Jeff Hostetler f954c7b8ff fsmonitor: never set CE_FSMONITOR_VALID on submodules
Never set CE_FSMONITOR_VALID on the cache-entry of submodule
directories.

During a client command like 'git status', we may need to recurse
into each submodule to compute a status summary for the submodule.
Since the purpose of the ce_flag is to let Git avoid scanning a
cache-entry, setting the flag causes the recursive call to be
avoided and we report incorrect (no status) for the submodule.

We created an OS watch on the root directory of our working
directory and we receive events for everything in the cone
under it.  When submodules are present inside our working
directory, we receive events for both our repo (the super) and
any subs within it.  Since our index doesn't have any information
for items within the submodules, we can't use those events.

We could try to truncate the paths of those events back to the
submodule boundary and mark the GITLINK as dirty, but that
feels expensive since we would have to prefix compare every FS
event that we receive against a list of submodule roots.  And
it still wouldn't be sufficient to correctly report status on
the submodule, since we don't have any space in the cache-entry
to cache the submodule's status (the 'SCMU' bits in porcelain
V2 speak).  That is, the CE_FSMONITOR_VALID bit just says that
we don't need to scan/inspect it because we already know the
answer -- it doesn't say that the item is clean -- and we
don't have space in the cache-entry to store those answers.
So we should always do the recursive scan.

Therefore, we should never set the flag on GITLINK cache-entries.

Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2022-05-26 15:59:27 -07:00

114 lines
3.7 KiB
C

#ifndef FSMONITOR_H
#define FSMONITOR_H
#include "cache.h"
#include "dir.h"
#include "fsmonitor-settings.h"
extern struct trace_key trace_fsmonitor;
/*
* Read the fsmonitor index extension and (if configured) restore the
* CE_FSMONITOR_VALID state.
*/
int read_fsmonitor_extension(struct index_state *istate, const void *data, unsigned long sz);
/*
* Fill the fsmonitor_dirty ewah bits with their state from the index,
* before it is split during writing.
*/
void fill_fsmonitor_bitmap(struct index_state *istate);
/*
* Write the CE_FSMONITOR_VALID state into the fsmonitor index
* extension. Reads from the fsmonitor_dirty ewah in the index.
*/
void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate);
/*
* Add/remove the fsmonitor index extension
*/
void add_fsmonitor(struct index_state *istate);
void remove_fsmonitor(struct index_state *istate);
/*
* Add/remove the fsmonitor index extension as necessary based on the current
* core.fsmonitor setting.
*/
void tweak_fsmonitor(struct index_state *istate);
/*
* Run the configured fsmonitor integration script and clear the
* CE_FSMONITOR_VALID bit for any files returned as dirty. Also invalidate
* any corresponding untracked cache directory structures. Optimized to only
* run the first time it is called.
*/
void refresh_fsmonitor(struct index_state *istate);
/*
* Does the received result contain the "trivial" response?
*/
int fsmonitor_is_trivial_response(const struct strbuf *query_result);
/*
* Check if refresh_fsmonitor has been called at least once.
* refresh_fsmonitor is idempotent. Returns true if fsmonitor is
* not enabled (since the state will be "fresh" w/ CE_FSMONITOR_VALID unset)
* This version is useful for assertions
*/
static inline int is_fsmonitor_refreshed(const struct index_state *istate)
{
enum fsmonitor_mode fsm_mode = fsm_settings__get_mode(istate->repo);
return fsm_mode <= FSMONITOR_MODE_DISABLED ||
istate->fsmonitor_has_run_once;
}
/*
* Set the given cache entries CE_FSMONITOR_VALID bit. This should be
* called any time the cache entry has been updated to reflect the
* current state of the file on disk.
*
* However, never mark submodules as valid. When commands like "git
* status" run they might need to recurse into the submodule (using a
* child process) to get a summary of the submodule state. We don't
* have (and don't want to create) the facility to translate every
* FS event that we receive and that happens to be deep inside of a
* submodule back to the submodule root, so we cannot correctly keep
* track of this bit on the gitlink directory. Therefore, we never
* set it on submodules.
*/
static inline void mark_fsmonitor_valid(struct index_state *istate, struct cache_entry *ce)
{
enum fsmonitor_mode fsm_mode = fsm_settings__get_mode(istate->repo);
if (fsm_mode > FSMONITOR_MODE_DISABLED &&
!(ce->ce_flags & CE_FSMONITOR_VALID)) {
if (S_ISGITLINK(ce->ce_mode))
return;
istate->cache_changed = 1;
ce->ce_flags |= CE_FSMONITOR_VALID;
trace_printf_key(&trace_fsmonitor, "mark_fsmonitor_clean '%s'", ce->name);
}
}
/*
* Clear the given cache entry's CE_FSMONITOR_VALID bit and invalidate
* any corresponding untracked cache directory structures. This should
* be called any time git creates or modifies a file that should
* trigger an lstat() or invalidate the untracked cache for the
* corresponding directory
*/
static inline void mark_fsmonitor_invalid(struct index_state *istate, struct cache_entry *ce)
{
enum fsmonitor_mode fsm_mode = fsm_settings__get_mode(istate->repo);
if (fsm_mode > FSMONITOR_MODE_DISABLED) {
ce->ce_flags &= ~CE_FSMONITOR_VALID;
untracked_cache_invalidate_path(istate, ce->name, 1);
trace_printf_key(&trace_fsmonitor, "mark_fsmonitor_invalid '%s'", ce->name);
}
}
#endif