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git/fsmonitor.h

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fsmonitor: teach git to optionally utilize a file system monitor to speed up detecting new or changed files. When the index is read from disk, the fsmonitor index extension is used to flag the last known potentially dirty index entries. The registered core.fsmonitor command is called with the time the index was last updated and returns the list of files changed since that time. This list is used to flag any additional dirty cache entries and untracked cache directories. We can then use this valid state to speed up preload_index(), ie_match_stat(), and refresh_cache_ent() as they do not need to lstat() files to detect potential changes for those entries marked CE_FSMONITOR_VALID. In addition, if the untracked cache is turned on valid_cached_dir() can skip checking directories for new or changed files as fsmonitor will invalidate the cache only for those directories that have been identified as having potential changes. To keep the CE_FSMONITOR_VALID state accurate during git operations; when git updates a cache entry to match the current state on disk, it will now set the CE_FSMONITOR_VALID bit. Inversely, anytime git changes a cache entry, the CE_FSMONITOR_VALID bit is cleared and the corresponding untracked cache directory is marked invalid. Signed-off-by: Ben Peart <benpeart@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-22 18:35:40 +02:00
#ifndef FSMONITOR_H
#define FSMONITOR_H
extern struct trace_key trace_fsmonitor;
/*
* Read the fsmonitor index extension and (if configured) restore the
* CE_FSMONITOR_VALID state.
*/
extern int read_fsmonitor_extension(struct index_state *istate, const void *data, unsigned long sz);
/*
fsmonitor: store fsmonitor bitmap before splitting index ba1b9cac ("fsmonitor: delay updating state until after split index is merged", 2017-10-27) resolved the problem of the fsmonitor data being applied to the non-base index when reading; however, a similar problem exists when writing the index. Specifically, writing of the fsmonitor extension happens only after the work to split the index has been applied -- as such, the information in the index is only for the non-"base" index, and thus the extension information contains only partial data. When saving, compute the ewah bitmap before the index is split, and store it in the fsmonitor_dirty field, mirroring the behavior that occurred during reading. fsmonitor_dirty is kept from being leaked by being freed when the extension data is written -- which always happens precisely once, no matter the split index configuration. Signed-off-by: Alex Vandiver <alexmv@dropbox.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-11-09 20:58:10 +01:00
* Fill the fsmonitor_dirty ewah bits with their state from the index,
* before it is split during writing.
*/
extern 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.
fsmonitor: teach git to optionally utilize a file system monitor to speed up detecting new or changed files. When the index is read from disk, the fsmonitor index extension is used to flag the last known potentially dirty index entries. The registered core.fsmonitor command is called with the time the index was last updated and returns the list of files changed since that time. This list is used to flag any additional dirty cache entries and untracked cache directories. We can then use this valid state to speed up preload_index(), ie_match_stat(), and refresh_cache_ent() as they do not need to lstat() files to detect potential changes for those entries marked CE_FSMONITOR_VALID. In addition, if the untracked cache is turned on valid_cached_dir() can skip checking directories for new or changed files as fsmonitor will invalidate the cache only for those directories that have been identified as having potential changes. To keep the CE_FSMONITOR_VALID state accurate during git operations; when git updates a cache entry to match the current state on disk, it will now set the CE_FSMONITOR_VALID bit. Inversely, anytime git changes a cache entry, the CE_FSMONITOR_VALID bit is cleared and the corresponding untracked cache directory is marked invalid. Signed-off-by: Ben Peart <benpeart@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-22 18:35:40 +02:00
*/
extern void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate);
/*
* Add/remove the fsmonitor index extension
*/
extern void add_fsmonitor(struct index_state *istate);
extern void remove_fsmonitor(struct index_state *istate);
/*
* Add/remove the fsmonitor index extension as necessary based on the current
* core.fsmonitor setting.
*/
extern 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.
*/
extern void refresh_fsmonitor(struct index_state *istate);
/*
* 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.
*/
static inline void mark_fsmonitor_valid(struct cache_entry *ce)
{
if (core_fsmonitor) {
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)
{
if (core_fsmonitor) {
ce->ce_flags &= ~CE_FSMONITOR_VALID;
dir.c: ignore paths containing .git when invalidating untracked cache read_directory() code ignores all paths named ".git" even if it's not a valid git repository. See treat_path() for details. Since ".git" is basically invisible to read_directory(), when we are asked to invalidate a path that contains ".git", we can safely ignore it because the slow path would not consider it anyway. This helps when fsmonitor is used and we have a real ".git" repo at worktree top. Occasionally .git/index will be updated and if the fsmonitor hook does not filter it, untracked cache is asked to invalidate the path ".git/index". Without this patch, we invalidate the root directory unncessarily, which: - makes read_directory() fall back to slow path for root directory (slower) - makes the index dirty (because UNTR extension is updated). Depending on the index size, writing it down could also be slow. A note about the new "safe_path" knob. Since this new check could be relatively expensive, avoid it when we know it's not needed. If the path comes from the index, it can't contain ".git". If it does contain, we may be screwed up at many more levels, not just this one. Noticed-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-02-07 10:21:40 +01:00
untracked_cache_invalidate_path(istate, ce->name, 1);
fsmonitor: teach git to optionally utilize a file system monitor to speed up detecting new or changed files. When the index is read from disk, the fsmonitor index extension is used to flag the last known potentially dirty index entries. The registered core.fsmonitor command is called with the time the index was last updated and returns the list of files changed since that time. This list is used to flag any additional dirty cache entries and untracked cache directories. We can then use this valid state to speed up preload_index(), ie_match_stat(), and refresh_cache_ent() as they do not need to lstat() files to detect potential changes for those entries marked CE_FSMONITOR_VALID. In addition, if the untracked cache is turned on valid_cached_dir() can skip checking directories for new or changed files as fsmonitor will invalidate the cache only for those directories that have been identified as having potential changes. To keep the CE_FSMONITOR_VALID state accurate during git operations; when git updates a cache entry to match the current state on disk, it will now set the CE_FSMONITOR_VALID bit. Inversely, anytime git changes a cache entry, the CE_FSMONITOR_VALID bit is cleared and the corresponding untracked cache directory is marked invalid. Signed-off-by: Ben Peart <benpeart@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-22 18:35:40 +02:00
trace_printf_key(&trace_fsmonitor, "mark_fsmonitor_invalid '%s'", ce->name);
}
}
#endif
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