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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 16:35:40 +00:00
#ifndef FSMONITOR_H
#define FSMONITOR_H
Add missing includes and forward declarations I looped over the toplevel header files, creating a temporary two-line C program for each consisting of #include "git-compat-util.h" #include $HEADER This patch is the result of manually fixing errors in compiling those tiny programs. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-15 17:54:05 +00:00
#include "cache.h"
#include "dir.h"
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 16:35:40 +00:00
extern struct trace_key trace_fsmonitor;
/*
* Read the fsmonitor index extension and (if configured) restore the
* CE_FSMONITOR_VALID state.
*/
*.[ch]: remove extern from function declarations using spatch There has been a push to remove extern from function declarations. Remove some instances of "extern" for function declarations which are caught by Coccinelle. Note that Coccinelle has some difficulty with processing functions with `__attribute__` or varargs so some `extern` declarations are left behind to be dealt with in a future patch. This was the Coccinelle patch used: @@ type T; identifier f; @@ - extern T f(...); and it was run with: $ git ls-files \*.{c,h} | grep -v ^compat/ | xargs spatch --sp-file contrib/coccinelle/noextern.cocci --in-place Files under `compat/` are intentionally excluded as some are directly copied from external sources and we should avoid churning them as much as possible. Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-29 08:28:14 +00:00
int read_fsmonitor_extension(struct index_state *istate, const void *data, unsigned long sz);
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 16:35:40 +00:00
/*
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 19:58:10 +00:00
* Fill the fsmonitor_dirty ewah bits with their state from the index,
* before it is split during writing.
*/
*.[ch]: remove extern from function declarations using spatch There has been a push to remove extern from function declarations. Remove some instances of "extern" for function declarations which are caught by Coccinelle. Note that Coccinelle has some difficulty with processing functions with `__attribute__` or varargs so some `extern` declarations are left behind to be dealt with in a future patch. This was the Coccinelle patch used: @@ type T; identifier f; @@ - extern T f(...); and it was run with: $ git ls-files \*.{c,h} | grep -v ^compat/ | xargs spatch --sp-file contrib/coccinelle/noextern.cocci --in-place Files under `compat/` are intentionally excluded as some are directly copied from external sources and we should avoid churning them as much as possible. Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-29 08:28:14 +00:00
void fill_fsmonitor_bitmap(struct index_state *istate);
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 19:58:10 +00:00
/*
* 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 16:35:40 +00:00
*/
*.[ch]: remove extern from function declarations using spatch There has been a push to remove extern from function declarations. Remove some instances of "extern" for function declarations which are caught by Coccinelle. Note that Coccinelle has some difficulty with processing functions with `__attribute__` or varargs so some `extern` declarations are left behind to be dealt with in a future patch. This was the Coccinelle patch used: @@ type T; identifier f; @@ - extern T f(...); and it was run with: $ git ls-files \*.{c,h} | grep -v ^compat/ | xargs spatch --sp-file contrib/coccinelle/noextern.cocci --in-place Files under `compat/` are intentionally excluded as some are directly copied from external sources and we should avoid churning them as much as possible. Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-29 08:28:14 +00:00
void write_fsmonitor_extension(struct strbuf *sb, struct index_state *istate);
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 16:35:40 +00:00
/*
* Add/remove the fsmonitor index extension
*/
*.[ch]: remove extern from function declarations using spatch There has been a push to remove extern from function declarations. Remove some instances of "extern" for function declarations which are caught by Coccinelle. Note that Coccinelle has some difficulty with processing functions with `__attribute__` or varargs so some `extern` declarations are left behind to be dealt with in a future patch. This was the Coccinelle patch used: @@ type T; identifier f; @@ - extern T f(...); and it was run with: $ git ls-files \*.{c,h} | grep -v ^compat/ | xargs spatch --sp-file contrib/coccinelle/noextern.cocci --in-place Files under `compat/` are intentionally excluded as some are directly copied from external sources and we should avoid churning them as much as possible. Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-29 08:28:14 +00:00
void add_fsmonitor(struct index_state *istate);
void remove_fsmonitor(struct index_state *istate);
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 16:35:40 +00:00
/*
* Add/remove the fsmonitor index extension as necessary based on the current
* core.fsmonitor setting.
*/
*.[ch]: remove extern from function declarations using spatch There has been a push to remove extern from function declarations. Remove some instances of "extern" for function declarations which are caught by Coccinelle. Note that Coccinelle has some difficulty with processing functions with `__attribute__` or varargs so some `extern` declarations are left behind to be dealt with in a future patch. This was the Coccinelle patch used: @@ type T; identifier f; @@ - extern T f(...); and it was run with: $ git ls-files \*.{c,h} | grep -v ^compat/ | xargs spatch --sp-file contrib/coccinelle/noextern.cocci --in-place Files under `compat/` are intentionally excluded as some are directly copied from external sources and we should avoid churning them as much as possible. Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-29 08:28:14 +00:00
void tweak_fsmonitor(struct index_state *istate);
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 16:35:40 +00:00
/*
* 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.
*/
*.[ch]: remove extern from function declarations using spatch There has been a push to remove extern from function declarations. Remove some instances of "extern" for function declarations which are caught by Coccinelle. Note that Coccinelle has some difficulty with processing functions with `__attribute__` or varargs so some `extern` declarations are left behind to be dealt with in a future patch. This was the Coccinelle patch used: @@ type T; identifier f; @@ - extern T f(...); and it was run with: $ git ls-files \*.{c,h} | grep -v ^compat/ | xargs spatch --sp-file contrib/coccinelle/noextern.cocci --in-place Files under `compat/` are intentionally excluded as some are directly copied from external sources and we should avoid churning them as much as possible. Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-29 08:28:14 +00:00
void refresh_fsmonitor(struct index_state *istate);
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 16:35:40 +00:00
fsmonitor: log invocation of FSMonitor hook to trace2 Let's measure the time taken to request and receive FSMonitor data via the hook API and the size of the response. Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Reviewed-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-03 15:34:47 +00:00
/*
* Does the received result contain the "trivial" response?
*/
int fsmonitor_is_trivial_response(const struct strbuf *query_result);
fsmonitor: add assertion that fsmonitor is valid to check_removed Validate that fsmonitor is valid to futureproof against bugs where check_removed might be called from places that haven't refreshed. Signed-off-by: Nipunn Koorapati <nipunn@dropbox.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-17 21:22:22 +00:00
/*
* 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)
{
return !core_fsmonitor || istate->fsmonitor_has_run_once;
}
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 16:35:40 +00:00
/*
* 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.
*/
mark_fsmonitor_valid(): mark the index as changed if needed Without this bug fix, t7519's four "status doesn't detect unreported modifications" test cases would fail occasionally (and, oddly enough, *a lot* more frequently on Windows). The reason is that these test cases intentionally use the side effect of `git status` to re-write the index if any updates were detected: they first clean the worktree, run `git status` to update the index as well as show the output to the casual reader, then make the worktree dirty again and expect no changes to reported if running with a mocked fsmonitor hook. The problem with this strategy was that the index was written during said `git status` on the clean worktree for the *wrong* reason: not because the index was marked as changed (it wasn't), but because the recorded mtimes were racy with the index' own mtime. As the mtime granularity on Windows is 100 nanoseconds (see e.g. https://docs.microsoft.com/en-us/windows/desktop/SysInfo/file-times), the mtimes of the files are often enough *not* racy with the index', so that that `git status` call currently does not always update the index (including the fsmonitor extension), causing the test case to fail. The obvious fix: if we change *any* index entry's `CE_FSMONITOR_VALID` flag, we should also mark the index as changed. That will cause the index to be written upon `git status`, *including* an updated fsmonitor extension. Side note: Even though the reader might think that the t7519 issue should be *much* more prevalent on Linux, given that the ext4 filesystem (that seems to be used by every Linux distribution) stores mtimes in nanosecond precision. However, ext4 uses `current_kernel_time()` (see https://unix.stackexchange.com/questions/11599#comment762968_11599; it is *amazingly* hard to find any proper source of information about such ext4 questions) whose accuracy seems to depend on many factors but is safely worse than the 100-nanosecond granularity of NTFS (again, it is *horribly* hard to find anything remotely authoritative about this question). So it seems that the racy index condition that hid the bug fixed by this patch simply is a lot more likely on Linux than on Windows. But not impossible ;-) Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-05-24 12:23:48 +00:00
static inline void mark_fsmonitor_valid(struct index_state *istate, struct cache_entry *ce)
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 16:35:40 +00:00
{
mark_fsmonitor_valid(): mark the index as changed if needed Without this bug fix, t7519's four "status doesn't detect unreported modifications" test cases would fail occasionally (and, oddly enough, *a lot* more frequently on Windows). The reason is that these test cases intentionally use the side effect of `git status` to re-write the index if any updates were detected: they first clean the worktree, run `git status` to update the index as well as show the output to the casual reader, then make the worktree dirty again and expect no changes to reported if running with a mocked fsmonitor hook. The problem with this strategy was that the index was written during said `git status` on the clean worktree for the *wrong* reason: not because the index was marked as changed (it wasn't), but because the recorded mtimes were racy with the index' own mtime. As the mtime granularity on Windows is 100 nanoseconds (see e.g. https://docs.microsoft.com/en-us/windows/desktop/SysInfo/file-times), the mtimes of the files are often enough *not* racy with the index', so that that `git status` call currently does not always update the index (including the fsmonitor extension), causing the test case to fail. The obvious fix: if we change *any* index entry's `CE_FSMONITOR_VALID` flag, we should also mark the index as changed. That will cause the index to be written upon `git status`, *including* an updated fsmonitor extension. Side note: Even though the reader might think that the t7519 issue should be *much* more prevalent on Linux, given that the ext4 filesystem (that seems to be used by every Linux distribution) stores mtimes in nanosecond precision. However, ext4 uses `current_kernel_time()` (see https://unix.stackexchange.com/questions/11599#comment762968_11599; it is *amazingly* hard to find any proper source of information about such ext4 questions) whose accuracy seems to depend on many factors but is safely worse than the 100-nanosecond granularity of NTFS (again, it is *horribly* hard to find anything remotely authoritative about this question). So it seems that the racy index condition that hid the bug fixed by this patch simply is a lot more likely on Linux than on Windows. But not impossible ;-) Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-05-24 12:23:48 +00:00
if (core_fsmonitor && !(ce->ce_flags & CE_FSMONITOR_VALID)) {
istate->cache_changed = 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 16:35:40 +00:00
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 09:21:40 +00:00
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 16:35:40 +00:00
trace_printf_key(&trace_fsmonitor, "mark_fsmonitor_invalid '%s'", ce->name);
}
}
#endif
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