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sd-journal: properly handle inotify queue overflow 

This adds proper handling of IN_Q_OVERFLOW: when the inotify queue runs
over we'll reiterate all directories we are looking at. At the same time
we'll mark all files and directories we encounter that way with a
generation counter we first increased. All files and directories not
marked like this are then unloaded.

With this logic we do the best when the inotify queue overflows: we
synchronize our in-memory state again with what's on disk.

This contains some refactoring of the directory logic, to share more
code between uuid directories and "root" directories and generally make
things a bit more readable by splitting things up into smaller bits.

See: #7998 #8032
This commit is contained in:
Lennart Poettering 2018-02-08 20:11:43 +01:00
parent a9be069269
commit 858749f731
3 changed files with 200 additions and 77 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/journal/journal-file.h
View File

@ -122,6 +122,8 @@ typedef struct JournalFile {
pthread_t offline_thread;
volatile OfflineState offline_state;
unsigned last_seen_generation;
#if HAVE_XZ || HAVE_LZ4
void *compress_buffer;
size_t compress_buffer_size;

2
src/journal/journal-internal.h
View File

@ -80,6 +80,7 @@ struct Directory {
char *path;
int wd;
bool is_root;
unsigned last_seen_generation;
};
struct sd_journal {
@ -104,6 +105,7 @@ struct sd_journal {
int inotify_fd;
unsigned current_invalidate_counter, last_invalidate_counter;
usec_t last_process_usec;
unsigned generation;
/* Iterating through unique fields and their data values */
char *unique_field;

273
src/journal/sd-journal.c
View File

@ -1262,8 +1262,16 @@ static int add_any_file(sd_journal *j, int fd, const char *path) {
assert(j);
assert(fd >= 0 || path);
if (path && ordered_hashmap_get(j->files, path))
return 0;
if (path) {
f = ordered_hashmap_get(j->files, path);
if (f) {
/* Mark this file as seen in this generation. This is used to GC old files in
* process_q_overflow() to detect journal files that are still and discern them from those who
* are gone. */
f->last_seen_generation = j->generation;
return 0;
}
}
if (ordered_hashmap_size(j->files) >= JOURNAL_FILES_MAX) {
log_debug("Too many open journal files, not adding %s.", path);
@ -1302,6 +1310,8 @@ static int add_any_file(sd_journal *j, int fd, const char *path) {
goto fail;
}
f->last_seen_generation = j->generation;
if (!j->has_runtime_files && path_has_prefix(j, f->path, "/run"))
j->has_runtime_files = true;
else if (!j->has_persistent_files && path_has_prefix(j, f->path, "/var"))
@ -1404,10 +1414,101 @@ static int dirname_is_machine_id(const char *fn) {
return sd_id128_equal(id, machine);
}
static bool dirent_is_journal_file(const struct dirent *de) {
assert(de);
if (!IN_SET(de->d_type, DT_REG, DT_LNK, DT_UNKNOWN))
return false;
return endswith(de->d_name, ".journal") ||
endswith(de->d_name, ".journal~");
}
static bool dirent_is_id128_subdir(const struct dirent *de) {
assert(de);
if (!IN_SET(de->d_type, DT_DIR, DT_LNK, DT_UNKNOWN))
return false;
return id128_is_valid(de->d_name);
}
static int directory_open(sd_journal *j, const char *path, DIR **ret) {
DIR *d;
assert(j);
assert(path);
assert(ret);
if (j->toplevel_fd < 0)
d = opendir(path);
else
/* Open the specified directory relative to the toplevel fd. Enforce that the path specified is
* relative, by dropping the initial slash */
d = xopendirat(j->toplevel_fd, skip_slash(path), 0);
if (!d)
return -errno;
*ret = d;
return 0;
}
static int add_directory(sd_journal *j, const char *prefix, const char *dirname);
static void directory_enumerate(sd_journal *j, Directory *m, DIR *d) {
struct dirent *de;
assert(j);
assert(m);
assert(d);
FOREACH_DIRENT_ALL(de, d, goto fail) {
if (dirent_is_journal_file(de))
(void) add_file(j, m->path, de->d_name);
if (m->is_root && dirent_is_id128_subdir(de))
(void) add_directory(j, m->path, de->d_name);
}
return;
fail:
log_debug_errno(errno, "Failed to enumerate directory %s, ignoring: %m", m->path);
}
static void directory_watch(sd_journal *j, Directory *m, int fd, uint32_t mask) {
int r;
assert(j);
assert(m);
assert(fd >= 0);
/* Watch this directory if that's enabled and if it not being watched yet. */
if (m->wd > 0) /* Already have a watch? */
return;
if (j->inotify_fd < 0) /* Not watching at all? */
return;
m->wd = inotify_add_watch_fd(j->inotify_fd, fd, mask);
if (m->wd < 0) {
log_debug_errno(errno, "Failed to watch journal directory '%s', ignoring: %m", m->path);
return;
}
r = hashmap_put(j->directories_by_wd, INT_TO_PTR(m->wd), m);
if (r == -EEXIST)
log_debug_errno(r, "Directory '%s' already being watched under a different path, ignoring: %m", m->path);
if (r < 0) {
log_debug_errno(r, "Failed to add watch for journal directory '%s' to hashmap, ignoring: %m", m->path);
(void) inotify_rm_watch(j->inotify_fd, m->wd);
m->wd = -1;
}
}
static int add_directory(sd_journal *j, const char *prefix, const char *dirname) {
_cleanup_free_ char *path = NULL;
_cleanup_closedir_ DIR *d = NULL;
struct dirent *de = NULL;
Directory *m;
int r, k;
@ -1426,22 +1527,16 @@ static int add_directory(sd_journal *j, const char *prefix, const char *dirname)
goto fail;
}
log_debug("Considering directory %s.", path);
log_debug("Considering directory '%s'.", path);
/* We consider everything local that is in a directory for the local machine ID, or that is stored in /run */
if ((j->flags & SD_JOURNAL_LOCAL_ONLY) &&
!((dirname && dirname_is_machine_id(dirname) > 0) || path_has_prefix(j, path, "/run")))
return 0;
return 0;
if (j->toplevel_fd < 0)
d = opendir(path);
else
/* Open the specified directory relative to the toplevel fd. Enforce that the path specified is
* relative, by dropping the initial slash */
d = xopendirat(j->toplevel_fd, skip_slash(path), 0);
if (!d) {
r = log_debug_errno(errno, "Failed to open directory %s: %m", path);
r = directory_open(j, path, &d);
if (r < 0) {
log_debug_errno(r, "Failed to open directory '%s': %m", path);
goto fail;
}
@ -1468,26 +1563,17 @@ static int add_directory(sd_journal *j, const char *prefix, const char *dirname)
log_debug("Directory %s added.", m->path);
} else if (m->is_root)
return 0;
return 0; /* Don't 'downgrade' from root directory */
if (m->wd <= 0 && j->inotify_fd >= 0) {
/* Watch this directory, if it not being watched yet. */
m->last_seen_generation = j->generation;
m->wd = inotify_add_watch_fd(j->inotify_fd, dirfd(d),
IN_CREATE|IN_MOVED_TO|IN_MODIFY|IN_ATTRIB|IN_DELETE|
IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_MOVED_FROM|
IN_ONLYDIR);
directory_watch(j, m, dirfd(d),
IN_CREATE|IN_MOVED_TO|IN_MODIFY|IN_ATTRIB|IN_DELETE|
IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_MOVED_FROM|
IN_ONLYDIR);
if (m->wd > 0 && hashmap_put(j->directories_by_wd, INT_TO_PTR(m->wd), m) < 0)
inotify_rm_watch(j->inotify_fd, m->wd);
}
FOREACH_DIRENT_ALL(de, d, r = log_debug_errno(errno, "Failed to read directory %s: %m", m->path); goto fail) {
if (dirent_is_file_with_suffix(de, ".journal") ||
dirent_is_file_with_suffix(de, ".journal~"))
(void) add_file(j, m->path, de->d_name);
}
if (!j->no_new_files)
directory_enumerate(j, m, d);
check_network(j, dirfd(d));
@ -1504,7 +1590,6 @@ fail:
static int add_root_directory(sd_journal *j, const char *p, bool missing_ok) {
_cleanup_closedir_ DIR *d = NULL;
struct dirent *de;
Directory *m;
int r, k;
@ -1517,6 +1602,8 @@ static int add_root_directory(sd_journal *j, const char *p, bool missing_ok) {
if (p) {
/* If there's a path specified, use it. */
log_debug("Considering root directory '%s'.", p);
if ((j->flags & SD_JOURNAL_RUNTIME_ONLY) &&
!path_has_prefix(j, p, "/run"))
return -EINVAL;
@ -1524,16 +1611,11 @@ static int add_root_directory(sd_journal *j, const char *p, bool missing_ok) {
if (j->prefix)
p = strjoina(j->prefix, p);
if (j->toplevel_fd < 0)
d = opendir(p);
else
d = xopendirat(j->toplevel_fd, skip_slash(p), 0);
if (!d) {
if (errno == ENOENT && missing_ok)
return 0;
r = log_debug_errno(errno, "Failed to open root directory %s: %m", p);
r = directory_open(j, p, &d);
if (r == -ENOENT && missing_ok)
return 0;
if (r < 0) {
log_debug_errno(r, "Failed to open root directory %s: %m", p);
goto fail;
}
} else {
@ -1591,29 +1673,12 @@ static int add_root_directory(sd_journal *j, const char *p, bool missing_ok) {
} else if (!m->is_root)
return 0;
if (m->wd <= 0 && j->inotify_fd >= 0) {
directory_watch(j, m, dirfd(d),
IN_CREATE|IN_MOVED_TO|IN_MODIFY|IN_ATTRIB|IN_DELETE|
IN_ONLYDIR);
m->wd = inotify_add_watch_fd(j->inotify_fd, dirfd(d),
IN_CREATE|IN_MOVED_TO|IN_MODIFY|IN_ATTRIB|IN_DELETE|
IN_ONLYDIR);
if (m->wd > 0 && hashmap_put(j->directories_by_wd, INT_TO_PTR(m->wd), m) < 0)
inotify_rm_watch(j->inotify_fd, m->wd);
}
if (j->no_new_files)
return 0;
FOREACH_DIRENT_ALL(de, d, r = log_debug_errno(errno, "Failed to read directory %s: %m", m->path); goto fail) {
sd_id128_t id;
if (dirent_is_file_with_suffix(de, ".journal") ||
dirent_is_file_with_suffix(de, ".journal~"))
(void) add_file(j, m->path, de->d_name);
else if (IN_SET(de->d_type, DT_DIR, DT_LNK, DT_UNKNOWN) &&
sd_id128_from_string(de->d_name, &id) >= 0)
(void) add_directory(j, m->path, de->d_name);
}
if (!j->no_new_files)
directory_enumerate(j, m, d);
check_network(j, dirfd(d));
@ -2288,6 +2353,24 @@ _public_ void sd_journal_restart_data(sd_journal *j) {
j->current_field = 0;
}
static int reiterate_all_paths(sd_journal *j) {
assert(j);
if (j->no_new_files)
return add_current_paths(j);
if (j->flags & SD_JOURNAL_OS_ROOT)
return add_search_paths(j);
if (j->toplevel_fd >= 0)
return add_root_directory(j, NULL, false);
if (j->path)
return add_root_directory(j, j->path, true);
return add_search_paths(j);
}
_public_ int sd_journal_get_fd(sd_journal *j) {
int r;
@ -2304,20 +2387,10 @@ _public_ int sd_journal_get_fd(sd_journal *j) {
if (r < 0)
return r;
log_debug("Reiterating files to get inotify watches established");
log_debug("Reiterating files to get inotify watches established.");
/* Iterate through all dirs again, to add them to the
* inotify */
if (j->no_new_files)
r = add_current_paths(j);
else if (j->flags & SD_JOURNAL_OS_ROOT)
r = add_search_paths(j);
else if (j->toplevel_fd >= 0)
r = add_root_directory(j, NULL, false);
else if (j->path)
r = add_root_directory(j, j->path, true);
else
r = add_search_paths(j);
/* Iterate through all dirs again, to add them to the inotify */
r = reiterate_all_paths(j);
if (r < 0)
return r;
@ -2360,12 +2433,58 @@ _public_ int sd_journal_get_timeout(sd_journal *j, uint64_t *timeout_usec) {
return 1;
}
static void process_q_overflow(sd_journal *j) {
JournalFile *f;
Directory *m;
Iterator i;
assert(j);
/* When the inotify queue overruns we need to enumerate and re-validate all journal files to bring our list
* back in sync with what's on disk. For this we pick a new generation counter value. It'll be assigned to all
* journal files we encounter. All journal files and all directories that don't carry it after reenumeration
* are subject for unloading. */
log_debug("Inotify queue overrun, reiterating everything.");
j->generation++;
(void) reiterate_all_paths(j);
ORDERED_HASHMAP_FOREACH(f, j->files, i) {
if (f->last_seen_generation == j->generation)
continue;
log_debug("File '%s' hasn't been seen in this enumeration, removing.", f->path);
remove_file_real(j, f);
}
HASHMAP_FOREACH(m, j->directories_by_path, i) {
if (m->last_seen_generation == j->generation)
continue;
if (m->is_root) /* Never GC root directories */
continue;
log_debug("Directory '%s' hasn't been seen in this enumeration, removing.", f->path);
remove_directory(j, m);
}
log_debug("Reiteration complete.");
}
static void process_inotify_event(sd_journal *j, struct inotify_event *e) {
Directory *d;
assert(j);
assert(e);
if (e->mask & IN_Q_OVERFLOW) {
process_q_overflow(j);
return;
}
/* Is this a subdirectory we watch? */
d = hashmap_get(j->directories_by_wd, INT_TO_PTR(e->wd));
if (d) {