From 7204e7f9ea3067bda7e5658a06e91b67c736f8ab Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 12 Feb 2018 16:14:58 +0100
Subject: [PATCH] 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
(cherry-picked from commit 858749f7312bd0adb5433075a92e1c35a2fb56ac)
Resolves: #1540538
---
src/journal/journal-file.h | 2 +
src/journal/journal-internal.h | 2 +
src/journal/sd-journal.c | 237 ++++++++++++++++++++++++++++++++---------
src/shared/path-util.c | 14 +++
src/shared/path-util.h | 2 +
5 files changed, 206 insertions(+), 51 deletions(-)
diff --git a/src/journal/journal-file.h b/src/journal/journal-file.h
index c74ad5fc5..dd8ef52d2 100644
--- a/src/journal/journal-file.h
+++ b/src/journal/journal-file.h
@@ -121,6 +121,8 @@ typedef struct JournalFile {
void *fsprg_seed;
size_t fsprg_seed_size;
+
+ unsigned last_seen_generation;
#endif
} JournalFile;
diff --git a/src/journal/journal-internal.h b/src/journal/journal-internal.h
index eb23ac28a..999e9d8cb 100644
--- a/src/journal/journal-internal.h
+++ b/src/journal/journal-internal.h
@@ -81,6 +81,7 @@ struct Directory {
char *path;
int wd;
bool is_root;
+ unsigned last_seen_generation;
};
struct sd_journal {
@@ -102,6 +103,7 @@ struct sd_journal {
int inotify_fd;
unsigned current_invalidate_counter, last_invalidate_counter;
usec_t last_process_usec;
+ unsigned generation;
char *unique_field;
JournalFile *unique_file;
diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c
index 14b65cfed..9186f5188 100644
--- a/src/journal/sd-journal.c
+++ b/src/journal/sd-journal.c
@@ -1229,8 +1229,16 @@ static int add_any_file(sd_journal *j, const char *path) {
assert(j);
assert(path);
- if (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);
@@ -1252,6 +1260,8 @@ static int add_any_file(sd_journal *j, const char *path) {
goto fail;
}
+ f->last_seen_generation = j->generation;
+
log_debug("File %s added.", f->path);
check_network(j, f->fd);
@@ -1346,10 +1356,96 @@ 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);
+
+ d = opendir(path);
+ 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;
@@ -1357,7 +1453,7 @@ static int add_directory(sd_journal *j, const char *prefix, const char *dirname)
assert(prefix);
assert(dirname);
- log_debug("Considering %s/%s.", prefix, dirname);
+ log_debug("Considering '%s/%s'.", prefix, dirname);
if ((j->flags & SD_JOURNAL_LOCAL_ONLY) &&
!(dirname_is_machine_id(dirname) > 0 || path_startswith(prefix, "/run")))
@@ -1369,9 +1465,9 @@ static int add_directory(sd_journal *j, const char *prefix, const char *dirname)
goto fail;
}
- d = opendir(path);
- if (!d) {
- r = log_debug_errno(errno, "Failed to open directory %s: %m", path);
+ r = directory_open(j, path, &d);
+ if (r < 0) {
+ r = log_debug_errno(errno, "Failed to open directory '%s': %m", path);
goto fail;
}
@@ -1398,25 +1494,17 @@ 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;
-
- if (m->wd <= 0 && j->inotify_fd >= 0) {
-
- m->wd = inotify_add_watch(j->inotify_fd, m->path,
- IN_CREATE|IN_MOVED_TO|IN_MODIFY|IN_ATTRIB|IN_DELETE|
- IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_MOVED_FROM|
- IN_ONLYDIR);
+ return 0; /* Don't 'downgrade' from root directory */
- 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);
- }
+ m->last_seen_generation = j->generation;
- FOREACH_DIRENT_ALL(de, d, return log_debug_errno(errno, "Failed to read directory %s: %m", m->path)) {
+ 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 (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));
@@ -1432,13 +1520,14 @@ 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;
assert(j);
assert(p);
+ log_debug("Considering root directory '%s'.", p);
+
if ((j->flags & SD_JOURNAL_RUNTIME_ONLY) &&
!path_startswith(p, "/run"))
return -EINVAL;
@@ -1446,12 +1535,11 @@ static int add_root_directory(sd_journal *j, const char *p, bool missing_ok) {
if (j->prefix)
p = strjoina(j->prefix, p);
- d = opendir(p);
- 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;
}
@@ -1495,19 +1583,12 @@ static int add_root_directory(sd_journal *j, const char *p, bool missing_ok) {
inotify_rm_watch(j->inotify_fd, m->wd);
}
- if (j->no_new_files)
- return 0;
-
- FOREACH_DIRENT_ALL(de, d, return log_debug_errno(errno, "Failed to read directory %s: %m", m->path)) {
- sd_id128_t id;
+ directory_watch(j, m, dirfd(d),
+ IN_CREATE|IN_MOVED_TO|IN_MODIFY|IN_ATTRIB|IN_DELETE|
+ IN_ONLYDIR);
- 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));
@@ -2068,6 +2149,18 @@ _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->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;
@@ -2081,15 +2174,11 @@ _public_ int sd_journal_get_fd(sd_journal *j) {
if (r < 0)
return r;
- /* Iterate through all dirs again, to add them to the
- * inotify */
- if (j->no_new_files)
- r = add_current_paths(j);
- else if (j->path)
- r = add_root_directory(j, j->path, true);
- else
- r = add_search_paths(j);
- if (r < 0)
+ log_debug("Reiterating files to get inotify watches established.");
+
+ /* Iterate through all dirs again, to add them to the inotify */
+ r = reiterate_all_paths(j);
+ if (r < 0)
return r;
return j->inotify_fd;
@@ -2131,12 +2220,58 @@ _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) {
diff --git a/src/shared/path-util.c b/src/shared/path-util.c
index 5d4de9ec4..fcc591686 100644
--- a/src/shared/path-util.c
+++ b/src/shared/path-util.c
@@ -861,3 +861,17 @@ char *prefix_root(const char *root, const char *path) {
strcpy(p, path);
return n;
}
+
+int inotify_add_watch_fd(int fd, int what, uint32_t mask) {
+ char path[strlen("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1];
+ int r;
+
+ /* This is like inotify_add_watch(), except that the file to watch is not referenced by a path, but by an fd */
+ xsprintf(path, "/proc/self/fd/%i", what);
+
+ r = inotify_add_watch(fd, path, mask);
+ if (r < 0)
+ return -errno;
+
+ return r;
+}
diff --git a/src/shared/path-util.h b/src/shared/path-util.h
index 34c016229..96490e12b 100644
--- a/src/shared/path-util.h
+++ b/src/shared/path-util.h
@@ -66,6 +66,8 @@ int fsck_exists(const char *fstype);
char *prefix_root(const char *root, const char *path);
+int inotify_add_watch_fd(int fd, int what, uint32_t mask);
+
/* Similar to prefix_root(), but returns an alloca() buffer, or
* possibly a const pointer into the path parameter */
#define prefix_roota(root, path) \