Typo: 'Descritptor' -> 'Descriptor'

[lttng-tools.git] / src / common / fd-tracker / fd-tracker.c

diff --git a/src/common/fd-tracker/fd-tracker.c b/src/common/fd-tracker/fd-tracker.c
index 417859abe889e0e8b94eabe88dd9fd0d00376f9c..772bf04bc5994efa5fc351a2ed933514506de36c 100644 (file)
--- a/src/common/fd-tracker/fd-tracker.c
+++ b/src/common/fd-tracker/fd-tracker.c
@@ -210,7 +210,7 @@ static void fs_handle_tracked_log(struct fs_handle_tracked *handle)
        const char *path;
 
        pthread_mutex_lock(&handle->lock);
-       lttng_inode_get_location(handle->inode, NULL, &path);
+       lttng_inode_borrow_location(handle->inode, NULL, &path);
 
        if (handle->fd >= 0) {
                DBG_NO_LOC("    %s [active, fd %d%s]", path, handle->fd,
@@ -230,7 +230,8 @@ static int fs_handle_tracked_suspend(struct fs_handle_tracked *handle)
        const struct lttng_directory_handle *node_directory_handle;
 
        pthread_mutex_lock(&handle->lock);
-       lttng_inode_get_location(handle->inode, &node_directory_handle, &path);
+       lttng_inode_borrow_location(
+                       handle->inode, &node_directory_handle, &path);
        assert(handle->fd >= 0);
        if (handle->in_use) {
                /* This handle can't be suspended as it is currently in use. */
@@ -288,7 +289,8 @@ static int fs_handle_tracked_restore(struct fs_handle_tracked *handle)
        const char *path;
        const struct lttng_directory_handle *node_directory_handle;
 
-       lttng_inode_get_location(handle->inode, &node_directory_handle, &path);
+       lttng_inode_borrow_location(
+                       handle->inode, &node_directory_handle, &path);
 
        assert(handle->fd == -1);
        assert(path);
@@ -358,6 +360,7 @@ end:
        return ret;
 }
 
+LTTNG_HIDDEN
 struct fd_tracker *fd_tracker_create(const char *unlinked_file_path,
                unsigned int capacity)
 {
@@ -403,6 +406,7 @@ error:
        return NULL;
 }
 
+LTTNG_HIDDEN
 void fd_tracker_log(struct fd_tracker *tracker)
 {
        struct fs_handle_tracked *handle;
@@ -451,10 +455,14 @@ void fd_tracker_log(struct fd_tracker *tracker)
        pthread_mutex_unlock(&tracker->lock);
 }
 
+LTTNG_HIDDEN
 int fd_tracker_destroy(struct fd_tracker *tracker)
 {
        int ret = 0;
 
+       if (!tracker) {
+               goto end;
+       }
        /*
         * Refuse to destroy the tracker as fs_handles may still old
         * weak references to the tracker.
@@ -483,6 +491,7 @@ end:
        return ret;
 }
 
+LTTNG_HIDDEN
 struct fs_handle *fd_tracker_open_fs_handle(struct fd_tracker *tracker,
                struct lttng_directory_handle *directory,
                const char *path,
@@ -600,6 +609,7 @@ static int fd_tracker_suspend_handles(
        return left_to_close ? -EMFILE : 0;
 }
 
+LTTNG_HIDDEN
 int fd_tracker_open_unsuspendable_fd(struct fd_tracker *tracker,
                int *out_fds,
                const char **names,
@@ -632,7 +642,7 @@ int fd_tracker_open_unsuspendable_fd(struct fd_tracker *tracker,
                } else {
                        /*
                         * There are not enough active suspendable file
-                        * descriptors to open a new fd and still accomodate the
+                        * descriptors to open a new fd and still accommodates the
                         * tracker's capacity.
                         */
                        WARN("Cannot open unsuspendable fd, too many unsuspendable file descriptors are opened (%u)",
@@ -697,6 +707,7 @@ end_free_entries:
        goto end_unlock;
 }
 
+LTTNG_HIDDEN
 int fd_tracker_close_unsuspendable_fd(struct fd_tracker *tracker,
                int *fds_in,
                unsigned int fd_count,
@@ -882,6 +893,7 @@ static int fs_handle_tracked_close(struct fs_handle *_handle)
        const char *path = NULL;
        struct fs_handle_tracked *handle =
                        container_of(_handle, struct fs_handle_tracked, parent);
+       struct lttng_directory_handle *inode_directory_handle = NULL;
 
        if (!handle) {
                ret = -EINVAL;
@@ -891,7 +903,29 @@ static int fs_handle_tracked_close(struct fs_handle *_handle)
        pthread_mutex_lock(&handle->tracker->lock);
        pthread_mutex_lock(&handle->lock);
        if (handle->inode) {
-               lttng_inode_get_location(handle->inode, NULL, &path);
+               lttng_inode_borrow_location(handle->inode, NULL, &path);
+               /*
+                * Here a reference to the inode's directory handle is acquired
+                * to prevent the last reference to it from being released while
+                * the tracker's lock is taken.
+                *
+                * If this wasn't done, the directory handle could attempt to
+                * close its underlying directory file descriptor, which would
+                * attempt to lock the tracker's lock, resulting in a deadlock.
+                *
+                * Since a new reference to the directory handle is taken within
+                * the scope of this function, it is not possible for the last
+                * reference to the inode's location directory handle to be
+                * released during the call to lttng_inode_put().
+                *
+                * We wait until the tracker's lock is released to release the
+                * reference. Hence, the call to the tracker is delayed just
+                * enough to not attempt to recursively acquire the tracker's
+                * lock twice.
+                */
+               inode_directory_handle =
+                               lttng_inode_get_location_directory_handle(
+                                               handle->inode);
        }
        fd_tracker_untrack(handle->tracker, handle);
        if (handle->fd >= 0) {
@@ -900,7 +934,7 @@ static int fs_handle_tracked_close(struct fs_handle *_handle)
                 * isn't much the user can do about it.
                 */
                if (close(handle->fd)) {
-                       PERROR("Failed to close the file descritptor (%d) of fs handle to %s, close() returned",
+                       PERROR("Failed to close the file descriptor (%d) of fs handle to %s, close() returned",
                                        handle->fd, path ? path : "Unknown");
                }
                handle->fd = -1;
@@ -912,6 +946,7 @@ static int fs_handle_tracked_close(struct fs_handle *_handle)
        pthread_mutex_destroy(&handle->lock);
        pthread_mutex_unlock(&handle->tracker->lock);
        free(handle);
+       lttng_directory_handle_put(inode_directory_handle);
 end:
        return ret;
 }