Added compiling target Android support

Documentation/Contributors.rst

@@ -59,6 +59,7 @@ Statistics for 6.x series
     "6.12", "20", "111881", "163548", "148", "+1868 -1804"
     "6.13", "25", "112756", "164722", "156", "+2780 -1579"
     "6.14", "20", "114592", "167178", "147", "+3847 -1391"
+    "6.15", "25", "114616", "167485", "190", "+2346 -2039"
 
 
 Legend:

Documentation/btrfs-filesystem.rst

@@ -118,7 +118,7 @@ defragment [options] <file>|<dir> [<file>|<dir>...]
                 compression. See also section *EXAMPLES*.
 
         -L|--level <level>
-                Since kernel 6.14 the compresison can also take the level parameter which will be used
+                Since kernel 6.15 the compresison can also take the level parameter which will be used
                 only for the defragmentation and overrides the eventual mount option compression level.
                 Valid levels depend on the compression algorithms: *zlib*
                 1..9, *lzo* does not have any levels, *zstd* the standard levels 1..15 and also the

Documentation/mkfs.btrfs.rst

@@ -213,6 +213,41 @@ OPTIONS
         :file:`hardlink1` and :file:`hardlink2` because :file:`hardlink3` will
         be inside a new subvolume.
 
+--inode-flags <flags>:<path>
+	Specify that *path* to have inode *flags*, other than the default one (which
+	implies data COW and data checksum).  The option *--rootdir* must also be
+	specified.  This option can be specified multiple times.
+
+	The supported flag(s) are:
+
+	* *nodatacow*: disable data COW, implies *nodatasum* for regular files.
+	* *nodatasum*: disable data checksum only.
+
+	*flags* can be separated by comma (*,*).
+
+	Children inodes will inherit the flags from their parent inodes, like the
+	following case:
+
+        .. code-block:: none
+
+		rootdir/
+		|- file1
+		|- file2
+		|- dir/
+		   |- file3
+
+	In that case, if *--inode-flags nodatacow:dir* is specified, both
+	:file:`dir` and :file:`file3` will have the *nodatacow* flag.
+
+	And this option also works with *--subvol* option, but the inode flag of
+	each subvolume is independent and will not inherit from the parent directory.
+	(The same as the kernel behavior.)
+
+        .. note::
+                Both *--inode-flags* and *--subvol* options are memory hungry,
+                will consume at least 8KiB for each option.  Please keep the
+                usage of both options to minimum.
+
 --shrink
         Shrink the filesystem to its minimal size, only works with *--rootdir* option.
 

Makefile

@@ -215,6 +215,8 @@ objects = \
 	kernel-shared/uuid-tree.o	\
 	kernel-shared/volumes.o	\
 	kernel-shared/zoned.o	\
+	android-compat/pthread.o	\
+	android-compat/qsort.o	\
 	common/array.o		\
 	common/cpu-utils.o	\
 	common/device-scan.o	\
@@ -292,8 +294,8 @@ tune_objects = tune/main.o tune/seeding.o tune/change-uuid.o tune/change-metadat
 all_objects = $(objects) $(cmds_objects) $(libbtrfs_objects) $(convert_objects) \
 	      $(mkfs_objects) $(image_objects) $(tune_objects) $(libbtrfsutil_objects)
 
-tags_files = $(addsuffix /*.[ch], . check cmds common convert crypto image include mkfs tune \
-	       kernel-lib kernel-shared kernel-shared/uapi \
+tags_files = $(addsuffix /*.[ch], . android-compat check cmds common convert crypto \
+	       image include mkfs tune kernel-lib kernel-shared kernel-shared/uapi \
 	       libbtrfs libbtrfsutil libbtrfsutil/python tests)
 
 udev_rules = 64-btrfs-dm.rules 64-btrfs-zoned.rules
@@ -917,6 +919,7 @@ clean: $(CLEANDIRS)
 		libbtrfs.a libbtrfsutil.a $(libs_shared) $(lib_links)
 	@echo "Cleaning object files and dependencies"
 	$(Q)$(RM) -f -- *.o .deps/*.o.d  \
+		android-compat/*.o android-compat/.deps/*.o.d \
 		check/*.o check/.deps/*.o.d \
 		cmds/*.o cmds/.deps/*.o.d \
 		common/*.o common/.deps/*.o.d \

android-compat/pthread.c

@@ -0,0 +1,57 @@
+
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include "include/config.h"
+
+#ifdef __ANDROID__
+
+/* Workaround for `pthread_cancel()` in Android, using `pthread_kill()` instead,
+ * as Android NDK does not support `pthread_cancel()`.
+ */
+
+#include <string.h>
+#include <signal.h>
+#include "android-compat/pthread.h"
+
+int pthread_setcanceltype(int type, int *oldtype) { return 0; }
+int pthread_setcancelstate(int state, int *oldstate) { return 0; }
+int pthread_cancel(pthread_t thread_id) {
+	int status;
+	if ((status = btrfs_set_thread_exit_handler()) == 0) {
+		status = pthread_kill(thread_id, SIGUSR1);
+	}
+	return status;
+}
+
+void btrfs_thread_exit_handler(int sig) {
+	pthread_exit(0);
+}
+
+int btrfs_set_thread_exit_handler() {
+	int rc;
+	struct sigaction actions;
+
+	memset(&actions, 0, sizeof(actions));
+	sigemptyset(&actions.sa_mask);
+	actions.sa_flags = 0;
+	actions.sa_handler = btrfs_thread_exit_handler;
+
+	rc = sigaction(SIGUSR1, &actions, NULL);
+	return rc;
+}
+
+#endif

android-compat/pthread.h

@@ -0,0 +1,45 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#ifndef __ANDROID_COMPAT_PTHREAD_H__
+#define __ANDROID_COMPAT_PTHREAD_H__
+
+#include "include/config.h"
+
+#include <pthread.h>
+
+#ifdef __ANDROID__
+
+/* Adding missing `pthread` related definitions in Android.
+ */
+
+#define PTHREAD_CANCELED ((void *) -1)
+
+#define PTHREAD_CANCEL_DEFERRED 0
+#define PTHREAD_CANCEL_ASYNCHRONOUS 0
+#define PTHREAD_CANCEL_ENABLE 0
+#define PTHREAD_CANCEL_DISABLE 0
+
+int pthread_setcanceltype(int type, int *oldtype);
+int pthread_setcancelstate(int state, int *oldstate);
+int pthread_cancel(pthread_t thread_id);
+
+int btrfs_set_thread_exit_handler();
+void btrfs_thread_exit_handler(int sig);
+
+#endif
+
+#endif

android-compat/qsort.c

@@ -0,0 +1,50 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#include "android-compat/qsort.h"
+#include <stdlib.h>
+
+struct qsort_r_context {
+	int (*compar)(const void *, const void *, void *);
+	void *arg;
+};
+
+#if __STDC_VERSION__ >= 201112L && !defined(__STDC_NO_THREADS__)
+static _Thread_local struct qsort_r_context *qsort_r_ctx = NULL;
+#else
+static __thread struct qsort_r_context *qsort_r_ctx = NULL;
+#endif
+
+static int qsort_r_stub_compare(const void *a, const void *b)
+{
+	return qsort_r_ctx->compar(a, b, qsort_r_ctx->arg);
+}
+
+void qsort_r(void *base, size_t nel, size_t width,
+		 int (*compar)(const void *, const void *, void *), void *arg)
+{
+	if (nel == 0) return;
+
+	struct qsort_r_context ctx;
+	ctx.compar = compar;
+	ctx.arg = arg;
+	struct qsort_r_context *old_ctx = qsort_r_ctx;
+	qsort_r_ctx = &ctx;
+	qsort(base, nel, width, qsort_r_stub_compare);
+
+	// Restore the old context after qsort is finished.
+	qsort_r_ctx = old_ctx;
+}

android-compat/qsort.h

@@ -0,0 +1,50 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public
+ * License along with this program; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 021110-1307, USA.
+ */
+
+#ifndef __ANDROID_COMPAT_QSORT_H__
+#define __ANDROID_COMPAT_QSORT_H__
+
+#include <sys/types.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief A compatible implementation of the GNU C Library (Glibc) qsort_r.
+ *
+ * Sorts an array using the quicksort algorithm. This function is thread-safe
+ * by allowing a custom context pointer (arg) to be passed to the comparison
+ * function.
+ *
+ * @param base   A pointer to the first element of the array to be sorted.
+ * @param nel    The number of elements in the array.
+ * @param width  The size in bytes of each element in the array.
+ * @param compar The comparison function, which takes two elements and a context
+ * pointer. The function must return:
+ * - A negative integer if the first element is less than the second.
+ * - Zero if the elements are equal.
+ * - A positive integer if the first element is greater than the second.
+ * @param arg    The custom pointer passed to the comparison function.
+ */
+void qsort_r(void *base, size_t nel, size_t width,
+	     int (*compar)(const void *, const void *, void *), void *arg);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

cmds/inspect.c

@@ -14,6 +14,7 @@
  * Boston, MA 021110-1307, USA.
  */
 
+#include "android-compat/qsort.h"
 #include "kerncompat.h"
 #include <sys/ioctl.h>
 #include <sys/stat.h>
@@ -878,9 +879,10 @@ static int print_list_chunks(struct list_chunks_ctx *ctx, const char *sortmode,
 	}
 
 	/* Skip additional sort if nothing defined by user. */
-	if (comp.count > 0)
+	if (comp.count > 0) {
 		qsort_r(ctx->stats, ctx->length, sizeof(ctx->stats[0]),
 			(sort_r_cmp_t)compare_cmp_multi, &comp);
+	}
 
 	col_count = 9;
 	/* Two rows for header and separator. */

cmds/rescue-chunk-recover.c

@@ -22,10 +22,13 @@
 #include <stdlib.h>
 #include <fcntl.h>
 #include <unistd.h>
-#include <pthread.h>
+#include "android-compat/pthread.h"
 #include <errno.h>
 #include <stddef.h>
 #include <string.h>
+#ifdef __ANDROID__
+#include <stdatomic.h>
+#endif
 #include "kernel-lib/list.h"
 #include "kernel-shared/accessors.h"
 #include "kernel-shared/extent-io-tree.h"
@@ -82,6 +85,9 @@ struct device_scan {
 	struct btrfs_device *dev;
 	int fd;
 	u64 bytenr;
+#ifdef __ANDROID__
+	atomic_flag thread_running;
+#endif
 };
 
 static struct extent_record *btrfs_new_extent_record(struct extent_buffer *eb)
@@ -761,8 +767,12 @@ static int scan_one_device(void *dev_scan_struct)
 		return 1;
 
 	buf = malloc(sizeof(*buf) + rc->nodesize);
-	if (!buf)
+	if (!buf) {
+#ifdef __ANDROID__
+		atomic_flag_clear(&dev_scan->thread_running);
+#endif
 		return -ENOMEM;
+	}
 	buf->len = rc->nodesize;
 
 	bytenr = 0;
@@ -823,6 +833,9 @@ static int scan_one_device(void *dev_scan_struct)
 out:
 	close(fd);
 	free(buf);
+#ifdef __ANDROID__
+	atomic_flag_clear(&dev_scan->thread_running);
+#endif
 	return ret;
 }
 
@@ -869,6 +882,9 @@ static int scan_devices(struct recover_control *rc)
 		dev_scans[devidx].dev = dev;
 		dev_scans[devidx].fd = fd;
 		dev_scans[devidx].bytenr = -1;
+#ifdef __ANDROID__
+		atomic_flag_test_and_set(&dev_scans[devidx].thread_running);
+#endif
 		devidx++;
 	}
 
@@ -887,8 +903,15 @@ static int scan_devices(struct recover_control *rc)
 		for (i = 0; i < devidx; i++) {
 			if (dev_scans[i].bytenr == -1)
 				continue;
+#ifdef __ANDROID__
+			if (atomic_flag_test_and_set(&dev_scans[i].thread_running))
+				ret = EBUSY;
+			else
+				ret = pthread_join(t_scans[i], (void **)&t_rets[i]);
+#else
 			ret = pthread_tryjoin_np(t_scans[i],
 						 (void **)&t_rets[i]);
+#endif
 			if (ret == EBUSY) {
 				all_done = false;
 				continue;

cmds/scrub.c

@@ -27,7 +27,7 @@
 #include <poll.h>
 #include <fcntl.h>
 #include <unistd.h>
-#include <pthread.h>
+#include "android-compat/pthread.h"
 #include <ctype.h>
 #include <signal.h>
 #include <stdarg.h>