Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1681 insertions, 0 deletions

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
new file mode 100644
index 0000000000..2d7f5a8d4a
--- /dev/null
+++ b/fs/ceph/super.c
@@ -0,0 +1,1681 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/ceph/ceph_debug.h>
+
+#include <linux/backing-dev.h>
+#include <linux/ctype.h>
+#include <linux/fs.h>
+#include <linux/inet.h>
+#include <linux/in6.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/statfs.h>
+#include <linux/string.h>
+
+#include "super.h"
+#include "mds_client.h"
+#include "cache.h"
+#include "crypto.h"
+
+#include <linux/ceph/ceph_features.h>
+#include <linux/ceph/decode.h>
+#include <linux/ceph/mon_client.h>
+#include <linux/ceph/auth.h>
+#include <linux/ceph/debugfs.h>
+
+#include <uapi/linux/magic.h>
+
+static DEFINE_SPINLOCK(ceph_fsc_lock);
+static LIST_HEAD(ceph_fsc_list);
+
+/*
+ * Ceph superblock operations
+ *
+ * Handle the basics of mounting, unmounting.
+ */
+
+/*
+ * super ops
+ */
+static void ceph_put_super(struct super_block *s)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(s);
+
+	dout("put_super\n");
+	ceph_fscrypt_free_dummy_policy(fsc);
+	ceph_mdsc_close_sessions(fsc->mdsc);
+}
+
+static int ceph_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct ceph_fs_client *fsc = ceph_inode_to_client(d_inode(dentry));
+	struct ceph_mon_client *monc = &fsc->client->monc;
+	struct ceph_statfs st;
+	int i, err;
+	u64 data_pool;
+
+	if (fsc->mdsc->mdsmap->m_num_data_pg_pools == 1) {
+		data_pool = fsc->mdsc->mdsmap->m_data_pg_pools[0];
+	} else {
+		data_pool = CEPH_NOPOOL;
+	}
+
+	dout("statfs\n");
+	err = ceph_monc_do_statfs(monc, data_pool, &st);
+	if (err < 0)
+		return err;
+
+	/* fill in kstatfs */
+	buf->f_type = CEPH_SUPER_MAGIC;  /* ?? */
+
+	/*
+	 * Express utilization in terms of large blocks to avoid
+	 * overflow on 32-bit machines.
+	 */
+	buf->f_frsize = 1 << CEPH_BLOCK_SHIFT;
+
+	/*
+	 * By default use root quota for stats; fallback to overall filesystem
+	 * usage if using 'noquotadf' mount option or if the root dir doesn't
+	 * have max_bytes quota set.
+	 */
+	if (ceph_test_mount_opt(fsc, NOQUOTADF) ||
+	    !ceph_quota_update_statfs(fsc, buf)) {
+		buf->f_blocks = le64_to_cpu(st.kb) >> (CEPH_BLOCK_SHIFT-10);
+		buf->f_bfree = le64_to_cpu(st.kb_avail) >> (CEPH_BLOCK_SHIFT-10);
+		buf->f_bavail = le64_to_cpu(st.kb_avail) >> (CEPH_BLOCK_SHIFT-10);
+	}
+
+	/*
+	 * NOTE: for the time being, we make bsize == frsize to humor
+	 * not-yet-ancient versions of glibc that are broken.
+	 * Someday, we will probably want to report a real block
+	 * size...  whatever that may mean for a network file system!
+	 */
+	buf->f_bsize = buf->f_frsize;
+
+	buf->f_files = le64_to_cpu(st.num_objects);
+	buf->f_ffree = -1;
+	buf->f_namelen = NAME_MAX;
+
+	/* Must convert the fsid, for consistent values across arches */
+	buf->f_fsid.val[0] = 0;
+	mutex_lock(&monc->mutex);
+	for (i = 0 ; i < sizeof(monc->monmap->fsid) / sizeof(__le32) ; ++i)
+		buf->f_fsid.val[0] ^= le32_to_cpu(((__le32 *)&monc->monmap->fsid)[i]);
+	mutex_unlock(&monc->mutex);
+
+	/* fold the fs_cluster_id into the upper bits */
+	buf->f_fsid.val[1] = monc->fs_cluster_id;
+
+	return 0;
+}
+
+static int ceph_sync_fs(struct super_block *sb, int wait)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
+
+	if (!wait) {
+		dout("sync_fs (non-blocking)\n");
+		ceph_flush_dirty_caps(fsc->mdsc);
+		dout("sync_fs (non-blocking) done\n");
+		return 0;
+	}
+
+	dout("sync_fs (blocking)\n");
+	ceph_osdc_sync(&fsc->client->osdc);
+	ceph_mdsc_sync(fsc->mdsc);
+	dout("sync_fs (blocking) done\n");
+	return 0;
+}
+
+/*
+ * mount options
+ */
+enum {
+	Opt_wsize,
+	Opt_rsize,
+	Opt_rasize,
+	Opt_caps_wanted_delay_min,
+	Opt_caps_wanted_delay_max,
+	Opt_caps_max,
+	Opt_readdir_max_entries,
+	Opt_readdir_max_bytes,
+	Opt_congestion_kb,
+	/* int args above */
+	Opt_snapdirname,
+	Opt_mds_namespace,
+	Opt_recover_session,
+	Opt_source,
+	Opt_mon_addr,
+	Opt_test_dummy_encryption,
+	/* string args above */
+	Opt_dirstat,
+	Opt_rbytes,
+	Opt_asyncreaddir,
+	Opt_dcache,
+	Opt_ino32,
+	Opt_fscache,
+	Opt_poolperm,
+	Opt_require_active_mds,
+	Opt_acl,
+	Opt_quotadf,
+	Opt_copyfrom,
+	Opt_wsync,
+	Opt_pagecache,
+	Opt_sparseread,
+};
+
+enum ceph_recover_session_mode {
+	ceph_recover_session_no,
+	ceph_recover_session_clean
+};
+
+static const struct constant_table ceph_param_recover[] = {
+	{ "no",		ceph_recover_session_no },
+	{ "clean",	ceph_recover_session_clean },
+	{}
+};
+
+static const struct fs_parameter_spec ceph_mount_parameters[] = {
+	fsparam_flag_no ("acl",				Opt_acl),
+	fsparam_flag_no ("asyncreaddir",		Opt_asyncreaddir),
+	fsparam_s32	("caps_max",			Opt_caps_max),
+	fsparam_u32	("caps_wanted_delay_max",	Opt_caps_wanted_delay_max),
+	fsparam_u32	("caps_wanted_delay_min",	Opt_caps_wanted_delay_min),
+	fsparam_u32	("write_congestion_kb",		Opt_congestion_kb),
+	fsparam_flag_no ("copyfrom",			Opt_copyfrom),
+	fsparam_flag_no ("dcache",			Opt_dcache),
+	fsparam_flag_no ("dirstat",			Opt_dirstat),
+	fsparam_flag_no	("fsc",				Opt_fscache), // fsc|nofsc
+	fsparam_string	("fsc",				Opt_fscache), // fsc=...
+	fsparam_flag_no ("ino32",			Opt_ino32),
+	fsparam_string	("mds_namespace",		Opt_mds_namespace),
+	fsparam_string	("mon_addr",			Opt_mon_addr),
+	fsparam_flag_no ("poolperm",			Opt_poolperm),
+	fsparam_flag_no ("quotadf",			Opt_quotadf),
+	fsparam_u32	("rasize",			Opt_rasize),
+	fsparam_flag_no ("rbytes",			Opt_rbytes),
+	fsparam_u32	("readdir_max_bytes",		Opt_readdir_max_bytes),
+	fsparam_u32	("readdir_max_entries",		Opt_readdir_max_entries),
+	fsparam_enum	("recover_session",		Opt_recover_session, ceph_param_recover),
+	fsparam_flag_no ("require_active_mds",		Opt_require_active_mds),
+	fsparam_u32	("rsize",			Opt_rsize),
+	fsparam_string	("snapdirname",			Opt_snapdirname),
+	fsparam_string	("source",			Opt_source),
+	fsparam_flag	("test_dummy_encryption",	Opt_test_dummy_encryption),
+	fsparam_string	("test_dummy_encryption",	Opt_test_dummy_encryption),
+	fsparam_u32	("wsize",			Opt_wsize),
+	fsparam_flag_no	("wsync",			Opt_wsync),
+	fsparam_flag_no	("pagecache",			Opt_pagecache),
+	fsparam_flag_no	("sparseread",			Opt_sparseread),
+	{}
+};
+
+struct ceph_parse_opts_ctx {
+	struct ceph_options		*copts;
+	struct ceph_mount_options	*opts;
+};
+
+/*
+ * Remove adjacent slashes and then the trailing slash, unless it is
+ * the only remaining character.
+ *
+ * E.g. "//dir1////dir2///" --> "/dir1/dir2", "///" --> "/".
+ */
+static void canonicalize_path(char *path)
+{
+	int i, j = 0;
+
+	for (i = 0; path[i] != '\0'; i++) {
+		if (path[i] != '/' || j < 1 || path[j - 1] != '/')
+			path[j++] = path[i];
+	}
+
+	if (j > 1 && path[j - 1] == '/')
+		j--;
+	path[j] = '\0';
+}
+
+/*
+ * Check if the mds namespace in ceph_mount_options matches
+ * the passed in namespace string. First time match (when
+ * ->mds_namespace is NULL) is treated specially, since
+ * ->mds_namespace needs to be initialized by the caller.
+ */
+static int namespace_equals(struct ceph_mount_options *fsopt,
+			    const char *namespace, size_t len)
+{
+	return !(fsopt->mds_namespace &&
+		 (strlen(fsopt->mds_namespace) != len ||
+		  strncmp(fsopt->mds_namespace, namespace, len)));
+}
+
+static int ceph_parse_old_source(const char *dev_name, const char *dev_name_end,
+				 struct fs_context *fc)
+{
+	int r;
+	struct ceph_parse_opts_ctx *pctx = fc->fs_private;
+	struct ceph_mount_options *fsopt = pctx->opts;
+
+	if (*dev_name_end != ':')
+		return invalfc(fc, "separator ':' missing in source");
+
+	r = ceph_parse_mon_ips(dev_name, dev_name_end - dev_name,
+			       pctx->copts, fc->log.log, ',');
+	if (r)
+		return r;
+
+	fsopt->new_dev_syntax = false;
+	return 0;
+}
+
+static int ceph_parse_new_source(const char *dev_name, const char *dev_name_end,
+				 struct fs_context *fc)
+{
+	size_t len;
+	struct ceph_fsid fsid;
+	struct ceph_parse_opts_ctx *pctx = fc->fs_private;
+	struct ceph_mount_options *fsopt = pctx->opts;
+	char *fsid_start, *fs_name_start;
+
+	if (*dev_name_end != '=') {
+		dout("separator '=' missing in source");
+		return -EINVAL;
+	}
+
+	fsid_start = strchr(dev_name, '@');
+	if (!fsid_start)
+		return invalfc(fc, "missing cluster fsid");
+	++fsid_start; /* start of cluster fsid */
+
+	fs_name_start = strchr(fsid_start, '.');
+	if (!fs_name_start)
+		return invalfc(fc, "missing file system name");
+
+	if (ceph_parse_fsid(fsid_start, &fsid))
+		return invalfc(fc, "Invalid FSID");
+
+	++fs_name_start; /* start of file system name */
+	len = dev_name_end - fs_name_start;
+
+	if (!namespace_equals(fsopt, fs_name_start, len))
+		return invalfc(fc, "Mismatching mds_namespace");
+	kfree(fsopt->mds_namespace);
+	fsopt->mds_namespace = kstrndup(fs_name_start, len, GFP_KERNEL);
+	if (!fsopt->mds_namespace)
+		return -ENOMEM;
+	dout("file system (mds namespace) '%s'\n", fsopt->mds_namespace);
+
+	fsopt->new_dev_syntax = true;
+	return 0;
+}
+
+/*
+ * Parse the source parameter for new device format. Distinguish the device
+ * spec from the path. Try parsing new device format and fallback to old
+ * format if needed.
+ *
+ * New device syntax will looks like:
+ *     <device_spec>=/<path>
+ * where
+ *     <device_spec> is name@fsid.fsname
+ *     <path> is optional, but if present must begin with '/'
+ * (monitor addresses are passed via mount option)
+ *
+ * Old device syntax is:
+ *     <server_spec>[,<server_spec>...]:[<path>]
+ * where
+ *     <server_spec> is <ip>[:<port>]
+ *     <path> is optional, but if present must begin with '/'
+ */
+static int ceph_parse_source(struct fs_parameter *param, struct fs_context *fc)
+{
+	struct ceph_parse_opts_ctx *pctx = fc->fs_private;
+	struct ceph_mount_options *fsopt = pctx->opts;
+	char *dev_name = param->string, *dev_name_end;
+	int ret;
+
+	dout("%s '%s'\n", __func__, dev_name);
+	if (!dev_name || !*dev_name)
+		return invalfc(fc, "Empty source");
+
+	dev_name_end = strchr(dev_name, '/');
+	if (dev_name_end) {
+		/*
+		 * The server_path will include the whole chars from userland
+		 * including the leading '/'.
+		 */
+		kfree(fsopt->server_path);
+		fsopt->server_path = kstrdup(dev_name_end, GFP_KERNEL);
+		if (!fsopt->server_path)
+			return -ENOMEM;
+
+		canonicalize_path(fsopt->server_path);
+	} else {
+		dev_name_end = dev_name + strlen(dev_name);
+	}
+
+	dev_name_end--;		/* back up to separator */
+	if (dev_name_end < dev_name)
+		return invalfc(fc, "Path missing in source");
+
+	dout("device name '%.*s'\n", (int)(dev_name_end - dev_name), dev_name);
+	if (fsopt->server_path)
+		dout("server path '%s'\n", fsopt->server_path);
+
+	dout("trying new device syntax");
+	ret = ceph_parse_new_source(dev_name, dev_name_end, fc);
+	if (ret) {
+		if (ret != -EINVAL)
+			return ret;
+		dout("trying old device syntax");
+		ret = ceph_parse_old_source(dev_name, dev_name_end, fc);
+		if (ret)
+			return ret;
+	}
+
+	fc->source = param->string;
+	param->string = NULL;
+	return 0;
+}
+
+static int ceph_parse_mon_addr(struct fs_parameter *param,
+			       struct fs_context *fc)
+{
+	struct ceph_parse_opts_ctx *pctx = fc->fs_private;
+	struct ceph_mount_options *fsopt = pctx->opts;
+
+	kfree(fsopt->mon_addr);
+	fsopt->mon_addr = param->string;
+	param->string = NULL;
+
+	return ceph_parse_mon_ips(fsopt->mon_addr, strlen(fsopt->mon_addr),
+				  pctx->copts, fc->log.log, '/');
+}
+
+static int ceph_parse_mount_param(struct fs_context *fc,
+				  struct fs_parameter *param)
+{
+	struct ceph_parse_opts_ctx *pctx = fc->fs_private;
+	struct ceph_mount_options *fsopt = pctx->opts;
+	struct fs_parse_result result;
+	unsigned int mode;
+	int token, ret;
+
+	ret = ceph_parse_param(param, pctx->copts, fc->log.log);
+	if (ret != -ENOPARAM)
+		return ret;
+
+	token = fs_parse(fc, ceph_mount_parameters, param, &result);
+	dout("%s fs_parse '%s' token %d\n", __func__, param->key, token);
+	if (token < 0)
+		return token;
+
+	switch (token) {
+	case Opt_snapdirname:
+		kfree(fsopt->snapdir_name);
+		fsopt->snapdir_name = param->string;
+		param->string = NULL;
+		break;
+	case Opt_mds_namespace:
+		if (!namespace_equals(fsopt, param->string, strlen(param->string)))
+			return invalfc(fc, "Mismatching mds_namespace");
+		kfree(fsopt->mds_namespace);
+		fsopt->mds_namespace = param->string;
+		param->string = NULL;
+		break;
+	case Opt_recover_session:
+		mode = result.uint_32;
+		if (mode == ceph_recover_session_no)
+			fsopt->flags &= ~CEPH_MOUNT_OPT_CLEANRECOVER;
+		else if (mode == ceph_recover_session_clean)
+			fsopt->flags |= CEPH_MOUNT_OPT_CLEANRECOVER;
+		else
+			BUG();
+		break;
+	case Opt_source:
+		if (fc->source)
+			return invalfc(fc, "Multiple sources specified");
+		return ceph_parse_source(param, fc);
+	case Opt_mon_addr:
+		return ceph_parse_mon_addr(param, fc);
+	case Opt_wsize:
+		if (result.uint_32 < PAGE_SIZE ||
+		    result.uint_32 > CEPH_MAX_WRITE_SIZE)
+			goto out_of_range;
+		fsopt->wsize = ALIGN(result.uint_32, PAGE_SIZE);
+		break;
+	case Opt_rsize:
+		if (result.uint_32 < PAGE_SIZE ||
+		    result.uint_32 > CEPH_MAX_READ_SIZE)
+			goto out_of_range;
+		fsopt->rsize = ALIGN(result.uint_32, PAGE_SIZE);
+		break;
+	case Opt_rasize:
+		fsopt->rasize = ALIGN(result.uint_32, PAGE_SIZE);
+		break;
+	case Opt_caps_wanted_delay_min:
+		if (result.uint_32 < 1)
+			goto out_of_range;
+		fsopt->caps_wanted_delay_min = result.uint_32;
+		break;
+	case Opt_caps_wanted_delay_max:
+		if (result.uint_32 < 1)
+			goto out_of_range;
+		fsopt->caps_wanted_delay_max = result.uint_32;
+		break;
+	case Opt_caps_max:
+		if (result.int_32 < 0)
+			goto out_of_range;
+		fsopt->caps_max = result.int_32;
+		break;
+	case Opt_readdir_max_entries:
+		if (result.uint_32 < 1)
+			goto out_of_range;
+		fsopt->max_readdir = result.uint_32;
+		break;
+	case Opt_readdir_max_bytes:
+		if (result.uint_32 < PAGE_SIZE && result.uint_32 != 0)
+			goto out_of_range;
+		fsopt->max_readdir_bytes = result.uint_32;
+		break;
+	case Opt_congestion_kb:
+		if (result.uint_32 < 1024) /* at least 1M */
+			goto out_of_range;
+		fsopt->congestion_kb = result.uint_32;
+		break;
+	case Opt_dirstat:
+		if (!result.negated)
+			fsopt->flags |= CEPH_MOUNT_OPT_DIRSTAT;
+		else
+			fsopt->flags &= ~CEPH_MOUNT_OPT_DIRSTAT;
+		break;
+	case Opt_rbytes:
+		if (!result.negated)
+			fsopt->flags |= CEPH_MOUNT_OPT_RBYTES;
+		else
+			fsopt->flags &= ~CEPH_MOUNT_OPT_RBYTES;
+		break;
+	case Opt_asyncreaddir:
+		if (!result.negated)
+			fsopt->flags &= ~CEPH_MOUNT_OPT_NOASYNCREADDIR;
+		else
+			fsopt->flags |= CEPH_MOUNT_OPT_NOASYNCREADDIR;
+		break;
+	case Opt_dcache:
+		if (!result.negated)
+			fsopt->flags |= CEPH_MOUNT_OPT_DCACHE;
+		else
+			fsopt->flags &= ~CEPH_MOUNT_OPT_DCACHE;
+		break;
+	case Opt_ino32:
+		if (!result.negated)
+			fsopt->flags |= CEPH_MOUNT_OPT_INO32;
+		else
+			fsopt->flags &= ~CEPH_MOUNT_OPT_INO32;
+		break;
+
+	case Opt_fscache:
+#ifdef CONFIG_CEPH_FSCACHE
+		kfree(fsopt->fscache_uniq);
+		fsopt->fscache_uniq = NULL;
+		if (result.negated) {
+			fsopt->flags &= ~CEPH_MOUNT_OPT_FSCACHE;
+		} else {
+			fsopt->flags |= CEPH_MOUNT_OPT_FSCACHE;
+			fsopt->fscache_uniq = param->string;
+			param->string = NULL;
+		}
+		break;
+#else
+		return invalfc(fc, "fscache support is disabled");
+#endif
+	case Opt_poolperm:
+		if (!result.negated)
+			fsopt->flags &= ~CEPH_MOUNT_OPT_NOPOOLPERM;
+		else
+			fsopt->flags |= CEPH_MOUNT_OPT_NOPOOLPERM;
+		break;
+	case Opt_require_active_mds:
+		if (!result.negated)
+			fsopt->flags &= ~CEPH_MOUNT_OPT_MOUNTWAIT;
+		else
+			fsopt->flags |= CEPH_MOUNT_OPT_MOUNTWAIT;
+		break;
+	case Opt_quotadf:
+		if (!result.negated)
+			fsopt->flags &= ~CEPH_MOUNT_OPT_NOQUOTADF;
+		else
+			fsopt->flags |= CEPH_MOUNT_OPT_NOQUOTADF;
+		break;
+	case Opt_copyfrom:
+		if (!result.negated)
+			fsopt->flags &= ~CEPH_MOUNT_OPT_NOCOPYFROM;
+		else
+			fsopt->flags |= CEPH_MOUNT_OPT_NOCOPYFROM;
+		break;
+	case Opt_acl:
+		if (!result.negated) {
+#ifdef CONFIG_CEPH_FS_POSIX_ACL
+			fc->sb_flags |= SB_POSIXACL;
+#else
+			return invalfc(fc, "POSIX ACL support is disabled");
+#endif
+		} else {
+			fc->sb_flags &= ~SB_POSIXACL;
+		}
+		break;
+	case Opt_wsync:
+		if (!result.negated)
+			fsopt->flags &= ~CEPH_MOUNT_OPT_ASYNC_DIROPS;
+		else
+			fsopt->flags |= CEPH_MOUNT_OPT_ASYNC_DIROPS;
+		break;
+	case Opt_pagecache:
+		if (result.negated)
+			fsopt->flags |= CEPH_MOUNT_OPT_NOPAGECACHE;
+		else
+			fsopt->flags &= ~CEPH_MOUNT_OPT_NOPAGECACHE;
+		break;
+	case Opt_sparseread:
+		if (result.negated)
+			fsopt->flags &= ~CEPH_MOUNT_OPT_SPARSEREAD;
+		else
+			fsopt->flags |= CEPH_MOUNT_OPT_SPARSEREAD;
+		break;
+	case Opt_test_dummy_encryption:
+#ifdef CONFIG_FS_ENCRYPTION
+		fscrypt_free_dummy_policy(&fsopt->dummy_enc_policy);
+		ret = fscrypt_parse_test_dummy_encryption(param,
+						&fsopt->dummy_enc_policy);
+		if (ret == -EINVAL) {
+			warnfc(fc, "Value of option \"%s\" is unrecognized",
+			       param->key);
+		} else if (ret == -EEXIST) {
+			warnfc(fc, "Conflicting test_dummy_encryption options");
+			ret = -EINVAL;
+		}
+#else
+		warnfc(fc,
+		       "FS encryption not supported: test_dummy_encryption mount option ignored");
+#endif
+		break;
+	default:
+		BUG();
+	}
+	return 0;
+
+out_of_range:
+	return invalfc(fc, "%s out of range", param->key);
+}
+
+static void destroy_mount_options(struct ceph_mount_options *args)
+{
+	dout("destroy_mount_options %p\n", args);
+	if (!args)
+		return;
+
+	kfree(args->snapdir_name);
+	kfree(args->mds_namespace);
+	kfree(args->server_path);
+	kfree(args->fscache_uniq);
+	kfree(args->mon_addr);
+	fscrypt_free_dummy_policy(&args->dummy_enc_policy);
+	kfree(args);
+}
+
+static int strcmp_null(const char *s1, const char *s2)
+{
+	if (!s1 && !s2)
+		return 0;
+	if (s1 && !s2)
+		return -1;
+	if (!s1 && s2)
+		return 1;
+	return strcmp(s1, s2);
+}
+
+static int compare_mount_options(struct ceph_mount_options *new_fsopt,
+				 struct ceph_options *new_opt,
+				 struct ceph_fs_client *fsc)
+{
+	struct ceph_mount_options *fsopt1 = new_fsopt;
+	struct ceph_mount_options *fsopt2 = fsc->mount_options;
+	int ofs = offsetof(struct ceph_mount_options, snapdir_name);
+	int ret;
+
+	ret = memcmp(fsopt1, fsopt2, ofs);
+	if (ret)
+		return ret;
+
+	ret = strcmp_null(fsopt1->snapdir_name, fsopt2->snapdir_name);
+	if (ret)
+		return ret;
+
+	ret = strcmp_null(fsopt1->mds_namespace, fsopt2->mds_namespace);
+	if (ret)
+		return ret;
+
+	ret = strcmp_null(fsopt1->server_path, fsopt2->server_path);
+	if (ret)
+		return ret;
+
+	ret = strcmp_null(fsopt1->fscache_uniq, fsopt2->fscache_uniq);
+	if (ret)
+		return ret;
+
+	ret = strcmp_null(fsopt1->mon_addr, fsopt2->mon_addr);
+	if (ret)
+		return ret;
+
+	return ceph_compare_options(new_opt, fsc->client);
+}
+
+/**
+ * ceph_show_options - Show mount options in /proc/mounts
+ * @m: seq_file to write to
+ * @root: root of that (sub)tree
+ */
+static int ceph_show_options(struct seq_file *m, struct dentry *root)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(root->d_sb);
+	struct ceph_mount_options *fsopt = fsc->mount_options;
+	size_t pos;
+	int ret;
+
+	/* a comma between MNT/MS and client options */
+	seq_putc(m, ',');
+	pos = m->count;
+
+	ret = ceph_print_client_options(m, fsc->client, false);
+	if (ret)
+		return ret;
+
+	/* retract our comma if no client options */
+	if (m->count == pos)
+		m->count--;
+
+	if (fsopt->flags & CEPH_MOUNT_OPT_DIRSTAT)
+		seq_puts(m, ",dirstat");
+	if ((fsopt->flags & CEPH_MOUNT_OPT_RBYTES))
+		seq_puts(m, ",rbytes");
+	if (fsopt->flags & CEPH_MOUNT_OPT_NOASYNCREADDIR)
+		seq_puts(m, ",noasyncreaddir");
+	if ((fsopt->flags & CEPH_MOUNT_OPT_DCACHE) == 0)
+		seq_puts(m, ",nodcache");
+	if (fsopt->flags & CEPH_MOUNT_OPT_INO32)
+		seq_puts(m, ",ino32");
+	if (fsopt->flags & CEPH_MOUNT_OPT_FSCACHE) {
+		seq_show_option(m, "fsc", fsopt->fscache_uniq);
+	}
+	if (fsopt->flags & CEPH_MOUNT_OPT_NOPOOLPERM)
+		seq_puts(m, ",nopoolperm");
+	if (fsopt->flags & CEPH_MOUNT_OPT_NOQUOTADF)
+		seq_puts(m, ",noquotadf");
+
+#ifdef CONFIG_CEPH_FS_POSIX_ACL
+	if (root->d_sb->s_flags & SB_POSIXACL)
+		seq_puts(m, ",acl");
+	else
+		seq_puts(m, ",noacl");
+#endif
+
+	if ((fsopt->flags & CEPH_MOUNT_OPT_NOCOPYFROM) == 0)
+		seq_puts(m, ",copyfrom");
+
+	/* dump mds_namespace when old device syntax is in use */
+	if (fsopt->mds_namespace && !fsopt->new_dev_syntax)
+		seq_show_option(m, "mds_namespace", fsopt->mds_namespace);
+
+	if (fsopt->mon_addr)
+		seq_printf(m, ",mon_addr=%s", fsopt->mon_addr);
+
+	if (fsopt->flags & CEPH_MOUNT_OPT_CLEANRECOVER)
+		seq_show_option(m, "recover_session", "clean");
+
+	if (!(fsopt->flags & CEPH_MOUNT_OPT_ASYNC_DIROPS))
+		seq_puts(m, ",wsync");
+	if (fsopt->flags & CEPH_MOUNT_OPT_NOPAGECACHE)
+		seq_puts(m, ",nopagecache");
+	if (fsopt->flags & CEPH_MOUNT_OPT_SPARSEREAD)
+		seq_puts(m, ",sparseread");
+
+	fscrypt_show_test_dummy_encryption(m, ',', root->d_sb);
+
+	if (fsopt->wsize != CEPH_MAX_WRITE_SIZE)
+		seq_printf(m, ",wsize=%u", fsopt->wsize);
+	if (fsopt->rsize != CEPH_MAX_READ_SIZE)
+		seq_printf(m, ",rsize=%u", fsopt->rsize);
+	if (fsopt->rasize != CEPH_RASIZE_DEFAULT)
+		seq_printf(m, ",rasize=%u", fsopt->rasize);
+	if (fsopt->congestion_kb != default_congestion_kb())
+		seq_printf(m, ",write_congestion_kb=%u", fsopt->congestion_kb);
+	if (fsopt->caps_max)
+		seq_printf(m, ",caps_max=%d", fsopt->caps_max);
+	if (fsopt->caps_wanted_delay_min != CEPH_CAPS_WANTED_DELAY_MIN_DEFAULT)
+		seq_printf(m, ",caps_wanted_delay_min=%u",
+			 fsopt->caps_wanted_delay_min);
+	if (fsopt->caps_wanted_delay_max != CEPH_CAPS_WANTED_DELAY_MAX_DEFAULT)
+		seq_printf(m, ",caps_wanted_delay_max=%u",
+			   fsopt->caps_wanted_delay_max);
+	if (fsopt->max_readdir != CEPH_MAX_READDIR_DEFAULT)
+		seq_printf(m, ",readdir_max_entries=%u", fsopt->max_readdir);
+	if (fsopt->max_readdir_bytes != CEPH_MAX_READDIR_BYTES_DEFAULT)
+		seq_printf(m, ",readdir_max_bytes=%u", fsopt->max_readdir_bytes);
+	if (strcmp(fsopt->snapdir_name, CEPH_SNAPDIRNAME_DEFAULT))
+		seq_show_option(m, "snapdirname", fsopt->snapdir_name);
+
+	return 0;
+}
+
+/*
+ * handle any mon messages the standard library doesn't understand.
+ * return error if we don't either.
+ */
+static int extra_mon_dispatch(struct ceph_client *client, struct ceph_msg *msg)
+{
+	struct ceph_fs_client *fsc = client->private;
+	int type = le16_to_cpu(msg->hdr.type);
+
+	switch (type) {
+	case CEPH_MSG_MDS_MAP:
+		ceph_mdsc_handle_mdsmap(fsc->mdsc, msg);
+		return 0;
+	case CEPH_MSG_FS_MAP_USER:
+		ceph_mdsc_handle_fsmap(fsc->mdsc, msg);
+		return 0;
+	default:
+		return -1;
+	}
+}
+
+/*
+ * create a new fs client
+ *
+ * Success or not, this function consumes @fsopt and @opt.
+ */
+static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
+					struct ceph_options *opt)
+{
+	struct ceph_fs_client *fsc;
+	int err;
+
+	fsc = kzalloc(sizeof(*fsc), GFP_KERNEL);
+	if (!fsc) {
+		err = -ENOMEM;
+		goto fail;
+	}
+
+	fsc->client = ceph_create_client(opt, fsc);
+	if (IS_ERR(fsc->client)) {
+		err = PTR_ERR(fsc->client);
+		goto fail;
+	}
+	opt = NULL; /* fsc->client now owns this */
+
+	fsc->client->extra_mon_dispatch = extra_mon_dispatch;
+	ceph_set_opt(fsc->client, ABORT_ON_FULL);
+
+	if (!fsopt->mds_namespace) {
+		ceph_monc_want_map(&fsc->client->monc, CEPH_SUB_MDSMAP,
+				   0, true);
+	} else {
+		ceph_monc_want_map(&fsc->client->monc, CEPH_SUB_FSMAP,
+				   0, false);
+	}
+
+	fsc->mount_options = fsopt;
+
+	fsc->sb = NULL;
+	fsc->mount_state = CEPH_MOUNT_MOUNTING;
+	fsc->filp_gen = 1;
+	fsc->have_copy_from2 = true;
+
+	atomic_long_set(&fsc->writeback_count, 0);
+	fsc->write_congested = false;
+
+	err = -ENOMEM;
+	/*
+	 * The number of concurrent works can be high but they don't need
+	 * to be processed in parallel, limit concurrency.
+	 */
+	fsc->inode_wq = alloc_workqueue("ceph-inode", WQ_UNBOUND, 0);
+	if (!fsc->inode_wq)
+		goto fail_client;
+	fsc->cap_wq = alloc_workqueue("ceph-cap", 0, 1);
+	if (!fsc->cap_wq)
+		goto fail_inode_wq;
+
+	hash_init(fsc->async_unlink_conflict);
+	spin_lock_init(&fsc->async_unlink_conflict_lock);
+
+	spin_lock(&ceph_fsc_lock);
+	list_add_tail(&fsc->metric_wakeup, &ceph_fsc_list);
+	spin_unlock(&ceph_fsc_lock);
+
+	return fsc;
+
+fail_inode_wq:
+	destroy_workqueue(fsc->inode_wq);
+fail_client:
+	ceph_destroy_client(fsc->client);
+fail:
+	kfree(fsc);
+	if (opt)
+		ceph_destroy_options(opt);
+	destroy_mount_options(fsopt);
+	return ERR_PTR(err);
+}
+
+static void flush_fs_workqueues(struct ceph_fs_client *fsc)
+{
+	flush_workqueue(fsc->inode_wq);
+	flush_workqueue(fsc->cap_wq);
+}
+
+static void destroy_fs_client(struct ceph_fs_client *fsc)
+{
+	dout("destroy_fs_client %p\n", fsc);
+
+	spin_lock(&ceph_fsc_lock);
+	list_del(&fsc->metric_wakeup);
+	spin_unlock(&ceph_fsc_lock);
+
+	ceph_mdsc_destroy(fsc);
+	destroy_workqueue(fsc->inode_wq);
+	destroy_workqueue(fsc->cap_wq);
+
+	destroy_mount_options(fsc->mount_options);
+
+	ceph_destroy_client(fsc->client);
+
+	kfree(fsc);
+	dout("destroy_fs_client %p done\n", fsc);
+}
+
+/*
+ * caches
+ */
+struct kmem_cache *ceph_inode_cachep;
+struct kmem_cache *ceph_cap_cachep;
+struct kmem_cache *ceph_cap_snap_cachep;
+struct kmem_cache *ceph_cap_flush_cachep;
+struct kmem_cache *ceph_dentry_cachep;
+struct kmem_cache *ceph_file_cachep;
+struct kmem_cache *ceph_dir_file_cachep;
+struct kmem_cache *ceph_mds_request_cachep;
+mempool_t *ceph_wb_pagevec_pool;
+
+static void ceph_inode_init_once(void *foo)
+{
+	struct ceph_inode_info *ci = foo;
+	inode_init_once(&ci->netfs.inode);
+}
+
+static int __init init_caches(void)
+{
+	int error = -ENOMEM;
+
+	ceph_inode_cachep = kmem_cache_create("ceph_inode_info",
+				      sizeof(struct ceph_inode_info),
+				      __alignof__(struct ceph_inode_info),
+				      SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD|
+				      SLAB_ACCOUNT, ceph_inode_init_once);
+	if (!ceph_inode_cachep)
+		return -ENOMEM;
+
+	ceph_cap_cachep = KMEM_CACHE(ceph_cap, SLAB_MEM_SPREAD);
+	if (!ceph_cap_cachep)
+		goto bad_cap;
+	ceph_cap_snap_cachep = KMEM_CACHE(ceph_cap_snap, SLAB_MEM_SPREAD);
+	if (!ceph_cap_snap_cachep)
+		goto bad_cap_snap;
+	ceph_cap_flush_cachep = KMEM_CACHE(ceph_cap_flush,
+					   SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
+	if (!ceph_cap_flush_cachep)
+		goto bad_cap_flush;
+
+	ceph_dentry_cachep = KMEM_CACHE(ceph_dentry_info,
+					SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD);
+	if (!ceph_dentry_cachep)
+		goto bad_dentry;
+
+	ceph_file_cachep = KMEM_CACHE(ceph_file_info, SLAB_MEM_SPREAD);
+	if (!ceph_file_cachep)
+		goto bad_file;
+
+	ceph_dir_file_cachep = KMEM_CACHE(ceph_dir_file_info, SLAB_MEM_SPREAD);
+	if (!ceph_dir_file_cachep)
+		goto bad_dir_file;
+
+	ceph_mds_request_cachep = KMEM_CACHE(ceph_mds_request, SLAB_MEM_SPREAD);
+	if (!ceph_mds_request_cachep)
+		goto bad_mds_req;
+
+	ceph_wb_pagevec_pool = mempool_create_kmalloc_pool(10, CEPH_MAX_WRITE_SIZE >> PAGE_SHIFT);
+	if (!ceph_wb_pagevec_pool)
+		goto bad_pagevec_pool;
+
+	return 0;
+
+bad_pagevec_pool:
+	kmem_cache_destroy(ceph_mds_request_cachep);
+bad_mds_req:
+	kmem_cache_destroy(ceph_dir_file_cachep);
+bad_dir_file:
+	kmem_cache_destroy(ceph_file_cachep);
+bad_file:
+	kmem_cache_destroy(ceph_dentry_cachep);
+bad_dentry:
+	kmem_cache_destroy(ceph_cap_flush_cachep);
+bad_cap_flush:
+	kmem_cache_destroy(ceph_cap_snap_cachep);
+bad_cap_snap:
+	kmem_cache_destroy(ceph_cap_cachep);
+bad_cap:
+	kmem_cache_destroy(ceph_inode_cachep);
+	return error;
+}
+
+static void destroy_caches(void)
+{
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+
+	kmem_cache_destroy(ceph_inode_cachep);
+	kmem_cache_destroy(ceph_cap_cachep);
+	kmem_cache_destroy(ceph_cap_snap_cachep);
+	kmem_cache_destroy(ceph_cap_flush_cachep);
+	kmem_cache_destroy(ceph_dentry_cachep);
+	kmem_cache_destroy(ceph_file_cachep);
+	kmem_cache_destroy(ceph_dir_file_cachep);
+	kmem_cache_destroy(ceph_mds_request_cachep);
+	mempool_destroy(ceph_wb_pagevec_pool);
+}
+
+static void __ceph_umount_begin(struct ceph_fs_client *fsc)
+{
+	ceph_osdc_abort_requests(&fsc->client->osdc, -EIO);
+	ceph_mdsc_force_umount(fsc->mdsc);
+	fsc->filp_gen++; // invalidate open files
+}
+
+/*
+ * ceph_umount_begin - initiate forced umount.  Tear down the
+ * mount, skipping steps that may hang while waiting for server(s).
+ */
+void ceph_umount_begin(struct super_block *sb)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
+
+	dout("ceph_umount_begin - starting forced umount\n");
+	if (!fsc)
+		return;
+	fsc->mount_state = CEPH_MOUNT_SHUTDOWN;
+	__ceph_umount_begin(fsc);
+}
+
+static const struct super_operations ceph_super_ops = {
+	.alloc_inode	= ceph_alloc_inode,
+	.free_inode	= ceph_free_inode,
+	.write_inode    = ceph_write_inode,
+	.drop_inode	= generic_delete_inode,
+	.evict_inode	= ceph_evict_inode,
+	.sync_fs        = ceph_sync_fs,
+	.put_super	= ceph_put_super,
+	.show_options   = ceph_show_options,
+	.statfs		= ceph_statfs,
+	.umount_begin   = ceph_umount_begin,
+};
+
+/*
+ * Bootstrap mount by opening the root directory.  Note the mount
+ * @started time from caller, and time out if this takes too long.
+ */
+static struct dentry *open_root_dentry(struct ceph_fs_client *fsc,
+				       const char *path,
+				       unsigned long started)
+{
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	struct ceph_mds_request *req = NULL;
+	int err;
+	struct dentry *root;
+
+	/* open dir */
+	dout("open_root_inode opening '%s'\n", path);
+	req = ceph_mdsc_create_request(mdsc, CEPH_MDS_OP_GETATTR, USE_ANY_MDS);
+	if (IS_ERR(req))
+		return ERR_CAST(req);
+	req->r_path1 = kstrdup(path, GFP_NOFS);
+	if (!req->r_path1) {
+		root = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+
+	req->r_ino1.ino = CEPH_INO_ROOT;
+	req->r_ino1.snap = CEPH_NOSNAP;
+	req->r_started = started;
+	req->r_timeout = fsc->client->options->mount_timeout;
+	req->r_args.getattr.mask = cpu_to_le32(CEPH_STAT_CAP_INODE);
+	req->r_num_caps = 2;
+	err = ceph_mdsc_do_request(mdsc, NULL, req);
+	if (err == 0) {
+		struct inode *inode = req->r_target_inode;
+		req->r_target_inode = NULL;
+		dout("open_root_inode success\n");
+		root = d_make_root(inode);
+		if (!root) {
+			root = ERR_PTR(-ENOMEM);
+			goto out;
+		}
+		dout("open_root_inode success, root dentry is %p\n", root);
+	} else {
+		root = ERR_PTR(err);
+	}
+out:
+	ceph_mdsc_put_request(req);
+	return root;
+}
+
+#ifdef CONFIG_FS_ENCRYPTION
+static int ceph_apply_test_dummy_encryption(struct super_block *sb,
+					    struct fs_context *fc,
+					    struct ceph_mount_options *fsopt)
+{
+	struct ceph_fs_client *fsc = sb->s_fs_info;
+
+	if (!fscrypt_is_dummy_policy_set(&fsopt->dummy_enc_policy))
+		return 0;
+
+	/* No changing encryption context on remount. */
+	if (fc->purpose == FS_CONTEXT_FOR_RECONFIGURE &&
+	    !fscrypt_is_dummy_policy_set(&fsc->fsc_dummy_enc_policy)) {
+		if (fscrypt_dummy_policies_equal(&fsopt->dummy_enc_policy,
+						 &fsc->fsc_dummy_enc_policy))
+			return 0;
+		errorfc(fc, "Can't set test_dummy_encryption on remount");
+		return -EINVAL;
+	}
+
+	/* Also make sure fsopt doesn't contain a conflicting value. */
+	if (fscrypt_is_dummy_policy_set(&fsc->fsc_dummy_enc_policy)) {
+		if (fscrypt_dummy_policies_equal(&fsopt->dummy_enc_policy,
+						 &fsc->fsc_dummy_enc_policy))
+			return 0;
+		errorfc(fc, "Conflicting test_dummy_encryption options");
+		return -EINVAL;
+	}
+
+	fsc->fsc_dummy_enc_policy = fsopt->dummy_enc_policy;
+	memset(&fsopt->dummy_enc_policy, 0, sizeof(fsopt->dummy_enc_policy));
+
+	warnfc(fc, "test_dummy_encryption mode enabled");
+	return 0;
+}
+#else
+static int ceph_apply_test_dummy_encryption(struct super_block *sb,
+					    struct fs_context *fc,
+					    struct ceph_mount_options *fsopt)
+{
+	return 0;
+}
+#endif
+
+/*
+ * mount: join the ceph cluster, and open root directory.
+ */
+static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc,
+				      struct fs_context *fc)
+{
+	int err;
+	unsigned long started = jiffies;  /* note the start time */
+	struct dentry *root;
+
+	dout("mount start %p\n", fsc);
+	mutex_lock(&fsc->client->mount_mutex);
+
+	if (!fsc->sb->s_root) {
+		const char *path = fsc->mount_options->server_path ?
+				     fsc->mount_options->server_path + 1 : "";
+
+		err = __ceph_open_session(fsc->client, started);
+		if (err < 0)
+			goto out;
+
+		/* setup fscache */
+		if (fsc->mount_options->flags & CEPH_MOUNT_OPT_FSCACHE) {
+			err = ceph_fscache_register_fs(fsc, fc);
+			if (err < 0)
+				goto out;
+		}
+
+		err = ceph_apply_test_dummy_encryption(fsc->sb, fc,
+						       fsc->mount_options);
+		if (err)
+			goto out;
+
+		dout("mount opening path '%s'\n", path);
+
+		ceph_fs_debugfs_init(fsc);
+
+		root = open_root_dentry(fsc, path, started);
+		if (IS_ERR(root)) {
+			err = PTR_ERR(root);
+			goto out;
+		}
+		fsc->sb->s_root = dget(root);
+	} else {
+		root = dget(fsc->sb->s_root);
+	}
+
+	fsc->mount_state = CEPH_MOUNT_MOUNTED;
+	dout("mount success\n");
+	mutex_unlock(&fsc->client->mount_mutex);
+	return root;
+
+out:
+	mutex_unlock(&fsc->client->mount_mutex);
+	ceph_fscrypt_free_dummy_policy(fsc);
+	return ERR_PTR(err);
+}
+
+static int ceph_set_super(struct super_block *s, struct fs_context *fc)
+{
+	struct ceph_fs_client *fsc = s->s_fs_info;
+	int ret;
+
+	dout("set_super %p\n", s);
+
+	s->s_maxbytes = MAX_LFS_FILESIZE;
+
+	s->s_xattr = ceph_xattr_handlers;
+	fsc->sb = s;
+	fsc->max_file_size = 1ULL << 40; /* temp value until we get mdsmap */
+
+	s->s_op = &ceph_super_ops;
+	s->s_d_op = &ceph_dentry_ops;
+	s->s_export_op = &ceph_export_ops;
+
+	s->s_time_gran = 1;
+	s->s_time_min = 0;
+	s->s_time_max = U32_MAX;
+	s->s_flags |= SB_NODIRATIME | SB_NOATIME;
+
+	ceph_fscrypt_set_ops(s);
+
+	ret = set_anon_super_fc(s, fc);
+	if (ret != 0)
+		fsc->sb = NULL;
+	return ret;
+}
+
+/*
+ * share superblock if same fs AND options
+ */
+static int ceph_compare_super(struct super_block *sb, struct fs_context *fc)
+{
+	struct ceph_fs_client *new = fc->s_fs_info;
+	struct ceph_mount_options *fsopt = new->mount_options;
+	struct ceph_options *opt = new->client->options;
+	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
+
+	dout("ceph_compare_super %p\n", sb);
+
+	if (compare_mount_options(fsopt, opt, fsc)) {
+		dout("monitor(s)/mount options don't match\n");
+		return 0;
+	}
+	if ((opt->flags & CEPH_OPT_FSID) &&
+	    ceph_fsid_compare(&opt->fsid, &fsc->client->fsid)) {
+		dout("fsid doesn't match\n");
+		return 0;
+	}
+	if (fc->sb_flags != (sb->s_flags & ~SB_BORN)) {
+		dout("flags differ\n");
+		return 0;
+	}
+
+	if (fsc->blocklisted && !ceph_test_mount_opt(fsc, CLEANRECOVER)) {
+		dout("client is blocklisted (and CLEANRECOVER is not set)\n");
+		return 0;
+	}
+
+	if (fsc->mount_state == CEPH_MOUNT_SHUTDOWN) {
+		dout("client has been forcibly unmounted\n");
+		return 0;
+	}
+
+	return 1;
+}
+
+/*
+ * construct our own bdi so we can control readahead, etc.
+ */
+static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
+
+static int ceph_setup_bdi(struct super_block *sb, struct ceph_fs_client *fsc)
+{
+	int err;
+
+	err = super_setup_bdi_name(sb, "ceph-%ld",
+				   atomic_long_inc_return(&bdi_seq));
+	if (err)
+		return err;
+
+	/* set ra_pages based on rasize mount option? */
+	sb->s_bdi->ra_pages = fsc->mount_options->rasize >> PAGE_SHIFT;
+
+	/* set io_pages based on max osd read size */
+	sb->s_bdi->io_pages = fsc->mount_options->rsize >> PAGE_SHIFT;
+
+	return 0;
+}
+
+static int ceph_get_tree(struct fs_context *fc)
+{
+	struct ceph_parse_opts_ctx *pctx = fc->fs_private;
+	struct ceph_mount_options *fsopt = pctx->opts;
+	struct super_block *sb;
+	struct ceph_fs_client *fsc;
+	struct dentry *res;
+	int (*compare_super)(struct super_block *, struct fs_context *) =
+		ceph_compare_super;
+	int err;
+
+	dout("ceph_get_tree\n");
+
+	if (!fc->source)
+		return invalfc(fc, "No source");
+	if (fsopt->new_dev_syntax && !fsopt->mon_addr)
+		return invalfc(fc, "No monitor address");
+
+	/* create client (which we may/may not use) */
+	fsc = create_fs_client(pctx->opts, pctx->copts);
+	pctx->opts = NULL;
+	pctx->copts = NULL;
+	if (IS_ERR(fsc)) {
+		err = PTR_ERR(fsc);
+		goto out_final;
+	}
+
+	err = ceph_mdsc_init(fsc);
+	if (err < 0)
+		goto out;
+
+	if (ceph_test_opt(fsc->client, NOSHARE))
+		compare_super = NULL;
+
+	fc->s_fs_info = fsc;
+	sb = sget_fc(fc, compare_super, ceph_set_super);
+	fc->s_fs_info = NULL;
+	if (IS_ERR(sb)) {
+		err = PTR_ERR(sb);
+		goto out;
+	}
+
+	if (ceph_sb_to_client(sb) != fsc) {
+		destroy_fs_client(fsc);
+		fsc = ceph_sb_to_client(sb);
+		dout("get_sb got existing client %p\n", fsc);
+	} else {
+		dout("get_sb using new client %p\n", fsc);
+		err = ceph_setup_bdi(sb, fsc);
+		if (err < 0)
+			goto out_splat;
+	}
+
+	res = ceph_real_mount(fsc, fc);
+	if (IS_ERR(res)) {
+		err = PTR_ERR(res);
+		goto out_splat;
+	}
+	dout("root %p inode %p ino %llx.%llx\n", res,
+	     d_inode(res), ceph_vinop(d_inode(res)));
+	fc->root = fsc->sb->s_root;
+	return 0;
+
+out_splat:
+	if (!ceph_mdsmap_is_cluster_available(fsc->mdsc->mdsmap)) {
+		pr_info("No mds server is up or the cluster is laggy\n");
+		err = -EHOSTUNREACH;
+	}
+
+	ceph_mdsc_close_sessions(fsc->mdsc);
+	deactivate_locked_super(sb);
+	goto out_final;
+
+out:
+	destroy_fs_client(fsc);
+out_final:
+	dout("ceph_get_tree fail %d\n", err);
+	return err;
+}
+
+static void ceph_free_fc(struct fs_context *fc)
+{
+	struct ceph_parse_opts_ctx *pctx = fc->fs_private;
+
+	if (pctx) {
+		destroy_mount_options(pctx->opts);
+		ceph_destroy_options(pctx->copts);
+		kfree(pctx);
+	}
+}
+
+static int ceph_reconfigure_fc(struct fs_context *fc)
+{
+	int err;
+	struct ceph_parse_opts_ctx *pctx = fc->fs_private;
+	struct ceph_mount_options *fsopt = pctx->opts;
+	struct super_block *sb = fc->root->d_sb;
+	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
+
+	err = ceph_apply_test_dummy_encryption(sb, fc, fsopt);
+	if (err)
+		return err;
+
+	if (fsopt->flags & CEPH_MOUNT_OPT_ASYNC_DIROPS)
+		ceph_set_mount_opt(fsc, ASYNC_DIROPS);
+	else
+		ceph_clear_mount_opt(fsc, ASYNC_DIROPS);
+
+	if (fsopt->flags & CEPH_MOUNT_OPT_SPARSEREAD)
+		ceph_set_mount_opt(fsc, SPARSEREAD);
+	else
+		ceph_clear_mount_opt(fsc, SPARSEREAD);
+
+	if (strcmp_null(fsc->mount_options->mon_addr, fsopt->mon_addr)) {
+		kfree(fsc->mount_options->mon_addr);
+		fsc->mount_options->mon_addr = fsopt->mon_addr;
+		fsopt->mon_addr = NULL;
+		pr_notice("ceph: monitor addresses recorded, but not used for reconnection");
+	}
+
+	sync_filesystem(sb);
+	return 0;
+}
+
+static const struct fs_context_operations ceph_context_ops = {
+	.free		= ceph_free_fc,
+	.parse_param	= ceph_parse_mount_param,
+	.get_tree	= ceph_get_tree,
+	.reconfigure	= ceph_reconfigure_fc,
+};
+
+/*
+ * Set up the filesystem mount context.
+ */
+static int ceph_init_fs_context(struct fs_context *fc)
+{
+	struct ceph_parse_opts_ctx *pctx;
+	struct ceph_mount_options *fsopt;
+
+	pctx = kzalloc(sizeof(*pctx), GFP_KERNEL);
+	if (!pctx)
+		return -ENOMEM;
+
+	pctx->copts = ceph_alloc_options();
+	if (!pctx->copts)
+		goto nomem;
+
+	pctx->opts = kzalloc(sizeof(*pctx->opts), GFP_KERNEL);
+	if (!pctx->opts)
+		goto nomem;
+
+	fsopt = pctx->opts;
+	fsopt->flags = CEPH_MOUNT_OPT_DEFAULT;
+
+	fsopt->wsize = CEPH_MAX_WRITE_SIZE;
+	fsopt->rsize = CEPH_MAX_READ_SIZE;
+	fsopt->rasize = CEPH_RASIZE_DEFAULT;
+	fsopt->snapdir_name = kstrdup(CEPH_SNAPDIRNAME_DEFAULT, GFP_KERNEL);
+	if (!fsopt->snapdir_name)
+		goto nomem;
+
+	fsopt->caps_wanted_delay_min = CEPH_CAPS_WANTED_DELAY_MIN_DEFAULT;
+	fsopt->caps_wanted_delay_max = CEPH_CAPS_WANTED_DELAY_MAX_DEFAULT;
+	fsopt->max_readdir = CEPH_MAX_READDIR_DEFAULT;
+	fsopt->max_readdir_bytes = CEPH_MAX_READDIR_BYTES_DEFAULT;
+	fsopt->congestion_kb = default_congestion_kb();
+
+#ifdef CONFIG_CEPH_FS_POSIX_ACL
+	fc->sb_flags |= SB_POSIXACL;
+#endif
+
+	fc->fs_private = pctx;
+	fc->ops = &ceph_context_ops;
+	return 0;
+
+nomem:
+	destroy_mount_options(pctx->opts);
+	ceph_destroy_options(pctx->copts);
+	kfree(pctx);
+	return -ENOMEM;
+}
+
+/*
+ * Return true if it successfully increases the blocker counter,
+ * or false if the mdsc is in stopping and flushed state.
+ */
+static bool __inc_stopping_blocker(struct ceph_mds_client *mdsc)
+{
+	spin_lock(&mdsc->stopping_lock);
+	if (mdsc->stopping >= CEPH_MDSC_STOPPING_FLUSHING) {
+		spin_unlock(&mdsc->stopping_lock);
+		return false;
+	}
+	atomic_inc(&mdsc->stopping_blockers);
+	spin_unlock(&mdsc->stopping_lock);
+	return true;
+}
+
+static void __dec_stopping_blocker(struct ceph_mds_client *mdsc)
+{
+	spin_lock(&mdsc->stopping_lock);
+	if (!atomic_dec_return(&mdsc->stopping_blockers) &&
+	    mdsc->stopping >= CEPH_MDSC_STOPPING_FLUSHING)
+		complete_all(&mdsc->stopping_waiter);
+	spin_unlock(&mdsc->stopping_lock);
+}
+
+/* For metadata IO requests */
+bool ceph_inc_mds_stopping_blocker(struct ceph_mds_client *mdsc,
+				   struct ceph_mds_session *session)
+{
+	mutex_lock(&session->s_mutex);
+	inc_session_sequence(session);
+	mutex_unlock(&session->s_mutex);
+
+	return __inc_stopping_blocker(mdsc);
+}
+
+void ceph_dec_mds_stopping_blocker(struct ceph_mds_client *mdsc)
+{
+	__dec_stopping_blocker(mdsc);
+}
+
+/* For data IO requests */
+bool ceph_inc_osd_stopping_blocker(struct ceph_mds_client *mdsc)
+{
+	return __inc_stopping_blocker(mdsc);
+}
+
+void ceph_dec_osd_stopping_blocker(struct ceph_mds_client *mdsc)
+{
+	__dec_stopping_blocker(mdsc);
+}
+
+static void ceph_kill_sb(struct super_block *s)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(s);
+	struct ceph_mds_client *mdsc = fsc->mdsc;
+	bool wait;
+
+	dout("kill_sb %p\n", s);
+
+	ceph_mdsc_pre_umount(mdsc);
+	flush_fs_workqueues(fsc);
+
+	/*
+	 * Though the kill_anon_super() will finally trigger the
+	 * sync_filesystem() anyway, we still need to do it here and
+	 * then bump the stage of shutdown. This will allow us to
+	 * drop any further message, which will increase the inodes'
+	 * i_count reference counters but makes no sense any more,
+	 * from MDSs.
+	 *
+	 * Without this when evicting the inodes it may fail in the
+	 * kill_anon_super(), which will trigger a warning when
+	 * destroying the fscrypt keyring and then possibly trigger
+	 * a further crash in ceph module when the iput() tries to
+	 * evict the inodes later.
+	 */
+	sync_filesystem(s);
+
+	spin_lock(&mdsc->stopping_lock);
+	mdsc->stopping = CEPH_MDSC_STOPPING_FLUSHING;
+	wait = !!atomic_read(&mdsc->stopping_blockers);
+	spin_unlock(&mdsc->stopping_lock);
+
+	if (wait && atomic_read(&mdsc->stopping_blockers)) {
+		long timeleft = wait_for_completion_killable_timeout(
+					&mdsc->stopping_waiter,
+					fsc->client->options->mount_timeout);
+		if (!timeleft) /* timed out */
+			pr_warn("umount timed out, %ld\n", timeleft);
+		else if (timeleft < 0) /* killed */
+			pr_warn("umount was killed, %ld\n", timeleft);
+	}
+
+	mdsc->stopping = CEPH_MDSC_STOPPING_FLUSHED;
+	kill_anon_super(s);
+
+	fsc->client->extra_mon_dispatch = NULL;
+	ceph_fs_debugfs_cleanup(fsc);
+
+	ceph_fscache_unregister_fs(fsc);
+
+	destroy_fs_client(fsc);
+}
+
+static struct file_system_type ceph_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "ceph",
+	.init_fs_context = ceph_init_fs_context,
+	.kill_sb	= ceph_kill_sb,
+	.fs_flags	= FS_RENAME_DOES_D_MOVE,
+};
+MODULE_ALIAS_FS("ceph");
+
+int ceph_force_reconnect(struct super_block *sb)
+{
+	struct ceph_fs_client *fsc = ceph_sb_to_client(sb);
+	int err = 0;
+
+	fsc->mount_state = CEPH_MOUNT_RECOVER;
+	__ceph_umount_begin(fsc);
+
+	/* Make sure all page caches get invalidated.
+	 * see remove_session_caps_cb() */
+	flush_workqueue(fsc->inode_wq);
+
+	/* In case that we were blocklisted. This also reset
+	 * all mon/osd connections */
+	ceph_reset_client_addr(fsc->client);
+
+	ceph_osdc_clear_abort_err(&fsc->client->osdc);
+
+	fsc->blocklisted = false;
+	fsc->mount_state = CEPH_MOUNT_MOUNTED;
+
+	if (sb->s_root) {
+		err = __ceph_do_getattr(d_inode(sb->s_root), NULL,
+					CEPH_STAT_CAP_INODE, true);
+	}
+	return err;
+}
+
+static int __init init_ceph(void)
+{
+	int ret = init_caches();
+	if (ret)
+		goto out;
+
+	ceph_flock_init();
+	ret = register_filesystem(&ceph_fs_type);
+	if (ret)
+		goto out_caches;
+
+	pr_info("loaded (mds proto %d)\n", CEPH_MDSC_PROTOCOL);
+
+	return 0;
+
+out_caches:
+	destroy_caches();
+out:
+	return ret;
+}
+
+static void __exit exit_ceph(void)
+{
+	dout("exit_ceph\n");
+	unregister_filesystem(&ceph_fs_type);
+	destroy_caches();
+}
+
+static int param_set_metrics(const char *val, const struct kernel_param *kp)
+{
+	struct ceph_fs_client *fsc;
+	int ret;
+
+	ret = param_set_bool(val, kp);
+	if (ret) {
+		pr_err("Failed to parse sending metrics switch value '%s'\n",
+		       val);
+		return ret;
+	} else if (!disable_send_metrics) {
+		// wake up all the mds clients
+		spin_lock(&ceph_fsc_lock);
+		list_for_each_entry(fsc, &ceph_fsc_list, metric_wakeup) {
+			metric_schedule_delayed(&fsc->mdsc->metric);
+		}
+		spin_unlock(&ceph_fsc_lock);
+	}
+
+	return 0;
+}
+
+static const struct kernel_param_ops param_ops_metrics = {
+	.set = param_set_metrics,
+	.get = param_get_bool,
+};
+
+bool disable_send_metrics = false;
+module_param_cb(disable_send_metrics, &param_ops_metrics, &disable_send_metrics, 0644);
+MODULE_PARM_DESC(disable_send_metrics, "Enable sending perf metrics to ceph cluster (default: on)");
+
+/* for both v1 and v2 syntax */
+static bool mount_support = true;
+static const struct kernel_param_ops param_ops_mount_syntax = {
+	.get = param_get_bool,
+};
+module_param_cb(mount_syntax_v1, &param_ops_mount_syntax, &mount_support, 0444);
+module_param_cb(mount_syntax_v2, &param_ops_mount_syntax, &mount_support, 0444);
+
+module_init(init_ceph);
+module_exit(exit_ceph);
+
+MODULE_AUTHOR("Sage Weil <sage@newdream.net>");
+MODULE_AUTHOR("Yehuda Sadeh <yehuda@hq.newdream.net>");
+MODULE_AUTHOR("Patience Warnick <patience@newdream.net>");
+MODULE_DESCRIPTION("Ceph filesystem for Linux");
+MODULE_LICENSE("GPL");