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-rw-r--r--fs/erofs/super.c1126
1 files changed, 1126 insertions, 0 deletions
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
new file mode 100644
index 000000000..bd8bf8fc2
--- /dev/null
+++ b/fs/erofs/super.c
@@ -0,0 +1,1126 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ * https://www.huawei.com/
+ * Copyright (C) 2021, Alibaba Cloud
+ */
+#include <linux/module.h>
+#include <linux/buffer_head.h>
+#include <linux/statfs.h>
+#include <linux/parser.h>
+#include <linux/seq_file.h>
+#include <linux/crc32c.h>
+#include <linux/fs_context.h>
+#include <linux/fs_parser.h>
+#include <linux/dax.h>
+#include <linux/exportfs.h>
+#include "xattr.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/erofs.h>
+
+static struct kmem_cache *erofs_inode_cachep __read_mostly;
+
+void _erofs_err(struct super_block *sb, const char *function,
+ const char *fmt, ...)
+{
+ struct va_format vaf;
+ va_list args;
+
+ va_start(args, fmt);
+
+ vaf.fmt = fmt;
+ vaf.va = &args;
+
+ pr_err("(device %s): %s: %pV", sb->s_id, function, &vaf);
+ va_end(args);
+}
+
+void _erofs_info(struct super_block *sb, const char *function,
+ const char *fmt, ...)
+{
+ struct va_format vaf;
+ va_list args;
+
+ va_start(args, fmt);
+
+ vaf.fmt = fmt;
+ vaf.va = &args;
+
+ pr_info("(device %s): %pV", sb->s_id, &vaf);
+ va_end(args);
+}
+
+static int erofs_superblock_csum_verify(struct super_block *sb, void *sbdata)
+{
+ struct erofs_super_block *dsb;
+ u32 expected_crc, crc;
+
+ dsb = kmemdup(sbdata + EROFS_SUPER_OFFSET,
+ EROFS_BLKSIZ - EROFS_SUPER_OFFSET, GFP_KERNEL);
+ if (!dsb)
+ return -ENOMEM;
+
+ expected_crc = le32_to_cpu(dsb->checksum);
+ dsb->checksum = 0;
+ /* to allow for x86 boot sectors and other oddities. */
+ crc = crc32c(~0, dsb, EROFS_BLKSIZ - EROFS_SUPER_OFFSET);
+ kfree(dsb);
+
+ if (crc != expected_crc) {
+ erofs_err(sb, "invalid checksum 0x%08x, 0x%08x expected",
+ crc, expected_crc);
+ return -EBADMSG;
+ }
+ return 0;
+}
+
+static void erofs_inode_init_once(void *ptr)
+{
+ struct erofs_inode *vi = ptr;
+
+ inode_init_once(&vi->vfs_inode);
+}
+
+static struct inode *erofs_alloc_inode(struct super_block *sb)
+{
+ struct erofs_inode *vi =
+ alloc_inode_sb(sb, erofs_inode_cachep, GFP_KERNEL);
+
+ if (!vi)
+ return NULL;
+
+ /* zero out everything except vfs_inode */
+ memset(vi, 0, offsetof(struct erofs_inode, vfs_inode));
+ return &vi->vfs_inode;
+}
+
+static void erofs_free_inode(struct inode *inode)
+{
+ struct erofs_inode *vi = EROFS_I(inode);
+
+ /* be careful of RCU symlink path */
+ if (inode->i_op == &erofs_fast_symlink_iops)
+ kfree(inode->i_link);
+ kfree(vi->xattr_shared_xattrs);
+
+ kmem_cache_free(erofs_inode_cachep, vi);
+}
+
+static bool check_layout_compatibility(struct super_block *sb,
+ struct erofs_super_block *dsb)
+{
+ const unsigned int feature = le32_to_cpu(dsb->feature_incompat);
+
+ EROFS_SB(sb)->feature_incompat = feature;
+
+ /* check if current kernel meets all mandatory requirements */
+ if (feature & (~EROFS_ALL_FEATURE_INCOMPAT)) {
+ erofs_err(sb,
+ "unidentified incompatible feature %x, please upgrade kernel version",
+ feature & ~EROFS_ALL_FEATURE_INCOMPAT);
+ return false;
+ }
+ return true;
+}
+
+#ifdef CONFIG_EROFS_FS_ZIP
+/* read variable-sized metadata, offset will be aligned by 4-byte */
+static void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
+ erofs_off_t *offset, int *lengthp)
+{
+ u8 *buffer, *ptr;
+ int len, i, cnt;
+
+ *offset = round_up(*offset, 4);
+ ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*offset), EROFS_KMAP);
+ if (IS_ERR(ptr))
+ return ptr;
+
+ len = le16_to_cpu(*(__le16 *)&ptr[erofs_blkoff(*offset)]);
+ if (!len)
+ len = U16_MAX + 1;
+ buffer = kmalloc(len, GFP_KERNEL);
+ if (!buffer)
+ return ERR_PTR(-ENOMEM);
+ *offset += sizeof(__le16);
+ *lengthp = len;
+
+ for (i = 0; i < len; i += cnt) {
+ cnt = min(EROFS_BLKSIZ - (int)erofs_blkoff(*offset), len - i);
+ ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*offset),
+ EROFS_KMAP);
+ if (IS_ERR(ptr)) {
+ kfree(buffer);
+ return ptr;
+ }
+ memcpy(buffer + i, ptr + erofs_blkoff(*offset), cnt);
+ *offset += cnt;
+ }
+ return buffer;
+}
+
+static int erofs_load_compr_cfgs(struct super_block *sb,
+ struct erofs_super_block *dsb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ unsigned int algs, alg;
+ erofs_off_t offset;
+ int size, ret = 0;
+
+ sbi->available_compr_algs = le16_to_cpu(dsb->u1.available_compr_algs);
+ if (sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS) {
+ erofs_err(sb, "try to load compressed fs with unsupported algorithms %x",
+ sbi->available_compr_algs & ~Z_EROFS_ALL_COMPR_ALGS);
+ return -EINVAL;
+ }
+
+ offset = EROFS_SUPER_OFFSET + sbi->sb_size;
+ alg = 0;
+ for (algs = sbi->available_compr_algs; algs; algs >>= 1, ++alg) {
+ void *data;
+
+ if (!(algs & 1))
+ continue;
+
+ data = erofs_read_metadata(sb, &buf, &offset, &size);
+ if (IS_ERR(data)) {
+ ret = PTR_ERR(data);
+ break;
+ }
+
+ switch (alg) {
+ case Z_EROFS_COMPRESSION_LZ4:
+ ret = z_erofs_load_lz4_config(sb, dsb, data, size);
+ break;
+ case Z_EROFS_COMPRESSION_LZMA:
+ ret = z_erofs_load_lzma_config(sb, dsb, data, size);
+ break;
+ default:
+ DBG_BUGON(1);
+ ret = -EFAULT;
+ }
+ kfree(data);
+ if (ret)
+ break;
+ }
+ erofs_put_metabuf(&buf);
+ return ret;
+}
+#else
+static int erofs_load_compr_cfgs(struct super_block *sb,
+ struct erofs_super_block *dsb)
+{
+ if (dsb->u1.available_compr_algs) {
+ erofs_err(sb, "try to load compressed fs when compression is disabled");
+ return -EINVAL;
+ }
+ return 0;
+}
+#endif
+
+static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
+ struct erofs_device_info *dif, erofs_off_t *pos)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ struct erofs_fscache *fscache;
+ struct erofs_deviceslot *dis;
+ struct block_device *bdev;
+ void *ptr;
+
+ ptr = erofs_read_metabuf(buf, sb, erofs_blknr(*pos), EROFS_KMAP);
+ if (IS_ERR(ptr))
+ return PTR_ERR(ptr);
+ dis = ptr + erofs_blkoff(*pos);
+
+ if (!dif->path) {
+ if (!dis->tag[0]) {
+ erofs_err(sb, "empty device tag @ pos %llu", *pos);
+ return -EINVAL;
+ }
+ dif->path = kmemdup_nul(dis->tag, sizeof(dis->tag), GFP_KERNEL);
+ if (!dif->path)
+ return -ENOMEM;
+ }
+
+ if (erofs_is_fscache_mode(sb)) {
+ fscache = erofs_fscache_register_cookie(sb, dif->path, 0);
+ if (IS_ERR(fscache))
+ return PTR_ERR(fscache);
+ dif->fscache = fscache;
+ } else {
+ bdev = blkdev_get_by_path(dif->path, FMODE_READ | FMODE_EXCL,
+ sb->s_type);
+ if (IS_ERR(bdev))
+ return PTR_ERR(bdev);
+ dif->bdev = bdev;
+ dif->dax_dev = fs_dax_get_by_bdev(bdev, &dif->dax_part_off,
+ NULL, NULL);
+ }
+
+ dif->blocks = le32_to_cpu(dis->blocks);
+ dif->mapped_blkaddr = le32_to_cpu(dis->mapped_blkaddr);
+ sbi->total_blocks += dif->blocks;
+ *pos += EROFS_DEVT_SLOT_SIZE;
+ return 0;
+}
+
+static int erofs_scan_devices(struct super_block *sb,
+ struct erofs_super_block *dsb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ unsigned int ondisk_extradevs;
+ erofs_off_t pos;
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ struct erofs_device_info *dif;
+ int id, err = 0;
+
+ sbi->total_blocks = sbi->primarydevice_blocks;
+ if (!erofs_sb_has_device_table(sbi))
+ ondisk_extradevs = 0;
+ else
+ ondisk_extradevs = le16_to_cpu(dsb->extra_devices);
+
+ if (sbi->devs->extra_devices &&
+ ondisk_extradevs != sbi->devs->extra_devices) {
+ erofs_err(sb, "extra devices don't match (ondisk %u, given %u)",
+ ondisk_extradevs, sbi->devs->extra_devices);
+ return -EINVAL;
+ }
+ if (!ondisk_extradevs)
+ return 0;
+
+ sbi->device_id_mask = roundup_pow_of_two(ondisk_extradevs + 1) - 1;
+ pos = le16_to_cpu(dsb->devt_slotoff) * EROFS_DEVT_SLOT_SIZE;
+ down_read(&sbi->devs->rwsem);
+ if (sbi->devs->extra_devices) {
+ idr_for_each_entry(&sbi->devs->tree, dif, id) {
+ err = erofs_init_device(&buf, sb, dif, &pos);
+ if (err)
+ break;
+ }
+ } else {
+ for (id = 0; id < ondisk_extradevs; id++) {
+ dif = kzalloc(sizeof(*dif), GFP_KERNEL);
+ if (!dif) {
+ err = -ENOMEM;
+ break;
+ }
+
+ err = idr_alloc(&sbi->devs->tree, dif, 0, 0, GFP_KERNEL);
+ if (err < 0) {
+ kfree(dif);
+ break;
+ }
+ ++sbi->devs->extra_devices;
+
+ err = erofs_init_device(&buf, sb, dif, &pos);
+ if (err)
+ break;
+ }
+ }
+ up_read(&sbi->devs->rwsem);
+ erofs_put_metabuf(&buf);
+ return err;
+}
+
+static int erofs_read_superblock(struct super_block *sb)
+{
+ struct erofs_sb_info *sbi;
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+ struct erofs_super_block *dsb;
+ unsigned int blkszbits;
+ void *data;
+ int ret;
+
+ data = erofs_read_metabuf(&buf, sb, 0, EROFS_KMAP);
+ if (IS_ERR(data)) {
+ erofs_err(sb, "cannot read erofs superblock");
+ return PTR_ERR(data);
+ }
+
+ sbi = EROFS_SB(sb);
+ dsb = (struct erofs_super_block *)(data + EROFS_SUPER_OFFSET);
+
+ ret = -EINVAL;
+ if (le32_to_cpu(dsb->magic) != EROFS_SUPER_MAGIC_V1) {
+ erofs_err(sb, "cannot find valid erofs superblock");
+ goto out;
+ }
+
+ sbi->feature_compat = le32_to_cpu(dsb->feature_compat);
+ if (erofs_sb_has_sb_chksum(sbi)) {
+ ret = erofs_superblock_csum_verify(sb, data);
+ if (ret)
+ goto out;
+ }
+
+ ret = -EINVAL;
+ blkszbits = dsb->blkszbits;
+ /* 9(512 bytes) + LOG_SECTORS_PER_BLOCK == LOG_BLOCK_SIZE */
+ if (blkszbits != LOG_BLOCK_SIZE) {
+ erofs_err(sb, "blkszbits %u isn't supported on this platform",
+ blkszbits);
+ goto out;
+ }
+
+ if (!check_layout_compatibility(sb, dsb))
+ goto out;
+
+ sbi->sb_size = 128 + dsb->sb_extslots * EROFS_SB_EXTSLOT_SIZE;
+ if (sbi->sb_size > EROFS_BLKSIZ) {
+ erofs_err(sb, "invalid sb_extslots %u (more than a fs block)",
+ sbi->sb_size);
+ goto out;
+ }
+ sbi->primarydevice_blocks = le32_to_cpu(dsb->blocks);
+ sbi->meta_blkaddr = le32_to_cpu(dsb->meta_blkaddr);
+#ifdef CONFIG_EROFS_FS_XATTR
+ sbi->xattr_blkaddr = le32_to_cpu(dsb->xattr_blkaddr);
+#endif
+ sbi->islotbits = ilog2(sizeof(struct erofs_inode_compact));
+ sbi->root_nid = le16_to_cpu(dsb->root_nid);
+ sbi->packed_nid = le64_to_cpu(dsb->packed_nid);
+ sbi->inos = le64_to_cpu(dsb->inos);
+
+ sbi->build_time = le64_to_cpu(dsb->build_time);
+ sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
+
+ memcpy(&sb->s_uuid, dsb->uuid, sizeof(dsb->uuid));
+
+ ret = strscpy(sbi->volume_name, dsb->volume_name,
+ sizeof(dsb->volume_name));
+ if (ret < 0) { /* -E2BIG */
+ erofs_err(sb, "bad volume name without NIL terminator");
+ ret = -EFSCORRUPTED;
+ goto out;
+ }
+
+ /* parse on-disk compression configurations */
+ if (erofs_sb_has_compr_cfgs(sbi))
+ ret = erofs_load_compr_cfgs(sb, dsb);
+ else
+ ret = z_erofs_load_lz4_config(sb, dsb, NULL, 0);
+ if (ret < 0)
+ goto out;
+
+ /* handle multiple devices */
+ ret = erofs_scan_devices(sb, dsb);
+
+ if (erofs_sb_has_ztailpacking(sbi))
+ erofs_info(sb, "EXPERIMENTAL compressed inline data feature in use. Use at your own risk!");
+ if (erofs_is_fscache_mode(sb))
+ erofs_info(sb, "EXPERIMENTAL fscache-based on-demand read feature in use. Use at your own risk!");
+ if (erofs_sb_has_fragments(sbi))
+ erofs_info(sb, "EXPERIMENTAL compressed fragments feature in use. Use at your own risk!");
+ if (erofs_sb_has_dedupe(sbi))
+ erofs_info(sb, "EXPERIMENTAL global deduplication feature in use. Use at your own risk!");
+out:
+ erofs_put_metabuf(&buf);
+ return ret;
+}
+
+/* set up default EROFS parameters */
+static void erofs_default_options(struct erofs_fs_context *ctx)
+{
+#ifdef CONFIG_EROFS_FS_ZIP
+ ctx->opt.cache_strategy = EROFS_ZIP_CACHE_READAROUND;
+ ctx->opt.max_sync_decompress_pages = 3;
+ ctx->opt.sync_decompress = EROFS_SYNC_DECOMPRESS_AUTO;
+#endif
+#ifdef CONFIG_EROFS_FS_XATTR
+ set_opt(&ctx->opt, XATTR_USER);
+#endif
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+ set_opt(&ctx->opt, POSIX_ACL);
+#endif
+}
+
+enum {
+ Opt_user_xattr,
+ Opt_acl,
+ Opt_cache_strategy,
+ Opt_dax,
+ Opt_dax_enum,
+ Opt_device,
+ Opt_fsid,
+ Opt_domain_id,
+ Opt_err
+};
+
+static const struct constant_table erofs_param_cache_strategy[] = {
+ {"disabled", EROFS_ZIP_CACHE_DISABLED},
+ {"readahead", EROFS_ZIP_CACHE_READAHEAD},
+ {"readaround", EROFS_ZIP_CACHE_READAROUND},
+ {}
+};
+
+static const struct constant_table erofs_dax_param_enums[] = {
+ {"always", EROFS_MOUNT_DAX_ALWAYS},
+ {"never", EROFS_MOUNT_DAX_NEVER},
+ {}
+};
+
+static const struct fs_parameter_spec erofs_fs_parameters[] = {
+ fsparam_flag_no("user_xattr", Opt_user_xattr),
+ fsparam_flag_no("acl", Opt_acl),
+ fsparam_enum("cache_strategy", Opt_cache_strategy,
+ erofs_param_cache_strategy),
+ fsparam_flag("dax", Opt_dax),
+ fsparam_enum("dax", Opt_dax_enum, erofs_dax_param_enums),
+ fsparam_string("device", Opt_device),
+ fsparam_string("fsid", Opt_fsid),
+ fsparam_string("domain_id", Opt_domain_id),
+ {}
+};
+
+static bool erofs_fc_set_dax_mode(struct fs_context *fc, unsigned int mode)
+{
+#ifdef CONFIG_FS_DAX
+ struct erofs_fs_context *ctx = fc->fs_private;
+
+ switch (mode) {
+ case EROFS_MOUNT_DAX_ALWAYS:
+ warnfc(fc, "DAX enabled. Warning: EXPERIMENTAL, use at your own risk");
+ set_opt(&ctx->opt, DAX_ALWAYS);
+ clear_opt(&ctx->opt, DAX_NEVER);
+ return true;
+ case EROFS_MOUNT_DAX_NEVER:
+ set_opt(&ctx->opt, DAX_NEVER);
+ clear_opt(&ctx->opt, DAX_ALWAYS);
+ return true;
+ default:
+ DBG_BUGON(1);
+ return false;
+ }
+#else
+ errorfc(fc, "dax options not supported");
+ return false;
+#endif
+}
+
+static int erofs_fc_parse_param(struct fs_context *fc,
+ struct fs_parameter *param)
+{
+ struct erofs_fs_context *ctx = fc->fs_private;
+ struct fs_parse_result result;
+ struct erofs_device_info *dif;
+ int opt, ret;
+
+ opt = fs_parse(fc, erofs_fs_parameters, param, &result);
+ if (opt < 0)
+ return opt;
+
+ switch (opt) {
+ case Opt_user_xattr:
+#ifdef CONFIG_EROFS_FS_XATTR
+ if (result.boolean)
+ set_opt(&ctx->opt, XATTR_USER);
+ else
+ clear_opt(&ctx->opt, XATTR_USER);
+#else
+ errorfc(fc, "{,no}user_xattr options not supported");
+#endif
+ break;
+ case Opt_acl:
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+ if (result.boolean)
+ set_opt(&ctx->opt, POSIX_ACL);
+ else
+ clear_opt(&ctx->opt, POSIX_ACL);
+#else
+ errorfc(fc, "{,no}acl options not supported");
+#endif
+ break;
+ case Opt_cache_strategy:
+#ifdef CONFIG_EROFS_FS_ZIP
+ ctx->opt.cache_strategy = result.uint_32;
+#else
+ errorfc(fc, "compression not supported, cache_strategy ignored");
+#endif
+ break;
+ case Opt_dax:
+ if (!erofs_fc_set_dax_mode(fc, EROFS_MOUNT_DAX_ALWAYS))
+ return -EINVAL;
+ break;
+ case Opt_dax_enum:
+ if (!erofs_fc_set_dax_mode(fc, result.uint_32))
+ return -EINVAL;
+ break;
+ case Opt_device:
+ dif = kzalloc(sizeof(*dif), GFP_KERNEL);
+ if (!dif)
+ return -ENOMEM;
+ dif->path = kstrdup(param->string, GFP_KERNEL);
+ if (!dif->path) {
+ kfree(dif);
+ return -ENOMEM;
+ }
+ down_write(&ctx->devs->rwsem);
+ ret = idr_alloc(&ctx->devs->tree, dif, 0, 0, GFP_KERNEL);
+ up_write(&ctx->devs->rwsem);
+ if (ret < 0) {
+ kfree(dif->path);
+ kfree(dif);
+ return ret;
+ }
+ ++ctx->devs->extra_devices;
+ break;
+#ifdef CONFIG_EROFS_FS_ONDEMAND
+ case Opt_fsid:
+ kfree(ctx->fsid);
+ ctx->fsid = kstrdup(param->string, GFP_KERNEL);
+ if (!ctx->fsid)
+ return -ENOMEM;
+ break;
+ case Opt_domain_id:
+ kfree(ctx->domain_id);
+ ctx->domain_id = kstrdup(param->string, GFP_KERNEL);
+ if (!ctx->domain_id)
+ return -ENOMEM;
+ break;
+#else
+ case Opt_fsid:
+ case Opt_domain_id:
+ errorfc(fc, "%s option not supported", erofs_fs_parameters[opt].name);
+ break;
+#endif
+ default:
+ return -ENOPARAM;
+ }
+ return 0;
+}
+
+#ifdef CONFIG_EROFS_FS_ZIP
+static const struct address_space_operations managed_cache_aops;
+
+static bool erofs_managed_cache_release_folio(struct folio *folio, gfp_t gfp)
+{
+ bool ret = true;
+ struct address_space *const mapping = folio->mapping;
+
+ DBG_BUGON(!folio_test_locked(folio));
+ DBG_BUGON(mapping->a_ops != &managed_cache_aops);
+
+ if (folio_test_private(folio))
+ ret = erofs_try_to_free_cached_page(&folio->page);
+
+ return ret;
+}
+
+/*
+ * It will be called only on inode eviction. In case that there are still some
+ * decompression requests in progress, wait with rescheduling for a bit here.
+ * We could introduce an extra locking instead but it seems unnecessary.
+ */
+static void erofs_managed_cache_invalidate_folio(struct folio *folio,
+ size_t offset, size_t length)
+{
+ const size_t stop = length + offset;
+
+ DBG_BUGON(!folio_test_locked(folio));
+
+ /* Check for potential overflow in debug mode */
+ DBG_BUGON(stop > folio_size(folio) || stop < length);
+
+ if (offset == 0 && stop == folio_size(folio))
+ while (!erofs_managed_cache_release_folio(folio, GFP_NOFS))
+ cond_resched();
+}
+
+static const struct address_space_operations managed_cache_aops = {
+ .release_folio = erofs_managed_cache_release_folio,
+ .invalidate_folio = erofs_managed_cache_invalidate_folio,
+};
+
+static int erofs_init_managed_cache(struct super_block *sb)
+{
+ struct erofs_sb_info *const sbi = EROFS_SB(sb);
+ struct inode *const inode = new_inode(sb);
+
+ if (!inode)
+ return -ENOMEM;
+
+ set_nlink(inode, 1);
+ inode->i_size = OFFSET_MAX;
+
+ inode->i_mapping->a_ops = &managed_cache_aops;
+ mapping_set_gfp_mask(inode->i_mapping, GFP_NOFS);
+ sbi->managed_cache = inode;
+ return 0;
+}
+#else
+static int erofs_init_managed_cache(struct super_block *sb) { return 0; }
+#endif
+
+static struct inode *erofs_nfs_get_inode(struct super_block *sb,
+ u64 ino, u32 generation)
+{
+ return erofs_iget(sb, ino);
+}
+
+static struct dentry *erofs_fh_to_dentry(struct super_block *sb,
+ struct fid *fid, int fh_len, int fh_type)
+{
+ return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+ erofs_nfs_get_inode);
+}
+
+static struct dentry *erofs_fh_to_parent(struct super_block *sb,
+ struct fid *fid, int fh_len, int fh_type)
+{
+ return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+ erofs_nfs_get_inode);
+}
+
+static struct dentry *erofs_get_parent(struct dentry *child)
+{
+ erofs_nid_t nid;
+ unsigned int d_type;
+ int err;
+
+ err = erofs_namei(d_inode(child), &dotdot_name, &nid, &d_type);
+ if (err)
+ return ERR_PTR(err);
+ return d_obtain_alias(erofs_iget(child->d_sb, nid));
+}
+
+static const struct export_operations erofs_export_ops = {
+ .fh_to_dentry = erofs_fh_to_dentry,
+ .fh_to_parent = erofs_fh_to_parent,
+ .get_parent = erofs_get_parent,
+};
+
+static int erofs_fc_fill_pseudo_super(struct super_block *sb, struct fs_context *fc)
+{
+ static const struct tree_descr empty_descr = {""};
+
+ return simple_fill_super(sb, EROFS_SUPER_MAGIC, &empty_descr);
+}
+
+static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
+{
+ struct inode *inode;
+ struct erofs_sb_info *sbi;
+ struct erofs_fs_context *ctx = fc->fs_private;
+ int err;
+
+ sb->s_magic = EROFS_SUPER_MAGIC;
+ sb->s_flags |= SB_RDONLY | SB_NOATIME;
+ sb->s_maxbytes = MAX_LFS_FILESIZE;
+ sb->s_op = &erofs_sops;
+
+ sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
+ if (!sbi)
+ return -ENOMEM;
+
+ sb->s_fs_info = sbi;
+ sbi->opt = ctx->opt;
+ sbi->devs = ctx->devs;
+ ctx->devs = NULL;
+ sbi->fsid = ctx->fsid;
+ ctx->fsid = NULL;
+ sbi->domain_id = ctx->domain_id;
+ ctx->domain_id = NULL;
+
+ if (erofs_is_fscache_mode(sb)) {
+ sb->s_blocksize = EROFS_BLKSIZ;
+ sb->s_blocksize_bits = LOG_BLOCK_SIZE;
+
+ err = erofs_fscache_register_fs(sb);
+ if (err)
+ return err;
+
+ err = super_setup_bdi(sb);
+ if (err)
+ return err;
+ } else {
+ if (!sb_set_blocksize(sb, EROFS_BLKSIZ)) {
+ erofs_err(sb, "failed to set erofs blksize");
+ return -EINVAL;
+ }
+
+ sbi->dax_dev = fs_dax_get_by_bdev(sb->s_bdev,
+ &sbi->dax_part_off,
+ NULL, NULL);
+ }
+
+ err = erofs_read_superblock(sb);
+ if (err)
+ return err;
+
+ if (test_opt(&sbi->opt, DAX_ALWAYS)) {
+ BUILD_BUG_ON(EROFS_BLKSIZ != PAGE_SIZE);
+
+ if (!sbi->dax_dev) {
+ errorfc(fc, "DAX unsupported by block device. Turning off DAX.");
+ clear_opt(&sbi->opt, DAX_ALWAYS);
+ }
+ }
+
+ sb->s_time_gran = 1;
+ sb->s_xattr = erofs_xattr_handlers;
+ sb->s_export_op = &erofs_export_ops;
+
+ if (test_opt(&sbi->opt, POSIX_ACL))
+ sb->s_flags |= SB_POSIXACL;
+ else
+ sb->s_flags &= ~SB_POSIXACL;
+
+#ifdef CONFIG_EROFS_FS_ZIP
+ xa_init(&sbi->managed_pslots);
+#endif
+
+ /* get the root inode */
+ inode = erofs_iget(sb, ROOT_NID(sbi));
+ if (IS_ERR(inode))
+ return PTR_ERR(inode);
+
+ if (!S_ISDIR(inode->i_mode)) {
+ erofs_err(sb, "rootino(nid %llu) is not a directory(i_mode %o)",
+ ROOT_NID(sbi), inode->i_mode);
+ iput(inode);
+ return -EINVAL;
+ }
+
+ sb->s_root = d_make_root(inode);
+ if (!sb->s_root)
+ return -ENOMEM;
+
+ erofs_shrinker_register(sb);
+ /* sb->s_umount is already locked, SB_ACTIVE and SB_BORN are not set */
+#ifdef CONFIG_EROFS_FS_ZIP
+ if (erofs_sb_has_fragments(sbi) && sbi->packed_nid) {
+ sbi->packed_inode = erofs_iget(sb, sbi->packed_nid);
+ if (IS_ERR(sbi->packed_inode)) {
+ err = PTR_ERR(sbi->packed_inode);
+ sbi->packed_inode = NULL;
+ return err;
+ }
+ }
+#endif
+ err = erofs_init_managed_cache(sb);
+ if (err)
+ return err;
+
+ err = erofs_register_sysfs(sb);
+ if (err)
+ return err;
+
+ erofs_info(sb, "mounted with root inode @ nid %llu.", ROOT_NID(sbi));
+ return 0;
+}
+
+static int erofs_fc_anon_get_tree(struct fs_context *fc)
+{
+ return get_tree_nodev(fc, erofs_fc_fill_pseudo_super);
+}
+
+static int erofs_fc_get_tree(struct fs_context *fc)
+{
+ struct erofs_fs_context *ctx = fc->fs_private;
+
+ if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && ctx->fsid)
+ return get_tree_nodev(fc, erofs_fc_fill_super);
+
+ return get_tree_bdev(fc, erofs_fc_fill_super);
+}
+
+static int erofs_fc_reconfigure(struct fs_context *fc)
+{
+ struct super_block *sb = fc->root->d_sb;
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ struct erofs_fs_context *ctx = fc->fs_private;
+
+ DBG_BUGON(!sb_rdonly(sb));
+
+ if (ctx->fsid || ctx->domain_id)
+ erofs_info(sb, "ignoring reconfiguration for fsid|domain_id.");
+
+ if (test_opt(&ctx->opt, POSIX_ACL))
+ fc->sb_flags |= SB_POSIXACL;
+ else
+ fc->sb_flags &= ~SB_POSIXACL;
+
+ sbi->opt = ctx->opt;
+
+ fc->sb_flags |= SB_RDONLY;
+ return 0;
+}
+
+static int erofs_release_device_info(int id, void *ptr, void *data)
+{
+ struct erofs_device_info *dif = ptr;
+
+ fs_put_dax(dif->dax_dev, NULL);
+ if (dif->bdev)
+ blkdev_put(dif->bdev, FMODE_READ | FMODE_EXCL);
+ erofs_fscache_unregister_cookie(dif->fscache);
+ dif->fscache = NULL;
+ kfree(dif->path);
+ kfree(dif);
+ return 0;
+}
+
+static void erofs_free_dev_context(struct erofs_dev_context *devs)
+{
+ if (!devs)
+ return;
+ idr_for_each(&devs->tree, &erofs_release_device_info, NULL);
+ idr_destroy(&devs->tree);
+ kfree(devs);
+}
+
+static void erofs_fc_free(struct fs_context *fc)
+{
+ struct erofs_fs_context *ctx = fc->fs_private;
+
+ erofs_free_dev_context(ctx->devs);
+ kfree(ctx->fsid);
+ kfree(ctx->domain_id);
+ kfree(ctx);
+}
+
+static const struct fs_context_operations erofs_context_ops = {
+ .parse_param = erofs_fc_parse_param,
+ .get_tree = erofs_fc_get_tree,
+ .reconfigure = erofs_fc_reconfigure,
+ .free = erofs_fc_free,
+};
+
+static const struct fs_context_operations erofs_anon_context_ops = {
+ .get_tree = erofs_fc_anon_get_tree,
+};
+
+static int erofs_init_fs_context(struct fs_context *fc)
+{
+ struct erofs_fs_context *ctx;
+
+ /* pseudo mount for anon inodes */
+ if (fc->sb_flags & SB_KERNMOUNT) {
+ fc->ops = &erofs_anon_context_ops;
+ return 0;
+ }
+
+ ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+ if (!ctx)
+ return -ENOMEM;
+ ctx->devs = kzalloc(sizeof(struct erofs_dev_context), GFP_KERNEL);
+ if (!ctx->devs) {
+ kfree(ctx);
+ return -ENOMEM;
+ }
+ fc->fs_private = ctx;
+
+ idr_init(&ctx->devs->tree);
+ init_rwsem(&ctx->devs->rwsem);
+ erofs_default_options(ctx);
+ fc->ops = &erofs_context_ops;
+ return 0;
+}
+
+/*
+ * could be triggered after deactivate_locked_super()
+ * is called, thus including umount and failed to initialize.
+ */
+static void erofs_kill_sb(struct super_block *sb)
+{
+ struct erofs_sb_info *sbi;
+
+ WARN_ON(sb->s_magic != EROFS_SUPER_MAGIC);
+
+ /* pseudo mount for anon inodes */
+ if (sb->s_flags & SB_KERNMOUNT) {
+ kill_anon_super(sb);
+ return;
+ }
+
+ if (erofs_is_fscache_mode(sb))
+ kill_anon_super(sb);
+ else
+ kill_block_super(sb);
+
+ sbi = EROFS_SB(sb);
+ if (!sbi)
+ return;
+
+ erofs_free_dev_context(sbi->devs);
+ fs_put_dax(sbi->dax_dev, NULL);
+ erofs_fscache_unregister_fs(sb);
+ kfree(sbi->fsid);
+ kfree(sbi->domain_id);
+ kfree(sbi);
+ sb->s_fs_info = NULL;
+}
+
+/* called when ->s_root is non-NULL */
+static void erofs_put_super(struct super_block *sb)
+{
+ struct erofs_sb_info *const sbi = EROFS_SB(sb);
+
+ DBG_BUGON(!sbi);
+
+ erofs_unregister_sysfs(sb);
+ erofs_shrinker_unregister(sb);
+#ifdef CONFIG_EROFS_FS_ZIP
+ iput(sbi->managed_cache);
+ sbi->managed_cache = NULL;
+ iput(sbi->packed_inode);
+ sbi->packed_inode = NULL;
+#endif
+ erofs_fscache_unregister_fs(sb);
+}
+
+struct file_system_type erofs_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "erofs",
+ .init_fs_context = erofs_init_fs_context,
+ .kill_sb = erofs_kill_sb,
+ .fs_flags = FS_REQUIRES_DEV | FS_ALLOW_IDMAP,
+};
+MODULE_ALIAS_FS("erofs");
+
+static int __init erofs_module_init(void)
+{
+ int err;
+
+ erofs_check_ondisk_layout_definitions();
+
+ erofs_inode_cachep = kmem_cache_create("erofs_inode",
+ sizeof(struct erofs_inode), 0,
+ SLAB_RECLAIM_ACCOUNT,
+ erofs_inode_init_once);
+ if (!erofs_inode_cachep) {
+ err = -ENOMEM;
+ goto icache_err;
+ }
+
+ err = erofs_init_shrinker();
+ if (err)
+ goto shrinker_err;
+
+ err = z_erofs_lzma_init();
+ if (err)
+ goto lzma_err;
+
+ erofs_pcpubuf_init();
+ err = z_erofs_init_zip_subsystem();
+ if (err)
+ goto zip_err;
+
+ err = erofs_init_sysfs();
+ if (err)
+ goto sysfs_err;
+
+ err = register_filesystem(&erofs_fs_type);
+ if (err)
+ goto fs_err;
+
+ return 0;
+
+fs_err:
+ erofs_exit_sysfs();
+sysfs_err:
+ z_erofs_exit_zip_subsystem();
+zip_err:
+ z_erofs_lzma_exit();
+lzma_err:
+ erofs_exit_shrinker();
+shrinker_err:
+ kmem_cache_destroy(erofs_inode_cachep);
+icache_err:
+ return err;
+}
+
+static void __exit erofs_module_exit(void)
+{
+ unregister_filesystem(&erofs_fs_type);
+
+ /* Ensure all RCU free inodes / pclusters are safe to be destroyed. */
+ rcu_barrier();
+
+ erofs_exit_sysfs();
+ z_erofs_exit_zip_subsystem();
+ z_erofs_lzma_exit();
+ erofs_exit_shrinker();
+ kmem_cache_destroy(erofs_inode_cachep);
+ erofs_pcpubuf_exit();
+}
+
+/* get filesystem statistics */
+static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+ struct super_block *sb = dentry->d_sb;
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ u64 id = 0;
+
+ if (!erofs_is_fscache_mode(sb))
+ id = huge_encode_dev(sb->s_bdev->bd_dev);
+
+ buf->f_type = sb->s_magic;
+ buf->f_bsize = EROFS_BLKSIZ;
+ buf->f_blocks = sbi->total_blocks;
+ buf->f_bfree = buf->f_bavail = 0;
+
+ buf->f_files = ULLONG_MAX;
+ buf->f_ffree = ULLONG_MAX - sbi->inos;
+
+ buf->f_namelen = EROFS_NAME_LEN;
+
+ buf->f_fsid = u64_to_fsid(id);
+ return 0;
+}
+
+static int erofs_show_options(struct seq_file *seq, struct dentry *root)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(root->d_sb);
+ struct erofs_mount_opts *opt = &sbi->opt;
+
+#ifdef CONFIG_EROFS_FS_XATTR
+ if (test_opt(opt, XATTR_USER))
+ seq_puts(seq, ",user_xattr");
+ else
+ seq_puts(seq, ",nouser_xattr");
+#endif
+#ifdef CONFIG_EROFS_FS_POSIX_ACL
+ if (test_opt(opt, POSIX_ACL))
+ seq_puts(seq, ",acl");
+ else
+ seq_puts(seq, ",noacl");
+#endif
+#ifdef CONFIG_EROFS_FS_ZIP
+ if (opt->cache_strategy == EROFS_ZIP_CACHE_DISABLED)
+ seq_puts(seq, ",cache_strategy=disabled");
+ else if (opt->cache_strategy == EROFS_ZIP_CACHE_READAHEAD)
+ seq_puts(seq, ",cache_strategy=readahead");
+ else if (opt->cache_strategy == EROFS_ZIP_CACHE_READAROUND)
+ seq_puts(seq, ",cache_strategy=readaround");
+#endif
+ if (test_opt(opt, DAX_ALWAYS))
+ seq_puts(seq, ",dax=always");
+ if (test_opt(opt, DAX_NEVER))
+ seq_puts(seq, ",dax=never");
+#ifdef CONFIG_EROFS_FS_ONDEMAND
+ if (sbi->fsid)
+ seq_printf(seq, ",fsid=%s", sbi->fsid);
+ if (sbi->domain_id)
+ seq_printf(seq, ",domain_id=%s", sbi->domain_id);
+#endif
+ return 0;
+}
+
+const struct super_operations erofs_sops = {
+ .put_super = erofs_put_super,
+ .alloc_inode = erofs_alloc_inode,
+ .free_inode = erofs_free_inode,
+ .statfs = erofs_statfs,
+ .show_options = erofs_show_options,
+};
+
+module_init(erofs_module_init);
+module_exit(erofs_module_exit);
+
+MODULE_DESCRIPTION("Enhanced ROM File System");
+MODULE_AUTHOR("Gao Xiang, Chao Yu, Miao Xie, CONSUMER BG, HUAWEI Inc.");
+MODULE_LICENSE("GPL");