erofs: move erofs out of staging

EROFS filesystem has been merged into linux-staging for a year.

EROFS is designed to be a better solution of saving extra storage
space with guaranteed end-to-end performance for read-only files
with the help of reduced metadata, fixed-sized output compression
and decompression inplace technologies.

In the past year, EROFS was greatly improved by many people as
a staging driver, self-tested, betaed by a large number of our
internal users, successfully applied to almost all in-service
HUAWEI smartphones as the part of EMUI 9.1 and proven to be stable
enough to be moved out of staging.

EROFS is a self-contained filesystem driver. Although there are
still some TODOs to be more generic, we have a dedicated team
actively keeping on working on EROFS in order to make it better
with the evolution of Linux kernel as the other in-kernel filesystems.

As Pavel suggested, it's better to do as one commit since git
can do moves and all histories will be saved in this way.

Let's promote it from staging and enhance it more actively as
a "real" part of kernel for more wider scenarios!

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Pavel Machek <pavel@denx.de>
Cc: David Sterba <dsterba@suse.cz>
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Darrick J . Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Richard Weinberger <richard@nod.at>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Chao Yu <yuchao0@huawei.com>
Cc: Miao Xie <miaoxie@huawei.com>
Cc: Li Guifu <bluce.liguifu@huawei.com>
Cc: Fang Wei <fangwei1@huawei.com>
Signed-off-by: Gao Xiang <gaoxiang25@huawei.com>
Link: https://lore.kernel.org/r/20190822213659.5501-1-hsiangkao@aol.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 332 insertions, 0 deletions

diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
new file mode 100644
index 000000000000..80f4fe919ee7
--- /dev/null
+++ b/fs/erofs/inode.c
@@ -0,0 +1,332 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2017-2018 HUAWEI, Inc.
+ *             http://www.huawei.com/
+ * Created by Gao Xiang <gaoxiang25@huawei.com>
+ */
+#include "xattr.h"
+
+#include <trace/events/erofs.h>
+
+/* no locking */
+static int read_inode(struct inode *inode, void *data)
+{
+	struct erofs_vnode *vi = EROFS_V(inode);
+	struct erofs_inode_v1 *v1 = data;
+	const unsigned int advise = le16_to_cpu(v1->i_advise);
+	erofs_blk_t nblks = 0;
+
+	vi->datamode = __inode_data_mapping(advise);
+
+	if (unlikely(vi->datamode >= EROFS_INODE_LAYOUT_MAX)) {
+		errln("unsupported data mapping %u of nid %llu",
+		      vi->datamode, vi->nid);
+		DBG_BUGON(1);
+		return -EOPNOTSUPP;
+	}
+
+	if (__inode_version(advise) == EROFS_INODE_LAYOUT_V2) {
+		struct erofs_inode_v2 *v2 = data;
+
+		vi->inode_isize = sizeof(struct erofs_inode_v2);
+		vi->xattr_isize = ondisk_xattr_ibody_size(v2->i_xattr_icount);
+
+		inode->i_mode = le16_to_cpu(v2->i_mode);
+		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+		    S_ISLNK(inode->i_mode))
+			vi->raw_blkaddr = le32_to_cpu(v2->i_u.raw_blkaddr);
+		else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
+			inode->i_rdev =
+				new_decode_dev(le32_to_cpu(v2->i_u.rdev));
+		else if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode))
+			inode->i_rdev = 0;
+		else
+			goto bogusimode;
+
+		i_uid_write(inode, le32_to_cpu(v2->i_uid));
+		i_gid_write(inode, le32_to_cpu(v2->i_gid));
+		set_nlink(inode, le32_to_cpu(v2->i_nlink));
+
+		/* ns timestamp */
+		inode->i_mtime.tv_sec = inode->i_ctime.tv_sec =
+			le64_to_cpu(v2->i_ctime);
+		inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec =
+			le32_to_cpu(v2->i_ctime_nsec);
+
+		inode->i_size = le64_to_cpu(v2->i_size);
+
+		/* total blocks for compressed files */
+		if (is_inode_layout_compression(inode))
+			nblks = le32_to_cpu(v2->i_u.compressed_blocks);
+	} else if (__inode_version(advise) == EROFS_INODE_LAYOUT_V1) {
+		struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
+
+		vi->inode_isize = sizeof(struct erofs_inode_v1);
+		vi->xattr_isize = ondisk_xattr_ibody_size(v1->i_xattr_icount);
+
+		inode->i_mode = le16_to_cpu(v1->i_mode);
+		if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+		    S_ISLNK(inode->i_mode))
+			vi->raw_blkaddr = le32_to_cpu(v1->i_u.raw_blkaddr);
+		else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))
+			inode->i_rdev =
+				new_decode_dev(le32_to_cpu(v1->i_u.rdev));
+		else if (S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode))
+			inode->i_rdev = 0;
+		else
+			goto bogusimode;
+
+		i_uid_write(inode, le16_to_cpu(v1->i_uid));
+		i_gid_write(inode, le16_to_cpu(v1->i_gid));
+		set_nlink(inode, le16_to_cpu(v1->i_nlink));
+
+		/* use build time to derive all file time */
+		inode->i_mtime.tv_sec = inode->i_ctime.tv_sec =
+			sbi->build_time;
+		inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec =
+			sbi->build_time_nsec;
+
+		inode->i_size = le32_to_cpu(v1->i_size);
+		if (is_inode_layout_compression(inode))
+			nblks = le32_to_cpu(v1->i_u.compressed_blocks);
+	} else {
+		errln("unsupported on-disk inode version %u of nid %llu",
+		      __inode_version(advise), vi->nid);
+		DBG_BUGON(1);
+		return -EOPNOTSUPP;
+	}
+
+	if (!nblks)
+		/* measure inode.i_blocks as generic filesystems */
+		inode->i_blocks = roundup(inode->i_size, EROFS_BLKSIZ) >> 9;
+	else
+		inode->i_blocks = nblks << LOG_SECTORS_PER_BLOCK;
+	return 0;
+
+bogusimode:
+	errln("bogus i_mode (%o) @ nid %llu", inode->i_mode, vi->nid);
+	DBG_BUGON(1);
+	return -EFSCORRUPTED;
+}
+
+/*
+ * try_lock can be required since locking order is:
+ *   file data(fs_inode)
+ *        meta(bd_inode)
+ * but the majority of the callers is "iget",
+ * in that case we are pretty sure no deadlock since
+ * no data operations exist. However I tend to
+ * try_lock since it takes no much overhead and
+ * will success immediately.
+ */
+static int fill_inline_data(struct inode *inode, void *data,
+			    unsigned int m_pofs)
+{
+	struct erofs_vnode *vi = EROFS_V(inode);
+	struct erofs_sb_info *sbi = EROFS_I_SB(inode);
+
+	/* should be inode inline C */
+	if (!is_inode_flat_inline(inode))
+		return 0;
+
+	/* fast symlink (following ext4) */
+	if (S_ISLNK(inode->i_mode) && inode->i_size < PAGE_SIZE) {
+		char *lnk = erofs_kmalloc(sbi, inode->i_size + 1, GFP_KERNEL);
+
+		if (unlikely(!lnk))
+			return -ENOMEM;
+
+		m_pofs += vi->inode_isize + vi->xattr_isize;
+
+		/* inline symlink data shouldn't across page boundary as well */
+		if (unlikely(m_pofs + inode->i_size > PAGE_SIZE)) {
+			kfree(lnk);
+			errln("inline data cross block boundary @ nid %llu",
+			      vi->nid);
+			DBG_BUGON(1);
+			return -EFSCORRUPTED;
+		}
+
+		/* get in-page inline data */
+		memcpy(lnk, data + m_pofs, inode->i_size);
+		lnk[inode->i_size] = '\0';
+
+		inode->i_link = lnk;
+		set_inode_fast_symlink(inode);
+	}
+	return 0;
+}
+
+static int fill_inode(struct inode *inode, int isdir)
+{
+	struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
+	struct erofs_vnode *vi = EROFS_V(inode);
+	struct page *page;
+	void *data;
+	int err;
+	erofs_blk_t blkaddr;
+	unsigned int ofs;
+	erofs_off_t inode_loc;
+
+	trace_erofs_fill_inode(inode, isdir);
+	inode_loc = iloc(sbi, vi->nid);
+	blkaddr = erofs_blknr(inode_loc);
+	ofs = erofs_blkoff(inode_loc);
+
+	debugln("%s, reading inode nid %llu at %u of blkaddr %u",
+		__func__, vi->nid, ofs, blkaddr);
+
+	page = erofs_get_meta_page(inode->i_sb, blkaddr, isdir);
+
+	if (IS_ERR(page)) {
+		errln("failed to get inode (nid: %llu) page, err %ld",
+		      vi->nid, PTR_ERR(page));
+		return PTR_ERR(page);
+	}
+
+	DBG_BUGON(!PageUptodate(page));
+	data = page_address(page);
+
+	err = read_inode(inode, data + ofs);
+	if (!err) {
+		/* setup the new inode */
+		if (S_ISREG(inode->i_mode)) {
+			inode->i_op = &erofs_generic_iops;
+			inode->i_fop = &generic_ro_fops;
+		} else if (S_ISDIR(inode->i_mode)) {
+			inode->i_op = &erofs_dir_iops;
+			inode->i_fop = &erofs_dir_fops;
+		} else if (S_ISLNK(inode->i_mode)) {
+			/* by default, page_get_link is used for symlink */
+			inode->i_op = &erofs_symlink_iops;
+			inode_nohighmem(inode);
+		} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
+			S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
+			inode->i_op = &erofs_generic_iops;
+			init_special_inode(inode, inode->i_mode, inode->i_rdev);
+			goto out_unlock;
+		} else {
+			err = -EFSCORRUPTED;
+			goto out_unlock;
+		}
+
+		if (is_inode_layout_compression(inode)) {
+			err = z_erofs_fill_inode(inode);
+			goto out_unlock;
+		}
+
+		inode->i_mapping->a_ops = &erofs_raw_access_aops;
+
+		/* fill last page if inline data is available */
+		err = fill_inline_data(inode, data, ofs);
+	}
+
+out_unlock:
+	unlock_page(page);
+	put_page(page);
+	return err;
+}
+
+/*
+ * erofs nid is 64bits, but i_ino is 'unsigned long', therefore
+ * we should do more for 32-bit platform to find the right inode.
+ */
+#if BITS_PER_LONG == 32
+static int erofs_ilookup_test_actor(struct inode *inode, void *opaque)
+{
+	const erofs_nid_t nid = *(erofs_nid_t *)opaque;
+
+	return EROFS_V(inode)->nid == nid;
+}
+
+static int erofs_iget_set_actor(struct inode *inode, void *opaque)
+{
+	const erofs_nid_t nid = *(erofs_nid_t *)opaque;
+
+	inode->i_ino = erofs_inode_hash(nid);
+	return 0;
+}
+#endif
+
+static inline struct inode *erofs_iget_locked(struct super_block *sb,
+					      erofs_nid_t nid)
+{
+	const unsigned long hashval = erofs_inode_hash(nid);
+
+#if BITS_PER_LONG >= 64
+	/* it is safe to use iget_locked for >= 64-bit platform */
+	return iget_locked(sb, hashval);
+#else
+	return iget5_locked(sb, hashval, erofs_ilookup_test_actor,
+		erofs_iget_set_actor, &nid);
+#endif
+}
+
+struct inode *erofs_iget(struct super_block *sb,
+			 erofs_nid_t nid,
+			 bool isdir)
+{
+	struct inode *inode = erofs_iget_locked(sb, nid);
+
+	if (unlikely(!inode))
+		return ERR_PTR(-ENOMEM);
+
+	if (inode->i_state & I_NEW) {
+		int err;
+		struct erofs_vnode *vi = EROFS_V(inode);
+
+		vi->nid = nid;
+
+		err = fill_inode(inode, isdir);
+		if (likely(!err))
+			unlock_new_inode(inode);
+		else {
+			iget_failed(inode);
+			inode = ERR_PTR(err);
+		}
+	}
+	return inode;
+}
+
+int erofs_getattr(const struct path *path, struct kstat *stat,
+		  u32 request_mask, unsigned int query_flags)
+{
+	struct inode *const inode = d_inode(path->dentry);
+
+	if (is_inode_layout_compression(inode))
+		stat->attributes |= STATX_ATTR_COMPRESSED;
+
+	stat->attributes |= STATX_ATTR_IMMUTABLE;
+	stat->attributes_mask |= (STATX_ATTR_COMPRESSED |
+				  STATX_ATTR_IMMUTABLE);
+
+	generic_fillattr(inode, stat);
+	return 0;
+}
+
+const struct inode_operations erofs_generic_iops = {
+	.getattr = erofs_getattr,
+#ifdef CONFIG_EROFS_FS_XATTR
+	.listxattr = erofs_listxattr,
+#endif
+	.get_acl = erofs_get_acl,
+};
+
+const struct inode_operations erofs_symlink_iops = {
+	.get_link = page_get_link,
+	.getattr = erofs_getattr,
+#ifdef CONFIG_EROFS_FS_XATTR
+	.listxattr = erofs_listxattr,
+#endif
+	.get_acl = erofs_get_acl,
+};
+
+const struct inode_operations erofs_fast_symlink_iops = {
+	.get_link = simple_get_link,
+	.getattr = erofs_getattr,
+#ifdef CONFIG_EROFS_FS_XATTR
+	.listxattr = erofs_listxattr,
+#endif
+	.get_acl = erofs_get_acl,
+};
+