1 files changed, 57 insertions, 49 deletions

diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 32ce5b35e1df..666873f745da 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -10,6 +10,7 @@
 #include <linux/fs_context.h>
 #include <linux/fs_parser.h>
 #include <linux/exportfs.h>
+#include <linux/backing-dev.h>
 #include "xattr.h"
 
 #define CREATE_TRACE_POINTS
@@ -108,22 +109,6 @@ static void erofs_free_inode(struct inode *inode)
 	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",
-			   feature & ~EROFS_ALL_FEATURE_INCOMPAT);
-		return false;
-	}
-	return true;
-}
-
 /* read variable-sized metadata, offset will be aligned by 4-byte */
 void *erofs_read_metadata(struct super_block *sb, struct erofs_buf *buf,
 			  erofs_off_t *offset, int *lengthp)
@@ -177,7 +162,7 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
 	struct erofs_fscache *fscache;
 	struct erofs_deviceslot *dis;
-	struct file *bdev_file;
+	struct file *file;
 
 	dis = erofs_read_metabuf(buf, sb, *pos, EROFS_KMAP);
 	if (IS_ERR(dis))
@@ -199,13 +184,17 @@ static int erofs_init_device(struct erofs_buf *buf, struct super_block *sb,
 			return PTR_ERR(fscache);
 		dif->fscache = fscache;
 	} else if (!sbi->devs->flatdev) {
-		bdev_file = bdev_file_open_by_path(dif->path, BLK_OPEN_READ,
-						sb->s_type, NULL);
-		if (IS_ERR(bdev_file))
-			return PTR_ERR(bdev_file);
-		dif->bdev_file = bdev_file;
-		dif->dax_dev = fs_dax_get_by_bdev(file_bdev(bdev_file),
-				&dif->dax_part_off, NULL, NULL);
+		file = erofs_is_fileio_mode(sbi) ?
+				filp_open(dif->path, O_RDONLY | O_LARGEFILE, 0) :
+				bdev_file_open_by_path(dif->path,
+						BLK_OPEN_READ, sb->s_type, NULL);
+		if (IS_ERR(file))
+			return PTR_ERR(file);
+
+		dif->file = file;
+		if (!erofs_is_fileio_mode(sbi))
+			dif->dax_dev = fs_dax_get_by_bdev(file_bdev(file),
+					&dif->dax_part_off, NULL, NULL);
 	}
 
 	dif->blocks = le32_to_cpu(dis->blocks);
@@ -279,7 +268,7 @@ static int erofs_scan_devices(struct super_block *sb,
 
 static int erofs_read_superblock(struct super_block *sb)
 {
-	struct erofs_sb_info *sbi;
+	struct erofs_sb_info *sbi = EROFS_SB(sb);
 	struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
 	struct erofs_super_block *dsb;
 	void *data;
@@ -291,9 +280,7 @@ static int erofs_read_superblock(struct super_block *sb)
 		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");
@@ -318,8 +305,12 @@ static int erofs_read_superblock(struct super_block *sb)
 	}
 
 	ret = -EINVAL;
-	if (!check_layout_compatibility(sb, dsb))
+	sbi->feature_incompat = le32_to_cpu(dsb->feature_incompat);
+	if (sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT) {
+		erofs_err(sb, "unidentified incompatible feature %x, please upgrade kernel",
+			  sbi->feature_incompat & ~EROFS_ALL_FEATURE_INCOMPAT);
 		goto out;
+	}
 
 	sbi->sb_size = 128 + dsb->sb_extslots * EROFS_SB_EXTSLOT_SIZE;
 	if (sbi->sb_size > PAGE_SIZE - EROFS_SUPER_OFFSET) {
@@ -362,7 +353,7 @@ static int erofs_read_superblock(struct super_block *sb)
 	ret = erofs_scan_devices(sb, dsb);
 
 	if (erofs_is_fscache_mode(sb))
-		erofs_info(sb, "EXPERIMENTAL fscache-based on-demand read feature in use. Use at your own risk!");
+		erofs_info(sb, "[deprecated] fscache-based on-demand read feature in use. Use at your own risk!");
 out:
 	erofs_put_metabuf(&buf);
 	return ret;
@@ -580,15 +571,16 @@ static void erofs_set_sysfs_name(struct super_block *sb)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
 
-	if (erofs_is_fscache_mode(sb)) {
-		if (sbi->domain_id)
-			super_set_sysfs_name_generic(sb, "%s,%s",sbi->domain_id,
-						     sbi->fsid);
-		else
-			super_set_sysfs_name_generic(sb, "%s", sbi->fsid);
-		return;
-	}
-	super_set_sysfs_name_id(sb);
+	if (sbi->domain_id)
+		super_set_sysfs_name_generic(sb, "%s,%s", sbi->domain_id,
+					     sbi->fsid);
+	else if (sbi->fsid)
+		super_set_sysfs_name_generic(sb, "%s", sbi->fsid);
+	else if (erofs_is_fileio_mode(sbi))
+		super_set_sysfs_name_generic(sb, "%s",
+					     bdi_dev_name(sb->s_bdi));
+	else
+		super_set_sysfs_name_id(sb);
 }
 
 static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
@@ -603,14 +595,15 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
 	sb->s_op = &erofs_sops;
 
 	sbi->blkszbits = PAGE_SHIFT;
-	if (erofs_is_fscache_mode(sb)) {
+	if (!sb->s_bdev) {
 		sb->s_blocksize = PAGE_SIZE;
 		sb->s_blocksize_bits = PAGE_SHIFT;
 
-		err = erofs_fscache_register_fs(sb);
-		if (err)
-			return err;
-
+		if (erofs_is_fscache_mode(sb)) {
+			err = erofs_fscache_register_fs(sb);
+			if (err)
+				return err;
+		}
 		err = super_setup_bdi(sb);
 		if (err)
 			return err;
@@ -658,7 +651,6 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
 		sb->s_flags |= SB_POSIXACL;
 	else
 		sb->s_flags &= ~SB_POSIXACL;
-	erofs_set_sysfs_name(sb);
 
 #ifdef CONFIG_EROFS_FS_ZIP
 	xa_init(&sbi->managed_pslots);
@@ -696,6 +688,7 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
 	if (err)
 		return err;
 
+	erofs_set_sysfs_name(sb);
 	err = erofs_register_sysfs(sb);
 	if (err)
 		return err;
@@ -707,11 +700,24 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
 static int erofs_fc_get_tree(struct fs_context *fc)
 {
 	struct erofs_sb_info *sbi = fc->s_fs_info;
+	int ret;
 
 	if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid)
 		return get_tree_nodev(fc, erofs_fc_fill_super);
 
-	return get_tree_bdev(fc, erofs_fc_fill_super);
+	ret = get_tree_bdev(fc, erofs_fc_fill_super);
+#ifdef CONFIG_EROFS_FS_BACKED_BY_FILE
+	if (ret == -ENOTBLK) {
+		if (!fc->source)
+			return invalf(fc, "No source specified");
+		sbi->fdev = filp_open(fc->source, O_RDONLY | O_LARGEFILE, 0);
+		if (IS_ERR(sbi->fdev))
+			return PTR_ERR(sbi->fdev);
+
+		return get_tree_nodev(fc, erofs_fc_fill_super);
+	}
+#endif
+	return ret;
 }
 
 static int erofs_fc_reconfigure(struct fs_context *fc)
@@ -741,8 +747,8 @@ 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_file)
-		fput(dif->bdev_file);
+	if (dif->file)
+		fput(dif->file);
 	erofs_fscache_unregister_cookie(dif->fscache);
 	dif->fscache = NULL;
 	kfree(dif->path);
@@ -805,7 +811,7 @@ static void erofs_kill_sb(struct super_block *sb)
 {
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
 
-	if (IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid)
+	if ((IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && sbi->fsid) || sbi->fdev)
 		kill_anon_super(sb);
 	else
 		kill_block_super(sb);
@@ -815,6 +821,8 @@ static void erofs_kill_sb(struct super_block *sb)
 	erofs_fscache_unregister_fs(sb);
 	kfree(sbi->fsid);
 	kfree(sbi->domain_id);
+	if (sbi->fdev)
+		fput(sbi->fdev);
 	kfree(sbi);
 	sb->s_fs_info = NULL;
 }
@@ -917,7 +925,7 @@ static int erofs_statfs(struct dentry *dentry, struct kstatfs *buf)
 	buf->f_namelen = EROFS_NAME_LEN;
 
 	if (uuid_is_null(&sb->s_uuid))
-		buf->f_fsid = u64_to_fsid(erofs_is_fscache_mode(sb) ? 0 :
+		buf->f_fsid = u64_to_fsid(!sb->s_bdev ? 0 :
 				huge_encode_dev(sb->s_bdev->bd_dev));
 	else
 		buf->f_fsid = uuid_to_fsid(sb->s_uuid.b);