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-rw-r--r--fs/erofs/Kconfig17
-rw-r--r--fs/erofs/data.c35
-rw-r--r--fs/erofs/inode.c5
-rw-r--r--fs/erofs/internal.h11
-rw-r--r--fs/erofs/super.c76
5 files changed, 100 insertions, 44 deletions
diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
index 7dcdce660cac..1428d0530e1c 100644
--- a/fs/erofs/Kconfig
+++ b/fs/erofs/Kconfig
@@ -74,6 +74,23 @@ config EROFS_FS_SECURITY
If you are not using a security module, say N.
+config EROFS_FS_BACKED_BY_FILE
+ bool "File-backed EROFS filesystem support"
+ depends on EROFS_FS
+ default y
+ help
+ This allows EROFS to use filesystem image files directly, without
+ the intercession of loopback block devices or likewise. It is
+ particularly useful for container images with numerous blobs and
+ other sandboxes, where loop devices behave intricately. It can also
+ be used to simplify error-prone lifetime management of unnecessary
+ virtual block devices.
+
+ Note that this feature, along with ongoing fanotify pre-content
+ hooks, will eventually replace "EROFS over fscache."
+
+ If you don't want to enable this feature, say N.
+
config EROFS_FS_ZIP
bool "EROFS Data Compression Support"
depends on EROFS_FS
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 1b7eba38ba1e..0fb31c588ae0 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -59,8 +59,12 @@ void *erofs_bread(struct erofs_buf *buf, erofs_off_t offset,
void erofs_init_metabuf(struct erofs_buf *buf, struct super_block *sb)
{
- if (erofs_is_fscache_mode(sb))
- buf->mapping = EROFS_SB(sb)->s_fscache->inode->i_mapping;
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+
+ if (erofs_is_fileio_mode(sbi))
+ buf->mapping = file_inode(sbi->fdev)->i_mapping;
+ else if (erofs_is_fscache_mode(sb))
+ buf->mapping = sbi->s_fscache->inode->i_mapping;
else
buf->mapping = sb->s_bdev->bd_mapping;
}
@@ -189,10 +193,22 @@ out:
return err;
}
+static void erofs_fill_from_devinfo(struct erofs_map_dev *map,
+ struct erofs_device_info *dif)
+{
+ map->m_bdev = NULL;
+ if (dif->file && S_ISBLK(file_inode(dif->file)->i_mode))
+ map->m_bdev = file_bdev(dif->file);
+ map->m_daxdev = dif->dax_dev;
+ map->m_dax_part_off = dif->dax_part_off;
+ map->m_fscache = dif->fscache;
+}
+
int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
{
struct erofs_dev_context *devs = EROFS_SB(sb)->devs;
struct erofs_device_info *dif;
+ erofs_off_t startoff, length;
int id;
map->m_bdev = sb->s_bdev;
@@ -212,29 +228,20 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
up_read(&devs->rwsem);
return 0;
}
- map->m_bdev = dif->bdev_file ? file_bdev(dif->bdev_file) : NULL;
- map->m_daxdev = dif->dax_dev;
- map->m_dax_part_off = dif->dax_part_off;
- map->m_fscache = dif->fscache;
+ erofs_fill_from_devinfo(map, dif);
up_read(&devs->rwsem);
} else if (devs->extra_devices && !devs->flatdev) {
down_read(&devs->rwsem);
idr_for_each_entry(&devs->tree, dif, id) {
- erofs_off_t startoff, length;
-
if (!dif->mapped_blkaddr)
continue;
+
startoff = erofs_pos(sb, dif->mapped_blkaddr);
length = erofs_pos(sb, dif->blocks);
-
if (map->m_pa >= startoff &&
map->m_pa < startoff + length) {
map->m_pa -= startoff;
- map->m_bdev = dif->bdev_file ?
- file_bdev(dif->bdev_file) : NULL;
- map->m_daxdev = dif->dax_dev;
- map->m_dax_part_off = dif->dax_part_off;
- map->m_fscache = dif->fscache;
+ erofs_fill_from_devinfo(map, dif);
break;
}
}
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index 4e3ea6689cb4..83a14b55327f 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -250,7 +250,10 @@ static int erofs_fill_inode(struct inode *inode)
}
mapping_set_large_folios(inode->i_mapping);
- if (erofs_inode_is_data_compressed(vi->datalayout)) {
+ if (erofs_is_fileio_mode(EROFS_SB(inode->i_sb))) {
+ /* XXX: data I/Os will be implemented in the following patches */
+ err = -EOPNOTSUPP;
+ } else if (erofs_inode_is_data_compressed(vi->datalayout)) {
#ifdef CONFIG_EROFS_FS_ZIP
DO_ONCE_LITE_IF(inode->i_blkbits != PAGE_SHIFT,
erofs_info, inode->i_sb,
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 45dc15ebd870..9bf4fb1cfa09 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -49,7 +49,7 @@ typedef u32 erofs_blk_t;
struct erofs_device_info {
char *path;
struct erofs_fscache *fscache;
- struct file *bdev_file;
+ struct file *file;
struct dax_device *dax_dev;
u64 dax_part_off;
@@ -130,6 +130,7 @@ struct erofs_sb_info {
struct erofs_sb_lz4_info lz4;
#endif /* CONFIG_EROFS_FS_ZIP */
+ struct file *fdev;
struct inode *packed_inode;
struct erofs_dev_context *devs;
struct dax_device *dax_dev;
@@ -190,9 +191,15 @@ struct erofs_sb_info {
#define set_opt(opt, option) ((opt)->mount_opt |= EROFS_MOUNT_##option)
#define test_opt(opt, option) ((opt)->mount_opt & EROFS_MOUNT_##option)
+static inline bool erofs_is_fileio_mode(struct erofs_sb_info *sbi)
+{
+ return IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE) && sbi->fdev;
+}
+
static inline bool erofs_is_fscache_mode(struct super_block *sb)
{
- return IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) && !sb->s_bdev;
+ return IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) &&
+ !erofs_is_fileio_mode(EROFS_SB(sb)) && !sb->s_bdev;
}
enum {
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index aae3fd15899a..9a7e67eceed4 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
@@ -161,7 +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))
@@ -183,13 +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);
@@ -566,15 +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)
@@ -589,14 +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;
@@ -693,11 +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)
@@ -727,8 +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);
@@ -791,7 +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);
@@ -801,6 +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;
}
@@ -903,7 +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);
generated by cgit (git 2.34.1) at 2026-01-06 16:16:23 +0000