exofs: Define on-disk per-inode optional layout attribute
* Layouts describe the way a file is spread on multiple devices.
The layout information is stored in the objects attribute introduced
in this patch.
* There can be multiple generating function for the layout.
Currently defined:
- No attribute present - use below moving-window on global
device table, all devices.
(This is the only one currently used in exofs)
- an obj_id generated moving window - the obj_id is a randomizing
factor in the otherwise global map layout.
- An explicit layout stored, including a data_map and a device
index list.
- More might be defined in future ...
* There are two attributes defined of the same structure:
A-data-files-layout - This layout is used by data-files. If present
at a directory, all files of that directory will
be created with this layout.
A-meta-data-layout - This layout is used by a directory and other
meta-data information. Also inherited at creation
of subdirectories.
* At creation time inodes are created with the layout specified above.
A usermode utility may change the creation layout on a give directory
or file. Which in the case of directories, will also apply to newly
created files/subdirectories, children of that directory.
In the simple unaltered case of a newly created exofs, no layout
attributes are present, and all layouts adhere to the layout specified
at the device-table.
* In case of a future file system loaded in an old exofs-driver.
At iget(), the generating_function is inspected and if not supported
will return an IO error to the application and the inode will not
be loaded. So not to damage any data.
Note: After this patch we do not yet support any type of layout
only the RAID0 patch that enables striping at the super-block
level will add support for RAID0 layouts above. This way we
are past and future compatible and fully bisectable.
* Access to the device table is done by an accessor since
it will change according to above information.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index 03189a9..0163546 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -859,6 +859,15 @@
return error;
}
+static const struct osd_attr g_attr_inode_file_layout = ATTR_DEF(
+ EXOFS_APAGE_FS_DATA,
+ EXOFS_ATTR_INODE_FILE_LAYOUT,
+ 0);
+static const struct osd_attr g_attr_inode_dir_layout = ATTR_DEF(
+ EXOFS_APAGE_FS_DATA,
+ EXOFS_ATTR_INODE_DIR_LAYOUT,
+ 0);
+
/*
* Read an inode from the OSD, and return it as is. We also return the size
* attribute in the 'obj_size' argument.
@@ -867,11 +876,16 @@
struct exofs_fcb *inode, uint64_t *obj_size)
{
struct exofs_sb_info *sbi = sb->s_fs_info;
- struct osd_attr attrs[2];
+ struct osd_attr attrs[] = {
+ [0] = g_attr_inode_data,
+ [1] = g_attr_inode_file_layout,
+ [2] = g_attr_inode_dir_layout,
+ [3] = g_attr_logical_length,
+ };
struct exofs_io_state *ios;
+ struct exofs_on_disk_inode_layout *layout;
int ret;
- *obj_size = ~0;
ret = exofs_get_io_state(&sbi->layout, &ios);
if (unlikely(ret)) {
EXOFS_ERR("%s: exofs_get_io_state failed.\n", __func__);
@@ -882,8 +896,9 @@
exofs_make_credential(oi->i_cred, &ios->obj);
ios->cred = oi->i_cred;
- attrs[0] = g_attr_inode_data;
- attrs[1] = g_attr_logical_length;
+ attrs[1].len = exofs_on_disk_inode_layout_size(sbi->layout.s_numdevs);
+ attrs[2].len = exofs_on_disk_inode_layout_size(sbi->layout.s_numdevs);
+
ios->in_attr = attrs;
ios->in_attr_len = ARRAY_SIZE(attrs);
@@ -901,11 +916,42 @@
ret = extract_attr_from_ios(ios, &attrs[1]);
if (ret) {
+ EXOFS_ERR("%s: extract_attr of inode_data failed\n", __func__);
+ goto out;
+ }
+ if (attrs[1].len) {
+ layout = attrs[1].val_ptr;
+ if (layout->gen_func != cpu_to_le16(LAYOUT_MOVING_WINDOW)) {
+ EXOFS_ERR("%s: unsupported files layout %d\n",
+ __func__, layout->gen_func);
+ ret = -ENOTSUPP;
+ goto out;
+ }
+ }
+
+ ret = extract_attr_from_ios(ios, &attrs[2]);
+ if (ret) {
+ EXOFS_ERR("%s: extract_attr of inode_data failed\n", __func__);
+ goto out;
+ }
+ if (attrs[2].len) {
+ layout = attrs[2].val_ptr;
+ if (layout->gen_func != cpu_to_le16(LAYOUT_MOVING_WINDOW)) {
+ EXOFS_ERR("%s: unsupported meta-data layout %d\n",
+ __func__, layout->gen_func);
+ ret = -ENOTSUPP;
+ goto out;
+ }
+ }
+
+ *obj_size = ~0;
+ ret = extract_attr_from_ios(ios, &attrs[3]);
+ if (ret) {
EXOFS_ERR("%s: extract_attr of logical_length failed\n",
__func__);
goto out;
}
- *obj_size = get_unaligned_be64(attrs[1].val_ptr);
+ *obj_size = get_unaligned_be64(attrs[3].val_ptr);
out:
exofs_put_io_state(ios);