exofs: Write sbi->s_nextid as part of the Create command
Before when creating a new inode, we'd set the sb->s_dirt flag,
and sometime later the system would write out s_nextid as part
of the sb_info. Also on inode sync we would force the sb sync
as well.
Define the s_nextid as a new partition attribute and set it
every time we create a new object.
At mount we read it from it's new place.
We now never set sb->s_dirt anywhere in exofs. write_super
is actually never called. The call to exofs_write_super from
exofs_put_super is also removed because the VFS always calls
->sync_fs before calling ->put_super twice.
To stay backward-and-forward compatible we also write the old
s_nextid in the super_block object at unmount, and support zero
length attribute on mount.
This also fixes a BUG where in layouts when group_width was not
a divisor of EXOFS_SUPER_ID (0x10000) the s_nextid was not read
from the device it was written to. Because of the sliding window
layout trick, and because the read was always done from the 0
device but the write was done via the raid engine that might slide
the device view. Now we read and write through the raid engine.
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
diff --git a/fs/exofs/common.h b/fs/exofs/common.h
index f0d5203..5e74ad3 100644
--- a/fs/exofs/common.h
+++ b/fs/exofs/common.h
@@ -53,10 +53,14 @@
#define EXOFS_ROOT_ID 0x10002 /* object ID for root directory */
/* exofs Application specific page/attribute */
+/* Inode attrs */
# define EXOFS_APAGE_FS_DATA (OSD_APAGE_APP_DEFINED_FIRST + 3)
# define EXOFS_ATTR_INODE_DATA 1
# define EXOFS_ATTR_INODE_FILE_LAYOUT 2
# define EXOFS_ATTR_INODE_DIR_LAYOUT 3
+/* Partition attrs */
+# define EXOFS_APAGE_SB_DATA (0xF0000000U + 3)
+# define EXOFS_ATTR_SB_STATS 1
/*
* The maximum number of files we can have is limited by the size of the
@@ -86,8 +90,8 @@
*/
enum {EXOFS_FSCB_VER = 1, EXOFS_DT_VER = 1};
struct exofs_fscb {
- __le64 s_nextid; /* Highest object ID used */
- __le64 s_numfiles; /* Number of files on fs */
+ __le64 s_nextid; /* Only used after mkfs */
+ __le64 s_numfiles; /* Only used after mkfs */
__le32 s_version; /* == EXOFS_FSCB_VER */
__le16 s_magic; /* Magic signature */
__le16 s_newfs; /* Non-zero if this is a new fs */
@@ -98,6 +102,16 @@
} __packed;
/*
+ * This struct is set on the FS partition's attributes.
+ * [EXOFS_APAGE_SB_DATA, EXOFS_ATTR_SB_STATS] and is written together
+ * with the create command, to atomically persist the sb writeable information.
+ */
+struct exofs_sb_stats {
+ __le64 s_nextid; /* Highest object ID used */
+ __le64 s_numfiles; /* Number of files on fs */
+} __packed;
+
+/*
* Describes the raid used in the FS. It is part of the device table.
* This here is taken from the pNFS-objects definition. In exofs we
* use one raid policy through-out the filesystem. (NOTE: the funny