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/super.c b/fs/exofs/super.c
index 474989e..5eb0851 100644
--- a/fs/exofs/super.c
+++ b/fs/exofs/super.c
@@ -213,6 +213,101 @@
static const struct super_operations exofs_sops;
static const struct export_operations exofs_export_ops;
+static const struct osd_attr g_attr_sb_stats = ATTR_DEF(
+ EXOFS_APAGE_SB_DATA,
+ EXOFS_ATTR_SB_STATS,
+ sizeof(struct exofs_sb_stats));
+
+static int __sbi_read_stats(struct exofs_sb_info *sbi)
+{
+ struct osd_attr attrs[] = {
+ [0] = g_attr_sb_stats,
+ };
+ struct exofs_io_state *ios;
+ int ret;
+
+ ret = exofs_get_io_state(&sbi->layout, &ios);
+ if (unlikely(ret)) {
+ EXOFS_ERR("%s: exofs_get_io_state failed.\n", __func__);
+ return ret;
+ }
+
+ ios->cred = sbi->s_cred;
+
+ ios->in_attr = attrs;
+ ios->in_attr_len = ARRAY_SIZE(attrs);
+
+ ret = exofs_sbi_read(ios);
+ if (unlikely(ret)) {
+ EXOFS_ERR("Error reading super_block stats => %d\n", ret);
+ goto out;
+ }
+
+ ret = extract_attr_from_ios(ios, &attrs[0]);
+ if (ret) {
+ EXOFS_ERR("%s: extract_attr of sb_stats failed\n", __func__);
+ goto out;
+ }
+ if (attrs[0].len) {
+ struct exofs_sb_stats *ess;
+
+ if (unlikely(attrs[0].len != sizeof(*ess))) {
+ EXOFS_ERR("%s: Wrong version of exofs_sb_stats "
+ "size(%d) != expected(%zd)\n",
+ __func__, attrs[0].len, sizeof(*ess));
+ goto out;
+ }
+
+ ess = attrs[0].val_ptr;
+ sbi->s_nextid = le64_to_cpu(ess->s_nextid);
+ sbi->s_numfiles = le32_to_cpu(ess->s_numfiles);
+ }
+
+out:
+ exofs_put_io_state(ios);
+ return ret;
+}
+
+static void stats_done(struct exofs_io_state *ios, void *p)
+{
+ exofs_put_io_state(ios);
+ /* Good thanks nothing to do anymore */
+}
+
+/* Asynchronously write the stats attribute */
+int exofs_sbi_write_stats(struct exofs_sb_info *sbi)
+{
+ struct osd_attr attrs[] = {
+ [0] = g_attr_sb_stats,
+ };
+ struct exofs_io_state *ios;
+ int ret;
+
+ ret = exofs_get_io_state(&sbi->layout, &ios);
+ if (unlikely(ret)) {
+ EXOFS_ERR("%s: exofs_get_io_state failed.\n", __func__);
+ return ret;
+ }
+
+ sbi->s_ess.s_nextid = cpu_to_le64(sbi->s_nextid);
+ sbi->s_ess.s_numfiles = cpu_to_le64(sbi->s_numfiles);
+ attrs[0].val_ptr = &sbi->s_ess;
+
+ ios->cred = sbi->s_cred;
+ ios->done = stats_done;
+ ios->private = sbi;
+ ios->out_attr = attrs;
+ ios->out_attr_len = ARRAY_SIZE(attrs);
+
+ ret = exofs_sbi_write(ios);
+ if (unlikely(ret)) {
+ EXOFS_ERR("%s: exofs_sbi_write failed.\n", __func__);
+ exofs_put_io_state(ios);
+ }
+
+ return ret;
+}
+
/*
* Write the superblock to the OSD
*/
@@ -223,18 +318,25 @@
struct exofs_io_state *ios;
int ret = -ENOMEM;
- lock_super(sb);
- sbi = sb->s_fs_info;
- fscb = &sbi->s_fscb;
+ fscb = kmalloc(sizeof(*fscb), GFP_KERNEL);
+ if (unlikely(!fscb))
+ return -ENOMEM;
+ sbi = sb->s_fs_info;
+
+ /* NOTE: We no longer dirty the super_block anywhere in exofs. The
+ * reason we write the fscb here on unmount is so we can stay backwards
+ * compatible with fscb->s_version == 1. (What we are not compatible
+ * with is if a new version FS crashed and then we try to mount an old
+ * version). Otherwise the exofs_fscb is read-only from mkfs time. All
+ * the writeable info is set in exofs_sbi_write_stats() above.
+ */
ret = exofs_get_io_state(&sbi->layout, &ios);
- if (ret)
+ if (unlikely(ret))
goto out;
- /* Note: We only write the changing part of the fscb. .i.e upto the
- * the fscb->s_dev_table_oid member. There is no read-modify-write
- * here.
- */
+ lock_super(sb);
+
ios->length = offsetof(struct exofs_fscb, s_dev_table_oid);
memset(fscb, 0, ios->length);
fscb->s_nextid = cpu_to_le64(sbi->s_nextid);
@@ -249,16 +351,17 @@
ios->cred = sbi->s_cred;
ret = exofs_sbi_write(ios);
- if (unlikely(ret)) {
+ if (unlikely(ret))
EXOFS_ERR("%s: exofs_sbi_write failed.\n", __func__);
- goto out;
- }
- sb->s_dirt = 0;
+ else
+ sb->s_dirt = 0;
+
+ unlock_super(sb);
out:
EXOFS_DBGMSG("s_nextid=0x%llx ret=%d\n", _LLU(sbi->s_nextid), ret);
exofs_put_io_state(ios);
- unlock_super(sb);
+ kfree(fscb);
return ret;
}
@@ -302,9 +405,6 @@
int num_pend;
struct exofs_sb_info *sbi = sb->s_fs_info;
- if (sb->s_dirt)
- exofs_write_super(sb);
-
/* make sure there are no pending commands */
for (num_pend = atomic_read(&sbi->s_curr_pending); num_pend > 0;
num_pend = atomic_read(&sbi->s_curr_pending)) {
@@ -629,6 +729,7 @@
goto free_sbi;
sb->s_magic = le16_to_cpu(fscb.s_magic);
+ /* NOTE: we read below to be backward compatible with old versions */
sbi->s_nextid = le64_to_cpu(fscb.s_nextid);
sbi->s_numfiles = le32_to_cpu(fscb.s_numfiles);
@@ -639,7 +740,7 @@
ret = -EINVAL;
goto free_sbi;
}
- if (le32_to_cpu(fscb.s_version) != EXOFS_FSCB_VER) {
+ if (le32_to_cpu(fscb.s_version) > EXOFS_FSCB_VER) {
EXOFS_ERR("ERROR: Bad FSCB version expected-%d got-%d\n",
EXOFS_FSCB_VER, le32_to_cpu(fscb.s_version));
ret = -EINVAL;
@@ -657,6 +758,8 @@
goto free_sbi;
}
+ __sbi_read_stats(sbi);
+
/* set up operation vectors */
sbi->bdi.ra_pages = __ra_pages(&sbi->layout);
sb->s_bdi = &sbi->bdi;