ocfs2: Remove i_generation from inode lock names
OCFS2 puts inode meta data in the "lock value block" provided by the DLM.
Typically, i_generation is encoded in the lock name so that a deleted inode
on and a new one in the same block don't share the same lvb.
Unfortunately, that scheme means that the read in ocfs2_read_locked_inode()
is potentially thrown away as soon as the meta data lock is taken - we
cannot encode the lock name without first knowing i_generation, which
requires a disk read.
This patch encodes i_generation in the inode meta data lvb, and removes the
value from the inode meta data lock name. This way, the read can be covered
by a lock, and at the same time we can distinguish between an up to date and
a stale LVB.
This will help cold-cache stat(2) performance in particular.
Since this patch changes the protocol version, we take the opportunity to do
a minor re-organization of two of the LVB fields.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
diff --git a/fs/ocfs2/cluster/tcp_internal.h b/fs/ocfs2/cluster/tcp_internal.h
index da42b51..4b46aac 100644
--- a/fs/ocfs2/cluster/tcp_internal.h
+++ b/fs/ocfs2/cluster/tcp_internal.h
@@ -44,6 +44,9 @@
* locking semantics of the file system using the protocol. It should
* be somewhere else, I'm sure, but right now it isn't.
*
+ * New in version 4:
+ * - Remove i_generation from lock names for better stat performance.
+ *
* New in version 3:
* - Replace dentry votes with a cluster lock
*
@@ -51,7 +54,7 @@
* - full 64 bit i_size in the metadata lock lvbs
* - introduction of "rw" lock and pushing meta/data locking down
*/
-#define O2NET_PROTOCOL_VERSION 3ULL
+#define O2NET_PROTOCOL_VERSION 4ULL
struct o2net_handshake {
__be64 protocol_version;
__be64 connector_id;
diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
index 6cd84df..ecb3cba 100644
--- a/fs/ocfs2/dlmglue.c
+++ b/fs/ocfs2/dlmglue.c
@@ -320,6 +320,7 @@
void ocfs2_inode_lock_res_init(struct ocfs2_lock_res *res,
enum ocfs2_lock_type type,
+ unsigned int generation,
struct inode *inode)
{
struct ocfs2_lock_res_ops *ops;
@@ -341,7 +342,7 @@
};
ocfs2_build_lock_name(type, OCFS2_I(inode)->ip_blkno,
- inode->i_generation, res->l_name);
+ generation, res->l_name);
ocfs2_lock_res_init_common(OCFS2_SB(inode->i_sb), res, type, ops, inode);
}
@@ -1173,17 +1174,19 @@
int ocfs2_create_new_lock(struct ocfs2_super *osb,
struct ocfs2_lock_res *lockres,
- int ex)
+ int ex,
+ int local)
{
int level = ex ? LKM_EXMODE : LKM_PRMODE;
unsigned long flags;
+ int lkm_flags = local ? LKM_LOCAL : 0;
spin_lock_irqsave(&lockres->l_lock, flags);
BUG_ON(lockres->l_flags & OCFS2_LOCK_ATTACHED);
lockres_or_flags(lockres, OCFS2_LOCK_LOCAL);
spin_unlock_irqrestore(&lockres->l_lock, flags);
- return ocfs2_lock_create(osb, lockres, level, LKM_LOCAL);
+ return ocfs2_lock_create(osb, lockres, level, lkm_flags);
}
/* Grants us an EX lock on the data and metadata resources, skipping
@@ -1212,19 +1215,23 @@
* on a resource which has an invalid one -- we'll set it
* valid when we release the EX. */
- ret = ocfs2_create_new_lock(osb, &OCFS2_I(inode)->ip_rw_lockres, 1);
+ ret = ocfs2_create_new_lock(osb, &OCFS2_I(inode)->ip_rw_lockres, 1, 1);
if (ret) {
mlog_errno(ret);
goto bail;
}
- ret = ocfs2_create_new_lock(osb, &OCFS2_I(inode)->ip_meta_lockres, 1);
+ /*
+ * We don't want to use LKM_LOCAL on a meta data lock as they
+ * don't use a generation in their lock names.
+ */
+ ret = ocfs2_create_new_lock(osb, &OCFS2_I(inode)->ip_meta_lockres, 1, 0);
if (ret) {
mlog_errno(ret);
goto bail;
}
- ret = ocfs2_create_new_lock(osb, &OCFS2_I(inode)->ip_data_lockres, 1);
+ ret = ocfs2_create_new_lock(osb, &OCFS2_I(inode)->ip_data_lockres, 1, 1);
if (ret) {
mlog_errno(ret);
goto bail;
@@ -1413,6 +1420,16 @@
lvb = (struct ocfs2_meta_lvb *) lockres->l_lksb.lvb;
+ /*
+ * Invalidate the LVB of a deleted inode - this way other
+ * nodes are forced to go to disk and discover the new inode
+ * status.
+ */
+ if (oi->ip_flags & OCFS2_INODE_DELETED) {
+ lvb->lvb_version = 0;
+ goto out;
+ }
+
lvb->lvb_version = OCFS2_LVB_VERSION;
lvb->lvb_isize = cpu_to_be64(i_size_read(inode));
lvb->lvb_iclusters = cpu_to_be32(oi->ip_clusters);
@@ -1429,6 +1446,7 @@
lvb->lvb_iattr = cpu_to_be32(oi->ip_attr);
lvb->lvb_igeneration = cpu_to_be32(inode->i_generation);
+out:
mlog_meta_lvb(0, lockres);
mlog_exit_void();
@@ -1727,6 +1745,18 @@
wait_event(osb->recovery_event,
ocfs2_node_map_is_empty(osb, &osb->recovery_map));
+ /*
+ * We only see this flag if we're being called from
+ * ocfs2_read_locked_inode(). It means we're locking an inode
+ * which hasn't been populated yet, so clear the refresh flag
+ * and let the caller handle it.
+ */
+ if (inode->i_state & I_NEW) {
+ status = 0;
+ ocfs2_complete_lock_res_refresh(lockres, 0);
+ goto bail;
+ }
+
/* This is fun. The caller may want a bh back, or it may
* not. ocfs2_meta_lock_update definitely wants one in, but
* may or may not read one, depending on what's in the
diff --git a/fs/ocfs2/dlmglue.h b/fs/ocfs2/dlmglue.h
index 45a74f4..4a27693 100644
--- a/fs/ocfs2/dlmglue.h
+++ b/fs/ocfs2/dlmglue.h
@@ -32,9 +32,9 @@
#define OCFS2_LVB_VERSION 4
struct ocfs2_meta_lvb {
- __be16 lvb_reserved0;
- __u8 lvb_reserved1;
__u8 lvb_version;
+ __u8 lvb_reserved0;
+ __be16 lvb_reserved1;
__be32 lvb_iclusters;
__be32 lvb_iuid;
__be32 lvb_igid;
@@ -62,13 +62,14 @@
void ocfs2_lock_res_init_once(struct ocfs2_lock_res *res);
void ocfs2_inode_lock_res_init(struct ocfs2_lock_res *res,
enum ocfs2_lock_type type,
+ unsigned int generation,
struct inode *inode);
void ocfs2_dentry_lock_res_init(struct ocfs2_dentry_lock *dl,
u64 parent, struct inode *inode);
void ocfs2_lock_res_free(struct ocfs2_lock_res *res);
int ocfs2_create_new_inode_locks(struct inode *inode);
int ocfs2_create_new_lock(struct ocfs2_super *osb,
- struct ocfs2_lock_res *lockres, int ex);
+ struct ocfs2_lock_res *lockres, int ex, int local);
int ocfs2_drop_inode_locks(struct inode *inode);
int ocfs2_data_lock_full(struct inode *inode,
int write,
diff --git a/fs/ocfs2/export.c b/fs/ocfs2/export.c
index ffcd797..fb91089 100644
--- a/fs/ocfs2/export.c
+++ b/fs/ocfs2/export.c
@@ -58,7 +58,7 @@
return ERR_PTR(-ESTALE);
}
- inode = ocfs2_iget(OCFS2_SB(sb), handle->ih_blkno);
+ inode = ocfs2_iget(OCFS2_SB(sb), handle->ih_blkno, 0);
if (IS_ERR(inode)) {
mlog_errno(PTR_ERR(inode));
@@ -115,7 +115,7 @@
goto bail_unlock;
}
- inode = ocfs2_iget(OCFS2_SB(dir->i_sb), blkno);
+ inode = ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0);
if (IS_ERR(inode)) {
mlog(ML_ERROR, "Unable to create inode %llu\n",
(unsigned long long)blkno);
diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index 66ca7a8..69d3db5 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -54,8 +54,6 @@
#include "buffer_head_io.h"
-#define OCFS2_FI_FLAG_NOWAIT 0x1
-#define OCFS2_FI_FLAG_DELETE 0x2
struct ocfs2_find_inode_args
{
u64 fi_blkno;
@@ -109,7 +107,7 @@
return ilookup5(osb->sb, args.fi_ino, ocfs2_find_actor, &args);
}
-struct inode *ocfs2_iget(struct ocfs2_super *osb, u64 blkno)
+struct inode *ocfs2_iget(struct ocfs2_super *osb, u64 blkno, int flags)
{
struct inode *inode = NULL;
struct super_block *sb = osb->sb;
@@ -127,7 +125,7 @@
}
args.fi_blkno = blkno;
- args.fi_flags = 0;
+ args.fi_flags = flags;
args.fi_ino = ino_from_blkno(sb, blkno);
inode = iget5_locked(sb, args.fi_ino, ocfs2_find_actor,
@@ -297,15 +295,11 @@
OCFS2_I(inode)->ip_orphaned_slot = OCFS2_INVALID_SLOT;
OCFS2_I(inode)->ip_attr = le32_to_cpu(fe->i_attr);
- if (create_ino)
- inode->i_ino = ino_from_blkno(inode->i_sb,
- le64_to_cpu(fe->i_blkno));
-
- mlog(0, "blkno = %llu, ino = %lu, create_ino = %s\n",
- (unsigned long long)fe->i_blkno, inode->i_ino, create_ino ? "true" : "false");
-
inode->i_nlink = le16_to_cpu(fe->i_links_count);
+ if (fe->i_flags & cpu_to_le32(OCFS2_SYSTEM_FL))
+ OCFS2_I(inode)->ip_flags |= OCFS2_INODE_SYSTEM_FILE;
+
if (fe->i_flags & cpu_to_le32(OCFS2_LOCAL_ALLOC_FL)) {
OCFS2_I(inode)->ip_flags |= OCFS2_INODE_BITMAP;
mlog(0, "local alloc inode: i_ino=%lu\n", inode->i_ino);
@@ -343,12 +337,28 @@
break;
}
+ if (create_ino) {
+ inode->i_ino = ino_from_blkno(inode->i_sb,
+ le64_to_cpu(fe->i_blkno));
+
+ /*
+ * If we ever want to create system files from kernel,
+ * the generation argument to
+ * ocfs2_inode_lock_res_init() will have to change.
+ */
+ BUG_ON(fe->i_flags & cpu_to_le32(OCFS2_SYSTEM_FL));
+
+ ocfs2_inode_lock_res_init(&OCFS2_I(inode)->ip_meta_lockres,
+ OCFS2_LOCK_TYPE_META, 0, inode);
+ }
+
ocfs2_inode_lock_res_init(&OCFS2_I(inode)->ip_rw_lockres,
- OCFS2_LOCK_TYPE_RW, inode);
- ocfs2_inode_lock_res_init(&OCFS2_I(inode)->ip_meta_lockres,
- OCFS2_LOCK_TYPE_META, inode);
+ OCFS2_LOCK_TYPE_RW, inode->i_generation,
+ inode);
+
ocfs2_inode_lock_res_init(&OCFS2_I(inode)->ip_data_lockres,
- OCFS2_LOCK_TYPE_DATA, inode);
+ OCFS2_LOCK_TYPE_DATA, inode->i_generation,
+ inode);
ocfs2_set_inode_flags(inode);
inode->i_flags |= S_NOATIME;
@@ -366,15 +376,15 @@
struct ocfs2_super *osb;
struct ocfs2_dinode *fe;
struct buffer_head *bh = NULL;
- int status;
- int sysfile = 0;
+ int status, can_lock;
+ u32 generation = 0;
mlog_entry("(0x%p, 0x%p)\n", inode, args);
status = -EINVAL;
if (inode == NULL || inode->i_sb == NULL) {
mlog(ML_ERROR, "bad inode\n");
- goto bail;
+ return status;
}
sb = inode->i_sb;
osb = OCFS2_SB(sb);
@@ -382,50 +392,110 @@
if (!args) {
mlog(ML_ERROR, "bad inode args\n");
make_bad_inode(inode);
- goto bail;
+ return status;
}
- /* Read the FE off disk. This is safe because the kernel only
- * does one read_inode2 for a new inode, and if it doesn't
- * exist yet then nobody can be working on it! */
- status = ocfs2_read_block(osb, args->fi_blkno, &bh, 0, NULL);
+ /*
+ * To improve performance of cold-cache inode stats, we take
+ * the cluster lock here if possible.
+ *
+ * Generally, OCFS2 never trusts the contents of an inode
+ * unless it's holding a cluster lock, so taking it here isn't
+ * a correctness issue as much as it is a performance
+ * improvement.
+ *
+ * There are three times when taking the lock is not a good idea:
+ *
+ * 1) During startup, before we have initialized the DLM.
+ *
+ * 2) If we are reading certain system files which never get
+ * cluster locks (local alloc, truncate log).
+ *
+ * 3) If the process doing the iget() is responsible for
+ * orphan dir recovery. We're holding the orphan dir lock and
+ * can get into a deadlock with another process on another
+ * node in ->delete_inode().
+ *
+ * #1 and #2 can be simply solved by never taking the lock
+ * here for system files (which are the only type we read
+ * during mount). It's a heavier approach, but our main
+ * concern is user-accesible files anyway.
+ *
+ * #3 works itself out because we'll eventually take the
+ * cluster lock before trusting anything anyway.
+ */
+ can_lock = !(args->fi_flags & OCFS2_FI_FLAG_SYSFILE)
+ && !(args->fi_flags & OCFS2_FI_FLAG_NOLOCK);
+
+ /*
+ * To maintain backwards compatibility with older versions of
+ * ocfs2-tools, we still store the generation value for system
+ * files. The only ones that actually matter to userspace are
+ * the journals, but it's easier and inexpensive to just flag
+ * all system files similarly.
+ */
+ if (args->fi_flags & OCFS2_FI_FLAG_SYSFILE)
+ generation = osb->fs_generation;
+
+ ocfs2_inode_lock_res_init(&OCFS2_I(inode)->ip_meta_lockres,
+ OCFS2_LOCK_TYPE_META,
+ generation, inode);
+
+ if (can_lock) {
+ status = ocfs2_meta_lock(inode, NULL, NULL, 0);
+ if (status) {
+ make_bad_inode(inode);
+ mlog_errno(status);
+ return status;
+ }
+ }
+
+ status = ocfs2_read_block(osb, args->fi_blkno, &bh, 0,
+ can_lock ? inode : NULL);
if (status < 0) {
mlog_errno(status);
- make_bad_inode(inode);
goto bail;
}
+ status = -EINVAL;
fe = (struct ocfs2_dinode *) bh->b_data;
if (!OCFS2_IS_VALID_DINODE(fe)) {
mlog(ML_ERROR, "Invalid dinode #%llu: signature = %.*s\n",
(unsigned long long)fe->i_blkno, 7, fe->i_signature);
- make_bad_inode(inode);
goto bail;
}
- if (fe->i_flags & cpu_to_le32(OCFS2_SYSTEM_FL))
- sysfile = 1;
+ /*
+ * This is a code bug. Right now the caller needs to
+ * understand whether it is asking for a system file inode or
+ * not so the proper lock names can be built.
+ */
+ mlog_bug_on_msg(!!(fe->i_flags & cpu_to_le32(OCFS2_SYSTEM_FL)) !=
+ !!(args->fi_flags & OCFS2_FI_FLAG_SYSFILE),
+ "Inode %llu: system file state is ambigous\n",
+ (unsigned long long)args->fi_blkno);
if (S_ISCHR(le16_to_cpu(fe->i_mode)) ||
S_ISBLK(le16_to_cpu(fe->i_mode)))
inode->i_rdev = huge_decode_dev(le64_to_cpu(fe->id1.dev1.i_rdev));
- status = -EINVAL;
if (ocfs2_populate_inode(inode, fe, 0) < 0) {
mlog(ML_ERROR, "populate failed! i_blkno=%llu, i_ino=%lu\n",
(unsigned long long)fe->i_blkno, inode->i_ino);
- make_bad_inode(inode);
goto bail;
}
BUG_ON(args->fi_blkno != le64_to_cpu(fe->i_blkno));
- if (sysfile)
- OCFS2_I(inode)->ip_flags |= OCFS2_INODE_SYSTEM_FILE;
-
status = 0;
bail:
+ if (can_lock)
+ ocfs2_meta_unlock(inode, 0);
+
+ if (status < 0)
+ make_bad_inode(inode);
+
if (args && bh)
brelse(bh);
@@ -898,9 +968,15 @@
goto bail_unlock_inode;
}
- /* Mark the inode as successfully deleted. This is important
- * for ocfs2_clear_inode as it will check this flag and skip
- * any checkpointing work */
+ /*
+ * Mark the inode as successfully deleted.
+ *
+ * This is important for ocfs2_clear_inode() as it will check
+ * this flag and skip any checkpointing work
+ *
+ * ocfs2_stuff_meta_lvb() also uses this flag to invalidate
+ * the LVB for other nodes.
+ */
OCFS2_I(inode)->ip_flags |= OCFS2_INODE_DELETED;
bail_unlock_inode:
diff --git a/fs/ocfs2/inode.h b/fs/ocfs2/inode.h
index 4d1e539..9957810 100644
--- a/fs/ocfs2/inode.h
+++ b/fs/ocfs2/inode.h
@@ -122,7 +122,13 @@
void ocfs2_clear_inode(struct inode *inode);
void ocfs2_delete_inode(struct inode *inode);
void ocfs2_drop_inode(struct inode *inode);
-struct inode *ocfs2_iget(struct ocfs2_super *osb, u64 feoff);
+
+/* Flags for ocfs2_iget() */
+#define OCFS2_FI_FLAG_NOWAIT 0x1
+#define OCFS2_FI_FLAG_DELETE 0x2
+#define OCFS2_FI_FLAG_SYSFILE 0x4
+#define OCFS2_FI_FLAG_NOLOCK 0x8
+struct inode *ocfs2_iget(struct ocfs2_super *osb, u64 feoff, int flags);
struct inode *ocfs2_ilookup_for_vote(struct ocfs2_super *osb,
u64 blkno,
int delete_vote);
diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
index f92bf1d..fd9734d 100644
--- a/fs/ocfs2/journal.c
+++ b/fs/ocfs2/journal.c
@@ -1493,7 +1493,8 @@
if (de->name_len == 2 && !strncmp("..", de->name, 2))
continue;
- iter = ocfs2_iget(osb, le64_to_cpu(de->inode));
+ iter = ocfs2_iget(osb, le64_to_cpu(de->inode),
+ OCFS2_FI_FLAG_NOLOCK);
if (IS_ERR(iter))
continue;
diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index 6fa9788..849c3b4 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -179,7 +179,7 @@
if (status < 0)
goto bail_add;
- inode = ocfs2_iget(OCFS2_SB(dir->i_sb), blkno);
+ inode = ocfs2_iget(OCFS2_SB(dir->i_sb), blkno, 0);
if (IS_ERR(inode)) {
mlog(ML_ERROR, "Unable to create inode %llu\n",
(unsigned long long)blkno);
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 33a6de6..4c29cd7 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -202,7 +202,7 @@
mlog_entry_void();
- new = ocfs2_iget(osb, osb->root_blkno);
+ new = ocfs2_iget(osb, osb->root_blkno, OCFS2_FI_FLAG_SYSFILE);
if (IS_ERR(new)) {
status = PTR_ERR(new);
mlog_errno(status);
@@ -210,7 +210,7 @@
}
osb->root_inode = new;
- new = ocfs2_iget(osb, osb->system_dir_blkno);
+ new = ocfs2_iget(osb, osb->system_dir_blkno, OCFS2_FI_FLAG_SYSFILE);
if (IS_ERR(new)) {
status = PTR_ERR(new);
mlog_errno(status);
diff --git a/fs/ocfs2/sysfile.c b/fs/ocfs2/sysfile.c
index 9843500..5df6e35 100644
--- a/fs/ocfs2/sysfile.c
+++ b/fs/ocfs2/sysfile.c
@@ -115,7 +115,7 @@
goto bail;
}
- inode = ocfs2_iget(osb, blkno);
+ inode = ocfs2_iget(osb, blkno, OCFS2_FI_FLAG_SYSFILE);
if (IS_ERR(inode)) {
mlog_errno(PTR_ERR(inode));
inode = NULL;