afs: Prospectively look up extra files when doing a single lookup

When afs_lookup() is called, prospectively look up the next 50 uncached
fids also from that same directory and cache the results, rather than just
looking up the one file requested.

This allows us to use the FS.InlineBulkStatus RPC op to increase efficiency
by fetching up to 50 file statuses at a time.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 250 insertions, 38 deletions

diff --git a/fs/afs/dir.c b/fs/afs/dir.c
index ba2b458b36d1..27c5231e89e7 100644
--- a/fs/afs/dir.c
+++ b/fs/afs/dir.c
@@ -29,8 +29,10 @@ static int afs_readdir(struct file *file, struct dir_context *ctx);
 static int afs_d_revalidate(struct dentry *dentry, unsigned int flags);
 static int afs_d_delete(const struct dentry *dentry);
 static void afs_d_release(struct dentry *dentry);
-static int afs_lookup_filldir(struct dir_context *ctx, const char *name, int nlen,
+static int afs_lookup_one_filldir(struct dir_context *ctx, const char *name, int nlen,
 				  loff_t fpos, u64 ino, unsigned dtype);
+static int afs_lookup_filldir(struct dir_context *ctx, const char *name, int nlen,
+			      loff_t fpos, u64 ino, unsigned dtype);
 static int afs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
 		      bool excl);
 static int afs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode);
@@ -134,11 +136,22 @@ struct afs_dir_page {
 	union afs_dir_block blocks[PAGE_SIZE / sizeof(union afs_dir_block)];
 };
 
+struct afs_lookup_one_cookie {
+	struct dir_context	ctx;
+	struct qstr		name;
+	bool			found;
+	struct afs_fid		fid;
+};
+
 struct afs_lookup_cookie {
-	struct dir_context ctx;
-	struct afs_fid	fid;
-	struct qstr name;
-	int		found;
+	struct dir_context	ctx;
+	struct qstr		name;
+	bool			found;
+	bool			one_only;
+	unsigned short		nr_fids;
+	struct afs_file_status	*statuses;
+	struct afs_callback	*callbacks;
+	struct afs_fid		fids[50];
 };
 
 /*
@@ -330,7 +343,8 @@ static int afs_dir_iterate_block(struct dir_context *ctx,
 		/* found the next entry */
 		if (!dir_emit(ctx, dire->u.name, nlen,
 			      ntohl(dire->u.vnode),
-			      ctx->actor == afs_lookup_filldir ?
+			      (ctx->actor == afs_lookup_filldir ||
+			       ctx->actor == afs_lookup_one_filldir)?
 			      ntohl(dire->u.unique) : DT_UNKNOWN)) {
 			_leave(" = 0 [full]");
 			return 0;
@@ -414,15 +428,15 @@ static int afs_readdir(struct file *file, struct dir_context *ctx)
 }
 
 /*
- * search the directory for a name
+ * Search the directory for a single name
  * - if afs_dir_iterate_block() spots this function, it'll pass the FID
  *   uniquifier through dtype
  */
-static int afs_lookup_filldir(struct dir_context *ctx, const char *name,
-			      int nlen, loff_t fpos, u64 ino, unsigned dtype)
+static int afs_lookup_one_filldir(struct dir_context *ctx, const char *name,
+				  int nlen, loff_t fpos, u64 ino, unsigned dtype)
 {
-	struct afs_lookup_cookie *cookie =
-		container_of(ctx, struct afs_lookup_cookie, ctx);
+	struct afs_lookup_one_cookie *cookie =
+		container_of(ctx, struct afs_lookup_one_cookie, ctx);
 
 	_enter("{%s,%u},%s,%u,,%llu,%u",
 	       cookie->name.name, cookie->name.len, name, nlen,
@@ -447,15 +461,15 @@ static int afs_lookup_filldir(struct dir_context *ctx, const char *name,
 }
 
 /*
- * do a lookup in a directory
+ * Do a lookup of a single name in a directory
  * - just returns the FID the dentry name maps to if found
  */
-static int afs_do_lookup(struct inode *dir, struct dentry *dentry,
-			 struct afs_fid *fid, struct key *key)
+static int afs_do_lookup_one(struct inode *dir, struct dentry *dentry,
+			     struct afs_fid *fid, struct key *key)
 {
 	struct afs_super_info *as = dir->i_sb->s_fs_info;
-	struct afs_lookup_cookie cookie = {
-		.ctx.actor = afs_lookup_filldir,
+	struct afs_lookup_one_cookie cookie = {
+		.ctx.actor = afs_lookup_one_filldir,
 		.name = dentry->d_name,
 		.fid.vid = as->volume->vid
 	};
@@ -482,6 +496,212 @@ static int afs_do_lookup(struct inode *dir, struct dentry *dentry,
 }
 
 /*
+ * search the directory for a name
+ * - if afs_dir_iterate_block() spots this function, it'll pass the FID
+ *   uniquifier through dtype
+ */
+static int afs_lookup_filldir(struct dir_context *ctx, const char *name,
+			      int nlen, loff_t fpos, u64 ino, unsigned dtype)
+{
+	struct afs_lookup_cookie *cookie =
+		container_of(ctx, struct afs_lookup_cookie, ctx);
+	int ret;
+
+	_enter("{%s,%u},%s,%u,,%llu,%u",
+	       cookie->name.name, cookie->name.len, name, nlen,
+	       (unsigned long long) ino, dtype);
+
+	/* insanity checks first */
+	BUILD_BUG_ON(sizeof(union afs_dir_block) != 2048);
+	BUILD_BUG_ON(sizeof(union afs_dirent) != 32);
+
+	if (cookie->found) {
+		if (cookie->nr_fids < 50) {
+			cookie->fids[cookie->nr_fids].vnode	= ino;
+			cookie->fids[cookie->nr_fids].unique	= dtype;
+			cookie->nr_fids++;
+		}
+	} else if (cookie->name.len == nlen &&
+		   memcmp(cookie->name.name, name, nlen) == 0) {
+		cookie->fids[0].vnode	= ino;
+		cookie->fids[0].unique	= dtype;
+		cookie->found = 1;
+		if (cookie->one_only)
+			return -1;
+	}
+
+	ret = cookie->nr_fids >= 50 ? -1 : 0;
+	_leave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * Do a lookup in a directory.  We make use of bulk lookup to query a slew of
+ * files in one go and create inodes for them.  The inode of the file we were
+ * asked for is returned.
+ */
+static struct inode *afs_do_lookup(struct inode *dir, struct dentry *dentry,
+				   struct key *key)
+{
+	struct afs_lookup_cookie *cookie;
+	struct afs_cb_interest *cbi = NULL;
+	struct afs_super_info *as = dir->i_sb->s_fs_info;
+	struct afs_iget_data data;
+	struct afs_fs_cursor fc;
+	struct afs_vnode *dvnode = AFS_FS_I(dir);
+	struct inode *inode = NULL;
+	int ret, i;
+
+	_enter("{%lu},%p{%pd},", dir->i_ino, dentry, dentry);
+
+	cookie = kzalloc(sizeof(struct afs_lookup_cookie), GFP_KERNEL);
+	if (!cookie)
+		return ERR_PTR(-ENOMEM);
+
+	cookie->ctx.actor = afs_lookup_filldir;
+	cookie->name = dentry->d_name;
+	cookie->nr_fids = 1; /* slot 0 is saved for the fid we actually want */
+
+	read_seqlock_excl(&dvnode->cb_lock);
+	if (dvnode->cb_interest &&
+	    dvnode->cb_interest->server &&
+	    test_bit(AFS_SERVER_FL_NO_IBULK, &dvnode->cb_interest->server->flags))
+		cookie->one_only = true;
+	read_sequnlock_excl(&dvnode->cb_lock);
+
+	for (i = 0; i < 50; i++)
+		cookie->fids[i].vid = as->volume->vid;
+
+	/* search the directory */
+	ret = afs_dir_iterate(dir, &cookie->ctx, key);
+	if (ret < 0) {
+		inode = ERR_PTR(ret);
+		goto out;
+	}
+
+	inode = ERR_PTR(-ENOENT);
+	if (!cookie->found)
+		goto out;
+
+	/* Check to see if we already have an inode for the primary fid. */
+	data.volume = dvnode->volume;
+	data.fid = cookie->fids[0];
+	inode = ilookup5(dir->i_sb, cookie->fids[0].vnode, afs_iget5_test, &data);
+	if (inode)
+		goto out;
+
+	/* Need space for examining all the selected files */
+	inode = ERR_PTR(-ENOMEM);
+	cookie->statuses = kcalloc(cookie->nr_fids, sizeof(struct afs_file_status),
+				   GFP_KERNEL);
+	if (!cookie->statuses)
+		goto out;
+
+	cookie->callbacks = kcalloc(cookie->nr_fids, sizeof(struct afs_callback),
+				    GFP_KERNEL);
+	if (!cookie->callbacks)
+		goto out_s;
+
+	/* Try FS.InlineBulkStatus first.  Abort codes for the individual
+	 * lookups contained therein are stored in the reply without aborting
+	 * the whole operation.
+	 */
+	if (cookie->one_only)
+		goto no_inline_bulk_status;
+
+	inode = ERR_PTR(-ERESTARTSYS);
+	if (afs_begin_vnode_operation(&fc, dvnode, key)) {
+		while (afs_select_fileserver(&fc)) {
+			if (test_bit(AFS_SERVER_FL_NO_IBULK,
+				      &fc.cbi->server->flags)) {
+				fc.ac.abort_code = RX_INVALID_OPERATION;
+				fc.ac.error = -ECONNABORTED;
+				break;
+			}
+			afs_fs_inline_bulk_status(&fc,
+						  afs_v2net(dvnode),
+						  cookie->fids,
+						  cookie->statuses,
+						  cookie->callbacks,
+						  cookie->nr_fids, NULL);
+		}
+
+		if (fc.ac.error == 0)
+			cbi = afs_get_cb_interest(fc.cbi);
+		if (fc.ac.abort_code == RX_INVALID_OPERATION)
+			set_bit(AFS_SERVER_FL_NO_IBULK, &fc.cbi->server->flags);
+		inode = ERR_PTR(afs_end_vnode_operation(&fc));
+	}
+
+	if (!IS_ERR(inode))
+		goto success;
+	if (fc.ac.abort_code != RX_INVALID_OPERATION)
+		goto out_c;
+
+no_inline_bulk_status:
+	/* We could try FS.BulkStatus next, but this aborts the entire op if
+	 * any of the lookups fails - so, for the moment, revert to
+	 * FS.FetchStatus for just the primary fid.
+	 */
+	cookie->nr_fids = 1;
+	inode = ERR_PTR(-ERESTARTSYS);
+	if (afs_begin_vnode_operation(&fc, dvnode, key)) {
+		while (afs_select_fileserver(&fc)) {
+			afs_fs_fetch_status(&fc,
+					    afs_v2net(dvnode),
+					    cookie->fids,
+					    cookie->statuses,
+					    cookie->callbacks,
+					    NULL);
+		}
+
+		if (fc.ac.error == 0)
+			cbi = afs_get_cb_interest(fc.cbi);
+		inode = ERR_PTR(afs_end_vnode_operation(&fc));
+	}
+
+	if (IS_ERR(inode))
+		goto out_c;
+
+	for (i = 0; i < cookie->nr_fids; i++)
+		cookie->statuses[i].abort_code = 0;
+
+success:
+	/* Turn all the files into inodes and save the first one - which is the
+	 * one we actually want.
+	 */
+	if (cookie->statuses[0].abort_code != 0)
+		inode = ERR_PTR(afs_abort_to_error(cookie->statuses[0].abort_code));
+
+	for (i = 0; i < cookie->nr_fids; i++) {
+		struct inode *ti;
+
+		if (cookie->statuses[i].abort_code != 0)
+			continue;
+
+		ti = afs_iget(dir->i_sb, key, &cookie->fids[i],
+			      &cookie->statuses[i],
+			      &cookie->callbacks[i],
+			      cbi);
+		if (i == 0) {
+			inode = ti;
+		} else {
+			if (!IS_ERR(ti))
+				iput(ti);
+		}
+	}
+
+out_c:
+	afs_put_cb_interest(afs_v2net(dvnode), cbi);
+	kfree(cookie->callbacks);
+out_s:
+	kfree(cookie->statuses);
+out:
+	kfree(cookie);
+	return inode;
+}
+
+/*
  * Probe to see if a cell may exist.  This prevents positive dentries from
  * being created unnecessarily.
  */
@@ -516,8 +736,7 @@ static int afs_probe_cell_name(struct dentry *dentry)
  * Try to auto mount the mountpoint with pseudo directory, if the autocell
  * operation is setted.
  */
-static struct inode *afs_try_auto_mntpt(struct dentry *dentry,
-					struct inode *dir, struct afs_fid *fid)
+static struct inode *afs_try_auto_mntpt(struct dentry *dentry, struct inode *dir)
 {
 	struct afs_vnode *vnode = AFS_FS_I(dir);
 	struct inode *inode;
@@ -539,7 +758,6 @@ static struct inode *afs_try_auto_mntpt(struct dentry *dentry,
 		goto out;
 	}
 
-	*fid = AFS_FS_I(inode)->fid;
 	_leave("= %p", inode);
 	return inode;
 
@@ -554,16 +772,13 @@ out:
 static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
 				 unsigned int flags)
 {
-	struct afs_vnode *vnode;
-	struct afs_fid fid;
+	struct afs_vnode *dvnode = AFS_FS_I(dir);
 	struct inode *inode;
 	struct key *key;
 	int ret;
 
-	vnode = AFS_FS_I(dir);
-
 	_enter("{%x:%u},%p{%pd},",
-	       vnode->fid.vid, vnode->fid.vnode, dentry, dentry);
+	       dvnode->fid.vid, dvnode->fid.vnode, dentry, dentry);
 
 	ASSERTCMP(d_inode(dentry), ==, NULL);
 
@@ -572,28 +787,29 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
 		return ERR_PTR(-ENAMETOOLONG);
 	}
 
-	if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) {
+	if (test_bit(AFS_VNODE_DELETED, &dvnode->flags)) {
 		_leave(" = -ESTALE");
 		return ERR_PTR(-ESTALE);
 	}
 
-	key = afs_request_key(vnode->volume->cell);
+	key = afs_request_key(dvnode->volume->cell);
 	if (IS_ERR(key)) {
 		_leave(" = %ld [key]", PTR_ERR(key));
 		return ERR_CAST(key);
 	}
 
-	ret = afs_validate(vnode, key);
+	ret = afs_validate(dvnode, key);
 	if (ret < 0) {
 		key_put(key);
 		_leave(" = %d [val]", ret);
 		return ERR_PTR(ret);
 	}
 
-	ret = afs_do_lookup(dir, dentry, &fid, key);
-	if (ret < 0) {
+	inode = afs_do_lookup(dir, dentry, key);
+	if (IS_ERR(inode)) {
+		ret = PTR_ERR(inode);
 		if (ret == -ENOENT) {
-			inode = afs_try_auto_mntpt(dentry, dir, &fid);
+			inode = afs_try_auto_mntpt(dentry, dir);
 			if (!IS_ERR(inode)) {
 				key_put(key);
 				goto success;
@@ -611,10 +827,9 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
 		_leave(" = %d [do]", ret);
 		return ERR_PTR(ret);
 	}
-	dentry->d_fsdata = (void *)(unsigned long) vnode->status.data_version;
+	dentry->d_fsdata = (void *)(unsigned long)dvnode->status.data_version;
 
 	/* instantiate the dentry */
-	inode = afs_iget(dir->i_sb, key, &fid, NULL, NULL, NULL);
 	key_put(key);
 	if (IS_ERR(inode)) {
 		_leave(" = %ld", PTR_ERR(inode));
@@ -623,9 +838,7 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry,
 
 success:
 	d_add(dentry, inode);
-	_leave(" = 0 { vn=%u u=%u } -> { ino=%lu v=%u }",
-	       fid.vnode,
-	       fid.unique,
+	_leave(" = 0 { ino=%lu v=%u }",
 	       d_inode(dentry)->i_ino,
 	       d_inode(dentry)->i_generation);
 
@@ -639,7 +852,6 @@ static struct dentry *afs_dynroot_lookup(struct inode *dir, struct dentry *dentr
 					 unsigned int flags)
 {
 	struct afs_vnode *vnode;
-	struct afs_fid fid;
 	struct inode *inode;
 	int ret;
 
@@ -654,7 +866,7 @@ static struct dentry *afs_dynroot_lookup(struct inode *dir, struct dentry *dentr
 		return ERR_PTR(-ENAMETOOLONG);
 	}
 
-	inode = afs_try_auto_mntpt(dentry, dir, &fid);
+	inode = afs_try_auto_mntpt(dentry, dir);
 	if (IS_ERR(inode)) {
 		ret = PTR_ERR(inode);
 		if (ret == -ENOENT) {
@@ -736,7 +948,7 @@ static int afs_d_revalidate(struct dentry *dentry, unsigned int flags)
 	_debug("dir modified");
 
 	/* search the directory for this vnode */
-	ret = afs_do_lookup(&dir->vfs_inode, dentry, &fid, key);
+	ret = afs_do_lookup_one(&dir->vfs_inode, dentry, &fid, key);
 	switch (ret) {
 	case 0:
 		/* the filename maps to something */