Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull parallel filesystem directory handling update from Al Viro.

This is the main parallel directory work by Al that makes the vfs layer
able to do lookup and readdir in parallel within a single directory.
That's a big change, since this used to be all protected by the
directory inode mutex.

The inode mutex is replaced by an rwsem, and serialization of lookups of
a single name is done by a "in-progress" dentry marker.

The series begins with xattr cleanups, and then ends with switching
filesystems over to actually doing the readdir in parallel (switching to
the "iterate_shared()" that only takes the read lock).

A more detailed explanation of the process from Al Viro:
 "The xattr work starts with some acl fixes, then switches ->getxattr to
  passing inode and dentry separately.  This is the point where the
  things start to get tricky - that got merged into the very beginning
  of the -rc3-based #work.lookups, to allow untangling the
  security_d_instantiate() mess.  The xattr work itself proceeds to
  switch a lot of filesystems to generic_...xattr(); no complications
  there.

  After that initial xattr work, the series then does the following:

   - untangle security_d_instantiate()

   - convert a bunch of open-coded lookup_one_len_unlocked() to calls of
     that thing; one such place (in overlayfs) actually yields a trivial
     conflict with overlayfs fixes later in the cycle - overlayfs ended
     up switching to a variant of lookup_one_len_unlocked() sans the
     permission checks.  I would've dropped that commit (it gets
     overridden on merge from #ovl-fixes in #for-next; proper resolution
     is to use the variant in mainline fs/overlayfs/super.c), but I
     didn't want to rebase the damn thing - it was fairly late in the
     cycle...

   - some filesystems had managed to depend on lookup/lookup exclusion
     for *fs-internal* data structures in a way that would break if we
     relaxed the VFS exclusion.  Fixing hadn't been hard, fortunately.

   - core of that series - parallel lookup machinery, replacing
     ->i_mutex with rwsem, making lookup_slow() take it only shared.  At
     that point lookups happen in parallel; lookups on the same name
     wait for the in-progress one to be done with that dentry.

     Surprisingly little code, at that - almost all of it is in
     fs/dcache.c, with fs/namei.c changes limited to lookup_slow() -
     making it use the new primitive and actually switching to locking
     shared.

   - parallel readdir stuff - first of all, we provide the exclusion on
     per-struct file basis, same as we do for read() vs lseek() for
     regular files.  That takes care of most of the needed exclusion in
     readdir/readdir; however, these guys are trickier than lookups, so
     I went for switching them one-by-one.  To do that, a new method
     '->iterate_shared()' is added and filesystems are switched to it
     as they are either confirmed to be OK with shared lock on directory
     or fixed to be OK with that.  I hope to kill the original method
     come next cycle (almost all in-tree filesystems are switched
     already), but it's still not quite finished.

   - several filesystems get switched to parallel readdir.  The
     interesting part here is dealing with dcache preseeding by readdir;
     that needs minor adjustment to be safe with directory locked only
     shared.

     Most of the filesystems doing that got switched to in those
     commits.  Important exception: NFS.  Turns out that NFS folks, with
     their, er, insistence on VFS getting the fuck out of the way of the
     Smart Filesystem Code That Knows How And What To Lock(tm) have
     grown the locking of their own.  They had their own homegrown
     rwsem, with lookup/readdir/atomic_open being *writers* (sillyunlink
     is the reader there).  Of course, with VFS getting the fuck out of
     the way, as requested, the actual smarts of the smart filesystem
     code etc. had become exposed...

   - do_last/lookup_open/atomic_open cleanups.  As the result, open()
     without O_CREAT locks the directory only shared.  Including the
     ->atomic_open() case.  Backmerge from #for-linus in the middle of
     that - atomic_open() fix got brought in.

   - then comes NFS switch to saner (VFS-based ;-) locking, killing the
     homegrown "lookup and readdir are writers" kinda-sorta rwsem.  All
     exclusion for sillyunlink/lookup is done by the parallel lookups
     mechanism.  Exclusion between sillyunlink and rmdir is a real rwsem
     now - rmdir being the writer.

     Result: NFS lookups/readdirs/O_CREAT-less opens happen in parallel
     now.

   - the rest of the series consists of switching a lot of filesystems
     to parallel readdir; in a lot of cases ->llseek() gets simplified
     as well.  One backmerge in there (again, #for-linus - rockridge
     fix)"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (74 commits)
  ext4: switch to ->iterate_shared()
  hfs: switch to ->iterate_shared()
  hfsplus: switch to ->iterate_shared()
  hostfs: switch to ->iterate_shared()
  hpfs: switch to ->iterate_shared()
  hpfs: handle allocation failures in hpfs_add_pos()
  gfs2: switch to ->iterate_shared()
  f2fs: switch to ->iterate_shared()
  afs: switch to ->iterate_shared()
  befs: switch to ->iterate_shared()
  befs: constify stuff a bit
  isofs: switch to ->iterate_shared()
  get_acorn_filename(): deobfuscate a bit
  btrfs: switch to ->iterate_shared()
  logfs: no need to lock directory in lseek
  switch ecryptfs to ->iterate_shared
  9p: switch to ->iterate_shared()
  fat: switch to ->iterate_shared()
  romfs, squashfs: switch to ->iterate_shared()
  more trivial ->iterate_shared conversions
  ...

6 files changed, 43 insertions, 79 deletions

diff --git a/fs/cifs/cifs_dfs_ref.c b/fs/cifs/cifs_dfs_ref.c
index e956cba94338..94f2c8a9ae6d 100644
--- a/fs/cifs/cifs_dfs_ref.c
+++ b/fs/cifs/cifs_dfs_ref.c
@@ -302,7 +302,7 @@ static struct vfsmount *cifs_dfs_do_automount(struct dentry *mntpt)
 	if (full_path == NULL)
 		goto cdda_exit;
 
-	cifs_sb = CIFS_SB(d_inode(mntpt)->i_sb);
+	cifs_sb = CIFS_SB(mntpt->d_sb);
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink)) {
 		mnt = ERR_CAST(tlink);
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index 89201564c346..aadb59388e90 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -1083,7 +1083,7 @@ const struct file_operations cifs_file_direct_nobrl_ops = {
 };
 
 const struct file_operations cifs_dir_ops = {
-	.iterate = cifs_readdir,
+	.iterate_shared = cifs_readdir,
 	.release = cifs_closedir,
 	.read    = generic_read_dir,
 	.unlocked_ioctl  = cifs_ioctl,
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 83aac8ba50b0..c89ecd7a5c39 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -123,7 +123,7 @@ extern int cifs_symlink(struct inode *inode, struct dentry *direntry,
 extern int	cifs_removexattr(struct dentry *, const char *);
 extern int	cifs_setxattr(struct dentry *, const char *, const void *,
 			size_t, int);
-extern ssize_t	cifs_getxattr(struct dentry *, const char *, void *, size_t);
+extern ssize_t	cifs_getxattr(struct dentry *, struct inode *, const char *, void *, size_t);
 extern ssize_t	cifs_listxattr(struct dentry *, char *, size_t);
 extern long cifs_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
 #ifdef CONFIG_CIFS_NFSD_EXPORT
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index 5f9ad5c42180..514dadb0575d 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -2418,8 +2418,7 @@ cifs_setattr_exit:
 int
 cifs_setattr(struct dentry *direntry, struct iattr *attrs)
 {
-	struct inode *inode = d_inode(direntry);
-	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
 	struct cifs_tcon *pTcon = cifs_sb_master_tcon(cifs_sb);
 
 	if (pTcon->unix_ext)
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index b30a4a6d98a0..867439c21001 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -78,20 +78,34 @@ cifs_prime_dcache(struct dentry *parent, struct qstr *name,
 {
 	struct dentry *dentry, *alias;
 	struct inode *inode;
-	struct super_block *sb = d_inode(parent)->i_sb;
+	struct super_block *sb = parent->d_sb;
 	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
+	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
 
 	cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
 
 	dentry = d_hash_and_lookup(parent, name);
+	if (!dentry) {
+		/*
+		 * If we know that the inode will need to be revalidated
+		 * immediately, then don't create a new dentry for it.
+		 * We'll end up doing an on the wire call either way and
+		 * this spares us an invalidation.
+		 */
+		if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
+			return;
+retry:
+		dentry = d_alloc_parallel(parent, name, &wq);
+	}
 	if (IS_ERR(dentry))
 		return;
-
-	if (dentry) {
+	if (!d_in_lookup(dentry)) {
 		inode = d_inode(dentry);
 		if (inode) {
-			if (d_mountpoint(dentry))
-				goto out;
+			if (d_mountpoint(dentry)) {
+				dput(dentry);
+				return;
+			}
 			/*
 			 * If we're generating inode numbers, then we don't
 			 * want to clobber the existing one with the one that
@@ -106,33 +120,22 @@ cifs_prime_dcache(struct dentry *parent, struct qstr *name,
 			    (inode->i_mode & S_IFMT) ==
 			    (fattr->cf_mode & S_IFMT)) {
 				cifs_fattr_to_inode(inode, fattr);
-				goto out;
+				dput(dentry);
+				return;
 			}
 		}
 		d_invalidate(dentry);
 		dput(dentry);
+		goto retry;
+	} else {
+		inode = cifs_iget(sb, fattr);
+		if (!inode)
+			inode = ERR_PTR(-ENOMEM);
+		alias = d_splice_alias(inode, dentry);
+		d_lookup_done(dentry);
+		if (alias && !IS_ERR(alias))
+			dput(alias);
 	}
-
-	/*
-	 * If we know that the inode will need to be revalidated immediately,
-	 * then don't create a new dentry for it. We'll end up doing an on
-	 * the wire call either way and this spares us an invalidation.
-	 */
-	if (fattr->cf_flags & CIFS_FATTR_NEED_REVAL)
-		return;
-
-	dentry = d_alloc(parent, name);
-	if (!dentry)
-		return;
-
-	inode = cifs_iget(sb, fattr);
-	if (!inode)
-		goto out;
-
-	alias = d_splice_alias(inode, dentry);
-	if (alias && !IS_ERR(alias))
-		dput(alias);
-out:
 	dput(dentry);
 }
 
diff --git a/fs/cifs/xattr.c b/fs/cifs/xattr.c
index f5dc2f0df4ad..5d57c85703a9 100644
--- a/fs/cifs/xattr.c
+++ b/fs/cifs/xattr.c
@@ -42,21 +42,11 @@ int cifs_removexattr(struct dentry *direntry, const char *ea_name)
 	int rc = -EOPNOTSUPP;
 #ifdef CONFIG_CIFS_XATTR
 	unsigned int xid;
-	struct cifs_sb_info *cifs_sb;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
 	struct tcon_link *tlink;
 	struct cifs_tcon *pTcon;
-	struct super_block *sb;
 	char *full_path = NULL;
 
-	if (direntry == NULL)
-		return -EIO;
-	if (d_really_is_negative(direntry))
-		return -EIO;
-	sb = d_inode(direntry)->i_sb;
-	if (sb == NULL)
-		return -EIO;
-
-	cifs_sb = CIFS_SB(sb);
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
 		return PTR_ERR(tlink);
@@ -103,21 +93,12 @@ int cifs_setxattr(struct dentry *direntry, const char *ea_name,
 	int rc = -EOPNOTSUPP;
 #ifdef CONFIG_CIFS_XATTR
 	unsigned int xid;
-	struct cifs_sb_info *cifs_sb;
+	struct super_block *sb = direntry->d_sb;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 	struct tcon_link *tlink;
 	struct cifs_tcon *pTcon;
-	struct super_block *sb;
 	char *full_path;
 
-	if (direntry == NULL)
-		return -EIO;
-	if (d_really_is_negative(direntry))
-		return -EIO;
-	sb = d_inode(direntry)->i_sb;
-	if (sb == NULL)
-		return -EIO;
-
-	cifs_sb = CIFS_SB(sb);
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
 		return PTR_ERR(tlink);
@@ -232,27 +213,18 @@ set_ea_exit:
 	return rc;
 }
 
-ssize_t cifs_getxattr(struct dentry *direntry, const char *ea_name,
-	void *ea_value, size_t buf_size)
+ssize_t cifs_getxattr(struct dentry *direntry, struct inode *inode,
+	const char *ea_name, void *ea_value, size_t buf_size)
 {
 	ssize_t rc = -EOPNOTSUPP;
 #ifdef CONFIG_CIFS_XATTR
 	unsigned int xid;
-	struct cifs_sb_info *cifs_sb;
+	struct super_block *sb = direntry->d_sb;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 	struct tcon_link *tlink;
 	struct cifs_tcon *pTcon;
-	struct super_block *sb;
 	char *full_path;
 
-	if (direntry == NULL)
-		return -EIO;
-	if (d_really_is_negative(direntry))
-		return -EIO;
-	sb = d_inode(direntry)->i_sb;
-	if (sb == NULL)
-		return -EIO;
-
-	cifs_sb = CIFS_SB(sb);
 	tlink = cifs_sb_tlink(cifs_sb);
 	if (IS_ERR(tlink))
 		return PTR_ERR(tlink);
@@ -324,7 +296,7 @@ ssize_t cifs_getxattr(struct dentry *direntry, const char *ea_name,
 				goto get_ea_exit; /* rc already EOPNOTSUPP */
 
 			pacl = pTcon->ses->server->ops->get_acl(cifs_sb,
-					d_inode(direntry), full_path, &acllen);
+					inode, full_path, &acllen);
 			if (IS_ERR(pacl)) {
 				rc = PTR_ERR(pacl);
 				cifs_dbg(VFS, "%s: error %zd getting sec desc\n",
@@ -374,21 +346,11 @@ ssize_t cifs_listxattr(struct dentry *direntry, char *data, size_t buf_size)
 	ssize_t rc = -EOPNOTSUPP;
 #ifdef CONFIG_CIFS_XATTR
 	unsigned int xid;
-	struct cifs_sb_info *cifs_sb;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(direntry->d_sb);
 	struct tcon_link *tlink;
 	struct cifs_tcon *pTcon;
-	struct super_block *sb;
 	char *full_path;
 
-	if (direntry == NULL)
-		return -EIO;
-	if (d_really_is_negative(direntry))
-		return -EIO;
-	sb = d_inode(direntry)->i_sb;
-	if (sb == NULL)
-		return -EIO;
-
-	cifs_sb = CIFS_SB(sb);
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_NO_XATTR)
 		return -EOPNOTSUPP;