reiserfs: fixup xattr_root caching

 The xattr_root caching was broken from my previous patch set. It wouldn't
 cause corruption, but could cause decreased performance due to allocating
 a larger chunk of the journal (~ 27 blocks) than it would actually use.

 This patch loads the xattr root dentry at xattr initialization and creates
 it on-demand. Since we're using the cached dentry, there's no point
 in keeping lookup_or_create_dir around, so that's removed.

Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
index 2891f78..c779844 100644 (file)
--- a/fs/reiserfs/xattr.c
+++ b/fs/reiserfs/xattr.c
@@ -113,36 +113,28 @@ static int xattr_rmdir(struct inode *dir, struct dentry *dentry)
 
 #define xattr_may_create(flags)        (!flags || flags & XATTR_CREATE)
 
-/* Returns and possibly creates the xattr dir. */
-static struct dentry *lookup_or_create_dir(struct dentry *parent,
-                                           const char *name, int flags)
+static struct dentry *open_xa_root(struct super_block *sb, int flags)
 {
-       struct dentry *dentry;
-       BUG_ON(!parent);
+       struct dentry *privroot = REISERFS_SB(sb)->priv_root;
+       struct dentry *xaroot;
+       if (!privroot->d_inode)
+               return ERR_PTR(-ENODATA);
 
-       mutex_lock_nested(&parent->d_inode->i_mutex, I_MUTEX_XATTR);
-       dentry = lookup_one_len(name, parent, strlen(name));
-       if (!IS_ERR(dentry) && !dentry->d_inode) {
-               int err = -ENODATA;
+       mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR);
 
+       xaroot = dget(REISERFS_SB(sb)->xattr_root);
+       if (!xaroot->d_inode) {
+               int err = -ENODATA;
                if (xattr_may_create(flags))
-                       err = xattr_mkdir(parent->d_inode, dentry, 0700);
-
+                       err = xattr_mkdir(privroot->d_inode, xaroot, 0700);
                if (err) {
-                       dput(dentry);
-                       dentry = ERR_PTR(err);
+                       dput(xaroot);
+                       xaroot = ERR_PTR(err);
                }
        }
-       mutex_unlock(&parent->d_inode->i_mutex);
-       return dentry;
-}
 
-static struct dentry *open_xa_root(struct super_block *sb, int flags)
-{
-       struct dentry *privroot = REISERFS_SB(sb)->priv_root;
-       if (!privroot)
-               return ERR_PTR(-ENODATA);
-       return lookup_or_create_dir(privroot, XAROOT_NAME, flags);
+       mutex_unlock(&privroot->d_inode->i_mutex);
+       return xaroot;
 }
 
 static struct dentry *open_xa_dir(const struct inode *inode, int flags)
@@ -158,10 +150,22 @@ static struct dentry *open_xa_dir(const struct inode *inode, int flags)
                 le32_to_cpu(INODE_PKEY(inode)->k_objectid),
                 inode->i_generation);
 
-       xadir = lookup_or_create_dir(xaroot, namebuf, flags);
+       mutex_lock_nested(&xaroot->d_inode->i_mutex, I_MUTEX_XATTR);
+
+       xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf));
+       if (!IS_ERR(xadir) && !xadir->d_inode) {
+               int err = -ENODATA;
+               if (xattr_may_create(flags))
+                       err = xattr_mkdir(xaroot->d_inode, xadir, 0700);
+               if (err) {
+                       dput(xadir);
+                       xadir = ERR_PTR(err);
+               }
+       }
+
+       mutex_unlock(&xaroot->d_inode->i_mutex);
        dput(xaroot);
        return xadir;
-
 }
 
 /* The following are side effects of other operations that aren't explicitly
@@ -986,19 +990,33 @@ int reiserfs_lookup_privroot(struct super_block *s)
 int reiserfs_xattr_init(struct super_block *s, int mount_flags)
 {
        int err = 0;
+       struct dentry *privroot = REISERFS_SB(s)->priv_root;
 
 #ifdef CONFIG_REISERFS_FS_XATTR
        err = xattr_mount_check(s);
        if (err)
                goto error;
 
-       if (!REISERFS_SB(s)->priv_root->d_inode && !(mount_flags & MS_RDONLY)) {
+       if (!privroot->d_inode && !(mount_flags & MS_RDONLY)) {
                mutex_lock(&s->s_root->d_inode->i_mutex);
                err = create_privroot(REISERFS_SB(s)->priv_root);
                mutex_unlock(&s->s_root->d_inode->i_mutex);
        }
-       if (!err)
+
+       if (privroot->d_inode) {
                s->s_xattr = reiserfs_xattr_handlers;
+               mutex_lock(&privroot->d_inode->i_mutex);
+               if (!REISERFS_SB(s)->xattr_root) {
+                       struct dentry *dentry;
+                       dentry = lookup_one_len(XAROOT_NAME, privroot,
+                                               strlen(XAROOT_NAME));
+                       if (!IS_ERR(dentry))
+                               REISERFS_SB(s)->xattr_root = dentry;
+                       else
+                               err = PTR_ERR(dentry);
+               }
+               mutex_unlock(&privroot->d_inode->i_mutex);
+       }
 
 error:
        if (err) {
@@ -1008,11 +1026,12 @@ error:
 #endif
 
        /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */
-       s->s_flags = s->s_flags & ~MS_POSIXACL;
 #ifdef CONFIG_REISERFS_FS_POSIX_ACL
        if (reiserfs_posixacl(s))
                s->s_flags |= MS_POSIXACL;
+       else
 #endif
+               s->s_flags &= ~MS_POSIXACL;
 
        return err;
 }

diff --git a/include/linux/reiserfs_fs_sb.h b/include/linux/reiserfs_fs_sb.h
index 6b361d2..8651640 100644 (file)
--- a/include/linux/reiserfs_fs_sb.h
+++ b/include/linux/reiserfs_fs_sb.h
@@ -402,7 +402,7 @@ struct reiserfs_sb_info {
        int reserved_blocks;    /* amount of blocks reserved for further allocations */
        spinlock_t bitmap_lock; /* this lock on now only used to protect reserved_blocks variable */
        struct dentry *priv_root;       /* root of /.reiserfs_priv */
-       struct dentry *xattr_root;      /* root of /.reiserfs_priv/.xa */
+       struct dentry *xattr_root;      /* root of /.reiserfs_priv/xattrs */
        int j_errno;
 #ifdef CONFIG_QUOTA
        char *s_qf_names[MAXQUOTAS];

diff --git a/include/linux/reiserfs_xattr.h b/include/linux/reiserfs_xattr.h
index fea1a8e..cdedc01 100644 (file)
--- a/include/linux/reiserfs_xattr.h
+++ b/include/linux/reiserfs_xattr.h
@@ -98,7 +98,7 @@ static inline size_t reiserfs_xattr_jcreate_nblocks(struct inode *inode)
 
        if ((REISERFS_I(inode)->i_flags & i_has_xattr_dir) == 0) {
                nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
-               if (REISERFS_SB(inode->i_sb)->xattr_root == NULL)
+               if (!REISERFS_SB(inode->i_sb)->xattr_root->d_inode)
                        nblocks += JOURNAL_BLOCKS_PER_OBJECT(inode->i_sb);
        }