ocfs: simplify symlink handling

seeing that "fast" symlinks still get allocation + copy, we might as
well simply switch them to pagecache-based variant of ->follow_link();
just need an appropriate ->readpage() for them...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

4 files changed, 31 insertions, 104 deletions

diff --git a/fs/ocfs2/inode.c b/fs/ocfs2/inode.c
index 735514ca400f..d89e08a81eda 100644
--- a/fs/ocfs2/inode.c
+++ b/fs/ocfs2/inode.c
@@ -273,11 +273,13 @@ void ocfs2_populate_inode(struct inode *inode, struct ocfs2_dinode *fe,
         inode->i_gid = le32_to_cpu(fe->i_gid);
 
         /* Fast symlinks will have i_size but no allocated clusters. */
-        if (S_ISLNK(inode->i_mode) && !fe->i_clusters)
+        if (S_ISLNK(inode->i_mode) && !fe->i_clusters) {
                 inode->i_blocks = 0;
-        else
+                inode->i_mapping->a_ops = &ocfs2_fast_symlink_aops;
+        } else {
                 inode->i_blocks = ocfs2_inode_sector_count(inode);
-        inode->i_mapping->a_ops = &ocfs2_aops;
+                inode->i_mapping->a_ops = &ocfs2_aops;
+        }
         inode->i_atime.tv_sec = le64_to_cpu(fe->i_atime);
         inode->i_atime.tv_nsec = le32_to_cpu(fe->i_atime_nsec);
         inode->i_mtime.tv_sec = le64_to_cpu(fe->i_mtime);
@@ -331,10 +333,7 @@ void ocfs2_populate_inode(struct inode *inode, struct ocfs2_dinode *fe,
                     OCFS2_I(inode)->ip_dir_lock_gen = 1;
                     break;
             case S_IFLNK:
-                    if (ocfs2_inode_is_fast_symlink(inode))
-                        inode->i_op = &ocfs2_fast_symlink_inode_operations;
-                    else
-                        inode->i_op = &ocfs2_symlink_inode_operations;
+                    inode->i_op = &ocfs2_symlink_inode_operations;
                     i_size_write(inode, le64_to_cpu(fe->i_size));
                     break;
             default:
diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index a9856e3eaaf0..9f39c640cddf 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -1724,15 +1724,16 @@ static int ocfs2_symlink(struct inode *dir,
         fe = (struct ocfs2_dinode *) new_fe_bh->b_data;
         inode->i_rdev = 0;
         newsize = l - 1;
+        inode->i_op = &ocfs2_symlink_inode_operations;
         if (l > ocfs2_fast_symlink_chars(sb)) {
                 u32 offset = 0;
 
-                inode->i_op = &ocfs2_symlink_inode_operations;
                 status = dquot_alloc_space_nodirty(inode,
                     ocfs2_clusters_to_bytes(osb->sb, 1));
                 if (status)
                         goto bail;
                 did_quota = 1;
+                inode->i_mapping->a_ops = &ocfs2_aops;
                 status = ocfs2_add_inode_data(osb, inode, &offset, 1, 0,
                                               new_fe_bh,
                                               handle, data_ac, NULL,
@@ -1750,7 +1751,7 @@ static int ocfs2_symlink(struct inode *dir,
                 i_size_write(inode, newsize);
                 inode->i_blocks = ocfs2_inode_sector_count(inode);
         } else {
-                inode->i_op = &ocfs2_fast_symlink_inode_operations;
+                inode->i_mapping->a_ops = &ocfs2_fast_symlink_aops;
                 memcpy((char *) fe->id2.i_symlink, symname, l);
                 i_size_write(inode, newsize);
                 inode->i_blocks = 0;
diff --git a/fs/ocfs2/symlink.c b/fs/ocfs2/symlink.c
index 5d22872e2bb3..f1fbb4b552ad 100644
--- a/fs/ocfs2/symlink.c
+++ b/fs/ocfs2/symlink.c
@@ -54,101 +54,40 @@
 #include "buffer_head_io.h"
 
 
-static char *ocfs2_fast_symlink_getlink(struct inode *inode,
-                                        struct buffer_head **bh)
+static int ocfs2_fast_symlink_readpage(struct file *unused, struct page *page)
 {
-        int status;
-        char *link = NULL;
+        struct inode *inode = page->mapping->host;
+        struct buffer_head *bh;
+        int status = ocfs2_read_inode_block(inode, &bh);
         struct ocfs2_dinode *fe;
+        const char *link;
+        void *kaddr;
+        size_t len;
 
-        status = ocfs2_read_inode_block(inode, bh);
         if (status < 0) {
                 mlog_errno(status);
-                link = ERR_PTR(status);
-                goto bail;
+                return status;
         }
 
-        fe = (struct ocfs2_dinode *) (*bh)->b_data;
+        fe = (struct ocfs2_dinode *) bh->b_data;
         link = (char *) fe->id2.i_symlink;
-bail:
-
-        return link;
-}
-
-static int ocfs2_readlink(struct dentry *dentry,
-                          char __user *buffer,
-                          int buflen)
-{
-        int ret;
-        char *link;
-        struct buffer_head *bh = NULL;
-        struct inode *inode = dentry->d_inode;
-
-        link = ocfs2_fast_symlink_getlink(inode, &bh);
-        if (IS_ERR(link)) {
-                ret = PTR_ERR(link);
-                goto out;
-        }
-
-        /*
-         * Without vfsmount we can't update atime now,
-         * but we will update atime here ultimately.
-         */
-        ret = vfs_readlink(dentry, buffer, buflen, link);
-
+        /* will be less than a page size */
+        len = strnlen(link, ocfs2_fast_symlink_chars(inode->i_sb));
+        kaddr = kmap_atomic(page);
+        memcpy(kaddr, link, len + 1);
+        kunmap_atomic(kaddr);
+        SetPageUptodate(page);
+        unlock_page(page);
         brelse(bh);
-out:
-        if (ret < 0)
-                mlog_errno(ret);
-        return ret;
+        return 0;
 }
 
-static void *ocfs2_fast_follow_link(struct dentry *dentry,
-                                    struct nameidata *nd)
-{
-        int status = 0;
-        int len;
-        char *target, *link = ERR_PTR(-ENOMEM);
-        struct inode *inode = dentry->d_inode;
-        struct buffer_head *bh = NULL;
-
-        BUG_ON(!ocfs2_inode_is_fast_symlink(inode));
-        target = ocfs2_fast_symlink_getlink(inode, &bh);
-        if (IS_ERR(target)) {
-                status = PTR_ERR(target);
-                mlog_errno(status);
-                goto bail;
-        }
-
-        /* Fast symlinks can't be large */
-        len = strnlen(target, ocfs2_fast_symlink_chars(inode->i_sb));
-        link = kzalloc(len + 1, GFP_NOFS);
-        if (!link) {
-                status = -ENOMEM;
-                mlog_errno(status);
-                goto bail;
-        }
-
-        memcpy(link, target, len);
-
-bail:
-        nd_set_link(nd, status ? ERR_PTR(status) : link);
-        brelse(bh);
-
-        if (status)
-                mlog_errno(status);
-        return NULL;
-}
-
-static void ocfs2_fast_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
-{
-        char *link = nd_get_link(nd);
-        if (!IS_ERR(link))
-                kfree(link);
-}
+const struct address_space_operations ocfs2_fast_symlink_aops = {
+        .readpage               = ocfs2_fast_symlink_readpage,
+};
 
 const struct inode_operations ocfs2_symlink_inode_operations = {