ocfs2: Read support for directories with inline data

This splits out extent based directory read support and implements
inline-data versions of those functions. All knowledge of inline-data versus
extent based directories is internalized. For lookups the code uses
ocfs2_find_entry_id(), full dir iterations make use of
ocfs2_dir_foreach_blk_id().

Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Reviewed-by: Joel Becker <joel.becker@oracle.com>

1 files changed, 168 insertions, 8 deletions

diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index f2e2ffbf6c95..8deed89330c7 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -81,6 +81,10 @@ static int ocfs2_do_extend_dir(struct super_block *sb,
                                struct ocfs2_alloc_context *meta_ac,
                                struct buffer_head **new_bh);
 
+/*
+ * bh passed here can be an inode block or a dir data block, depending
+ * on the inode inline data flag.
+ */
 static int ocfs2_check_dir_entry(struct inode * dir,
                                  struct ocfs2_dir_entry * de,
                                  struct buffer_head * bh,
@@ -125,6 +129,8 @@ static int inline ocfs2_search_dirblock(struct buffer_head *bh,
                                         struct inode *dir,
                                         const char *name, int namelen,
                                         unsigned long offset,
+                                        char *first_de,
+                                        unsigned int bytes,
                                         struct ocfs2_dir_entry **res_dir)
 {
         struct ocfs2_dir_entry *de;
@@ -134,8 +140,8 @@ static int inline ocfs2_search_dirblock(struct buffer_head *bh,
 
         mlog_entry_void();
 
-        de_buf = bh->b_data;
-        dlimit = de_buf + dir->i_sb->s_blocksize;
+        de_buf = first_de;
+        dlimit = de_buf + bytes;
 
         while (de_buf < dlimit) {
                 /* this code is executed quadratically often */
@@ -171,9 +177,39 @@ bail:
         return ret;
 }
 
-struct buffer_head *ocfs2_find_entry(const char *name, int namelen,
-                                     struct inode *dir,
-                                     struct ocfs2_dir_entry **res_dir)
+static struct buffer_head *ocfs2_find_entry_id(const char *name,
+                                               int namelen,
+                                               struct inode *dir,
+                                               struct ocfs2_dir_entry **res_dir)
+{
+        int ret, found;
+        struct buffer_head *di_bh = NULL;
+        struct ocfs2_dinode *di;
+        struct ocfs2_inline_data *data;
+
+        ret = ocfs2_read_block(OCFS2_SB(dir->i_sb), OCFS2_I(dir)->ip_blkno,
+                               &di_bh, OCFS2_BH_CACHED, dir);
+        if (ret) {
+                mlog_errno(ret);
+                goto out;
+        }
+
+        di = (struct ocfs2_dinode *)di_bh->b_data;
+        data = &di->id2.i_data;
+
+        found = ocfs2_search_dirblock(di_bh, dir, name, namelen, 0,
+                                      data->id_data, i_size_read(dir), res_dir);
+        if (found == 1)
+                return di_bh;
+
+        brelse(di_bh);
+out:
+        return NULL;
+}
+
+struct buffer_head *ocfs2_find_entry_el(const char *name, int namelen,
+                                        struct inode *dir,
+                                        struct ocfs2_dir_entry **res_dir)
 {
         struct super_block *sb;
         struct buffer_head *bh_use[NAMEI_RA_SIZE];
@@ -188,7 +224,6 @@ struct buffer_head *ocfs2_find_entry(const char *name, int namelen,
 
         mlog_entry_void();
 
-        *res_dir = NULL;
         sb = dir->i_sb;
 
         nblocks = i_size_read(dir) >> sb->s_blocksize_bits;
@@ -236,6 +271,7 @@ restart:
                 }
                 i = ocfs2_search_dirblock(bh, dir, name, namelen,
                                           block << sb->s_blocksize_bits,
+                                          bh->b_data, sb->s_blocksize,
                                           res_dir);
                 if (i == 1) {
                         OCFS2_I(dir)->ip_dir_start_lookup = block;
@@ -271,6 +307,30 @@ cleanup_and_exit:
         return ret;
 }
 
+/*
+ * Try to find an entry of the provided name within 'dir'.
+ *
+ * If nothing was found, NULL is returned. Otherwise, a buffer_head
+ * and pointer to the dir entry are passed back.
+ *
+ * Caller can NOT assume anything about the contents of the
+ * buffer_head - it is passed back only so that it can be passed into
+ * any one of the manipulation functions (add entry, delete entry,
+ * etc). As an example, bh in the extent directory case is a data
+ * block, in the inline-data case it actually points to an inode.
+ */
+struct buffer_head *ocfs2_find_entry(const char *name, int namelen,
+                                     struct inode *dir,
+                                     struct ocfs2_dir_entry **res_dir)
+{
+        *res_dir = NULL;
+
+        if (OCFS2_I(dir)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
+                return ocfs2_find_entry_id(name, namelen, dir, res_dir);
+
+        return ocfs2_find_entry_el(name, namelen, dir, res_dir);
+}
+
 int ocfs2_update_entry(struct inode *dir, handle_t *handle,
                        struct buffer_head *de_bh, struct ocfs2_dir_entry *de,
                        struct inode *new_entry_inode)
@@ -459,8 +519,98 @@ bail:
         return retval;
 }
 
-static int ocfs2_dir_foreach_blk(struct inode *inode, unsigned long *f_version,
-                                 loff_t *f_pos, void *priv, filldir_t filldir)
+static int ocfs2_dir_foreach_blk_id(struct inode *inode,
+                                    unsigned long *f_version,
+                                    loff_t *f_pos, void *priv,
+                                    filldir_t filldir)
+{
+        int ret, i, filldir_ret;
+        unsigned long offset = *f_pos;
+        struct buffer_head *di_bh = NULL;
+        struct ocfs2_dinode *di;
+        struct ocfs2_inline_data *data;
+        struct ocfs2_dir_entry *de;
+
+        ret = ocfs2_read_block(OCFS2_SB(inode->i_sb), OCFS2_I(inode)->ip_blkno,
+                               &di_bh, OCFS2_BH_CACHED, inode);
+        if (ret) {
+                mlog(ML_ERROR, "Unable to read inode block for dir %llu\n",
+                     (unsigned long long)OCFS2_I(inode)->ip_blkno);
+                goto out;
+        }
+
+        di = (struct ocfs2_dinode *)di_bh->b_data;
+        data = &di->id2.i_data;
+
+        while (*f_pos < i_size_read(inode)) {
+revalidate:
+                /* If the dir block has changed since the last call to
+                 * readdir(2), then we might be pointing to an invalid
+                 * dirent right now.  Scan from the start of the block
+                 * to make sure. */
+                if (*f_version != inode->i_version) {
+                        for (i = 0; i < i_size_read(inode) && i < offset; ) {
+                                de = (struct ocfs2_dir_entry *)
+                                        (data->id_data + i);
+                                /* It's too expensive to do a full
+                                 * dirent test each time round this
+                                 * loop, but we do have to test at
+                                 * least that it is non-zero.  A
+                                 * failure will be detected in the
+                                 * dirent test below. */
+                                if (le16_to_cpu(de->rec_len) <
+                                    OCFS2_DIR_REC_LEN(1))
+                                        break;
+                                i += le16_to_cpu(de->rec_len);
+                        }
+                        *f_pos = offset = i;
+                        *f_version = inode->i_version;
+                }
+
+                de = (struct ocfs2_dir_entry *) (data->id_data + *f_pos);
+                if (!ocfs2_check_dir_entry(inode, de, di_bh, *f_pos)) {
+                        /* On error, skip the f_pos to the end. */
+                        *f_pos = i_size_read(inode);
+                        goto out;
+                }
+                offset += le16_to_cpu(de->rec_len);
+                if (le64_to_cpu(de->inode)) {
+                        /* We might block in the next section
+                         * if the data destination is
+                         * currently swapped out.  So, use a
+                         * version stamp to detect whether or
+                         * not the directory has been modified
+                         * during the copy operation.
+                         */
+                        unsigned long version = *f_version;
+                        unsigned char d_type = DT_UNKNOWN;
+
+                        if (de->file_type < OCFS2_FT_MAX)
+                                d_type = ocfs2_filetype_table[de->file_type];
+
+                        filldir_ret = filldir(priv, de->name,
+                                              de->name_len,
+                                              *f_pos,
+                                              le64_to_cpu(de->inode),
+                                              d_type);
+                        if (filldir_ret)
+                                break;
+                        if (version != *f_version)
+                                goto revalidate;
+                }
+                *f_pos += le16_to_cpu(de->rec_len);
+        }
+
+out:
+        brelse(di_bh);
+
+        return 0;
+}
+
+static int ocfs2_dir_foreach_blk_el(struct inode *inode,
+                                    unsigned long *f_version,
+                                    loff_t *f_pos, void *priv,
+                                    filldir_t filldir)
 {
         int error = 0;
         unsigned long offset, blk, last_ra_blk = 0;
@@ -576,6 +726,16 @@ out:
         return stored;
 }
 
+static int ocfs2_dir_foreach_blk(struct inode *inode, unsigned long *f_version,
+                                 loff_t *f_pos, void *priv, filldir_t filldir)
+{
+        if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL)
+                return ocfs2_dir_foreach_blk_id(inode, f_version, f_pos, priv,
+                                                filldir);
+
+        return ocfs2_dir_foreach_blk_el(inode, f_version, f_pos, priv, filldir);
+}
+
 /*
  * This is intended to be called from inside other kernel functions,
  * so we fake some arguments.