ocfs2: Wrap dirblock reads in a dedicated function.

We have ocfs2_bread() as a vestige of the original ext-based dir code.
It's only used by directories, though.  Turn it into
ocfs2_read_dir_block(), with a prototype matching the other metadata
read functions.  It's set up to validate dirblocks when the time comes.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

1 files changed, 88 insertions, 62 deletions

diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index 5777045f1a67..c2f3fd93be5c 100644
--- a/fs/ocfs2/dir.c
+++ b/fs/ocfs2/dir.c
@@ -82,49 +82,6 @@ static int ocfs2_do_extend_dir(struct super_block *sb,
                                struct ocfs2_alloc_context *meta_ac,
                                struct buffer_head **new_bh);
 
-static struct buffer_head *ocfs2_bread(struct inode *inode,
-                                       int block, int *err, int reada)
-{
-        struct buffer_head *bh = NULL;
-        int tmperr;
-        u64 p_blkno;
-        int readflags = 0;
-
-        if (reada)
-                readflags |= OCFS2_BH_READAHEAD;
-
-        if (((u64)block << inode->i_sb->s_blocksize_bits) >=
-            i_size_read(inode)) {
-                BUG_ON(!reada);
-                return NULL;
-        }
-
-        down_read(&OCFS2_I(inode)->ip_alloc_sem);
-        tmperr = ocfs2_extent_map_get_blocks(inode, block, &p_blkno, NULL,
-                                             NULL);
-        up_read(&OCFS2_I(inode)->ip_alloc_sem);
-        if (tmperr < 0) {
-                mlog_errno(tmperr);
-                goto fail;
-        }
-
-        tmperr = ocfs2_read_blocks(inode, p_blkno, 1, &bh, readflags);
-        if (tmperr < 0)
-                goto fail;
-
-        tmperr = 0;
-
-        *err = 0;
-        return bh;
-
-fail:
-        brelse(bh);
-        bh = NULL;
-
-        *err = -EIO;
-        return NULL;
-}
-
 /*
  * bh passed here can be an inode block or a dir data block, depending
  * on the inode inline data flag.
@@ -250,6 +207,76 @@ out:
         return NULL;
 }
 
+static int ocfs2_validate_dir_block(struct super_block *sb,
+                                    struct buffer_head *bh)
+{
+        /*
+         * Nothing yet.  We don't validate dirents here, that's handled
+         * in-place when the code walks them.
+         */
+
+        return 0;
+}
+
+/*
+ * This function forces all errors to -EIO for consistency with its
+ * predecessor, ocfs2_bread().  We haven't audited what returning the
+ * real error codes would do to callers.  We log the real codes with
+ * mlog_errno() before we squash them.
+ */
+static int ocfs2_read_dir_block(struct inode *inode, u64 v_block,
+                                struct buffer_head **bh, int flags)
+{
+        int rc = 0;
+        struct buffer_head *tmp = *bh;
+        u64 p_blkno;
+
+        if (((u64)v_block << inode->i_sb->s_blocksize_bits) >=
+            i_size_read(inode)) {
+                BUG_ON(!(flags & OCFS2_BH_READAHEAD));
+                goto out;
+        }
+
+        down_read(&OCFS2_I(inode)->ip_alloc_sem);
+        rc = ocfs2_extent_map_get_blocks(inode, v_block, &p_blkno, NULL,
+                                         NULL);
+        up_read(&OCFS2_I(inode)->ip_alloc_sem);
+        if (rc) {
+                mlog_errno(rc);
+                goto out;
+        }
+
+        if (!p_blkno) {
+                rc = -EIO;
+                mlog(ML_ERROR,
+                     "Directory #%llu contains a hole at offset %llu\n",
+                     (unsigned long long)OCFS2_I(inode)->ip_blkno,
+                     (unsigned long long)v_block << inode->i_sb->s_blocksize_bits);
+                goto out;
+        }
+
+        rc = ocfs2_read_blocks(inode, p_blkno, 1, &tmp, flags);
+        if (rc) {
+                mlog_errno(rc);
+                goto out;
+        }
+
+        if (!(flags & OCFS2_BH_READAHEAD)) {
+                rc = ocfs2_validate_dir_block(inode->i_sb, tmp);
+                if (rc) {
+                        brelse(tmp);
+                        goto out;
+                }
+        }
+
+        /* If ocfs2_read_blocks() got us a new bh, pass it up.  */
+        if (!*bh)
+                *bh = tmp;
+
+out:
+        return rc ? -EIO : 0;
+}
+
 static struct buffer_head *ocfs2_find_entry_el(const char *name, int namelen,
                                                struct inode *dir,
                                                struct ocfs2_dir_entry **res_dir)
@@ -296,15 +323,17 @@ restart:
                                 }
                                 num++;
 
-                                bh = ocfs2_bread(dir, b++, &err, 1);
+                                bh = NULL;
+                                err = ocfs2_read_dir_block(dir, b++, &bh,
+                                                           OCFS2_BH_READAHEAD);
                                 bh_use[ra_max] = bh;
                         }
                 }
                 if ((bh = bh_use[ra_ptr++]) == NULL)
                         goto next;
-                if (ocfs2_read_block(dir, block, &bh)) {
+                if (ocfs2_read_dir_block(dir, block, &bh, 0)) {
                         /* read error, skip block & hope for the best.
-                         * ocfs2_read_block() has released the bh. */
+                         * ocfs2_read_dir_block() has released the bh. */
                         ocfs2_error(dir->i_sb, "reading directory %llu, "
                                     "offset %lu\n",
                                     (unsigned long long)OCFS2_I(dir)->ip_blkno,
@@ -724,7 +753,6 @@ static int ocfs2_dir_foreach_blk_el(struct inode *inode,
         int i, stored;
         struct buffer_head * bh, * tmp;
         struct ocfs2_dir_entry * de;
-        int err;
         struct super_block * sb = inode->i_sb;
         unsigned int ra_sectors = 16;
 
@@ -735,12 +763,8 @@ static int ocfs2_dir_foreach_blk_el(struct inode *inode,
 
         while (!error && !stored && *f_pos < i_size_read(inode)) {
                 blk = (*f_pos) >> sb->s_blocksize_bits;
-                bh = ocfs2_bread(inode, blk, &err, 0);
-                if (!bh) {
-                        mlog(ML_ERROR,
-                             "directory #%llu contains a hole at offset %lld\n",
-                             (unsigned long long)OCFS2_I(inode)->ip_blkno,
-                             *f_pos);
+                if (ocfs2_read_dir_block(inode, blk, &bh, 0)) {
+                        /* Skip the corrupt dirblock and keep trying */
                         *f_pos += sb->s_blocksize - offset;
                         continue;
                 }
@@ -754,8 +778,10 @@ static int ocfs2_dir_foreach_blk_el(struct inode *inode,
                     || (((last_ra_blk - blk) << 9) <= (ra_sectors / 2))) {
                         for (i = ra_sectors >> (sb->s_blocksize_bits - 9);
                              i > 0; i--) {
-                                tmp = ocfs2_bread(inode, ++blk, &err, 1);
-                                brelse(tmp);
+                                tmp = NULL;
+                                if (!ocfs2_read_dir_block(inode, ++blk, &tmp,
+                                                          OCFS2_BH_READAHEAD))
+                                        brelse(tmp);
                         }
                         last_ra_blk = blk;
                         ra_sectors = 8;
@@ -828,6 +854,7 @@ revalidate:
                 }
                 offset = 0;
                 brelse(bh);
+                bh = NULL;
         }
 
         stored = 0;
@@ -1680,8 +1707,8 @@ static int ocfs2_find_dir_space_el(struct inode *dir, const char *name,
         struct super_block *sb = dir->i_sb;
         int status;
 
-        bh = ocfs2_bread(dir, 0, &status, 0);
-        if (!bh) {
+        status = ocfs2_read_dir_block(dir, 0, &bh, 0);
+        if (status) {
                 mlog_errno(status);
                 goto bail;
         }
@@ -1702,11 +1729,10 @@ static int ocfs2_find_dir_space_el(struct inode *dir, const char *name,
                                 status = -ENOSPC;
                                 goto bail;
                         }
-                        bh = ocfs2_bread(dir,
-                                         offset >> sb->s_blocksize_bits,
-                                         &status,
-                                         0);
-                        if (!bh) {
+                        status = ocfs2_read_dir_block(dir,
+                                             offset >> sb->s_blocksize_bits,
+                                             &bh, 0);
+                        if (status) {
                                 mlog_errno(status);
                                 goto bail;
                         }