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Subject[PATCH 38/45] ocfs2: Wrap dirblock reads in a dedicated function.
Date
From: Joel Becker <joel.becker@oracle.com>

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>
---
fs/ocfs2/dir.c | 150 +++++++++++++++++++++++++++++++++-----------------------
1 files changed, 88 insertions(+), 62 deletions(-)
diff --git a/fs/ocfs2/dir.c b/fs/ocfs2/dir.c
index 5777045..c2f3fd9 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;
}
--
1.5.6


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