aboutsummaryrefslogtreecommitdiff
path: root/fs
diff options
context:
space:
mode:
authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2008-01-28 23:58:26 -0500
committerTheodore Ts'o <tytso@mit.edu>2008-01-28 23:58:26 -0500
commit389d1b083c767a360ec84b27a95da06244becec8 (patch)
treea315c892f615545fd0ce72f7e0d660f5772fb4b2 /fs
parentbb4f397a1a7f2330cb173233599aa159f5780f58 (diff)
downloadlinux-389d1b083c767a360ec84b27a95da06244becec8.tar.gz
Add buffer head related helper functions
Add buffer head related helper function bh_uptodate_or_lock and bh_submit_read which can be used by file system Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/buffer.c44
1 files changed, 44 insertions, 0 deletions
diff --git a/fs/buffer.c b/fs/buffer.c
index 7249e014819..456c9ab7705 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3213,6 +3213,50 @@ static int buffer_cpu_notify(struct notifier_block *self,
return NOTIFY_OK;
}
+/**
+ * bh_uptodate_or_lock: Test whether the buffer is uptodate
+ * @bh: struct buffer_head
+ *
+ * Return true if the buffer is up-to-date and false,
+ * with the buffer locked, if not.
+ */
+int bh_uptodate_or_lock(struct buffer_head *bh)
+{
+ if (!buffer_uptodate(bh)) {
+ lock_buffer(bh);
+ if (!buffer_uptodate(bh))
+ return 0;
+ unlock_buffer(bh);
+ }
+ return 1;
+}
+EXPORT_SYMBOL(bh_uptodate_or_lock);
+
+/**
+ * bh_submit_read: Submit a locked buffer for reading
+ * @bh: struct buffer_head
+ *
+ * Returns zero on success and -EIO on error.
+ */
+int bh_submit_read(struct buffer_head *bh)
+{
+ BUG_ON(!buffer_locked(bh));
+
+ if (buffer_uptodate(bh)) {
+ unlock_buffer(bh);
+ return 0;
+ }
+
+ get_bh(bh);
+ bh->b_end_io = end_buffer_read_sync;
+ submit_bh(READ, bh);
+ wait_on_buffer(bh);
+ if (buffer_uptodate(bh))
+ return 0;
+ return -EIO;
+}
+EXPORT_SYMBOL(bh_submit_read);
+
void __init buffer_init(void)
{
int nrpages;