Commit 389d1b08 authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Theodore Ts'o

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: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
parent bb4f397a
......@@ -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;
......
......@@ -192,6 +192,8 @@ int sync_dirty_buffer(struct buffer_head *bh);
int submit_bh(int, struct buffer_head *);
void write_boundary_block(struct block_device *bdev,
sector_t bblock, unsigned blocksize);
int bh_uptodate_or_lock(struct buffer_head *bh);
int bh_submit_read(struct buffer_head *bh);
extern int buffer_heads_over_limit;
......
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