From: David Howells <dhowells@redhat.com>
The attached patch fixes some discrepancies between the latest version of
the kernel and CacheFS; namely: BIO_RW_BARRIER may now cause an error if
the underlying blockdev doesn't support it and i_op->write_inode() now
returns an error.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/fs/cachefs/cachefs-int.h | 8 ++-
25-akpm/fs/cachefs/inode.c | 3 -
25-akpm/fs/cachefs/journal.c | 83 +++++++++++++++++++++++++++++++++++++--
25-akpm/fs/cachefs/super.c | 9 +++-
4 files changed, 94 insertions(+), 9 deletions(-)
diff -puN fs/cachefs/cachefs-int.h~fix-cachefs-barrier-handling-and-other-kernel-discrepancies fs/cachefs/cachefs-int.h
--- 25/fs/cachefs/cachefs-int.h~fix-cachefs-barrier-handling-and-other-kernel-discrepancies Thu Sep 23 14:33:00 2004
+++ 25-akpm/fs/cachefs/cachefs-int.h Thu Sep 23 14:33:00 2004
@@ -73,6 +73,8 @@ struct cachefs_super
#define CACHEFS_SUPER_WITHDRAWN 4 /* T if cache has been withdrawn */
#define CACHEFS_SUPER_REPLAYING_UJNL 5 /* T if replaying u-journal */
+ int bio_wr_barrier; /* command to submit a write barrier BIO */
+
/* index management */
struct list_head ino_list; /* list of data/index inodes */
spinlock_t ino_list_lock;
@@ -154,8 +156,6 @@ struct cachefs_super
wait_queue_head_t batch_timer_wq; /* batch timer wait queue */
wait_queue_head_t batch_sync_wq; /* batch sync wait queue */
- struct list_head jnld_link; /* journalling daemon list */
-
/* validity journal tracking */
unsigned long *vjnl_map; /* bitmap of free entries (1 page) */
unsigned vjnl_count; /* number of free entries */
@@ -200,6 +200,8 @@ extern void cachefs_recycle_transfer_sta
extern void cachefs_recycle_reclaim(struct cachefs_super *super);
extern void cachefs_recycle_unallocate_data_block(struct cachefs_super *super);
+extern int cachefs_ujnl_check_barrier_cap(struct cachefs_super *super);
+
/*****************************************************************************/
/*
* block management record
@@ -384,7 +386,7 @@ extern struct file_operations cachefs_st
extern struct cachefs_inode *cachefs_iget(struct cachefs_super *super,
ino_t ino);
-extern void cachefs_write_inode(struct inode *_inode, int sync);
+extern int cachefs_write_inode(struct inode *_inode, int sync);
extern void cachefs_clear_inode(struct inode *vfs_inode);
static inline struct cachefs_inode *cachefs_igrab(struct cachefs_inode *iinode)
diff -puN fs/cachefs/inode.c~fix-cachefs-barrier-handling-and-other-kernel-discrepancies fs/cachefs/inode.c
--- 25/fs/cachefs/inode.c~fix-cachefs-barrier-handling-and-other-kernel-discrepancies Thu Sep 23 14:33:00 2004
+++ 25-akpm/fs/cachefs/inode.c Thu Sep 23 14:33:00 2004
@@ -366,9 +366,10 @@ struct cachefs_inode *cachefs_iget(struc
* - don't use generic_file_write() to write out the meta-data file's meta-data
* as it updates the mtime & ctime and marks the inode dirty again
*/
-void cachefs_write_inode(struct inode *vfs_inode, int sync)
+int cachefs_write_inode(struct inode *vfs_inode, int sync)
{
_enter("{sb=%p ino=%lu},%d", vfs_inode->i_sb, vfs_inode->i_ino, sync);
+ return 0;
} /* end cachefs_write_inode() */
diff -puN fs/cachefs/journal.c~fix-cachefs-barrier-handling-and-other-kernel-discrepancies fs/cachefs/journal.c
--- 25/fs/cachefs/journal.c~fix-cachefs-barrier-handling-and-other-kernel-discrepancies Thu Sep 23 14:33:00 2004
+++ 25-akpm/fs/cachefs/journal.c Thu Sep 23 14:33:00 2004
@@ -1040,7 +1040,7 @@ static void cachefs_trans_batch_write_uj
/* submit for write (with barrier on last chunk) */
rw = WRITE;
if (super->ujnl_tail == jstop)
- rw |= 1 << BIO_RW_BARRIER;
+ rw = super->bio_wr_barrier;
submit_bio(rw, bio);
} while (super->ujnl_tail != jstop);
@@ -1237,7 +1237,7 @@ static void cachefs_trans_batch_write_ma
/* and send to disc */
//dump_bio(bio,1);
- submit_bio(WRITE | (1 << BIO_RW_BARRIER), bio);
+ submit_bio(super->bio_wr_barrier, bio);
cachefs_block_put(jblock);
_leave("");
@@ -1317,7 +1317,7 @@ static void cachefs_trans_batch_write_ac
/* and send to disc */
//dump_bio(bio,1);
- submit_bio(WRITE | (1 << BIO_RW_BARRIER), bio);
+ submit_bio(super->bio_wr_barrier, bio);
/* wait for I/O completion */
set_current_state(TASK_UNINTERRUPTIBLE);
@@ -1669,3 +1669,80 @@ void cachefs_trans_sync(struct cachefs_s
_leave("");
} /* end cachefs_trans_sync() */
+
+/*****************************************************************************/
+/*
+ * barrier capabability check complete
+ */
+static int cachefs_ujnl_barrier_cap_checked(struct bio *bio,
+ unsigned int bytes_done,
+ int error)
+{
+ kenter("%p{%lx},%u,%d", bio, bio->bi_flags, bytes_done, error);
+
+ /* we're only interested in completion */
+ if (bio->bi_size > 0) {
+ kleave(" = 1");
+ return 1;
+ }
+
+ *(int*) bio->bi_private = error;
+ end_page_writeback(bio->bi_io_vec[0].bv_page);
+
+ bio_put(bio);
+ kleave(" = 0");
+ return 0;
+
+} /* end cachefs_trans_ack_written() */
+
+/*****************************************************************************/
+/*
+ * determine whether the block device supports barriers
+ * - need barriers to be able to journal properly
+ */
+int cachefs_ujnl_check_barrier_cap(struct cachefs_super *super)
+{
+ struct page *superpage;
+ struct bio *bio;
+ int ret;
+
+ super->bio_wr_barrier = WRITE | (1 << BIO_RW_BARRIER);
+
+ /* attempt a barriered write on the superblock */
+ superpage = virt_to_page(super->layout);
+ wait_on_page_writeback(superpage);
+ SetPageWriteback(superpage);
+
+ ret = -ENOMEM;
+ bio = bio_alloc(GFP_KERNEL, 1);
+ if (!bio)
+ goto error;
+
+ bio->bi_bdev = super->sb->s_bdev;
+ bio->bi_private = &ret;
+ bio->bi_end_io = cachefs_ujnl_barrier_cap_checked;
+ bio->bi_sector = 0;
+
+ if (!bio_add_page(bio, superpage, PAGE_SIZE, 0))
+ BUG();
+
+ /* and send to disc */
+ //dump_bio(bio,1);
+ ret = 0;
+ submit_bio(super->bio_wr_barrier, bio);
+ wait_on_page_writeback(superpage);
+
+ if (ret < 0) {
+ if (ret == -EOPNOTSUPP) {
+ /* it appears barriers are not supported */
+ printk("CacheFS:"
+ " The blockdev does not support barriers,"
+ " so the journal may not be reliable\n");
+ super->bio_wr_barrier = WRITE;
+ ret = 0;
+ }
+ }
+
+ error:
+ return ret;
+} /* end cachefs_ujnl_check_barrier_cap() */
diff -puN fs/cachefs/super.c~fix-cachefs-barrier-handling-and-other-kernel-discrepancies fs/cachefs/super.c
--- 25/fs/cachefs/super.c~fix-cachefs-barrier-handling-and-other-kernel-discrepancies Thu Sep 23 14:33:00 2004
+++ 25-akpm/fs/cachefs/super.c Thu Sep 23 14:33:00 2004
@@ -297,7 +297,6 @@ static int cachefs_fill_super(struct sup
INIT_LIST_HEAD(&super->ujnl_replayq);
spin_lock_init(&super->njalt_lock);
- INIT_LIST_HEAD(&super->jnld_link);
init_MUTEX(&super->batch_sem);
init_MUTEX(&super->batch_uj_sem);
@@ -396,12 +395,19 @@ static int cachefs_fill_super(struct sup
ret = -EROFS;
if (bdev_read_only(sb->s_bdev)) {
printk("CacheFS: blockdev read-only\n");
+ goto error;
}
if (sb->s_flags & MS_RDONLY) {
printk("CacheFS: filesystem mounted read-only\n");
+ goto error;
}
+ /* check for barrier capability on the blockdev */
+ ret = cachefs_ujnl_check_barrier_cap(super);
+ if (ret < 0)
+ goto error;
+
/* replay the journal if the cache was initialised */
super->ujnl_jsof = super->layout->bix_ujournal;
super->ujnl_jsof <<= (PAGE_SHIFT - super->sb->s_blocksize_bits);
@@ -794,7 +800,6 @@ static void cachefs_put_super(struct sup
DECLARE_WAITQUEUE(myself, current);
- printk("\n\n");
_enter("{%p}", super);
BUG_ON(!super);
_