On Wed, Mar 14, 2012 at 06:13:28PM +0100, Andor Daam wrote:
> This patch allows backends to register to cleancache even after
> filesystems were mounted. Calls to inif_fs and init_shared_fs are
> remembered, fake poolids but no real tmem_pools created. On backend
> registration the fake poolids are mapped to real poolids and respective
> tmem_pools.
>
> Signed-off-by: Stefan Hengelein <ilendir@xxxxxxxxxxxxxx>
> Signed-off-by: Florian Schmaus <fschmaus@xxxxxxxxx>
> Signed-off-by: Andor Daam <andor.daam@xxxxxxxxxxxxxx>
> ---
> mm/cleancache.c | 157 +++++++++++++++++++++++++++++++++++++++++++++++++------
> 1 files changed, 140 insertions(+), 17 deletions(-)
>
> diff --git a/mm/cleancache.c b/mm/cleancache.c
> index 5646c74..9f504b6 100644
> --- a/mm/cleancache.c
> +++ b/mm/cleancache.c
> @@ -45,15 +45,42 @@ static u64 cleancache_puts;
> static u64 cleancache_invalidates;
>
> /*
> + * When no backend is registered all calls to init_fs and init_shard_fs
> + * are registered and fake poolids are given to the respective
> + * super block but no tmem_pools are created. When a backend
> + * registers with cleancache the previous calls to init_fs and
> + * init_shared_fs are executed to create tmem_pools and set the
> + * respective poolids. While no backend is registered all "puts",
> + * "gets" and "flushes" are ignored or fail.
> + */
> +#define MAX_INITIALIZABLE_FS 32
> +#define FAKE_FS_POOLID_OFFSET 1000
Hmm, why 1000?
> +#define FAKE_SHARED_FS_POOLID_OFFSET 2000
> +static int fs_poolid_map[MAX_INITIALIZABLE_FS];
> +static int shared_fs_poolid_map[MAX_INITIALIZABLE_FS];
> +static char *uuids[MAX_INITIALIZABLE_FS];
Could all of this be remade into a struct and a list?
And potentially a 'hot' item which is the one last accessed?
> +static int backend_registered;
> +
> +/*
> * register operations for cleancache, returning previous thus allowing
> * detection of multiple backends and possible nesting
> */
> struct cleancache_ops cleancache_register_ops(struct cleancache_ops *ops)
> {
> struct cleancache_ops old = cleancache_ops;
> + int i;
>
> cleancache_ops = *ops;
> - cleancache_enabled = 1;
> +
> + backend_registered = 1;
> + for (i = 0; i < MAX_INITIALIZABLE_FS; i++) {
> + if (fs_poolid_map[i] == -1)
> + fs_poolid_map[i] = (*cleancache_ops.init_fs)(PAGE_SIZE);
> + if (shared_fs_poolid_map[i] == -1)
> + shared_fs_poolid_map[i] =
> + (*cleancache_ops.init_shared_fs)
> + (uuids[i], PAGE_SIZE);
> + }
> return old;
> }
> EXPORT_SYMBOL(cleancache_register_ops);
> @@ -61,15 +88,42 @@ EXPORT_SYMBOL(cleancache_register_ops);
> /* Called by a cleancache-enabled filesystem at time of mount */
> void __cleancache_init_fs(struct super_block *sb)
> {
> - sb->cleancache_poolid = (*cleancache_ops.init_fs)(PAGE_SIZE);
> + int i;
> +
> + for (i = 0; i < MAX_INITIALIZABLE_FS; i++) {
> + if (fs_poolid_map[i] == -2) {
> + sb->cleancache_poolid =
> + i + FAKE_FS_POOLID_OFFSET;
> + if (backend_registered)
> + fs_poolid_map[i] =
> + (*cleancache_ops.init_fs)(PAGE_SIZE);
> + else
> + fs_poolid_map[i] = -1;
> + break;
> + }
> + }
> }
> EXPORT_SYMBOL(__cleancache_init_fs);
>
> /* Called by a cleancache-enabled clustered filesystem at time of mount */
> void __cleancache_init_shared_fs(char *uuid, struct super_block *sb)
> {
> - sb->cleancache_poolid =
> - (*cleancache_ops.init_shared_fs)(uuid, PAGE_SIZE);
> + int i;
> +
> + for (i = 0; i < MAX_INITIALIZABLE_FS; i++) {
> + if (shared_fs_poolid_map[i] == -2) {
> + sb->cleancache_poolid =
> + i + FAKE_SHARED_FS_POOLID_OFFSET;
> + uuids[i] = uuid;
> + if (backend_registered)
> + shared_fs_poolid_map[i] =
> + (*cleancache_ops.init_shared_fs)
> + (uuid, PAGE_SIZE);
> + else
> + shared_fs_poolid_map[i] = -1;
> + break;
> + }
> + }
> }
> EXPORT_SYMBOL(__cleancache_init_shared_fs);
>
> @@ -101,6 +155,19 @@ static int cleancache_get_key(struct inode *inode,
> }
>
> /*
> + * Returns a pool_id that is associated with a given fake poolid.
> + */
> +static int get_poolid_from_fake(int fake_pool_id)
> +{
> + if (fake_pool_id >= FAKE_SHARED_FS_POOLID_OFFSET)
> + return shared_fs_poolid_map[fake_pool_id -
> + FAKE_SHARED_FS_POOLID_OFFSET];
> + else if (fake_pool_id >= FAKE_FS_POOLID_OFFSET)
> + return fs_poolid_map[fake_pool_id - FAKE_FS_POOLID_OFFSET];
> + return -1;
> +}
> +
> +/*
> * "Get" data from cleancache associated with the poolid/inode/index
> * that were specified when the data was put to cleanache and, if
> * successful, use it to fill the specified page with data and return 0.
> @@ -111,17 +178,26 @@ int __cleancache_get_page(struct page *page)
> {
> int ret = -1;
> int pool_id;
> + int fake_pool_id;
> struct cleancache_filekey key = { .u.key = { 0 } };
>
> + if (!backend_registered) {
> + cleancache_failed_gets++;
> + goto out;
> + }
> +
> VM_BUG_ON(!PageLocked(page));
> - pool_id = page->mapping->host->i_sb->cleancache_poolid;
> - if (pool_id < 0)
> + fake_pool_id = page->mapping->host->i_sb->cleancache_poolid;
> + if (fake_pool_id < 0)
> goto out;
> + pool_id = get_poolid_from_fake(fake_pool_id);
>
> if (cleancache_get_key(page->mapping->host, &key) < 0)
> goto out;
>
> - ret = (*cleancache_ops.get_page)(pool_id, key, page->index, page);
> + if (pool_id >= 0)
> + ret = (*cleancache_ops.get_page)(pool_id,
> + key, page->index, page);
> if (ret == 0)
> cleancache_succ_gets++;
> else
> @@ -140,12 +216,23 @@ EXPORT_SYMBOL(__cleancache_get_page);
> void __cleancache_put_page(struct page *page)
> {
> int pool_id;
> + int fake_pool_id;
> struct cleancache_filekey key = { .u.key = { 0 } };
>
> + if (!backend_registered) {
> + cleancache_puts++;
> + return;
> + }
> +
> VM_BUG_ON(!PageLocked(page));
> - pool_id = page->mapping->host->i_sb->cleancache_poolid;
> + fake_pool_id = page->mapping->host->i_sb->cleancache_poolid;
> + if (fake_pool_id < 0)
> + return;
> +
> + pool_id = get_poolid_from_fake(fake_pool_id);
> +
> if (pool_id >= 0 &&
> - cleancache_get_key(page->mapping->host, &key) >= 0) {
> + cleancache_get_key(page->mapping->host, &key) >= 0) {
> (*cleancache_ops.put_page)(pool_id, key, page->index, page);
> cleancache_puts++;
> }
> @@ -160,14 +247,22 @@ void __cleancache_invalidate_page(struct address_space *mapping,
> struct page *page)
> {
> /* careful... page->mapping is NULL sometimes when this is called */
> - int pool_id = mapping->host->i_sb->cleancache_poolid;
> + int pool_id;
> + int fake_pool_id = mapping->host->i_sb->cleancache_poolid;
> struct cleancache_filekey key = { .u.key = { 0 } };
>
> - if (pool_id >= 0) {
> + if (!backend_registered)
> + return;
> +
> + if (fake_pool_id >= 0) {
> + pool_id = get_poolid_from_fake(fake_pool_id);
> + if (pool_id < 0)
> + return;
> +
> VM_BUG_ON(!PageLocked(page));
> if (cleancache_get_key(mapping->host, &key) >= 0) {
> (*cleancache_ops.invalidate_page)(pool_id,
> - key, page->index);
> + key, page->index);
> cleancache_invalidates++;
> }
> }
> @@ -181,9 +276,18 @@ EXPORT_SYMBOL(__cleancache_invalidate_page);
> */
> void __cleancache_invalidate_inode(struct address_space *mapping)
> {
> - int pool_id = mapping->host->i_sb->cleancache_poolid;
> + int pool_id;
> + int fake_pool_id = mapping->host->i_sb->cleancache_poolid;
> struct cleancache_filekey key = { .u.key = { 0 } };
>
> + if (!backend_registered)
> + return;
> +
> + if (fake_pool_id < 0)
> + return;
> +
> + pool_id = get_poolid_from_fake(fake_pool_id);
> +
> if (pool_id >= 0 && cleancache_get_key(mapping->host, &key) >= 0)
> (*cleancache_ops.invalidate_inode)(pool_id, key);
> }
> @@ -196,16 +300,30 @@ EXPORT_SYMBOL(__cleancache_invalidate_inode);
> */
> void __cleancache_invalidate_fs(struct super_block *sb)
> {
> - if (sb->cleancache_poolid >= 0) {
> - int old_poolid = sb->cleancache_poolid;
> - sb->cleancache_poolid = -1;
> - (*cleancache_ops.invalidate_fs)(old_poolid);
> + int old_poolid;
> + int index;
> + int fake_pool_id = sb->cleancache_poolid;
> +
> + if (fake_pool_id >= FAKE_SHARED_FS_POOLID_OFFSET) {
> + index = fake_pool_id - FAKE_SHARED_FS_POOLID_OFFSET;
> + old_poolid = shared_fs_poolid_map[index];
> + shared_fs_poolid_map[index] = -2;
> + uuids[index] = NULL;
> + } else if (fake_pool_id >= FAKE_FS_POOLID_OFFSET) {
> + index = fake_pool_id - FAKE_FS_POOLID_OFFSET;
> + old_poolid = fs_poolid_map[index];
> + fs_poolid_map[index] = -2;
> }
> + sb->cleancache_poolid = -1;
> + if (backend_registered)
> + (*cleancache_ops.invalidate_fs)(old_poolid);
> }
> EXPORT_SYMBOL(__cleancache_invalidate_fs);
>
> static int __init init_cleancache(void)
> {
> + int i;
> +
> #ifdef CONFIG_DEBUG_FS
> struct dentry *root = debugfs_create_dir("cleancache", NULL);
> if (root == NULL)
> @@ -217,6 +335,11 @@ static int __init init_cleancache(void)
> debugfs_create_u64("invalidates", S_IRUGO,
> root, &cleancache_invalidates);
> #endif
> + for (i = 0; i < MAX_INITIALIZABLE_FS; i++) {
> + fs_poolid_map[i] = -2;
> + shared_fs_poolid_map[i] = -2;
You should declare an #define for these. But I am wondering
whether this would be made easier if you had something like this:
struct cleancache_clients {
struct list_head next;
struct cleancache_clients *hot;
#define UNREGISTERED (0<<1)
#define REGISTERED (1<<1)
#define SOMETHING (2<<1)
unsigned int flags;
int poolid;
...
}
> + }
> + cleancache_enabled = 1;
> return 0;
> }
> module_init(init_cleancache)
> --
> 1.7.5.4
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