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linux-next/fs/cachefiles/interface.c
Tejun Heo 5a0e3ad6af include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-30 22:02:32 +09:00

471 lines
13 KiB
C

/* FS-Cache interface to CacheFiles
*
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/slab.h>
#include <linux/mount.h>
#include <linux/buffer_head.h>
#include "internal.h"
#define list_to_page(head) (list_entry((head)->prev, struct page, lru))
struct cachefiles_lookup_data {
struct cachefiles_xattr *auxdata; /* auxiliary data */
char *key; /* key path */
};
static int cachefiles_attr_changed(struct fscache_object *_object);
/*
* allocate an object record for a cookie lookup and prepare the lookup data
*/
static struct fscache_object *cachefiles_alloc_object(
struct fscache_cache *_cache,
struct fscache_cookie *cookie)
{
struct cachefiles_lookup_data *lookup_data;
struct cachefiles_object *object;
struct cachefiles_cache *cache;
struct cachefiles_xattr *auxdata;
unsigned keylen, auxlen;
void *buffer;
char *key;
cache = container_of(_cache, struct cachefiles_cache, cache);
_enter("{%s},%p,", cache->cache.identifier, cookie);
lookup_data = kmalloc(sizeof(*lookup_data), GFP_KERNEL);
if (!lookup_data)
goto nomem_lookup_data;
/* create a new object record and a temporary leaf image */
object = kmem_cache_alloc(cachefiles_object_jar, GFP_KERNEL);
if (!object)
goto nomem_object;
ASSERTCMP(object->backer, ==, NULL);
BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
atomic_set(&object->usage, 1);
fscache_object_init(&object->fscache, cookie, &cache->cache);
object->type = cookie->def->type;
/* get hold of the raw key
* - stick the length on the front and leave space on the back for the
* encoder
*/
buffer = kmalloc((2 + 512) + 3, GFP_KERNEL);
if (!buffer)
goto nomem_buffer;
keylen = cookie->def->get_key(cookie->netfs_data, buffer + 2, 512);
ASSERTCMP(keylen, <, 512);
*(uint16_t *)buffer = keylen;
((char *)buffer)[keylen + 2] = 0;
((char *)buffer)[keylen + 3] = 0;
((char *)buffer)[keylen + 4] = 0;
/* turn the raw key into something that can work with as a filename */
key = cachefiles_cook_key(buffer, keylen + 2, object->type);
if (!key)
goto nomem_key;
/* get hold of the auxiliary data and prepend the object type */
auxdata = buffer;
auxlen = 0;
if (cookie->def->get_aux) {
auxlen = cookie->def->get_aux(cookie->netfs_data,
auxdata->data, 511);
ASSERTCMP(auxlen, <, 511);
}
auxdata->len = auxlen + 1;
auxdata->type = cookie->def->type;
lookup_data->auxdata = auxdata;
lookup_data->key = key;
object->lookup_data = lookup_data;
_leave(" = %p [%p]", &object->fscache, lookup_data);
return &object->fscache;
nomem_key:
kfree(buffer);
nomem_buffer:
BUG_ON(test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
kmem_cache_free(cachefiles_object_jar, object);
fscache_object_destroyed(&cache->cache);
nomem_object:
kfree(lookup_data);
nomem_lookup_data:
_leave(" = -ENOMEM");
return ERR_PTR(-ENOMEM);
}
/*
* attempt to look up the nominated node in this cache
* - return -ETIMEDOUT to be scheduled again
*/
static int cachefiles_lookup_object(struct fscache_object *_object)
{
struct cachefiles_lookup_data *lookup_data;
struct cachefiles_object *parent, *object;
struct cachefiles_cache *cache;
const struct cred *saved_cred;
int ret;
_enter("{OBJ%x}", _object->debug_id);
cache = container_of(_object->cache, struct cachefiles_cache, cache);
parent = container_of(_object->parent,
struct cachefiles_object, fscache);
object = container_of(_object, struct cachefiles_object, fscache);
lookup_data = object->lookup_data;
ASSERTCMP(lookup_data, !=, NULL);
/* look up the key, creating any missing bits */
cachefiles_begin_secure(cache, &saved_cred);
ret = cachefiles_walk_to_object(parent, object,
lookup_data->key,
lookup_data->auxdata);
cachefiles_end_secure(cache, saved_cred);
/* polish off by setting the attributes of non-index files */
if (ret == 0 &&
object->fscache.cookie->def->type != FSCACHE_COOKIE_TYPE_INDEX)
cachefiles_attr_changed(&object->fscache);
if (ret < 0 && ret != -ETIMEDOUT) {
if (ret != -ENOBUFS)
printk(KERN_WARNING
"CacheFiles: Lookup failed error %d\n", ret);
fscache_object_lookup_error(&object->fscache);
}
_leave(" [%d]", ret);
return ret;
}
/*
* indication of lookup completion
*/
static void cachefiles_lookup_complete(struct fscache_object *_object)
{
struct cachefiles_object *object;
object = container_of(_object, struct cachefiles_object, fscache);
_enter("{OBJ%x,%p}", object->fscache.debug_id, object->lookup_data);
if (object->lookup_data) {
kfree(object->lookup_data->key);
kfree(object->lookup_data->auxdata);
kfree(object->lookup_data);
object->lookup_data = NULL;
}
}
/*
* increment the usage count on an inode object (may fail if unmounting)
*/
static
struct fscache_object *cachefiles_grab_object(struct fscache_object *_object)
{
struct cachefiles_object *object =
container_of(_object, struct cachefiles_object, fscache);
_enter("{OBJ%x,%d}", _object->debug_id, atomic_read(&object->usage));
#ifdef CACHEFILES_DEBUG_SLAB
ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
#endif
atomic_inc(&object->usage);
return &object->fscache;
}
/*
* update the auxilliary data for an object object on disk
*/
static void cachefiles_update_object(struct fscache_object *_object)
{
struct cachefiles_object *object;
struct cachefiles_xattr *auxdata;
struct cachefiles_cache *cache;
struct fscache_cookie *cookie;
const struct cred *saved_cred;
unsigned auxlen;
_enter("{OBJ%x}", _object->debug_id);
object = container_of(_object, struct cachefiles_object, fscache);
cache = container_of(object->fscache.cache, struct cachefiles_cache,
cache);
cookie = object->fscache.cookie;
if (!cookie->def->get_aux) {
_leave(" [no aux]");
return;
}
auxdata = kmalloc(2 + 512 + 3, GFP_KERNEL);
if (!auxdata) {
_leave(" [nomem]");
return;
}
auxlen = cookie->def->get_aux(cookie->netfs_data, auxdata->data, 511);
ASSERTCMP(auxlen, <, 511);
auxdata->len = auxlen + 1;
auxdata->type = cookie->def->type;
cachefiles_begin_secure(cache, &saved_cred);
cachefiles_update_object_xattr(object, auxdata);
cachefiles_end_secure(cache, saved_cred);
kfree(auxdata);
_leave("");
}
/*
* discard the resources pinned by an object and effect retirement if
* requested
*/
static void cachefiles_drop_object(struct fscache_object *_object)
{
struct cachefiles_object *object;
struct cachefiles_cache *cache;
const struct cred *saved_cred;
ASSERT(_object);
object = container_of(_object, struct cachefiles_object, fscache);
_enter("{OBJ%x,%d}",
object->fscache.debug_id, atomic_read(&object->usage));
cache = container_of(object->fscache.cache,
struct cachefiles_cache, cache);
#ifdef CACHEFILES_DEBUG_SLAB
ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
#endif
/* delete retired objects */
if (object->fscache.state == FSCACHE_OBJECT_RECYCLING &&
_object != cache->cache.fsdef
) {
_debug("- retire object OBJ%x", object->fscache.debug_id);
cachefiles_begin_secure(cache, &saved_cred);
cachefiles_delete_object(cache, object);
cachefiles_end_secure(cache, saved_cred);
}
/* close the filesystem stuff attached to the object */
if (object->backer != object->dentry)
dput(object->backer);
object->backer = NULL;
/* note that the object is now inactive */
if (test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags)) {
write_lock(&cache->active_lock);
if (!test_and_clear_bit(CACHEFILES_OBJECT_ACTIVE,
&object->flags))
BUG();
rb_erase(&object->active_node, &cache->active_nodes);
wake_up_bit(&object->flags, CACHEFILES_OBJECT_ACTIVE);
write_unlock(&cache->active_lock);
}
dput(object->dentry);
object->dentry = NULL;
_leave("");
}
/*
* dispose of a reference to an object
*/
static void cachefiles_put_object(struct fscache_object *_object)
{
struct cachefiles_object *object;
struct fscache_cache *cache;
ASSERT(_object);
object = container_of(_object, struct cachefiles_object, fscache);
_enter("{OBJ%x,%d}",
object->fscache.debug_id, atomic_read(&object->usage));
#ifdef CACHEFILES_DEBUG_SLAB
ASSERT((atomic_read(&object->usage) & 0xffff0000) != 0x6b6b0000);
#endif
ASSERTIFCMP(object->fscache.parent,
object->fscache.parent->n_children, >, 0);
if (atomic_dec_and_test(&object->usage)) {
_debug("- kill object OBJ%x", object->fscache.debug_id);
ASSERT(!test_bit(CACHEFILES_OBJECT_ACTIVE, &object->flags));
ASSERTCMP(object->fscache.parent, ==, NULL);
ASSERTCMP(object->backer, ==, NULL);
ASSERTCMP(object->dentry, ==, NULL);
ASSERTCMP(object->fscache.n_ops, ==, 0);
ASSERTCMP(object->fscache.n_children, ==, 0);
if (object->lookup_data) {
kfree(object->lookup_data->key);
kfree(object->lookup_data->auxdata);
kfree(object->lookup_data);
object->lookup_data = NULL;
}
cache = object->fscache.cache;
fscache_object_destroy(&object->fscache);
kmem_cache_free(cachefiles_object_jar, object);
fscache_object_destroyed(cache);
}
_leave("");
}
/*
* sync a cache
*/
static void cachefiles_sync_cache(struct fscache_cache *_cache)
{
struct cachefiles_cache *cache;
const struct cred *saved_cred;
int ret;
_enter("%p", _cache);
cache = container_of(_cache, struct cachefiles_cache, cache);
/* make sure all pages pinned by operations on behalf of the netfs are
* written to disc */
cachefiles_begin_secure(cache, &saved_cred);
down_read(&cache->mnt->mnt_sb->s_umount);
ret = sync_filesystem(cache->mnt->mnt_sb);
up_read(&cache->mnt->mnt_sb->s_umount);
cachefiles_end_secure(cache, saved_cred);
if (ret == -EIO)
cachefiles_io_error(cache,
"Attempt to sync backing fs superblock"
" returned error %d",
ret);
}
/*
* notification the attributes on an object have changed
* - called with reads/writes excluded by FS-Cache
*/
static int cachefiles_attr_changed(struct fscache_object *_object)
{
struct cachefiles_object *object;
struct cachefiles_cache *cache;
const struct cred *saved_cred;
struct iattr newattrs;
uint64_t ni_size;
loff_t oi_size;
int ret;
_object->cookie->def->get_attr(_object->cookie->netfs_data, &ni_size);
_enter("{OBJ%x},[%llu]",
_object->debug_id, (unsigned long long) ni_size);
object = container_of(_object, struct cachefiles_object, fscache);
cache = container_of(object->fscache.cache,
struct cachefiles_cache, cache);
if (ni_size == object->i_size)
return 0;
if (!object->backer)
return -ENOBUFS;
ASSERT(S_ISREG(object->backer->d_inode->i_mode));
fscache_set_store_limit(&object->fscache, ni_size);
oi_size = i_size_read(object->backer->d_inode);
if (oi_size == ni_size)
return 0;
cachefiles_begin_secure(cache, &saved_cred);
mutex_lock(&object->backer->d_inode->i_mutex);
/* if there's an extension to a partial page at the end of the backing
* file, we need to discard the partial page so that we pick up new
* data after it */
if (oi_size & ~PAGE_MASK && ni_size > oi_size) {
_debug("discard tail %llx", oi_size);
newattrs.ia_valid = ATTR_SIZE;
newattrs.ia_size = oi_size & PAGE_MASK;
ret = notify_change(object->backer, &newattrs);
if (ret < 0)
goto truncate_failed;
}
newattrs.ia_valid = ATTR_SIZE;
newattrs.ia_size = ni_size;
ret = notify_change(object->backer, &newattrs);
truncate_failed:
mutex_unlock(&object->backer->d_inode->i_mutex);
cachefiles_end_secure(cache, saved_cred);
if (ret == -EIO) {
fscache_set_store_limit(&object->fscache, 0);
cachefiles_io_error_obj(object, "Size set failed");
ret = -ENOBUFS;
}
_leave(" = %d", ret);
return ret;
}
/*
* dissociate a cache from all the pages it was backing
*/
static void cachefiles_dissociate_pages(struct fscache_cache *cache)
{
_enter("");
}
const struct fscache_cache_ops cachefiles_cache_ops = {
.name = "cachefiles",
.alloc_object = cachefiles_alloc_object,
.lookup_object = cachefiles_lookup_object,
.lookup_complete = cachefiles_lookup_complete,
.grab_object = cachefiles_grab_object,
.update_object = cachefiles_update_object,
.drop_object = cachefiles_drop_object,
.put_object = cachefiles_put_object,
.sync_cache = cachefiles_sync_cache,
.attr_changed = cachefiles_attr_changed,
.read_or_alloc_page = cachefiles_read_or_alloc_page,
.read_or_alloc_pages = cachefiles_read_or_alloc_pages,
.allocate_page = cachefiles_allocate_page,
.allocate_pages = cachefiles_allocate_pages,
.write_page = cachefiles_write_page,
.uncache_page = cachefiles_uncache_page,
.dissociate_pages = cachefiles_dissociate_pages,
};