linux/fs/9p/cache.c

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/*
* V9FS cache definitions.
*
* Copyright (C) 2009 by Abhishek Kulkarni <adkulkar@umail.iu.edu>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to:
* Free Software Foundation
* 51 Franklin Street, Fifth Floor
* Boston, MA 02111-1301 USA
*
*/
#include <linux/jiffies.h>
#include <linux/file.h>
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>
2010-03-24 09:04:11 +01:00
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/sched.h>
#include <linux/fs.h>
#include <net/9p/9p.h>
#include "v9fs.h"
#include "cache.h"
#define CACHETAG_LEN 11
struct fscache_netfs v9fs_cache_netfs = {
.name = "9p",
.version = 0,
};
/**
* v9fs_random_cachetag - Generate a random tag to be associated
* with a new cache session.
*
* The value of jiffies is used for a fairly randomly cache tag.
*/
static
int v9fs_random_cachetag(struct v9fs_session_info *v9ses)
{
v9ses->cachetag = kmalloc(CACHETAG_LEN, GFP_KERNEL);
if (!v9ses->cachetag)
return -ENOMEM;
return scnprintf(v9ses->cachetag, CACHETAG_LEN, "%lu", jiffies);
}
static uint16_t v9fs_cache_session_get_key(const void *cookie_netfs_data,
void *buffer, uint16_t bufmax)
{
struct v9fs_session_info *v9ses;
uint16_t klen = 0;
v9ses = (struct v9fs_session_info *)cookie_netfs_data;
p9_debug(P9_DEBUG_FSC, "session %p buf %p size %u\n",
v9ses, buffer, bufmax);
if (v9ses->cachetag)
klen = strlen(v9ses->cachetag);
if (klen > bufmax)
return 0;
memcpy(buffer, v9ses->cachetag, klen);
p9_debug(P9_DEBUG_FSC, "cache session tag %s\n", v9ses->cachetag);
return klen;
}
const struct fscache_cookie_def v9fs_cache_session_index_def = {
.name = "9P.session",
.type = FSCACHE_COOKIE_TYPE_INDEX,
.get_key = v9fs_cache_session_get_key,
};
void v9fs_cache_session_get_cookie(struct v9fs_session_info *v9ses)
{
/* If no cache session tag was specified, we generate a random one. */
if (!v9ses->cachetag)
v9fs_random_cachetag(v9ses);
v9ses->fscache = fscache_acquire_cookie(v9fs_cache_netfs.primary_index,
&v9fs_cache_session_index_def,
FS-Cache: Provide the ability to enable/disable cookies Provide the ability to enable and disable fscache cookies. A disabled cookie will reject or ignore further requests to: Acquire a child cookie Invalidate and update backing objects Check the consistency of a backing object Allocate storage for backing page Read backing pages Write to backing pages but still allows: Checks/waits on the completion of already in-progress objects Uncaching of pages Relinquishment of cookies Two new operations are provided: (1) Disable a cookie: void fscache_disable_cookie(struct fscache_cookie *cookie, bool invalidate); If the cookie is not already disabled, this locks the cookie against other dis/enablement ops, marks the cookie as being disabled, discards or invalidates any backing objects and waits for cessation of activity on any associated object. This is a wrapper around a chunk split out of fscache_relinquish_cookie(), but it reinitialises the cookie such that it can be reenabled. All possible failures are handled internally. The caller should consider calling fscache_uncache_all_inode_pages() afterwards to make sure all page markings are cleared up. (2) Enable a cookie: void fscache_enable_cookie(struct fscache_cookie *cookie, bool (*can_enable)(void *data), void *data) If the cookie is not already enabled, this locks the cookie against other dis/enablement ops, invokes can_enable() and, if the cookie is not an index cookie, will begin the procedure of acquiring backing objects. The optional can_enable() function is passed the data argument and returns a ruling as to whether or not enablement should actually be permitted to begin. All possible failures are handled internally. The cookie will only be marked as enabled if provisional backing objects are allocated. A later patch will introduce these to NFS. Cookie enablement during nfs_open() is then contingent on i_writecount <= 0. can_enable() checks for a race between open(O_RDONLY) and open(O_WRONLY/O_RDWR). This simplifies NFS's cookie handling and allows us to get rid of open(O_RDONLY) accidentally introducing caching to an inode that's open for writing already. One operation has its API modified: (3) Acquire a cookie. struct fscache_cookie *fscache_acquire_cookie( struct fscache_cookie *parent, const struct fscache_cookie_def *def, void *netfs_data, bool enable); This now has an additional argument that indicates whether the requested cookie should be enabled by default. It doesn't need the can_enable() function because the caller must prevent multiple calls for the same netfs object and it doesn't need to take the enablement lock because no one else can get at the cookie before this returns. Signed-off-by: David Howells <dhowells@redhat.com
2013-09-21 01:09:31 +02:00
v9ses, true);
p9_debug(P9_DEBUG_FSC, "session %p get cookie %p\n",
v9ses, v9ses->fscache);
}
void v9fs_cache_session_put_cookie(struct v9fs_session_info *v9ses)
{
p9_debug(P9_DEBUG_FSC, "session %p put cookie %p\n",
v9ses, v9ses->fscache);
fscache_relinquish_cookie(v9ses->fscache, 0);
v9ses->fscache = NULL;
}
static uint16_t v9fs_cache_inode_get_key(const void *cookie_netfs_data,
void *buffer, uint16_t bufmax)
{
const struct v9fs_inode *v9inode = cookie_netfs_data;
memcpy(buffer, &v9inode->qid.path, sizeof(v9inode->qid.path));
p9_debug(P9_DEBUG_FSC, "inode %p get key %llu\n",
&v9inode->vfs_inode, v9inode->qid.path);
return sizeof(v9inode->qid.path);
}
static void v9fs_cache_inode_get_attr(const void *cookie_netfs_data,
uint64_t *size)
{
const struct v9fs_inode *v9inode = cookie_netfs_data;
*size = i_size_read(&v9inode->vfs_inode);
p9_debug(P9_DEBUG_FSC, "inode %p get attr %llu\n",
&v9inode->vfs_inode, *size);
}
static uint16_t v9fs_cache_inode_get_aux(const void *cookie_netfs_data,
void *buffer, uint16_t buflen)
{
const struct v9fs_inode *v9inode = cookie_netfs_data;
memcpy(buffer, &v9inode->qid.version, sizeof(v9inode->qid.version));
p9_debug(P9_DEBUG_FSC, "inode %p get aux %u\n",
&v9inode->vfs_inode, v9inode->qid.version);
return sizeof(v9inode->qid.version);
}
static enum
fscache_checkaux v9fs_cache_inode_check_aux(void *cookie_netfs_data,
const void *buffer,
uint16_t buflen)
{
const struct v9fs_inode *v9inode = cookie_netfs_data;
if (buflen != sizeof(v9inode->qid.version))
return FSCACHE_CHECKAUX_OBSOLETE;
if (memcmp(buffer, &v9inode->qid.version,
sizeof(v9inode->qid.version)))
return FSCACHE_CHECKAUX_OBSOLETE;
return FSCACHE_CHECKAUX_OKAY;
}
static void v9fs_cache_inode_now_uncached(void *cookie_netfs_data)
{
struct v9fs_inode *v9inode = cookie_netfs_data;
struct pagevec pvec;
pgoff_t first;
int loop, nr_pages;
pagevec_init(&pvec, 0);
first = 0;
for (;;) {
nr_pages = pagevec_lookup(&pvec, v9inode->vfs_inode.i_mapping,
first,
PAGEVEC_SIZE - pagevec_count(&pvec));
if (!nr_pages)
break;
for (loop = 0; loop < nr_pages; loop++)
ClearPageFsCache(pvec.pages[loop]);
first = pvec.pages[nr_pages - 1]->index + 1;
pvec.nr = nr_pages;
pagevec_release(&pvec);
cond_resched();
}
}
const struct fscache_cookie_def v9fs_cache_inode_index_def = {
.name = "9p.inode",
.type = FSCACHE_COOKIE_TYPE_DATAFILE,
.get_key = v9fs_cache_inode_get_key,
.get_attr = v9fs_cache_inode_get_attr,
.get_aux = v9fs_cache_inode_get_aux,
.check_aux = v9fs_cache_inode_check_aux,
.now_uncached = v9fs_cache_inode_now_uncached,
};
void v9fs_cache_inode_get_cookie(struct inode *inode)
{
struct v9fs_inode *v9inode;
struct v9fs_session_info *v9ses;
if (!S_ISREG(inode->i_mode))
return;
v9inode = V9FS_I(inode);
if (v9inode->fscache)
return;
v9ses = v9fs_inode2v9ses(inode);
v9inode->fscache = fscache_acquire_cookie(v9ses->fscache,
&v9fs_cache_inode_index_def,
FS-Cache: Provide the ability to enable/disable cookies Provide the ability to enable and disable fscache cookies. A disabled cookie will reject or ignore further requests to: Acquire a child cookie Invalidate and update backing objects Check the consistency of a backing object Allocate storage for backing page Read backing pages Write to backing pages but still allows: Checks/waits on the completion of already in-progress objects Uncaching of pages Relinquishment of cookies Two new operations are provided: (1) Disable a cookie: void fscache_disable_cookie(struct fscache_cookie *cookie, bool invalidate); If the cookie is not already disabled, this locks the cookie against other dis/enablement ops, marks the cookie as being disabled, discards or invalidates any backing objects and waits for cessation of activity on any associated object. This is a wrapper around a chunk split out of fscache_relinquish_cookie(), but it reinitialises the cookie such that it can be reenabled. All possible failures are handled internally. The caller should consider calling fscache_uncache_all_inode_pages() afterwards to make sure all page markings are cleared up. (2) Enable a cookie: void fscache_enable_cookie(struct fscache_cookie *cookie, bool (*can_enable)(void *data), void *data) If the cookie is not already enabled, this locks the cookie against other dis/enablement ops, invokes can_enable() and, if the cookie is not an index cookie, will begin the procedure of acquiring backing objects. The optional can_enable() function is passed the data argument and returns a ruling as to whether or not enablement should actually be permitted to begin. All possible failures are handled internally. The cookie will only be marked as enabled if provisional backing objects are allocated. A later patch will introduce these to NFS. Cookie enablement during nfs_open() is then contingent on i_writecount <= 0. can_enable() checks for a race between open(O_RDONLY) and open(O_WRONLY/O_RDWR). This simplifies NFS's cookie handling and allows us to get rid of open(O_RDONLY) accidentally introducing caching to an inode that's open for writing already. One operation has its API modified: (3) Acquire a cookie. struct fscache_cookie *fscache_acquire_cookie( struct fscache_cookie *parent, const struct fscache_cookie_def *def, void *netfs_data, bool enable); This now has an additional argument that indicates whether the requested cookie should be enabled by default. It doesn't need the can_enable() function because the caller must prevent multiple calls for the same netfs object and it doesn't need to take the enablement lock because no one else can get at the cookie before this returns. Signed-off-by: David Howells <dhowells@redhat.com
2013-09-21 01:09:31 +02:00
v9inode, true);
p9_debug(P9_DEBUG_FSC, "inode %p get cookie %p\n",
inode, v9inode->fscache);
}
void v9fs_cache_inode_put_cookie(struct inode *inode)
{
struct v9fs_inode *v9inode = V9FS_I(inode);
if (!v9inode->fscache)
return;
p9_debug(P9_DEBUG_FSC, "inode %p put cookie %p\n",
inode, v9inode->fscache);
fscache_relinquish_cookie(v9inode->fscache, 0);
v9inode->fscache = NULL;
}
void v9fs_cache_inode_flush_cookie(struct inode *inode)
{
struct v9fs_inode *v9inode = V9FS_I(inode);
if (!v9inode->fscache)
return;
p9_debug(P9_DEBUG_FSC, "inode %p flush cookie %p\n",
inode, v9inode->fscache);
fscache_relinquish_cookie(v9inode->fscache, 1);
v9inode->fscache = NULL;
}
void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *filp)
{
struct v9fs_inode *v9inode = V9FS_I(inode);
if (!v9inode->fscache)
return;
spin_lock(&v9inode->fscache_lock);
if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
v9fs_cache_inode_flush_cookie(inode);
else
v9fs_cache_inode_get_cookie(inode);
spin_unlock(&v9inode->fscache_lock);
}
void v9fs_cache_inode_reset_cookie(struct inode *inode)
{
struct v9fs_inode *v9inode = V9FS_I(inode);
struct v9fs_session_info *v9ses;
struct fscache_cookie *old;
if (!v9inode->fscache)
return;
old = v9inode->fscache;
spin_lock(&v9inode->fscache_lock);
fscache_relinquish_cookie(v9inode->fscache, 1);
v9ses = v9fs_inode2v9ses(inode);
v9inode->fscache = fscache_acquire_cookie(v9ses->fscache,
&v9fs_cache_inode_index_def,
FS-Cache: Provide the ability to enable/disable cookies Provide the ability to enable and disable fscache cookies. A disabled cookie will reject or ignore further requests to: Acquire a child cookie Invalidate and update backing objects Check the consistency of a backing object Allocate storage for backing page Read backing pages Write to backing pages but still allows: Checks/waits on the completion of already in-progress objects Uncaching of pages Relinquishment of cookies Two new operations are provided: (1) Disable a cookie: void fscache_disable_cookie(struct fscache_cookie *cookie, bool invalidate); If the cookie is not already disabled, this locks the cookie against other dis/enablement ops, marks the cookie as being disabled, discards or invalidates any backing objects and waits for cessation of activity on any associated object. This is a wrapper around a chunk split out of fscache_relinquish_cookie(), but it reinitialises the cookie such that it can be reenabled. All possible failures are handled internally. The caller should consider calling fscache_uncache_all_inode_pages() afterwards to make sure all page markings are cleared up. (2) Enable a cookie: void fscache_enable_cookie(struct fscache_cookie *cookie, bool (*can_enable)(void *data), void *data) If the cookie is not already enabled, this locks the cookie against other dis/enablement ops, invokes can_enable() and, if the cookie is not an index cookie, will begin the procedure of acquiring backing objects. The optional can_enable() function is passed the data argument and returns a ruling as to whether or not enablement should actually be permitted to begin. All possible failures are handled internally. The cookie will only be marked as enabled if provisional backing objects are allocated. A later patch will introduce these to NFS. Cookie enablement during nfs_open() is then contingent on i_writecount <= 0. can_enable() checks for a race between open(O_RDONLY) and open(O_WRONLY/O_RDWR). This simplifies NFS's cookie handling and allows us to get rid of open(O_RDONLY) accidentally introducing caching to an inode that's open for writing already. One operation has its API modified: (3) Acquire a cookie. struct fscache_cookie *fscache_acquire_cookie( struct fscache_cookie *parent, const struct fscache_cookie_def *def, void *netfs_data, bool enable); This now has an additional argument that indicates whether the requested cookie should be enabled by default. It doesn't need the can_enable() function because the caller must prevent multiple calls for the same netfs object and it doesn't need to take the enablement lock because no one else can get at the cookie before this returns. Signed-off-by: David Howells <dhowells@redhat.com
2013-09-21 01:09:31 +02:00
v9inode, true);
p9_debug(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p\n",
inode, old, v9inode->fscache);
spin_unlock(&v9inode->fscache_lock);
}
int __v9fs_fscache_release_page(struct page *page, gfp_t gfp)
{
struct inode *inode = page->mapping->host;
struct v9fs_inode *v9inode = V9FS_I(inode);
BUG_ON(!v9inode->fscache);
return fscache_maybe_release_page(v9inode->fscache, page, gfp);
}
void __v9fs_fscache_invalidate_page(struct page *page)
{
struct inode *inode = page->mapping->host;
struct v9fs_inode *v9inode = V9FS_I(inode);
BUG_ON(!v9inode->fscache);
if (PageFsCache(page)) {
fscache_wait_on_page_write(v9inode->fscache, page);
BUG_ON(!PageLocked(page));
fscache_uncache_page(v9inode->fscache, page);
}
}
static void v9fs_vfs_readpage_complete(struct page *page, void *data,
int error)
{
if (!error)
SetPageUptodate(page);
unlock_page(page);
}
/**
* __v9fs_readpage_from_fscache - read a page from cache
*
* Returns 0 if the pages are in cache and a BIO is submitted,
* 1 if the pages are not in cache and -error otherwise.
*/
int __v9fs_readpage_from_fscache(struct inode *inode, struct page *page)
{
int ret;
const struct v9fs_inode *v9inode = V9FS_I(inode);
p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);
if (!v9inode->fscache)
return -ENOBUFS;
ret = fscache_read_or_alloc_page(v9inode->fscache,
page,
v9fs_vfs_readpage_complete,
NULL,
GFP_KERNEL);
switch (ret) {
case -ENOBUFS:
case -ENODATA:
p9_debug(P9_DEBUG_FSC, "page/inode not in cache %d\n", ret);
return 1;
case 0:
p9_debug(P9_DEBUG_FSC, "BIO submitted\n");
return ret;
default:
p9_debug(P9_DEBUG_FSC, "ret %d\n", ret);
return ret;
}
}
/**
* __v9fs_readpages_from_fscache - read multiple pages from cache
*
* Returns 0 if the pages are in cache and a BIO is submitted,
* 1 if the pages are not in cache and -error otherwise.
*/
int __v9fs_readpages_from_fscache(struct inode *inode,
struct address_space *mapping,
struct list_head *pages,
unsigned *nr_pages)
{
int ret;
const struct v9fs_inode *v9inode = V9FS_I(inode);
p9_debug(P9_DEBUG_FSC, "inode %p pages %u\n", inode, *nr_pages);
if (!v9inode->fscache)
return -ENOBUFS;
ret = fscache_read_or_alloc_pages(v9inode->fscache,
mapping, pages, nr_pages,
v9fs_vfs_readpage_complete,
NULL,
mapping_gfp_mask(mapping));
switch (ret) {
case -ENOBUFS:
case -ENODATA:
p9_debug(P9_DEBUG_FSC, "pages/inodes not in cache %d\n", ret);
return 1;
case 0:
BUG_ON(!list_empty(pages));
BUG_ON(*nr_pages != 0);
p9_debug(P9_DEBUG_FSC, "BIO submitted\n");
return ret;
default:
p9_debug(P9_DEBUG_FSC, "ret %d\n", ret);
return ret;
}
}
/**
* __v9fs_readpage_to_fscache - write a page to the cache
*
*/
void __v9fs_readpage_to_fscache(struct inode *inode, struct page *page)
{
int ret;
const struct v9fs_inode *v9inode = V9FS_I(inode);
p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);
ret = fscache_write_page(v9inode->fscache, page, GFP_KERNEL);
p9_debug(P9_DEBUG_FSC, "ret = %d\n", ret);
if (ret != 0)
v9fs_uncache_page(inode, page);
}
/*
* wait for a page to complete writing to the cache
*/
void __v9fs_fscache_wait_on_page_write(struct inode *inode, struct page *page)
{
const struct v9fs_inode *v9inode = V9FS_I(inode);
p9_debug(P9_DEBUG_FSC, "inode %p page %p\n", inode, page);
if (PageFsCache(page))
fscache_wait_on_page_write(v9inode->fscache, page);
}