OpenCloudOS-Kernel/fs/cachefiles/io.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/* kiocb-using read/write
*
* Copyright (C) 2021 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/mount.h>
#include <linux/slab.h>
#include <linux/file.h>
#include <linux/uio.h>
#include <linux/falloc.h>
#include <linux/sched/mm.h>
#include <trace/events/fscache.h>
#include "internal.h"
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
struct cachefiles_kiocb {
struct kiocb iocb;
refcount_t ki_refcnt;
loff_t start;
union {
size_t skipped;
size_t len;
};
struct cachefiles_object *object;
netfs_io_terminated_t term_func;
void *term_func_priv;
bool was_async;
unsigned int inval_counter; /* Copy of cookie->inval_counter */
u64 b_writing;
};
static inline void cachefiles_put_kiocb(struct cachefiles_kiocb *ki)
{
if (refcount_dec_and_test(&ki->ki_refcnt)) {
cachefiles_put_object(ki->object, cachefiles_obj_put_ioreq);
fput(ki->iocb.ki_filp);
kfree(ki);
}
}
/*
* Handle completion of a read from the cache.
*/
static void cachefiles_read_complete(struct kiocb *iocb, long ret)
{
struct cachefiles_kiocb *ki = container_of(iocb, struct cachefiles_kiocb, iocb);
struct inode *inode = file_inode(ki->iocb.ki_filp);
_enter("%ld", ret);
if (ret < 0)
trace_cachefiles_io_error(ki->object, inode, ret,
cachefiles_trace_read_error);
if (ki->term_func) {
if (ret >= 0) {
if (ki->object->cookie->inval_counter == ki->inval_counter)
ki->skipped += ret;
else
ret = -ESTALE;
}
ki->term_func(ki->term_func_priv, ret, ki->was_async);
}
cachefiles_put_kiocb(ki);
}
/*
* Initiate a read from the cache.
*/
static int cachefiles_read(struct netfs_cache_resources *cres,
loff_t start_pos,
struct iov_iter *iter,
enum netfs_read_from_hole read_hole,
netfs_io_terminated_t term_func,
void *term_func_priv)
{
struct cachefiles_object *object;
struct cachefiles_kiocb *ki;
struct file *file;
unsigned int old_nofs;
ssize_t ret = -ENOBUFS;
size_t len = iov_iter_count(iter), skipped = 0;
if (!fscache_wait_for_operation(cres, FSCACHE_WANT_READ))
goto presubmission_error;
fscache_count_read();
object = cachefiles_cres_object(cres);
file = cachefiles_cres_file(cres);
_enter("%pD,%li,%llx,%zx/%llx",
file, file_inode(file)->i_ino, start_pos, len,
i_size_read(file_inode(file)));
/* If the caller asked us to seek for data before doing the read, then
* we should do that now. If we find a gap, we fill it with zeros.
*/
if (read_hole != NETFS_READ_HOLE_IGNORE) {
loff_t off = start_pos, off2;
off2 = cachefiles_inject_read_error();
if (off2 == 0)
off2 = vfs_llseek(file, off, SEEK_DATA);
if (off2 < 0 && off2 >= (loff_t)-MAX_ERRNO && off2 != -ENXIO) {
skipped = 0;
ret = off2;
goto presubmission_error;
}
if (off2 == -ENXIO || off2 >= start_pos + len) {
/* The region is beyond the EOF or there's no more data
* in the region, so clear the rest of the buffer and
* return success.
*/
ret = -ENODATA;
if (read_hole == NETFS_READ_HOLE_FAIL)
goto presubmission_error;
iov_iter_zero(len, iter);
skipped = len;
ret = 0;
goto presubmission_error;
}
skipped = off2 - off;
iov_iter_zero(skipped, iter);
}
ret = -ENOMEM;
ki = kzalloc(sizeof(struct cachefiles_kiocb), GFP_KERNEL);
if (!ki)
goto presubmission_error;
refcount_set(&ki->ki_refcnt, 2);
ki->iocb.ki_filp = file;
ki->iocb.ki_pos = start_pos + skipped;
ki->iocb.ki_flags = IOCB_DIRECT;
ki->iocb.ki_ioprio = get_current_ioprio();
ki->skipped = skipped;
ki->object = object;
ki->inval_counter = cres->inval_counter;
ki->term_func = term_func;
ki->term_func_priv = term_func_priv;
ki->was_async = true;
if (ki->term_func)
ki->iocb.ki_complete = cachefiles_read_complete;
get_file(ki->iocb.ki_filp);
cachefiles_grab_object(object, cachefiles_obj_get_ioreq);
trace_cachefiles_read(object, file_inode(file), ki->iocb.ki_pos, len - skipped);
old_nofs = memalloc_nofs_save();
ret = cachefiles_inject_read_error();
if (ret == 0)
ret = vfs_iocb_iter_read(file, &ki->iocb, iter);
memalloc_nofs_restore(old_nofs);
switch (ret) {
case -EIOCBQUEUED:
goto in_progress;
case -ERESTARTSYS:
case -ERESTARTNOINTR:
case -ERESTARTNOHAND:
case -ERESTART_RESTARTBLOCK:
/* There's no easy way to restart the syscall since other AIO's
* may be already running. Just fail this IO with EINTR.
*/
ret = -EINTR;
fallthrough;
default:
ki->was_async = false;
cachefiles_read_complete(&ki->iocb, ret);
if (ret > 0)
ret = 0;
break;
}
in_progress:
cachefiles_put_kiocb(ki);
_leave(" = %zd", ret);
return ret;
presubmission_error:
if (term_func)
term_func(term_func_priv, ret < 0 ? ret : skipped, false);
return ret;
}
/*
* Query the occupancy of the cache in a region, returning where the next chunk
* of data starts and how long it is.
*/
static int cachefiles_query_occupancy(struct netfs_cache_resources *cres,
loff_t start, size_t len, size_t granularity,
loff_t *_data_start, size_t *_data_len)
{
struct cachefiles_object *object;
struct file *file;
loff_t off, off2;
*_data_start = -1;
*_data_len = 0;
if (!fscache_wait_for_operation(cres, FSCACHE_WANT_READ))
return -ENOBUFS;
object = cachefiles_cres_object(cres);
file = cachefiles_cres_file(cres);
granularity = max_t(size_t, object->volume->cache->bsize, granularity);
_enter("%pD,%li,%llx,%zx/%llx",
file, file_inode(file)->i_ino, start, len,
i_size_read(file_inode(file)));
off = cachefiles_inject_read_error();
if (off == 0)
off = vfs_llseek(file, start, SEEK_DATA);
if (off == -ENXIO)
return -ENODATA; /* Beyond EOF */
if (off < 0 && off >= (loff_t)-MAX_ERRNO)
return -ENOBUFS; /* Error. */
if (round_up(off, granularity) >= start + len)
return -ENODATA; /* No data in range */
off2 = cachefiles_inject_read_error();
if (off2 == 0)
off2 = vfs_llseek(file, off, SEEK_HOLE);
if (off2 == -ENXIO)
return -ENODATA; /* Beyond EOF */
if (off2 < 0 && off2 >= (loff_t)-MAX_ERRNO)
return -ENOBUFS; /* Error. */
/* Round away partial blocks */
off = round_up(off, granularity);
off2 = round_down(off2, granularity);
if (off2 <= off)
return -ENODATA;
*_data_start = off;
if (off2 > start + len)
*_data_len = len;
else
*_data_len = off2 - off;
return 0;
}
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
/*
* Handle completion of a write to the cache.
*/
static void cachefiles_write_complete(struct kiocb *iocb, long ret)
{
struct cachefiles_kiocb *ki = container_of(iocb, struct cachefiles_kiocb, iocb);
struct cachefiles_object *object = ki->object;
struct inode *inode = file_inode(ki->iocb.ki_filp);
_enter("%ld", ret);
/* Tell lockdep we inherited freeze protection from submission thread */
__sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
__sb_end_write(inode->i_sb, SB_FREEZE_WRITE);
if (ret < 0)
trace_cachefiles_io_error(object, inode, ret,
cachefiles_trace_write_error);
atomic_long_sub(ki->b_writing, &object->volume->cache->b_writing);
set_bit(FSCACHE_COOKIE_HAVE_DATA, &object->cookie->flags);
if (ki->term_func)
ki->term_func(ki->term_func_priv, ret, ki->was_async);
cachefiles_put_kiocb(ki);
}
/*
* Initiate a write to the cache.
*/
int __cachefiles_write(struct cachefiles_object *object,
struct file *file,
loff_t start_pos,
struct iov_iter *iter,
netfs_io_terminated_t term_func,
void *term_func_priv)
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
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{
struct cachefiles_cache *cache;
struct cachefiles_kiocb *ki;
struct inode *inode;
unsigned int old_nofs;
ssize_t ret;
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
size_t len = iov_iter_count(iter);
fscache_count_write();
cache = object->volume->cache;
_enter("%pD,%li,%llx,%zx/%llx",
file, file_inode(file)->i_ino, start_pos, len,
i_size_read(file_inode(file)));
ki = kzalloc(sizeof(struct cachefiles_kiocb), GFP_KERNEL);
if (!ki) {
if (term_func)
term_func(term_func_priv, -ENOMEM, false);
return -ENOMEM;
}
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
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refcount_set(&ki->ki_refcnt, 2);
ki->iocb.ki_filp = file;
ki->iocb.ki_pos = start_pos;
ki->iocb.ki_flags = IOCB_DIRECT | IOCB_WRITE;
ki->iocb.ki_ioprio = get_current_ioprio();
ki->object = object;
ki->start = start_pos;
ki->len = len;
ki->term_func = term_func;
ki->term_func_priv = term_func_priv;
ki->was_async = true;
ki->b_writing = (len + (1 << cache->bshift) - 1) >> cache->bshift;
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
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if (ki->term_func)
ki->iocb.ki_complete = cachefiles_write_complete;
atomic_long_add(ki->b_writing, &cache->b_writing);
/* Open-code file_start_write here to grab freeze protection, which
* will be released by another thread in aio_complete_rw(). Fool
* lockdep by telling it the lock got released so that it doesn't
* complain about the held lock when we return to userspace.
*/
inode = file_inode(file);
__sb_start_write(inode->i_sb, SB_FREEZE_WRITE);
__sb_writers_release(inode->i_sb, SB_FREEZE_WRITE);
get_file(ki->iocb.ki_filp);
cachefiles_grab_object(object, cachefiles_obj_get_ioreq);
trace_cachefiles_write(object, inode, ki->iocb.ki_pos, len);
old_nofs = memalloc_nofs_save();
ret = cachefiles_inject_write_error();
if (ret == 0)
ret = vfs_iocb_iter_write(file, &ki->iocb, iter);
memalloc_nofs_restore(old_nofs);
switch (ret) {
case -EIOCBQUEUED:
goto in_progress;
case -ERESTARTSYS:
case -ERESTARTNOINTR:
case -ERESTARTNOHAND:
case -ERESTART_RESTARTBLOCK:
/* There's no easy way to restart the syscall since other AIO's
* may be already running. Just fail this IO with EINTR.
*/
ret = -EINTR;
fallthrough;
default:
ki->was_async = false;
cachefiles_write_complete(&ki->iocb, ret);
if (ret > 0)
ret = 0;
break;
}
in_progress:
cachefiles_put_kiocb(ki);
_leave(" = %zd", ret);
return ret;
}
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
static int cachefiles_write(struct netfs_cache_resources *cres,
loff_t start_pos,
struct iov_iter *iter,
netfs_io_terminated_t term_func,
void *term_func_priv)
{
if (!fscache_wait_for_operation(cres, FSCACHE_WANT_WRITE)) {
if (term_func)
term_func(term_func_priv, -ENOBUFS, false);
return -ENOBUFS;
}
return __cachefiles_write(cachefiles_cres_object(cres),
cachefiles_cres_file(cres),
start_pos, iter,
term_func, term_func_priv);
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
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}
/*
* Prepare a read operation, shortening it to a cached/uncached
* boundary as appropriate.
*/
static enum netfs_io_source cachefiles_prepare_read(struct netfs_io_subrequest *subreq,
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
loff_t i_size)
{
enum cachefiles_prepare_read_trace why;
struct netfs_io_request *rreq = subreq->rreq;
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
struct netfs_cache_resources *cres = &rreq->cache_resources;
struct cachefiles_object *object;
struct cachefiles_cache *cache;
struct fscache_cookie *cookie = fscache_cres_cookie(cres);
const struct cred *saved_cred;
struct file *file = cachefiles_cres_file(cres);
enum netfs_io_source ret = NETFS_DOWNLOAD_FROM_SERVER;
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
loff_t off, to;
ino_t ino = file ? file_inode(file)->i_ino : 0;
int rc;
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
_enter("%zx @%llx/%llx", subreq->len, subreq->start, i_size);
if (subreq->start >= i_size) {
ret = NETFS_FILL_WITH_ZEROES;
why = cachefiles_trace_read_after_eof;
goto out_no_object;
}
if (test_bit(FSCACHE_COOKIE_NO_DATA_TO_READ, &cookie->flags)) {
__set_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags);
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
why = cachefiles_trace_read_no_data;
if (!test_bit(NETFS_SREQ_ONDEMAND, &subreq->flags))
goto out_no_object;
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
}
/* The object and the file may be being created in the background. */
if (!file) {
why = cachefiles_trace_read_no_file;
if (!fscache_wait_for_operation(cres, FSCACHE_WANT_READ))
goto out_no_object;
file = cachefiles_cres_file(cres);
if (!file)
goto out_no_object;
ino = file_inode(file)->i_ino;
}
object = cachefiles_cres_object(cres);
cache = object->volume->cache;
cachefiles_begin_secure(cache, &saved_cred);
retry:
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
off = cachefiles_inject_read_error();
if (off == 0)
off = vfs_llseek(file, subreq->start, SEEK_DATA);
if (off < 0 && off >= (loff_t)-MAX_ERRNO) {
if (off == (loff_t)-ENXIO) {
why = cachefiles_trace_read_seek_nxio;
goto download_and_store;
}
trace_cachefiles_io_error(object, file_inode(file), off,
cachefiles_trace_seek_error);
why = cachefiles_trace_read_seek_error;
goto out;
}
if (off >= subreq->start + subreq->len) {
why = cachefiles_trace_read_found_hole;
goto download_and_store;
}
if (off > subreq->start) {
off = round_up(off, cache->bsize);
subreq->len = off - subreq->start;
why = cachefiles_trace_read_found_part;
goto download_and_store;
}
to = cachefiles_inject_read_error();
if (to == 0)
to = vfs_llseek(file, subreq->start, SEEK_HOLE);
if (to < 0 && to >= (loff_t)-MAX_ERRNO) {
trace_cachefiles_io_error(object, file_inode(file), to,
cachefiles_trace_seek_error);
why = cachefiles_trace_read_seek_error;
goto out;
}
if (to < subreq->start + subreq->len) {
if (subreq->start + subreq->len >= i_size)
to = round_up(to, cache->bsize);
else
to = round_down(to, cache->bsize);
subreq->len = to - subreq->start;
}
why = cachefiles_trace_read_have_data;
ret = NETFS_READ_FROM_CACHE;
goto out;
download_and_store:
__set_bit(NETFS_SREQ_COPY_TO_CACHE, &subreq->flags);
if (test_bit(NETFS_SREQ_ONDEMAND, &subreq->flags)) {
rc = cachefiles_ondemand_read(object, subreq->start,
subreq->len);
if (!rc) {
__clear_bit(NETFS_SREQ_ONDEMAND, &subreq->flags);
goto retry;
}
ret = NETFS_INVALID_READ;
}
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
out:
cachefiles_end_secure(cache, saved_cred);
out_no_object:
trace_cachefiles_prep_read(subreq, ret, why, ino);
return ret;
}
/*
* Prepare for a write to occur.
*/
int __cachefiles_prepare_write(struct cachefiles_object *object,
struct file *file,
loff_t *_start, size_t *_len,
bool no_space_allocated_yet)
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
{
struct cachefiles_cache *cache = object->volume->cache;
loff_t start = *_start, pos;
size_t len = *_len, down;
int ret;
/* Round to DIO size */
down = start - round_down(start, PAGE_SIZE);
*_start = start - down;
*_len = round_up(down + len, PAGE_SIZE);
/* We need to work out whether there's sufficient disk space to perform
* the write - but we can skip that check if we have space already
* allocated.
*/
if (no_space_allocated_yet)
goto check_space;
pos = cachefiles_inject_read_error();
if (pos == 0)
pos = vfs_llseek(file, *_start, SEEK_DATA);
if (pos < 0 && pos >= (loff_t)-MAX_ERRNO) {
if (pos == -ENXIO)
goto check_space; /* Unallocated tail */
trace_cachefiles_io_error(object, file_inode(file), pos,
cachefiles_trace_seek_error);
return pos;
}
if ((u64)pos >= (u64)*_start + *_len)
goto check_space; /* Unallocated region */
/* We have a block that's at least partially filled - if we're low on
* space, we need to see if it's fully allocated. If it's not, we may
* want to cull it.
*/
if (cachefiles_has_space(cache, 0, *_len / PAGE_SIZE,
cachefiles_has_space_check) == 0)
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
return 0; /* Enough space to simply overwrite the whole block */
pos = cachefiles_inject_read_error();
if (pos == 0)
pos = vfs_llseek(file, *_start, SEEK_HOLE);
if (pos < 0 && pos >= (loff_t)-MAX_ERRNO) {
trace_cachefiles_io_error(object, file_inode(file), pos,
cachefiles_trace_seek_error);
return pos;
}
if ((u64)pos >= (u64)*_start + *_len)
return 0; /* Fully allocated */
/* Partially allocated, but insufficient space: cull. */
fscache_count_no_write_space();
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
ret = cachefiles_inject_remove_error();
if (ret == 0)
ret = vfs_fallocate(file, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
*_start, *_len);
if (ret < 0) {
trace_cachefiles_io_error(object, file_inode(file), ret,
cachefiles_trace_fallocate_error);
cachefiles_io_error_obj(object,
"CacheFiles: fallocate failed (%d)\n", ret);
ret = -EIO;
}
return ret;
check_space:
return cachefiles_has_space(cache, 0, *_len / PAGE_SIZE,
cachefiles_has_space_for_write);
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
}
static int cachefiles_prepare_write(struct netfs_cache_resources *cres,
loff_t *_start, size_t *_len, loff_t i_size,
bool no_space_allocated_yet)
{
struct cachefiles_object *object = cachefiles_cres_object(cres);
struct cachefiles_cache *cache = object->volume->cache;
const struct cred *saved_cred;
int ret;
if (!cachefiles_cres_file(cres)) {
if (!fscache_wait_for_operation(cres, FSCACHE_WANT_WRITE))
return -ENOBUFS;
if (!cachefiles_cres_file(cres))
return -ENOBUFS;
}
cachefiles_begin_secure(cache, &saved_cred);
ret = __cachefiles_prepare_write(object, cachefiles_cres_file(cres),
_start, _len,
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
no_space_allocated_yet);
cachefiles_end_secure(cache, saved_cred);
return ret;
}
/*
* Clean up an operation.
*/
static void cachefiles_end_operation(struct netfs_cache_resources *cres)
{
struct file *file = cachefiles_cres_file(cres);
if (file)
fput(file);
fscache_end_cookie_access(fscache_cres_cookie(cres), fscache_access_io_end);
}
static const struct netfs_cache_ops cachefiles_netfs_cache_ops = {
.end_operation = cachefiles_end_operation,
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 07:19:46 +08:00
.read = cachefiles_read,
.write = cachefiles_write,
.prepare_read = cachefiles_prepare_read,
.prepare_write = cachefiles_prepare_write,
.query_occupancy = cachefiles_query_occupancy,
};
/*
* Open the cache file when beginning a cache operation.
*/
bool cachefiles_begin_operation(struct netfs_cache_resources *cres,
enum fscache_want_state want_state)
{
struct cachefiles_object *object = cachefiles_cres_object(cres);
if (!cachefiles_cres_file(cres)) {
cres->ops = &cachefiles_netfs_cache_ops;
if (object->file) {
spin_lock(&object->lock);
if (!cres->cache_priv2 && object->file)
cres->cache_priv2 = get_file(object->file);
spin_unlock(&object->lock);
}
}
if (!cachefiles_cres_file(cres) && want_state != FSCACHE_WANT_PARAMS) {
pr_err("failed to get cres->file\n");
return false;
}
return true;
}