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cachefiles: Implement cookie resize for truncate

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Implement resizing an object, using truncate and/or fallocate to adjust the
object.

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/r/163819646631.215744.13819016478175576761.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906952877.143852.4140962906331914859.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967162168.1823006.5941985259926902274.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021560394.640689.9972155785508094960.stgit@warthog.procyon.org.uk/ # v4
This commit is contained in:
David Howells 2021-10-21 08:50:10 +01:00
parent 287fd61123
commit 7623ed6772
1 changed files with 78 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

78
fs/cachefiles/interface.c
View file

@ -220,6 +220,83 @@ static bool cachefiles_lookup_cookie(struct fscache_cookie *cookie)
return false;
}
/*
* Shorten the backing object to discard any dirty data and free up
* any unused granules.
*/
static bool cachefiles_shorten_object(struct cachefiles_object *object,
struct file *file, loff_t new_size)
{
struct cachefiles_cache *cache = object->volume->cache;
struct inode *inode = file_inode(file);
loff_t i_size, dio_size;
int ret;
dio_size = round_up(new_size, CACHEFILES_DIO_BLOCK_SIZE);
i_size = i_size_read(inode);
trace_cachefiles_trunc(object, inode, i_size, dio_size,
cachefiles_trunc_shrink);
ret = cachefiles_inject_remove_error();
if (ret == 0)
ret = vfs_truncate(&file->f_path, dio_size);
if (ret < 0) {
trace_cachefiles_io_error(object, file_inode(file), ret,
cachefiles_trace_trunc_error);
cachefiles_io_error_obj(object, "Trunc-to-size failed %d", ret);
cachefiles_remove_object_xattr(cache, object, file->f_path.dentry);
return false;
}
if (new_size < dio_size) {
trace_cachefiles_trunc(object, inode, dio_size, new_size,
cachefiles_trunc_dio_adjust);
ret = cachefiles_inject_write_error();
if (ret == 0)
ret = vfs_fallocate(file, FALLOC_FL_ZERO_RANGE,
new_size, dio_size);
if (ret < 0) {
trace_cachefiles_io_error(object, file_inode(file), ret,
cachefiles_trace_fallocate_error);
cachefiles_io_error_obj(object, "Trunc-to-dio-size failed %d", ret);
cachefiles_remove_object_xattr(cache, object, file->f_path.dentry);
return false;
}
}
return true;
}
/*
* Resize the backing object.
*/
static void cachefiles_resize_cookie(struct netfs_cache_resources *cres,
loff_t new_size)
{
struct cachefiles_object *object = cachefiles_cres_object(cres);
struct cachefiles_cache *cache = object->volume->cache;
struct fscache_cookie *cookie = object->cookie;
const struct cred *saved_cred;
struct file *file = cachefiles_cres_file(cres);
loff_t old_size = cookie->object_size;
_enter("%llu->%llu", old_size, new_size);
if (new_size < old_size) {
cachefiles_begin_secure(cache, &saved_cred);
cachefiles_shorten_object(object, file, new_size);
cachefiles_end_secure(cache, saved_cred);
object->cookie->object_size = new_size;
return;
}
/* The file is being expanded. We don't need to do anything
* particularly. cookie->initial_size doesn't change and so the point
* at which we have to download before doesn't change.
*/
cookie->object_size = new_size;
}
/*
* Commit changes to the object as we drop it.
*/
@ -363,5 +440,6 @@ const struct fscache_cache_ops cachefiles_cache_ops = {
.withdraw_cookie = cachefiles_withdraw_cookie,
.invalidate_cookie = cachefiles_invalidate_cookie,
.begin_operation = cachefiles_begin_operation,
.resize_cookie = cachefiles_resize_cookie,
.prepare_to_write = cachefiles_prepare_to_write,
};