diff options
Diffstat (limited to 'fs/cachefiles/io.c')
-rw-r--r-- | fs/cachefiles/io.c | 420 |
1 files changed, 0 insertions, 420 deletions
diff --git a/fs/cachefiles/io.c b/fs/cachefiles/io.c deleted file mode 100644 index effe37ef8629..000000000000 --- a/fs/cachefiles/io.c +++ /dev/null @@ -1,420 +0,0 @@ -// 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/sched/mm.h> -#include <linux/netfs.h> -#include "internal.h" - -struct cachefiles_kiocb { - struct kiocb iocb; - refcount_t ki_refcnt; - loff_t start; - union { - size_t skipped; - size_t len; - }; - netfs_io_terminated_t term_func; - void *term_func_priv; - bool was_async; -}; - -static inline void cachefiles_put_kiocb(struct cachefiles_kiocb *ki) -{ - if (refcount_dec_and_test(&ki->ki_refcnt)) { - 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); - - _enter("%ld", ret); - - if (ki->term_func) { - if (ret >= 0) - ret += ki->skipped; - 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, - bool seek_data, - netfs_io_terminated_t term_func, - void *term_func_priv) -{ - struct cachefiles_kiocb *ki; - struct file *file = cres->cache_priv2; - unsigned int old_nofs; - ssize_t ret = -ENOBUFS; - size_t len = iov_iter_count(iter), skipped = 0; - - _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 (seek_data) { - loff_t off = start_pos, off2; - - 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. - */ - iov_iter_zero(len, iter); - skipped = len; - ret = 0; - goto presubmission_error; - } - - skipped = off2 - off; - iov_iter_zero(skipped, iter); - } - - ret = -ENOBUFS; - 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_hint = ki_hint_validate(file_write_hint(file)); - ki->iocb.ki_ioprio = get_current_ioprio(); - ki->skipped = skipped; - 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); - - old_nofs = memalloc_nofs_save(); - 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; -} - -/* - * 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 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 (ki->term_func) - ki->term_func(ki->term_func_priv, ret, ki->was_async); - - cachefiles_put_kiocb(ki); -} - -/* - * Initiate a write to the cache. - */ -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) -{ - struct cachefiles_kiocb *ki; - struct inode *inode; - struct file *file = cres->cache_priv2; - unsigned int old_nofs; - ssize_t ret = -ENOBUFS; - size_t len = iov_iter_count(iter); - - _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) - goto presubmission_error; - - 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_hint = ki_hint_validate(file_write_hint(file)); - ki->iocb.ki_ioprio = get_current_ioprio(); - ki->start = start_pos; - ki->len = len; - 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_write_complete; - - /* 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); - - old_nofs = memalloc_nofs_save(); - 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; - -presubmission_error: - if (term_func) - term_func(term_func_priv, -ENOMEM, false); - return -ENOMEM; -} - -/* - * Prepare a read operation, shortening it to a cached/uncached - * boundary as appropriate. - */ -static enum netfs_read_source cachefiles_prepare_read(struct netfs_read_subrequest *subreq, - loff_t i_size) -{ - struct fscache_retrieval *op = subreq->rreq->cache_resources.cache_priv; - struct cachefiles_object *object; - struct cachefiles_cache *cache; - const struct cred *saved_cred; - struct file *file = subreq->rreq->cache_resources.cache_priv2; - loff_t off, to; - - _enter("%zx @%llx/%llx", subreq->len, subreq->start, i_size); - - object = container_of(op->op.object, - struct cachefiles_object, fscache); - cache = container_of(object->fscache.cache, - struct cachefiles_cache, cache); - - if (!file) - goto cache_fail_nosec; - - if (subreq->start >= i_size) - return NETFS_FILL_WITH_ZEROES; - - cachefiles_begin_secure(cache, &saved_cred); - - off = vfs_llseek(file, subreq->start, SEEK_DATA); - if (off < 0 && off >= (loff_t)-MAX_ERRNO) { - if (off == (loff_t)-ENXIO) - goto download_and_store; - goto cache_fail; - } - - if (off >= subreq->start + subreq->len) - goto download_and_store; - - if (off > subreq->start) { - off = round_up(off, cache->bsize); - subreq->len = off - subreq->start; - goto download_and_store; - } - - to = vfs_llseek(file, subreq->start, SEEK_HOLE); - if (to < 0 && to >= (loff_t)-MAX_ERRNO) - goto cache_fail; - - 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; - } - - cachefiles_end_secure(cache, saved_cred); - return NETFS_READ_FROM_CACHE; - -download_and_store: - if (cachefiles_has_space(cache, 0, (subreq->len + PAGE_SIZE - 1) / PAGE_SIZE) == 0) - __set_bit(NETFS_SREQ_WRITE_TO_CACHE, &subreq->flags); -cache_fail: - cachefiles_end_secure(cache, saved_cred); -cache_fail_nosec: - return NETFS_DOWNLOAD_FROM_SERVER; -} - -/* - * Prepare for a write to occur. - */ -static int cachefiles_prepare_write(struct netfs_cache_resources *cres, - loff_t *_start, size_t *_len, loff_t i_size) -{ - loff_t start = *_start; - size_t len = *_len, down; - - /* Round to DIO size */ - down = start - round_down(start, PAGE_SIZE); - *_start = start - down; - *_len = round_up(down + len, PAGE_SIZE); - return 0; -} - -/* - * Clean up an operation. - */ -static void cachefiles_end_operation(struct netfs_cache_resources *cres) -{ - struct fscache_retrieval *op = cres->cache_priv; - struct file *file = cres->cache_priv2; - - _enter(""); - - if (file) - fput(file); - if (op) { - fscache_op_complete(&op->op, false); - fscache_put_retrieval(op); - } - - _leave(""); -} - -static const struct netfs_cache_ops cachefiles_netfs_cache_ops = { - .end_operation = cachefiles_end_operation, - .read = cachefiles_read, - .write = cachefiles_write, - .prepare_read = cachefiles_prepare_read, - .prepare_write = cachefiles_prepare_write, -}; - -/* - * Open the cache file when beginning a cache operation. - */ -int cachefiles_begin_read_operation(struct netfs_read_request *rreq, - struct fscache_retrieval *op) -{ - struct cachefiles_object *object; - struct cachefiles_cache *cache; - struct path path; - struct file *file; - - _enter(""); - - object = container_of(op->op.object, - struct cachefiles_object, fscache); - cache = container_of(object->fscache.cache, - struct cachefiles_cache, cache); - - path.mnt = cache->mnt; - path.dentry = object->backer; - file = open_with_fake_path(&path, O_RDWR | O_LARGEFILE | O_DIRECT, - d_inode(object->backer), cache->cache_cred); - if (IS_ERR(file)) - return PTR_ERR(file); - if (!S_ISREG(file_inode(file)->i_mode)) - goto error_file; - if (unlikely(!file->f_op->read_iter) || - unlikely(!file->f_op->write_iter)) { - pr_notice("Cache does not support read_iter and write_iter\n"); - goto error_file; - } - - fscache_get_retrieval(op); - rreq->cache_resources.cache_priv = op; - rreq->cache_resources.cache_priv2 = file; - rreq->cache_resources.ops = &cachefiles_netfs_cache_ops; - rreq->cache_resources.debug_id = object->fscache.debug_id; - _leave(""); - return 0; - -error_file: - fput(file); - return -EIO; -} |