~~~~~~~~~
For filesystems using Linux's pagecache, the ``->readpage()`` and
-``->readpages()`` methods must be modified to verify pages before they
+``->readahead()`` methods must be modified to verify pages before they
are marked Uptodate. Merely hooking ``->read_iter()`` would be
insufficient, since ``->read_iter()`` is not used for memory maps.
verification. Finally, pages where no decryption or verity error
occurred are marked Uptodate, and the pages are unlocked.
-Files on ext4 and f2fs may contain holes. Normally, ``->readpages()``
+Files on ext4 and f2fs may contain holes. Normally, ``->readahead()``
simply zeroes holes and sets the corresponding pages Uptodate; no bios
are issued. To prevent this case from bypassing fs-verity, these
filesystems use fsverity_verify_page() to verify hole pages.
- To prevent bypassing verification, pages must not be marked
Uptodate until they've been verified. Currently, each
filesystem is responsible for marking pages Uptodate via
- ``->readpages()``. Therefore, currently it's not possible for
+ ``->readahead()``. Therefore, currently it's not possible for
the VFS to do the verification on its own. Changing this would
require significant changes to the VFS and all filesystems.
int (*writepages)(struct address_space *, struct writeback_control *);
bool (*dirty_folio)(struct address_space *, struct folio *folio);
void (*readahead)(struct readahead_control *);
- int (*readpages)(struct file *filp, struct address_space *mapping,
- struct list_head *pages, unsigned nr_pages);
int (*write_begin)(struct file *, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata);
writepages:
dirty_folio maybe
readahead: yes, unlocks shared
-readpages: no shared
write_begin: locks the page exclusive
write_end: yes, unlocks exclusive
bmap:
->readahead() unlocks the pages that I/O is attempted on like ->readpage().
-->readpages() populates the pagecache with the passed pages and starts
-I/O against them. They come unlocked upon I/O completion.
-
->writepage() is used for two purposes: for "memory cleansing" and for
"sync". These are quite different operations and the behaviour may differ
depending upon the mode.
int (*writepages)(struct address_space *, struct writeback_control *);
bool (*dirty_folio)(struct address_space *, struct folio *);
void (*readahead)(struct readahead_control *);
- int (*readpages)(struct file *filp, struct address_space *mapping,
- struct list_head *pages, unsigned nr_pages);
int (*write_begin)(struct file *, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
struct page **pagep, void **fsdata);
completes successfully. Setting PageError on any page will be
ignored; simply unlock the page if an I/O error occurs.
-``readpages``
- called by the VM to read pages associated with the address_space
- object. This is essentially just a vector version of readpage.
- Instead of just one page, several pages are requested.
- readpages is only used for read-ahead, so read errors are
- ignored. If anything goes wrong, feel free to give up.
- This interface is deprecated and will be removed by the end of
- 2020; implement readahead instead.
-
``write_begin``
Called by the generic buffered write code to ask the filesystem
to prepare to write len bytes at the given offset in the file.
int ret;
/*
- * Lock destination range to serialize with concurrent readpages() and
+ * Lock destination range to serialize with concurrent readahead() and
* source range to serialize with relocation.
*/
btrfs_double_extent_lock(src, loff, dst, dst_loff, len);
}
/*
- * Lock destination range to serialize with concurrent readpages() and
+ * Lock destination range to serialize with concurrent readahead() and
* source range to serialize with relocation.
*/
btrfs_double_extent_lock(src, off, inode, destoff, len);
set_credits(server, server->maxReq);
/* probably no need to store and check maxvcs */
server->maxBuf = le32_to_cpu(pSMBr->MaxBufferSize);
- /* set up max_read for readpages check */
+ /* set up max_read for readahead check */
server->max_read = server->maxBuf;
server->max_rw = le32_to_cpu(pSMBr->MaxRawSize);
cifs_dbg(NOISY, "Max buf = %d\n", ses->server->maxBuf);
inode->i_fop = &cifs_file_ops;
}
- /* check if server can support readpages */
+ /* check if server can support readahead */
if (cifs_sb_master_tcon(cifs_sb)->ses->server->max_read <
PAGE_SIZE + MAX_CIFS_HDR_SIZE)
inode->i_data.a_ops = &cifs_addr_ops_smallbuf;
* which must still be locked and not uptodate. Normally, blocksize ==
* PAGE_SIZE and the whole page is decrypted at once.
*
- * This is for use by the filesystem's ->readpages() method.
+ * This is for use by the filesystem's ->readahead() method.
*
* Return: 0 on success; -errno on failure
*/
struct bio *bio = ctx->bio;
/*
- * fsverity_verify_bio() may call readpages() again, and although verity
+ * fsverity_verify_bio() may call readahead() again, and although verity
* will be disabled for that, decryption may still be needed, causing
* another bio_post_read_ctx to be allocated. So to guarantee that
* mempool_alloc() never deadlocks we must free the current ctx first.
bool may_have_compressed_pages = (ctx->enabled_steps & STEP_DECOMPRESS);
/*
- * fsverity_verify_bio() may call readpages() again, and while verity
+ * fsverity_verify_bio() may call readahead() again, and while verity
* will be disabled for this, decryption and/or decompression may still
* be needed, resulting in another bio_post_read_ctx being allocated.
* So to prevent deadlocks we need to release the current ctx to the
if (!f2fs_is_compress_backend_ready(inode))
return;
- /* If the file has inline data, skip readpages */
+ /* If the file has inline data, skip readahead */
if (f2fs_has_inline_data(inode))
return;
/** Connection successful. Only set in INIT */
unsigned conn_init:1;
- /** Do readpages asynchronously? Only set in INIT */
+ /** Do readahead asynchronously? Only set in INIT */
unsigned async_read:1;
/** Return an unique read error after abort. Only set in INIT */
// SPDX-License-Identifier: GPL-2.0
/*
- * Data verification functions, i.e. hooks for ->readpages()
+ * Data verification functions, i.e. hooks for ->readahead()
*
* Copyright 2019 Google LLC
*/
* that fail verification are set to the Error state. Verification is skipped
* for pages already in the Error state, e.g. due to fscrypt decryption failure.
*
- * This is a helper function for use by the ->readpages() method of filesystems
+ * This is a helper function for use by the ->readahead() method of filesystems
* that issue bios to read data directly into the page cache. Filesystems that
* populate the page cache without issuing bios (e.g. non block-based
* filesystems) must instead call fsverity_verify_page() directly on each page.
/* Mark a folio dirty. Return true if this dirtied it */
bool (*dirty_folio)(struct address_space *, struct folio *);
- /*
- * Reads in the requested pages. Unlike ->readpage(), this is
- * PURELY used for read-ahead!.
- */
- int (*readpages)(struct file *filp, struct address_space *mapping,
- struct list_head *pages, unsigned nr_pages);
void (*readahead)(struct readahead_control *);
int (*write_begin)(struct file *, struct address_space *mapping,
*
* This checks whether ->i_verity_info has been set.
*
- * Filesystems call this from ->readpages() to check whether the pages need to
+ * Filesystems call this from ->readahead() to check whether the pages need to
* be verified or not. Don't use IS_VERITY() for this purpose; it's subject to
* a race condition where the file is being read concurrently with
* FS_IOC_ENABLE_VERITY completing. (S_VERITY is set before ->i_verity_info.)
* the page cache as the locked folio would then be enough to
* synchronize with hole punching. But there are code paths
* such as filemap_update_page() filling in partially uptodate
- * pages or ->readpages() that need to hold invalidate_lock
+ * pages or ->readahead() that need to hold invalidate_lock
* while mapping blocks for IO so let's hold the lock here as
* well to keep locking rules simple.
*/
unlock_page(page);
put_page(page);
}
- } else if (aops->readpages) {
- aops->readpages(rac->file, rac->mapping, pages,
- readahead_count(rac));
- /* Clean up the remaining pages */
- put_pages_list(pages);
- rac->_index += rac->_nr_pages;
- rac->_nr_pages = 0;
} else {
while ((page = readahead_page(rac))) {
aops->readpage(rac->file, page);
folio = filemap_alloc_folio(gfp_mask, 0);
if (!folio)
break;
- if (mapping->a_ops->readpages) {
- folio->index = index + i;
- list_add(&folio->lru, &page_pool);
- } else if (filemap_add_folio(mapping, folio, index + i,
+ if (filemap_add_folio(mapping, folio, index + i,
gfp_mask) < 0) {
folio_put(folio);
read_pages(ractl, &page_pool, true);
struct backing_dev_info *bdi = inode_to_bdi(mapping->host);
unsigned long max_pages, index;
- if (unlikely(!mapping->a_ops->readpage && !mapping->a_ops->readpages &&
- !mapping->a_ops->readahead))
+ if (unlikely(!mapping->a_ops->readpage && !mapping->a_ops->readahead))
return;
/*
projects / kernel.git / commitdiff