include/linux/netfs.h

1 /* SPDX-License-Identifier: GPL-2.0-or-later */
25  * Overload PG_private_2 to give us PG_fscache - this is used to indicate that
36  * folio_start_fscache - Start an fscache write on a folio.
40  * second write before the first one finishes is not allowed.
50  * folio_end_fscache - End an fscache write on a folio.
54  * This will wake any sleepers waiting on this folio.
62  * folio_wait_fscache - Wait for an fscache write on this folio to end.
65  * If this folio is currently being written to a local cache, wait for
66  * the write to finish.  Another write may start after this one finishes,
75  * folio_wait_fscache_killable - Wait for an fscache write on this folio to end.
78  * If this folio is currently being written to a local cache, wait
79  * for the write to finish or for a fatal signal to be received.
80  * Another write may start after this one finishes, unless the caller
84  * - 0 if successful.
85  * - -EINTR if a fatal signal was encountered.
112 /* Marks used on xarray-based buffers */
113 #define NETFS_BUF_PUT_MARK	XA_MARK_0	/* - Page needs putting  */
114 #define NETFS_BUF_PAGECACHE_MARK XA_MARK_1	/* - Page needs wb/dirty flag wrangling */
130  * Per-inode context.  This wraps the VFS inode.
140 						 * on the server */
144 #define NETFS_ICTX_WRITETHROUGH	2		/* Write-through caching */
145 #define NETFS_ICTX_NO_WRITE_STREAMING	3	/* Don't engage in write-streaming */
149  * A netfs group - for instance a ceph snap.  This is marked on dirty pages and
160  * folio->private
164 	unsigned int		dirty_offset;	/* Write-streaming dirty data offset */
165 	unsigned int		dirty_len;	/* Write-streaming dirty data length */
167 #define NETFS_FOLIO_INFO	0x1UL	/* OR'd with folio->private. */
185 		return finfo->netfs_group;  in netfs_folio_group()
190  * Resources required to do operations on a cache.
197 	unsigned int			inval_counter;	/* object->inval_counter at begin_op */
202  * individual read/write from/to a server, a cache, a journal, etc..
205  * the pages it points to can be relied on to exist for the duration.
210 	struct list_head	rreq_link;	/* Link in rreq->subrequests */
219 	enum netfs_io_source	source;		/* Where to read from/write to */
224 #define NETFS_SREQ_SEEK_DATA_READ	3	/* Set if ->read() should SEEK_DATA first */
226 #define NETFS_SREQ_ONDEMAND		5	/* Set if it's from on-demand read mode */
232 	NETFS_READ_FOR_WRITE,		/* This read is to prepare a write */
233 	NETFS_WRITEBACK,		/* This write was triggered by writepages */
234 	NETFS_WRITETHROUGH,		/* This write was made by netfs_perform_write() */
235 	NETFS_LAUNDER_WRITE,		/* This is triggered by ->launder_folio() */
236 	NETFS_UNBUFFERED_WRITE,		/* This is an unbuffered write */
238 	NETFS_DIO_WRITE,		/* This is a direct I/O write */
257 	struct iov_iter		iter;		/* Unencrypted-side iterator */
258 	struct iov_iter		io_iter;	/* I/O (Encrypted-side) iterator */
260 	struct bio_vec		*direct_bv;	/* DIO buffer list (when handling iovec-iter) */
264 	unsigned int		wsize;		/* Maximum write size (0 for none) */
265 	unsigned int		subreq_counter;	/* Next subreq->debug_index */
267 	atomic_t		nr_copy_ops;	/* Number of copy-to-cache ops in progress */
281 #define NETFS_RREQ_COPY_TO_CACHE	1	/* Need to write to the cache */
282 #define NETFS_RREQ_NO_UNLOCK_FOLIO	2	/* Don't unlock no_unlock_folio on completion */
283 #define NETFS_RREQ_DONT_UNLOCK_FOLIOS	3	/* Don't unlock the folios on completion */
286 #define NETFS_RREQ_WRITE_TO_CACHE	7	/* Need to write to the cache */
287 #define NETFS_RREQ_UPLOAD_TO_SERVER	8	/* Need to write to the server */
316 	/* Write request handling */
346 	/* Write data to the cache */
347 	int (*write)(struct netfs_cache_resources *cres,  member
363 	/* Prepare a write operation, working out what part of the write we can
370 	/* Prepare an on-demand read operation, shortening it to a cached/uncached
386 /* High-level read API. */
391 /* High-level write API */
444  * netfs_inode - Get the netfs inode context from the inode
448  * context struct is expected to directly follow on from the VFS inode struct.
456  * netfs_inode_init - Initialise a netfslib inode context
461  * Initialise the netfs library context struct.  This is expected to follow on
468 	ctx->ops = ops;  in netfs_inode_init()
469 	ctx->remote_i_size = i_size_read(&ctx->inode);  in netfs_inode_init()
470 	ctx->zero_point = LLONG_MAX;  in netfs_inode_init()
471 	ctx->flags = 0;  in netfs_inode_init()
473 	ctx->cache = NULL;  in netfs_inode_init()
475 	/* ->releasepage() drives zero_point */  in netfs_inode_init()
477 		ctx->zero_point = ctx->remote_i_size;  in netfs_inode_init()
478 		mapping_set_release_always(ctx->inode.i_mapping);  in netfs_inode_init()
483  * netfs_resize_file - Note that a file got resized
494 		ctx->remote_i_size = new_i_size;  in netfs_resize_file()
495 	if (new_i_size < ctx->zero_point)  in netfs_resize_file()
496 		ctx->zero_point = new_i_size;  in netfs_resize_file()
500  * netfs_i_cookie - Get the cache cookie from the inode
508 	return ctx->cache;  in netfs_i_cookie()