Merge tag 'vfs-6.10.netfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull netfs updates from Christian Brauner:
 "This reworks the netfslib writeback implementation so that pages read
  from the cache are written to the cache through ->writepages(),
  thereby allowing the fscache page flag to be retired.

  The reworking also:

   - builds on top of the new writeback_iter() infrastructure

   - makes it possible to use vectored write RPCs as discontiguous
     streams of pages can be accommodated

   - makes it easier to do simultaneous content crypto and stream
     division

   - provides support for retrying writes and re-dividing a stream

   - replaces the ->launder_folio() op, so that ->writepages() is used
     instead

   - uses mempools to allocate the netfs_io_request and
     netfs_io_subrequest structs to avoid allocation failure in the
     writeback path

  Some code that uses the fscache page flag is retained for
  compatibility purposes with nfs and ceph. The code is switched to
  using the synonymous private_2 label instead and marked with
  deprecation comments.

  The merge commit contains additional details on the new algorithm that
  I've left out of here as it would probably be excessively detailed.

  On top of the netfslib infrastructure this contains the work to
  convert cifs over to netfslib"

* tag 'vfs-6.10.netfs' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (38 commits)
  cifs: Enable large folio support
  cifs: Remove some code that's no longer used, part 3
  cifs: Remove some code that's no longer used, part 2
  cifs: Remove some code that's no longer used, part 1
  cifs: Cut over to using netfslib
  cifs: Implement netfslib hooks
  cifs: Make add_credits_and_wake_if() clear deducted credits
  cifs: Add mempools for cifs_io_request and cifs_io_subrequest structs
  cifs: Set zero_point in the copy_file_range() and remap_file_range()
  cifs: Move cifs_loose_read_iter() and cifs_file_write_iter() to file.c
  cifs: Replace the writedata replay bool with a netfs sreq flag
  cifs: Make wait_mtu_credits take size_t args
  cifs: Use more fields from netfs_io_subrequest
  cifs: Replace cifs_writedata with a wrapper around netfs_io_subrequest
  cifs: Replace cifs_readdata with a wrapper around netfs_io_subrequest
  cifs: Use alternative invalidation to using launder_folio
  netfs, afs: Use writeback retry to deal with alternate keys
  netfs: Miscellaneous tidy ups
  netfs: Remove the old writeback code
  netfs: Cut over to using new writeback code
  ...

3 files changed, 116 insertions, 105 deletions

diff --git a/include/linux/fscache.h b/include/linux/fscache.h
index 6e8562cbcc43..9de27643607f 100644
--- a/include/linux/fscache.h
+++ b/include/linux/fscache.h
@@ -172,9 +172,12 @@ extern void __fscache_invalidate(struct fscache_cookie *, const void *, loff_t,
 extern int __fscache_begin_read_operation(struct netfs_cache_resources *, struct fscache_cookie *);
 extern int __fscache_begin_write_operation(struct netfs_cache_resources *, struct fscache_cookie *);
 
-extern void __fscache_write_to_cache(struct fscache_cookie *, struct address_space *,
-				     loff_t, size_t, loff_t, netfs_io_terminated_t, void *,
-				     bool);
+void __fscache_write_to_cache(struct fscache_cookie *cookie,
+			      struct address_space *mapping,
+			      loff_t start, size_t len, loff_t i_size,
+			      netfs_io_terminated_t term_func,
+			      void *term_func_priv,
+			      bool using_pgpriv2, bool cond);
 extern void __fscache_clear_page_bits(struct address_space *, loff_t, size_t);
 
 /**
@@ -597,7 +600,8 @@ static inline void fscache_clear_page_bits(struct address_space *mapping,
  * @i_size: The new size of the inode
  * @term_func: The function to call upon completion
  * @term_func_priv: The private data for @term_func
- * @caching: If PG_fscache has been set
+ * @using_pgpriv2: If we're using PG_private_2 to mark in-progress write
+ * @caching: If we actually want to do the caching
  *
  * Helper function for a netfs to write dirty data from an inode into the cache
  * object that's backing it.
@@ -608,19 +612,21 @@ static inline void fscache_clear_page_bits(struct address_space *mapping,
  * marked with PG_fscache.
  *
  * If given, @term_func will be called upon completion and supplied with
- * @term_func_priv.  Note that the PG_fscache flags will have been cleared by
- * this point, so the netfs must retain its own pin on the mapping.
+ * @term_func_priv.  Note that if @using_pgpriv2 is set, the PG_private_2 flags
+ * will have been cleared by this point, so the netfs must retain its own pin
+ * on the mapping.
  */
 static inline void fscache_write_to_cache(struct fscache_cookie *cookie,
 					  struct address_space *mapping,
 					  loff_t start, size_t len, loff_t i_size,
 					  netfs_io_terminated_t term_func,
 					  void *term_func_priv,
-					  bool caching)
+					  bool using_pgpriv2, bool caching)
 {
 	if (caching)
 		__fscache_write_to_cache(cookie, mapping, start, len, i_size,
-					 term_func, term_func_priv, caching);
+					 term_func, term_func_priv,
+					 using_pgpriv2, caching);
 	else if (term_func)
 		term_func(term_func_priv, -ENOBUFS, false);
 
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 100cbb261269..f45d06284f2f 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -20,95 +20,24 @@
 #include <linux/uio.h>
 
 enum netfs_sreq_ref_trace;
-
-/*
- * Overload PG_private_2 to give us PG_fscache - this is used to indicate that
- * a page is currently backed by a local disk cache
- */
-#define folio_test_fscache(folio)	folio_test_private_2(folio)
-#define PageFsCache(page)		PagePrivate2((page))
-#define SetPageFsCache(page)		SetPagePrivate2((page))
-#define ClearPageFsCache(page)		ClearPagePrivate2((page))
-#define TestSetPageFsCache(page)	TestSetPagePrivate2((page))
-#define TestClearPageFsCache(page)	TestClearPagePrivate2((page))
+typedef struct mempool_s mempool_t;
 
 /**
- * folio_start_fscache - Start an fscache write on a folio.
+ * folio_start_private_2 - Start an fscache write on a folio.  [DEPRECATED]
  * @folio: The folio.
  *
  * Call this function before writing a folio to a local cache.  Starting a
  * second write before the first one finishes is not allowed.
+ *
+ * Note that this should no longer be used.
  */
-static inline void folio_start_fscache(struct folio *folio)
+static inline void folio_start_private_2(struct folio *folio)
 {
 	VM_BUG_ON_FOLIO(folio_test_private_2(folio), folio);
 	folio_get(folio);
 	folio_set_private_2(folio);
 }
 
-/**
- * folio_end_fscache - End an fscache write on a folio.
- * @folio: The folio.
- *
- * Call this function after the folio has been written to the local cache.
- * This will wake any sleepers waiting on this folio.
- */
-static inline void folio_end_fscache(struct folio *folio)
-{
-	folio_end_private_2(folio);
-}
-
-/**
- * folio_wait_fscache - Wait for an fscache write on this folio to end.
- * @folio: The folio.
- *
- * If this folio is currently being written to a local cache, wait for
- * the write to finish.  Another write may start after this one finishes,
- * unless the caller holds the folio lock.
- */
-static inline void folio_wait_fscache(struct folio *folio)
-{
-	folio_wait_private_2(folio);
-}
-
-/**
- * folio_wait_fscache_killable - Wait for an fscache write on this folio to end.
- * @folio: The folio.
- *
- * If this folio is currently being written to a local cache, wait
- * for the write to finish or for a fatal signal to be received.
- * Another write may start after this one finishes, unless the caller
- * holds the folio lock.
- *
- * Return:
- * - 0 if successful.
- * - -EINTR if a fatal signal was encountered.
- */
-static inline int folio_wait_fscache_killable(struct folio *folio)
-{
-	return folio_wait_private_2_killable(folio);
-}
-
-static inline void set_page_fscache(struct page *page)
-{
-	folio_start_fscache(page_folio(page));
-}
-
-static inline void end_page_fscache(struct page *page)
-{
-	folio_end_private_2(page_folio(page));
-}
-
-static inline void wait_on_page_fscache(struct page *page)
-{
-	folio_wait_private_2(page_folio(page));
-}
-
-static inline int wait_on_page_fscache_killable(struct page *page)
-{
-	return folio_wait_private_2_killable(page_folio(page));
-}
-
 /* Marks used on xarray-based buffers */
 #define NETFS_BUF_PUT_MARK	XA_MARK_0	/* - Page needs putting  */
 #define NETFS_BUF_PAGECACHE_MARK XA_MARK_1	/* - Page needs wb/dirty flag wrangling */
@@ -135,6 +64,7 @@ struct netfs_inode {
 #if IS_ENABLED(CONFIG_FSCACHE)
 	struct fscache_cookie	*cache;
 #endif
+	struct mutex		wb_lock;	/* Writeback serialisation */
 	loff_t			remote_i_size;	/* Size of the remote file */
 	loff_t			zero_point;	/* Size after which we assume there's no data
 						 * on the server */
@@ -142,7 +72,8 @@ struct netfs_inode {
 #define NETFS_ICTX_ODIRECT	0		/* The file has DIO in progress */
 #define NETFS_ICTX_UNBUFFERED	1		/* I/O should not use the pagecache */
 #define NETFS_ICTX_WRITETHROUGH	2		/* Write-through caching */
-#define NETFS_ICTX_NO_WRITE_STREAMING	3	/* Don't engage in write-streaming */
+#define NETFS_ICTX_USE_PGPRIV2	31		/* [DEPRECATED] Use PG_private_2 to mark
+						 * write to cache on read */
 };
 
 /*
@@ -165,16 +96,25 @@ struct netfs_folio {
 	unsigned int		dirty_len;	/* Write-streaming dirty data length */
 };
 #define NETFS_FOLIO_INFO	0x1UL	/* OR'd with folio->private. */
+#define NETFS_FOLIO_COPY_TO_CACHE ((struct netfs_group *)0x356UL) /* Write to the cache only */
 
-static inline struct netfs_folio *netfs_folio_info(struct folio *folio)
+static inline bool netfs_is_folio_info(const void *priv)
 {
-	void *priv = folio_get_private(folio);
+	return (unsigned long)priv & NETFS_FOLIO_INFO;
+}
 
-	if ((unsigned long)priv & NETFS_FOLIO_INFO)
+static inline struct netfs_folio *__netfs_folio_info(const void *priv)
+{
+	if (netfs_is_folio_info(priv))
 		return (struct netfs_folio *)((unsigned long)priv & ~NETFS_FOLIO_INFO);
 	return NULL;
 }
 
+static inline struct netfs_folio *netfs_folio_info(struct folio *folio)
+{
+	return __netfs_folio_info(folio_get_private(folio));
+}
+
 static inline struct netfs_group *netfs_folio_group(struct folio *folio)
 {
 	struct netfs_folio *finfo;
@@ -187,6 +127,33 @@ static inline struct netfs_group *netfs_folio_group(struct folio *folio)
 }
 
 /*
+ * Stream of I/O subrequests going to a particular destination, such as the
+ * server or the local cache.  This is mainly intended for writing where we may
+ * have to write to multiple destinations concurrently.
+ */
+struct netfs_io_stream {
+	/* Submission tracking */
+	struct netfs_io_subrequest *construct;	/* Op being constructed */
+	unsigned int		submit_off;	/* Folio offset we're submitting from */
+	unsigned int		submit_len;	/* Amount of data left to submit */
+	unsigned int		submit_max_len;	/* Amount I/O can be rounded up to */
+	void (*prepare_write)(struct netfs_io_subrequest *subreq);
+	void (*issue_write)(struct netfs_io_subrequest *subreq);
+	/* Collection tracking */
+	struct list_head	subrequests;	/* Contributory I/O operations */
+	struct netfs_io_subrequest *front;	/* Op being collected */
+	unsigned long long	collected_to;	/* Position we've collected results to */
+	size_t			transferred;	/* The amount transferred from this stream */
+	enum netfs_io_source	source;		/* Where to read from/write to */
+	unsigned short		error;		/* Aggregate error for the stream */
+	unsigned char		stream_nr;	/* Index of stream in parent table */
+	bool			avail;		/* T if stream is available */
+	bool			active;		/* T if stream is active */
+	bool			need_retry;	/* T if this stream needs retrying */
+	bool			failed;		/* T if this stream failed */
+};
+
+/*
  * Resources required to do operations on a cache.
  */
 struct netfs_cache_resources {
@@ -209,14 +176,17 @@ struct netfs_io_subrequest {
 	struct work_struct	work;
 	struct list_head	rreq_link;	/* Link in rreq->subrequests */
 	struct iov_iter		io_iter;	/* Iterator for this subrequest */
-	loff_t			start;		/* Where to start the I/O */
+	unsigned long long	start;		/* Where to start the I/O */
+	size_t			max_len;	/* Maximum size of the I/O */
 	size_t			len;		/* Size of the I/O */
 	size_t			transferred;	/* Amount of data transferred */
 	refcount_t		ref;
 	short			error;		/* 0 or error that occurred */
 	unsigned short		debug_index;	/* Index in list (for debugging output) */
+	unsigned int		nr_segs;	/* Number of segs in io_iter */
 	unsigned int		max_nr_segs;	/* 0 or max number of segments in an iterator */
 	enum netfs_io_source	source;		/* Where to read from/write to */
+	unsigned char		stream_nr;	/* I/O stream this belongs to */
 	unsigned long		flags;
 #define NETFS_SREQ_COPY_TO_CACHE	0	/* Set if should copy the data to the cache */
 #define NETFS_SREQ_CLEAR_TAIL		1	/* Set if the rest of the read should be cleared */
@@ -224,15 +194,20 @@ struct netfs_io_subrequest {
 #define NETFS_SREQ_SEEK_DATA_READ	3	/* Set if ->read() should SEEK_DATA first */
 #define NETFS_SREQ_NO_PROGRESS		4	/* Set if we didn't manage to read any data */
 #define NETFS_SREQ_ONDEMAND		5	/* Set if it's from on-demand read mode */
+#define NETFS_SREQ_BOUNDARY		6	/* Set if ends on hard boundary (eg. ceph object) */
+#define NETFS_SREQ_IN_PROGRESS		8	/* Unlocked when the subrequest completes */
+#define NETFS_SREQ_NEED_RETRY		9	/* Set if the filesystem requests a retry */
+#define NETFS_SREQ_RETRYING		10	/* Set if we're retrying */
+#define NETFS_SREQ_FAILED		11	/* Set if the subreq failed unretryably */
 };
 
 enum netfs_io_origin {
 	NETFS_READAHEAD,		/* This read was triggered by readahead */
 	NETFS_READPAGE,			/* This read is a synchronous read */
 	NETFS_READ_FOR_WRITE,		/* This read is to prepare a write */
+	NETFS_COPY_TO_CACHE,		/* This write is to copy a read to the cache */
 	NETFS_WRITEBACK,		/* This write was triggered by writepages */
 	NETFS_WRITETHROUGH,		/* This write was made by netfs_perform_write() */
-	NETFS_LAUNDER_WRITE,		/* This is triggered by ->launder_folio() */
 	NETFS_UNBUFFERED_WRITE,		/* This is an unbuffered write */
 	NETFS_DIO_READ,			/* This is a direct I/O read */
 	NETFS_DIO_WRITE,		/* This is a direct I/O write */
@@ -254,26 +229,36 @@ struct netfs_io_request {
 	struct netfs_cache_resources cache_resources;
 	struct list_head	proc_link;	/* Link in netfs_iorequests */
 	struct list_head	subrequests;	/* Contributory I/O operations */
+	struct netfs_io_stream	io_streams[2];	/* Streams of parallel I/O operations */
+#define NR_IO_STREAMS 2 //wreq->nr_io_streams
+	struct netfs_group	*group;		/* Writeback group being written back */
 	struct iov_iter		iter;		/* Unencrypted-side iterator */
 	struct iov_iter		io_iter;	/* I/O (Encrypted-side) iterator */
 	void			*netfs_priv;	/* Private data for the netfs */
+	void			*netfs_priv2;	/* Private data for the netfs */
 	struct bio_vec		*direct_bv;	/* DIO buffer list (when handling iovec-iter) */
 	unsigned int		direct_bv_count; /* Number of elements in direct_bv[] */
 	unsigned int		debug_id;
 	unsigned int		rsize;		/* Maximum read size (0 for none) */
 	unsigned int		wsize;		/* Maximum write size (0 for none) */
-	unsigned int		subreq_counter;	/* Next subreq->debug_index */
+	atomic_t		subreq_counter;	/* Next subreq->debug_index */
+	unsigned int		nr_group_rel;	/* Number of refs to release on ->group */
+	spinlock_t		lock;		/* Lock for queuing subreqs */
 	atomic_t		nr_outstanding;	/* Number of ops in progress */
 	atomic_t		nr_copy_ops;	/* Number of copy-to-cache ops in progress */
-	size_t			submitted;	/* Amount submitted for I/O so far */
-	size_t			len;		/* Length of the request */
 	size_t			upper_len;	/* Length can be extended to here */
+	unsigned long long	submitted;	/* Amount submitted for I/O so far */
+	unsigned long long	len;		/* Length of the request */
 	size_t			transferred;	/* Amount to be indicated as transferred */
 	short			error;		/* 0 or error that occurred */
 	enum netfs_io_origin	origin;		/* Origin of the request */
 	bool			direct_bv_unpin; /* T if direct_bv[] must be unpinned */
-	loff_t			i_size;		/* Size of the file */
-	loff_t			start;		/* Start position */
+	unsigned long long	i_size;		/* Size of the file */
+	unsigned long long	start;		/* Start position */
+	atomic64_t		issued_to;	/* Write issuer folio cursor */
+	unsigned long long	contiguity;	/* Tracking for gaps in the writeback sequence */
+	unsigned long long	collected_to;	/* Point we've collected to */
+	unsigned long long	cleaned_to;	/* Position we've cleaned folios to */
 	pgoff_t			no_unlock_folio; /* Don't unlock this folio after read */
 	refcount_t		ref;
 	unsigned long		flags;
@@ -287,6 +272,11 @@ struct netfs_io_request {
 #define NETFS_RREQ_UPLOAD_TO_SERVER	8	/* Need to write to the server */
 #define NETFS_RREQ_NONBLOCK		9	/* Don't block if possible (O_NONBLOCK) */
 #define NETFS_RREQ_BLOCKED		10	/* We blocked */
+#define NETFS_RREQ_PAUSE		11	/* Pause subrequest generation */
+#define NETFS_RREQ_USE_IO_ITER		12	/* Use ->io_iter rather than ->i_pages */
+#define NETFS_RREQ_ALL_QUEUED		13	/* All subreqs are now queued */
+#define NETFS_RREQ_USE_PGPRIV2		31	/* [DEPRECATED] Use PG_private_2 to mark
+						 * write to cache on read */
 	const struct netfs_request_ops *netfs_ops;
 	void (*cleanup)(struct netfs_io_request *req);
 };
@@ -295,8 +285,8 @@ struct netfs_io_request {
  * Operations the network filesystem can/must provide to the helpers.
  */
 struct netfs_request_ops {
-	unsigned int	io_request_size;	/* Alloc size for netfs_io_request struct */
-	unsigned int	io_subrequest_size;	/* Alloc size for netfs_io_subrequest struct */
+	mempool_t *request_pool;
+	mempool_t *subrequest_pool;
 	int (*init_request)(struct netfs_io_request *rreq, struct file *file);
 	void (*free_request)(struct netfs_io_request *rreq);
 	void (*free_subrequest)(struct netfs_io_subrequest *rreq);
@@ -312,10 +302,13 @@ struct netfs_request_ops {
 
 	/* Modification handling */
 	void (*update_i_size)(struct inode *inode, loff_t i_size);
+	void (*post_modify)(struct inode *inode);
 
 	/* Write request handling */
-	void (*create_write_requests)(struct netfs_io_request *wreq,
-				      loff_t start, size_t len);
+	void (*begin_writeback)(struct netfs_io_request *wreq);
+	void (*prepare_write)(struct netfs_io_subrequest *subreq);
+	void (*issue_write)(struct netfs_io_subrequest *subreq);
+	void (*retry_request)(struct netfs_io_request *wreq, struct netfs_io_stream *stream);
 	void (*invalidate_cache)(struct netfs_io_request *wreq);
 };
 
@@ -350,15 +343,27 @@ struct netfs_cache_ops {
 		     netfs_io_terminated_t term_func,
 		     void *term_func_priv);
 
+	/* Write data to the cache from a netfs subrequest. */
+	void (*issue_write)(struct netfs_io_subrequest *subreq);
+
 	/* Expand readahead request */
 	void (*expand_readahead)(struct netfs_cache_resources *cres,
-				 loff_t *_start, size_t *_len, loff_t i_size);
+				 unsigned long long *_start,
+				 unsigned long long *_len,
+				 unsigned long long i_size);
 
 	/* Prepare a read operation, shortening it to a cached/uncached
 	 * boundary as appropriate.
 	 */
 	enum netfs_io_source (*prepare_read)(struct netfs_io_subrequest *subreq,
-					     loff_t i_size);
+					     unsigned long long i_size);
+
+	/* Prepare a write subrequest, working out if we're allowed to do it
+	 * and finding out the maximum amount of data to gather before
+	 * attempting to submit.  If we're not permitted to do it, the
+	 * subrequest should be marked failed.
+	 */
+	void (*prepare_write_subreq)(struct netfs_io_subrequest *subreq);
 
 	/* Prepare a write operation, working out what part of the write we can
 	 * actually do.
@@ -410,7 +415,6 @@ int netfs_unpin_writeback(struct inode *inode, struct writeback_control *wbc);
 void netfs_clear_inode_writeback(struct inode *inode, const void *aux);
 void netfs_invalidate_folio(struct folio *folio, size_t offset, size_t length);
 bool netfs_release_folio(struct folio *folio, gfp_t gfp);
-int netfs_launder_folio(struct folio *folio);
 
 /* VMA operations API. */
 vm_fault_t netfs_page_mkwrite(struct vm_fault *vmf, struct netfs_group *netfs_group);
@@ -426,9 +430,7 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,
 				iov_iter_extraction_t extraction_flags);
 size_t netfs_limit_iter(const struct iov_iter *iter, size_t start_offset,
 			size_t max_size, size_t max_segs);
-struct netfs_io_subrequest *netfs_create_write_request(
-	struct netfs_io_request *wreq, enum netfs_io_source dest,
-	loff_t start, size_t len, work_func_t worker);
+void netfs_prepare_write_failed(struct netfs_io_subrequest *subreq);
 void netfs_write_subrequest_terminated(void *_op, ssize_t transferred_or_error,
 				       bool was_async);
 void netfs_queue_write_request(struct netfs_io_subrequest *subreq);
@@ -472,6 +474,7 @@ static inline void netfs_inode_init(struct netfs_inode *ctx,
 #if IS_ENABLED(CONFIG_FSCACHE)
 	ctx->cache = NULL;
 #endif
+	mutex_init(&ctx->wb_lock);
 	/* ->releasepage() drives zero_point */
 	if (use_zero_point) {
 		ctx->zero_point = ctx->remote_i_size;
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 2df35e65557d..c5e33e2ca48a 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -40,6 +40,8 @@ int filemap_fdatawait_keep_errors(struct address_space *mapping);
 int filemap_fdatawait_range(struct address_space *, loff_t lstart, loff_t lend);
 int filemap_fdatawait_range_keep_errors(struct address_space *mapping,
 		loff_t start_byte, loff_t end_byte);
+int filemap_invalidate_inode(struct inode *inode, bool flush,
+			     loff_t start, loff_t end);
 
 static inline int filemap_fdatawait(struct address_space *mapping)
 {