]> asedeno.scripts.mit.edu Git - linux.git/commitdiff
afs: Get rid of the afs_writeback record
authorDavid Howells <dhowells@redhat.com>
Thu, 2 Nov 2017 15:27:52 +0000 (15:27 +0000)
committerDavid Howells <dhowells@redhat.com>
Mon, 13 Nov 2017 15:38:20 +0000 (15:38 +0000)
Get rid of the afs_writeback record that kAFS is using to match keys with
writes made by that key.

Instead, keep a list of keys that have a file open for writing and/or
sync'ing and iterate through those.

Signed-off-by: David Howells <dhowells@redhat.com>
fs/afs/file.c
fs/afs/fsclient.c
fs/afs/inode.c
fs/afs/internal.h
fs/afs/super.c
fs/afs/write.c
mm/filemap.c

index e33b34f0179523dadf97d92b559027693a341b75..c3a7bc1281f5d3ed0a9e1940262195f0ce9db4ce 100644 (file)
@@ -23,7 +23,6 @@ static int afs_readpage(struct file *file, struct page *page);
 static void afs_invalidatepage(struct page *page, unsigned int offset,
                               unsigned int length);
 static int afs_releasepage(struct page *page, gfp_t gfp_flags);
-static int afs_launder_page(struct page *page);
 
 static int afs_readpages(struct file *filp, struct address_space *mapping,
                         struct list_head *pages, unsigned nr_pages);
@@ -62,6 +61,50 @@ const struct address_space_operations afs_fs_aops = {
        .writepages     = afs_writepages,
 };
 
+/*
+ * Discard a pin on a writeback key.
+ */
+void afs_put_wb_key(struct afs_wb_key *wbk)
+{
+       if (refcount_dec_and_test(&wbk->usage)) {
+               key_put(wbk->key);
+               kfree(wbk);
+       }
+}
+
+/*
+ * Cache key for writeback.
+ */
+int afs_cache_wb_key(struct afs_vnode *vnode, struct afs_file *af)
+{
+       struct afs_wb_key *wbk, *p;
+
+       wbk = kzalloc(sizeof(struct afs_wb_key), GFP_KERNEL);
+       if (!wbk)
+               return -ENOMEM;
+       refcount_set(&wbk->usage, 2);
+       wbk->key = af->key;
+
+       spin_lock(&vnode->wb_lock);
+       list_for_each_entry(p, &vnode->wb_keys, vnode_link) {
+               if (p->key == wbk->key)
+                       goto found;
+       }
+
+       key_get(wbk->key);
+       list_add_tail(&wbk->vnode_link, &vnode->wb_keys);
+       spin_unlock(&vnode->wb_lock);
+       af->wb = wbk;
+       return 0;
+
+found:
+       refcount_inc(&p->usage);
+       spin_unlock(&vnode->wb_lock);
+       af->wb = p;
+       kfree(wbk);
+       return 0;
+}
+
 /*
  * open an AFS file or directory and attach a key to it
  */
@@ -85,12 +128,18 @@ int afs_open(struct inode *inode, struct file *file)
                ret = -ENOMEM;
                goto error_key;
        }
+       af->key = key;
 
        ret = afs_validate(vnode, key);
        if (ret < 0)
                goto error_af;
 
-       af->key = key;
+       if (file->f_mode & FMODE_WRITE) {
+               ret = afs_cache_wb_key(vnode, af);
+               if (ret < 0)
+                       goto error_af;
+       }
+       
        file->private_data = af;
        _leave(" = 0");
        return 0;
@@ -115,8 +164,11 @@ int afs_release(struct inode *inode, struct file *file)
        _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode);
 
        file->private_data = NULL;
+       if (af->wb)
+               afs_put_wb_key(af->wb);
        key_put(af->key);
        kfree(af);
+       afs_prune_wb_keys(vnode);
        _leave(" = 0");
        return 0;
 }
@@ -516,16 +568,6 @@ static int afs_readpages(struct file *file, struct address_space *mapping,
        return ret;
 }
 
-/*
- * write back a dirty page
- */
-static int afs_launder_page(struct page *page)
-{
-       _enter("{%lu}", page->index);
-
-       return 0;
-}
-
 /*
  * invalidate part or all of a page
  * - release a page and clean up its private data if offset is 0 (indicating
@@ -534,8 +576,6 @@ static int afs_launder_page(struct page *page)
 static void afs_invalidatepage(struct page *page, unsigned int offset,
                               unsigned int length)
 {
-       struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
-
        _enter("{%lu},%u,%u", page->index, offset, length);
 
        BUG_ON(!PageLocked(page));
@@ -551,13 +591,8 @@ static void afs_invalidatepage(struct page *page, unsigned int offset,
 #endif
 
                if (PagePrivate(page)) {
-                       if (wb && !PageWriteback(page)) {
-                               set_page_private(page, 0);
-                               afs_put_writeback(wb);
-                       }
-
-                       if (!page_private(page))
-                               ClearPagePrivate(page);
+                       set_page_private(page, 0);
+                       ClearPagePrivate(page);
                }
        }
 
@@ -570,7 +605,6 @@ static void afs_invalidatepage(struct page *page, unsigned int offset,
  */
 static int afs_releasepage(struct page *page, gfp_t gfp_flags)
 {
-       struct afs_writeback *wb = (struct afs_writeback *) page_private(page);
        struct afs_vnode *vnode = AFS_FS_I(page->mapping->host);
 
        _enter("{{%x:%u}[%lu],%lx},%x",
@@ -587,10 +621,7 @@ static int afs_releasepage(struct page *page, gfp_t gfp_flags)
 #endif
 
        if (PagePrivate(page)) {
-               if (wb) {
-                       set_page_private(page, 0);
-                       afs_put_writeback(wb);
-               }
+               set_page_private(page, 0);
                ClearPagePrivate(page);
        }
 
index 10e5ead629c25ee050c6a7af7b95cb0b77fe7e25..b90ef39ae914aa688580887a28d4aa433591da2c 100644 (file)
@@ -1119,18 +1119,18 @@ static const struct afs_call_type afs_RXFSStoreData64 = {
  * store a set of pages to a very large file
  */
 static int afs_fs_store_data64(struct afs_fs_cursor *fc,
-                              struct afs_writeback *wb,
+                              struct address_space *mapping,
                               pgoff_t first, pgoff_t last,
                               unsigned offset, unsigned to,
                               loff_t size, loff_t pos, loff_t i_size)
 {
-       struct afs_vnode *vnode = wb->vnode;
+       struct afs_vnode *vnode = fc->vnode;
        struct afs_call *call;
        struct afs_net *net = afs_v2net(vnode);
        __be32 *bp;
 
        _enter(",%x,{%x:%u},,",
-              key_serial(wb->key), vnode->fid.vid, vnode->fid.vnode);
+              key_serial(fc->key), vnode->fid.vid, vnode->fid.vnode);
 
        call = afs_alloc_flat_call(net, &afs_RXFSStoreData64,
                                   (4 + 6 + 3 * 2) * 4,
@@ -1138,10 +1138,9 @@ static int afs_fs_store_data64(struct afs_fs_cursor *fc,
        if (!call)
                return -ENOMEM;
 
-       call->wb = wb;
-       call->key = wb->key;
+       call->key = fc->key;
+       call->mapping = mapping;
        call->reply[0] = vnode;
-       call->mapping = vnode->vfs_inode.i_mapping;
        call->first = first;
        call->last = last;
        call->first_offset = offset;
@@ -1177,18 +1176,18 @@ static int afs_fs_store_data64(struct afs_fs_cursor *fc,
 /*
  * store a set of pages
  */
-int afs_fs_store_data(struct afs_fs_cursor *fc, struct afs_writeback *wb,
+int afs_fs_store_data(struct afs_fs_cursor *fc, struct address_space *mapping,
                      pgoff_t first, pgoff_t last,
                      unsigned offset, unsigned to)
 {
-       struct afs_vnode *vnode = wb->vnode;
+       struct afs_vnode *vnode = fc->vnode;
        struct afs_call *call;
        struct afs_net *net = afs_v2net(vnode);
        loff_t size, pos, i_size;
        __be32 *bp;
 
        _enter(",%x,{%x:%u},,",
-              key_serial(wb->key), vnode->fid.vid, vnode->fid.vnode);
+              key_serial(fc->key), vnode->fid.vid, vnode->fid.vnode);
 
        size = (loff_t)to - (loff_t)offset;
        if (first != last)
@@ -1205,7 +1204,7 @@ int afs_fs_store_data(struct afs_fs_cursor *fc, struct afs_writeback *wb,
               (unsigned long long) i_size);
 
        if (pos >> 32 || i_size >> 32 || size >> 32 || (pos + size) >> 32)
-               return afs_fs_store_data64(fc, wb, first, last, offset, to,
+               return afs_fs_store_data64(fc, mapping, first, last, offset, to,
                                           size, pos, i_size);
 
        call = afs_alloc_flat_call(net, &afs_RXFSStoreData,
@@ -1214,10 +1213,9 @@ int afs_fs_store_data(struct afs_fs_cursor *fc, struct afs_writeback *wb,
        if (!call)
                return -ENOMEM;
 
-       call->wb = wb;
-       call->key = wb->key;
+       call->key = fc->key;
+       call->mapping = mapping;
        call->reply[0] = vnode;
-       call->mapping = vnode->vfs_inode.i_mapping;
        call->first = first;
        call->last = last;
        call->first_offset = offset;
index da2ba7a68cac7163b5d5ca4a169cce008472f957..3415eb7484f6ba5653e3f08c8e3035ab29b2eaa3 100644 (file)
@@ -482,7 +482,12 @@ void afs_evict_inode(struct inode *inode)
                vnode->cb_interest = NULL;
        }
 
-       ASSERT(list_empty(&vnode->writebacks));
+       while (!list_empty(&vnode->wb_keys)) {
+               struct afs_wb_key *wbk = list_entry(vnode->wb_keys.next,
+                                                   struct afs_wb_key, vnode_link);
+               list_del(&wbk->vnode_link);
+               afs_put_wb_key(wbk);
+       }
 
 #ifdef CONFIG_AFS_FSCACHE
        fscache_relinquish_cookie(vnode->cache, 0);
@@ -514,10 +519,8 @@ int afs_setattr(struct dentry *dentry, struct iattr *attr)
        }
 
        /* flush any dirty data outstanding on a regular file */
-       if (S_ISREG(vnode->vfs_inode.i_mode)) {
+       if (S_ISREG(vnode->vfs_inode.i_mode))
                filemap_write_and_wait(vnode->vfs_inode.i_mapping);
-               afs_writeback_all(vnode);
-       }
 
        if (attr->ia_valid & ATTR_FILE) {
                key = afs_file_key(attr->ia_file);
index facf5b9844d27c580c1bc56e8dc3e1a6de16d73a..688562ae3bf826850cef231dbac39586af641cf1 100644 (file)
@@ -89,8 +89,7 @@ struct afs_call {
        struct afs_server       *cm_server;     /* Server affected by incoming CM call */
        struct afs_cb_interest  *cbi;           /* Callback interest for server used */
        void                    *request;       /* request data (first part) */
-       struct address_space    *mapping;       /* page set */
-       struct afs_writeback    *wb;            /* writeback being performed */
+       struct address_space    *mapping;       /* Pages being written from */
        void                    *buffer;        /* reply receive buffer */
        void                    *reply[4];      /* Where to put the reply */
        pgoff_t                 first;          /* first page in mapping to deal with */
@@ -138,11 +137,21 @@ struct afs_call_type {
        void (*work)(struct work_struct *work);
 };
 
+/*
+ * Key available for writeback on a file.
+ */
+struct afs_wb_key {
+       refcount_t              usage;
+       struct key              *key;
+       struct list_head        vnode_link;     /* Link in vnode->wb_keys */
+};
+
 /*
  * AFS open file information record.  Pointed to by file->private_data.
  */
 struct afs_file {
        struct key              *key;           /* The key this file was opened with */
+       struct afs_wb_key       *wb;            /* Writeback key record for this file */
 };
 
 static inline struct key *afs_file_key(struct file *file)
@@ -167,32 +176,6 @@ struct afs_read {
        struct page             *pages[];
 };
 
-/*
- * record of an outstanding writeback on a vnode
- */
-struct afs_writeback {
-       struct list_head        link;           /* link in vnode->writebacks */
-       struct work_struct      writer;         /* work item to perform the writeback */
-       struct afs_vnode        *vnode;         /* vnode to which this write applies */
-       struct key              *key;           /* owner of this write */
-       wait_queue_head_t       waitq;          /* completion and ready wait queue */
-       pgoff_t                 first;          /* first page in batch */
-       pgoff_t                 point;          /* last page in current store op */
-       pgoff_t                 last;           /* last page in batch (inclusive) */
-       unsigned                offset_first;   /* offset into first page of start of write */
-       unsigned                to_last;        /* offset into last page of end of write */
-       int                     num_conflicts;  /* count of conflicting writes in list */
-       int                     usage;
-       bool                    conflicts;      /* T if has dependent conflicts */
-       enum {
-               AFS_WBACK_SYNCING,              /* synchronisation being performed */
-               AFS_WBACK_PENDING,              /* write pending */
-               AFS_WBACK_CONFLICTING,          /* conflicting writes posted */
-               AFS_WBACK_WRITING,              /* writing back */
-               AFS_WBACK_COMPLETE              /* the writeback record has been unlinked */
-       } state __attribute__((packed));
-};
-
 /*
  * AFS superblock private data
  * - there's one superblock per volume
@@ -460,7 +443,7 @@ struct afs_vnode {
        struct afs_permits      *permit_cache;  /* cache of permits so far obtained */
        struct mutex            io_lock;        /* Lock for serialising I/O on this mutex */
        struct mutex            validate_lock;  /* lock for validating this vnode */
-       spinlock_t              writeback_lock; /* lock for writebacks */
+       spinlock_t              wb_lock;        /* lock for wb_keys */
        spinlock_t              lock;           /* waitqueue/flags lock */
        unsigned long           flags;
 #define AFS_VNODE_CB_PROMISED  0               /* Set if vnode has a callback promise */
@@ -476,7 +459,7 @@ struct afs_vnode {
 #define AFS_VNODE_AUTOCELL     10              /* set if Vnode is an auto mount point */
 #define AFS_VNODE_PSEUDODIR    11              /* set if Vnode is a pseudo directory */
 
-       struct list_head        writebacks;     /* alterations in pagecache that need writing */
+       struct list_head        wb_keys;        /* List of keys available for writeback */
        struct list_head        pending_locks;  /* locks waiting to be granted */
        struct list_head        granted_locks;  /* locks granted on this file */
        struct delayed_work     lock_work;      /* work to be done in locking */
@@ -648,6 +631,8 @@ extern const struct address_space_operations afs_fs_aops;
 extern const struct inode_operations afs_file_inode_operations;
 extern const struct file_operations afs_file_operations;
 
+extern int afs_cache_wb_key(struct afs_vnode *, struct afs_file *);
+extern void afs_put_wb_key(struct afs_wb_key *);
 extern int afs_open(struct inode *, struct file *);
 extern int afs_release(struct inode *, struct file *);
 extern int afs_fetch_data(struct afs_vnode *, struct key *, struct afs_read *);
@@ -678,7 +663,7 @@ extern int afs_fs_symlink(struct afs_fs_cursor *, const char *, const char *,
                          struct afs_fid *, struct afs_file_status *);
 extern int afs_fs_rename(struct afs_fs_cursor *, const char *,
                         struct afs_vnode *, const char *);
-extern int afs_fs_store_data(struct afs_fs_cursor *, struct afs_writeback *,
+extern int afs_fs_store_data(struct afs_fs_cursor *, struct address_space *,
                             pgoff_t, pgoff_t, unsigned, unsigned);
 extern int afs_fs_setattr(struct afs_fs_cursor *, struct iattr *);
 extern int afs_fs_get_volume_status(struct afs_fs_cursor *, struct afs_volume_status *);
@@ -889,7 +874,6 @@ extern int afs_check_volume_status(struct afs_volume *, struct key *);
  * write.c
  */
 extern int afs_set_page_dirty(struct page *);
-extern void afs_put_writeback(struct afs_writeback *);
 extern int afs_write_begin(struct file *file, struct address_space *mapping,
                        loff_t pos, unsigned len, unsigned flags,
                        struct page **pagep, void **fsdata);
@@ -900,9 +884,10 @@ extern int afs_writepage(struct page *, struct writeback_control *);
 extern int afs_writepages(struct address_space *, struct writeback_control *);
 extern void afs_pages_written_back(struct afs_vnode *, struct afs_call *);
 extern ssize_t afs_file_write(struct kiocb *, struct iov_iter *);
-extern int afs_writeback_all(struct afs_vnode *);
 extern int afs_flush(struct file *, fl_owner_t);
 extern int afs_fsync(struct file *, loff_t, loff_t, int);
+extern void afs_prune_wb_keys(struct afs_vnode *);
+extern int afs_launder_page(struct page *);
 
 /*
  * xattr.c
index af1e769aaebff3356e93262abcc3022718caeae1..875b5eb02242a0ae29b008b149770f4f6e1d3985 100644 (file)
@@ -546,9 +546,9 @@ static void afs_i_init_once(void *_vnode)
        inode_init_once(&vnode->vfs_inode);
        mutex_init(&vnode->io_lock);
        mutex_init(&vnode->validate_lock);
-       spin_lock_init(&vnode->writeback_lock);
+       spin_lock_init(&vnode->wb_lock);
        spin_lock_init(&vnode->lock);
-       INIT_LIST_HEAD(&vnode->writebacks);
+       INIT_LIST_HEAD(&vnode->wb_keys);
        INIT_LIST_HEAD(&vnode->pending_locks);
        INIT_LIST_HEAD(&vnode->granted_locks);
        INIT_DELAYED_WORK(&vnode->lock_work, afs_lock_work);
index 1cdd0e3cd531896d9f3470ce3686cc23fef7a197..4c131371005b93155b0330919640096ce24bc4a2 100644 (file)
@@ -8,6 +8,7 @@
  * as published by the Free Software Foundation; either version
  * 2 of the License, or (at your option) any later version.
  */
+
 #include <linux/backing-dev.h>
 #include <linux/slab.h>
 #include <linux/fs.h>
 #include <linux/pagevec.h>
 #include "internal.h"
 
-static int afs_write_back_from_locked_page(struct afs_writeback *wb,
-                                          struct page *page);
+/*
+ * We use page->private to hold the amount of the page that we've written to,
+ * splitting the field into two parts.  However, we need to represent a range
+ * 0...PAGE_SIZE inclusive, so we can't support 64K pages on a 32-bit system.
+ */
+#if PAGE_SIZE > 32768
+#define AFS_PRIV_MAX   0xffffffff
+#define AFS_PRIV_SHIFT 32
+#else
+#define AFS_PRIV_MAX   0xffff
+#define AFS_PRIV_SHIFT 16
+#endif
 
 /*
  * mark a page as having been made dirty and thus needing writeback
@@ -28,58 +39,6 @@ int afs_set_page_dirty(struct page *page)
        return __set_page_dirty_nobuffers(page);
 }
 
-/*
- * unlink a writeback record because its usage has reached zero
- * - must be called with the wb->vnode->writeback_lock held
- */
-static void afs_unlink_writeback(struct afs_writeback *wb)
-{
-       struct afs_writeback *front;
-       struct afs_vnode *vnode = wb->vnode;
-
-       list_del_init(&wb->link);
-       if (!list_empty(&vnode->writebacks)) {
-               /* if an fsync rises to the front of the queue then wake it
-                * up */
-               front = list_entry(vnode->writebacks.next,
-                                  struct afs_writeback, link);
-               if (front->state == AFS_WBACK_SYNCING) {
-                       _debug("wake up sync");
-                       front->state = AFS_WBACK_COMPLETE;
-                       wake_up(&front->waitq);
-               }
-       }
-}
-
-/*
- * free a writeback record
- */
-static void afs_free_writeback(struct afs_writeback *wb)
-{
-       _enter("");
-       key_put(wb->key);
-       kfree(wb);
-}
-
-/*
- * dispose of a reference to a writeback record
- */
-void afs_put_writeback(struct afs_writeback *wb)
-{
-       struct afs_vnode *vnode = wb->vnode;
-
-       _enter("{%d}", wb->usage);
-
-       spin_lock(&vnode->writeback_lock);
-       if (--wb->usage == 0)
-               afs_unlink_writeback(wb);
-       else
-               wb = NULL;
-       spin_unlock(&vnode->writeback_lock);
-       if (wb)
-               afs_free_writeback(wb);
-}
-
 /*
  * partly or wholly fill a page that's under preparation for writing
  */
@@ -125,42 +84,32 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
                    loff_t pos, unsigned len, unsigned flags,
                    struct page **pagep, void **fsdata)
 {
-       struct afs_writeback *candidate, *wb;
        struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
        struct page *page;
        struct key *key = afs_file_key(file);
-       unsigned from = pos & (PAGE_SIZE - 1);
-       unsigned to = from + len;
+       unsigned long priv;
+       unsigned f, from = pos & (PAGE_SIZE - 1);
+       unsigned t, to = from + len;
        pgoff_t index = pos >> PAGE_SHIFT;
        int ret;
 
        _enter("{%x:%u},{%lx},%u,%u",
               vnode->fid.vid, vnode->fid.vnode, index, from, to);
 
-       candidate = kzalloc(sizeof(*candidate), GFP_KERNEL);
-       if (!candidate)
-               return -ENOMEM;
-       candidate->vnode = vnode;
-       candidate->first = candidate->last = index;
-       candidate->offset_first = from;
-       candidate->to_last = to;
-       INIT_LIST_HEAD(&candidate->link);
-       candidate->usage = 1;
-       candidate->state = AFS_WBACK_PENDING;
-       init_waitqueue_head(&candidate->waitq);
+       /* We want to store information about how much of a page is altered in
+        * page->private.
+        */
+       BUILD_BUG_ON(PAGE_SIZE > 32768 && sizeof(page->private) < 8);
 
        page = grab_cache_page_write_begin(mapping, index, flags);
-       if (!page) {
-               kfree(candidate);
+       if (!page)
                return -ENOMEM;
-       }
 
        if (!PageUptodate(page) && len != PAGE_SIZE) {
                ret = afs_fill_page(vnode, key, pos & PAGE_MASK, PAGE_SIZE, page);
                if (ret < 0) {
                        unlock_page(page);
                        put_page(page);
-                       kfree(candidate);
                        _leave(" = %d [prep]", ret);
                        return ret;
                }
@@ -171,79 +120,52 @@ int afs_write_begin(struct file *file, struct address_space *mapping,
        *pagep = page;
 
 try_again:
-       spin_lock(&vnode->writeback_lock);
-
-       /* see if this page is already pending a writeback under a suitable key
-        * - if so we can just join onto that one */
-       wb = (struct afs_writeback *) page_private(page);
-       if (wb) {
-               if (wb->key == key && wb->state == AFS_WBACK_PENDING)
-                       goto subsume_in_current_wb;
-               goto flush_conflicting_wb;
+       /* See if this page is already partially written in a way that we can
+        * merge the new write with.
+        */
+       t = f = 0;
+       if (PagePrivate(page)) {
+               priv = page_private(page);
+               f = priv & AFS_PRIV_MAX;
+               t = priv >> AFS_PRIV_SHIFT;
+               ASSERTCMP(f, <=, t);
        }
 
-       if (index > 0) {
-               /* see if we can find an already pending writeback that we can
-                * append this page to */
-               list_for_each_entry(wb, &vnode->writebacks, link) {
-                       if (wb->last == index - 1 && wb->key == key &&
-                           wb->state == AFS_WBACK_PENDING)
-                               goto append_to_previous_wb;
-               }
+       if (f != t) {
+               if (to < f || from > t)
+                       goto flush_conflicting_write;
+               if (from < f)
+                       f = from;
+               if (to > t)
+                       t = to;
+       } else {
+               f = from;
+               t = to;
        }
 
-       list_add_tail(&candidate->link, &vnode->writebacks);
-       candidate->key = key_get(key);
-       spin_unlock(&vnode->writeback_lock);
+       priv = (unsigned long)t << AFS_PRIV_SHIFT;
+       priv |= f;
        SetPagePrivate(page);
-       set_page_private(page, (unsigned long) candidate);
-       _leave(" = 0 [new]");
-       return 0;
-
-subsume_in_current_wb:
-       _debug("subsume");
-       ASSERTRANGE(wb->first, <=, index, <=, wb->last);
-       if (index == wb->first && from < wb->offset_first)
-               wb->offset_first = from;
-       if (index == wb->last && to > wb->to_last)
-               wb->to_last = to;
-       spin_unlock(&vnode->writeback_lock);
-       kfree(candidate);
-       _leave(" = 0 [sub]");
-       return 0;
-
-append_to_previous_wb:
-       _debug("append into %lx-%lx", wb->first, wb->last);
-       wb->usage++;
-       wb->last++;
-       wb->to_last = to;
-       spin_unlock(&vnode->writeback_lock);
-       SetPagePrivate(page);
-       set_page_private(page, (unsigned long) wb);
-       kfree(candidate);
-       _leave(" = 0 [app]");
+       set_page_private(page, priv);
+       _leave(" = 0");
        return 0;
 
-       /* the page is currently bound to another context, so if it's dirty we
-        * need to flush it before we can use the new context */
-flush_conflicting_wb:
+       /* The previous write and this write aren't adjacent or overlapping, so
+        * flush the page out.
+        */
+flush_conflicting_write:
        _debug("flush conflict");
-       if (wb->state == AFS_WBACK_PENDING)
-               wb->state = AFS_WBACK_CONFLICTING;
-       spin_unlock(&vnode->writeback_lock);
-       if (clear_page_dirty_for_io(page)) {
-               ret = afs_write_back_from_locked_page(wb, page);
-               if (ret < 0) {
-                       afs_put_writeback(candidate);
-                       _leave(" = %d", ret);
-                       return ret;
-               }
+       ret = write_one_page(page);
+       if (ret < 0) {
+               _leave(" = %d", ret);
+               return ret;
        }
 
-       /* the page holds a ref on the writeback record */
-       afs_put_writeback(wb);
-       set_page_private(page, 0);
-       ClearPagePrivate(page);
+       ret = lock_page_killable(page);
+       if (ret < 0) {
+               _leave(" = %d", ret);
+               return ret;
+       }
        goto try_again;
 }
 
@@ -266,11 +188,11 @@ int afs_write_end(struct file *file, struct address_space *mapping,
 
        i_size = i_size_read(&vnode->vfs_inode);
        if (maybe_i_size > i_size) {
-               spin_lock(&vnode->writeback_lock);
+               spin_lock(&vnode->wb_lock);
                i_size = i_size_read(&vnode->vfs_inode);
                if (maybe_i_size > i_size)
                        i_size_write(&vnode->vfs_inode, maybe_i_size);
-               spin_unlock(&vnode->writeback_lock);
+               spin_unlock(&vnode->wb_lock);
        }
 
        if (!PageUptodate(page)) {
@@ -299,9 +221,10 @@ int afs_write_end(struct file *file, struct address_space *mapping,
 /*
  * kill all the pages in the given range
  */
-static void afs_kill_pages(struct afs_vnode *vnode, bool error,
+static void afs_kill_pages(struct address_space *mapping,
                           pgoff_t first, pgoff_t last)
 {
+       struct afs_vnode *vnode = AFS_FS_I(mapping->host);
        struct pagevec pv;
        unsigned count, loop;
 
@@ -316,23 +239,62 @@ static void afs_kill_pages(struct afs_vnode *vnode, bool error,
                count = last - first + 1;
                if (count > PAGEVEC_SIZE)
                        count = PAGEVEC_SIZE;
-               pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping,
-                                             first, count, pv.pages);
+               pv.nr = find_get_pages_contig(mapping, first, count, pv.pages);
                ASSERTCMP(pv.nr, ==, count);
 
                for (loop = 0; loop < count; loop++) {
                        struct page *page = pv.pages[loop];
                        ClearPageUptodate(page);
-                       if (error)
-                               SetPageError(page);
-                       if (PageWriteback(page))
-                               end_page_writeback(page);
+                       SetPageError(page);
+                       end_page_writeback(page);
                        if (page->index >= first)
                                first = page->index + 1;
+                       lock_page(page);
+                       generic_error_remove_page(mapping, page);
                }
 
                __pagevec_release(&pv);
-       } while (first < last);
+       } while (first <= last);
+
+       _leave("");
+}
+
+/*
+ * Redirty all the pages in a given range.
+ */
+static void afs_redirty_pages(struct writeback_control *wbc,
+                             struct address_space *mapping,
+                             pgoff_t first, pgoff_t last)
+{
+       struct afs_vnode *vnode = AFS_FS_I(mapping->host);
+       struct pagevec pv;
+       unsigned count, loop;
+
+       _enter("{%x:%u},%lx-%lx",
+              vnode->fid.vid, vnode->fid.vnode, first, last);
+
+       pagevec_init(&pv, 0);
+
+       do {
+               _debug("redirty %lx-%lx", first, last);
+
+               count = last - first + 1;
+               if (count > PAGEVEC_SIZE)
+                       count = PAGEVEC_SIZE;
+               pv.nr = find_get_pages_contig(mapping, first, count, pv.pages);
+               ASSERTCMP(pv.nr, ==, count);
+
+               for (loop = 0; loop < count; loop++) {
+                       struct page *page = pv.pages[loop];
+
+                       redirty_page_for_writepage(wbc, page);
+                       end_page_writeback(page);
+                       if (page->index >= first)
+                               first = page->index + 1;
+               }
+
+               __pagevec_release(&pv);
+       } while (first <= last);
 
        _leave("");
 }
@@ -340,26 +302,55 @@ static void afs_kill_pages(struct afs_vnode *vnode, bool error,
 /*
  * write to a file
  */
-static int afs_store_data(struct afs_writeback *wb, pgoff_t first, pgoff_t last,
+static int afs_store_data(struct address_space *mapping,
+                         pgoff_t first, pgoff_t last,
                          unsigned offset, unsigned to)
 {
+       struct afs_vnode *vnode = AFS_FS_I(mapping->host);
        struct afs_fs_cursor fc;
-       struct afs_vnode *vnode = wb->vnode;
-       int ret;
+       struct afs_wb_key *wbk = NULL;
+       struct list_head *p;
+       int ret = -ENOKEY, ret2;
 
-       _enter("%s{%x:%u.%u},%x,%lx,%lx,%x,%x",
+       _enter("%s{%x:%u.%u},%lx,%lx,%x,%x",
               vnode->volume->name,
               vnode->fid.vid,
               vnode->fid.vnode,
               vnode->fid.unique,
-              key_serial(wb->key),
               first, last, offset, to);
 
+       spin_lock(&vnode->wb_lock);
+       p = vnode->wb_keys.next;
+
+       /* Iterate through the list looking for a valid key to use. */
+try_next_key:
+       while (p != &vnode->wb_keys) {
+               wbk = list_entry(p, struct afs_wb_key, vnode_link);
+               _debug("wbk %u", key_serial(wbk->key));
+               ret2 = key_validate(wbk->key);
+               if (ret2 == 0)
+                       goto found_key;
+               if (ret == -ENOKEY)
+                       ret = ret2;
+               p = p->next;
+       }
+
+       spin_unlock(&vnode->wb_lock);
+       afs_put_wb_key(wbk);
+       _leave(" = %d [no keys]", ret);
+       return ret;
+
+found_key:
+       refcount_inc(&wbk->usage);
+       spin_unlock(&vnode->wb_lock);
+
+       _debug("USE WB KEY %u", key_serial(wbk->key));
+
        ret = -ERESTARTSYS;
-       if (afs_begin_vnode_operation(&fc, vnode, wb->key)) {
+       if (afs_begin_vnode_operation(&fc, vnode, wbk->key)) {
                while (afs_select_fileserver(&fc)) {
                        fc.cb_break = vnode->cb_break + vnode->cb_s_break;
-                       afs_fs_store_data(&fc, wb, first, last, offset, to);
+                       afs_fs_store_data(&fc, mapping, first, last, offset, to);
                }
 
                afs_check_for_remote_deletion(&fc, fc.vnode);
@@ -367,20 +358,37 @@ static int afs_store_data(struct afs_writeback *wb, pgoff_t first, pgoff_t last,
                ret = afs_end_vnode_operation(&fc);
        }
 
+       switch (ret) {
+       case -EACCES:
+       case -EPERM:
+       case -ENOKEY:
+       case -EKEYEXPIRED:
+       case -EKEYREJECTED:
+       case -EKEYREVOKED:
+               _debug("next");
+               spin_lock(&vnode->wb_lock);
+               p = wbk->vnode_link.next;
+               afs_put_wb_key(wbk);
+               goto try_next_key;
+       }
+
+       afs_put_wb_key(wbk);
        _leave(" = %d", ret);
        return ret;
 }
 
 /*
- * synchronously write back the locked page and any subsequent non-locked dirty
- * pages also covered by the same writeback record
+ * Synchronously write back the locked page and any subsequent non-locked dirty
+ * pages.
  */
-static int afs_write_back_from_locked_page(struct afs_writeback *wb,
-                                          struct page *primary_page)
+static int afs_write_back_from_locked_page(struct address_space *mapping,
+                                          struct writeback_control *wbc,
+                                          struct page *primary_page,
+                                          pgoff_t final_page)
 {
        struct page *pages[8], *page;
-       unsigned long count;
-       unsigned n, offset, to;
+       unsigned long count, priv;
+       unsigned n, offset, to, f, t;
        pgoff_t start, first, last;
        int loop, ret;
 
@@ -390,20 +398,28 @@ static int afs_write_back_from_locked_page(struct afs_writeback *wb,
        if (test_set_page_writeback(primary_page))
                BUG();
 
-       /* find all consecutive lockable dirty pages, stopping when we find a
-        * page that is not immediately lockable, is not dirty or is missing,
-        * or we reach the end of the range */
+       /* Find all consecutive lockable dirty pages that have contiguous
+        * written regions, stopping when we find a page that is not
+        * immediately lockable, is not dirty or is missing, or we reach the
+        * end of the range.
+        */
        start = primary_page->index;
-       if (start >= wb->last)
+       priv = page_private(primary_page);
+       offset = priv & AFS_PRIV_MAX;
+       to = priv >> AFS_PRIV_SHIFT;
+
+       WARN_ON(offset == to);
+
+       if (start >= final_page || to < PAGE_SIZE)
                goto no_more;
+
        start++;
        do {
                _debug("more %lx [%lx]", start, count);
-               n = wb->last - start + 1;
+               n = final_page - start + 1;
                if (n > ARRAY_SIZE(pages))
                        n = ARRAY_SIZE(pages);
-               n = find_get_pages_contig(wb->vnode->vfs_inode.i_mapping,
-                                         start, n, pages);
+               n = find_get_pages_contig(mapping, start, ARRAY_SIZE(pages), pages);
                _debug("fgpc %u", n);
                if (n == 0)
                        goto no_more;
@@ -415,16 +431,27 @@ static int afs_write_back_from_locked_page(struct afs_writeback *wb,
                }
 
                for (loop = 0; loop < n; loop++) {
+                       if (to != PAGE_SIZE)
+                               break;
                        page = pages[loop];
-                       if (page->index > wb->last)
+                       if (page->index > final_page)
                                break;
                        if (!trylock_page(page))
                                break;
-                       if (!PageDirty(page) ||
-                           page_private(page) != (unsigned long) wb) {
+                       if (!PageDirty(page) || PageWriteback(page)) {
+                               unlock_page(page);
+                               break;
+                       }
+
+                       priv = page_private(page);
+                       f = priv & AFS_PRIV_MAX;
+                       t = priv >> AFS_PRIV_SHIFT;
+                       if (f != 0) {
                                unlock_page(page);
                                break;
                        }
+                       to = t;
+
                        if (!clear_page_dirty_for_io(page))
                                BUG();
                        if (test_set_page_writeback(page))
@@ -440,50 +467,55 @@ static int afs_write_back_from_locked_page(struct afs_writeback *wb,
                }
 
                start += loop;
-       } while (start <= wb->last && count < 65536);
+       } while (start <= final_page && count < 65536);
 
 no_more:
-       /* we now have a contiguous set of dirty pages, each with writeback set
-        * and the dirty mark cleared; the first page is locked and must remain
-        * so, all the rest are unlocked */
+       /* We now have a contiguous set of dirty pages, each with writeback
+        * set; the first page is still locked at this point, but all the rest
+        * have been unlocked.
+        */
+       unlock_page(primary_page);
+
        first = primary_page->index;
        last = first + count - 1;
 
-       offset = (first == wb->first) ? wb->offset_first : 0;
-       to = (last == wb->last) ? wb->to_last : PAGE_SIZE;
-
        _debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to);
 
-       ret = afs_store_data(wb, first, last, offset, to);
-       if (ret < 0) {
-               switch (ret) {
-               case -EDQUOT:
-               case -ENOSPC:
-                       mapping_set_error(wb->vnode->vfs_inode.i_mapping, -ENOSPC);
-                       break;
-               case -EROFS:
-               case -EIO:
-               case -EREMOTEIO:
-               case -EFBIG:
-               case -ENOENT:
-               case -ENOMEDIUM:
-               case -ENXIO:
-                       afs_kill_pages(wb->vnode, true, first, last);
-                       mapping_set_error(wb->vnode->vfs_inode.i_mapping, -EIO);
-                       break;
-               case -EACCES:
-               case -EPERM:
-               case -ENOKEY:
-               case -EKEYEXPIRED:
-               case -EKEYREJECTED:
-               case -EKEYREVOKED:
-                       afs_kill_pages(wb->vnode, false, first, last);
-                       break;
-               default:
-                       break;
-               }
-       } else {
+       ret = afs_store_data(mapping, first, last, offset, to);
+       switch (ret) {
+       case 0:
                ret = count;
+               break;
+
+       default:
+               pr_notice("kAFS: Unexpected error from FS.StoreData %d\n", ret);
+               /* Fall through */
+       case -EACCES:
+       case -EPERM:
+       case -ENOKEY:
+       case -EKEYEXPIRED:
+       case -EKEYREJECTED:
+       case -EKEYREVOKED:
+               afs_redirty_pages(wbc, mapping, first, last);
+               mapping_set_error(mapping, ret);
+               break;
+
+       case -EDQUOT:
+       case -ENOSPC:
+               afs_redirty_pages(wbc, mapping, first, last);
+               mapping_set_error(mapping, -ENOSPC);
+               break;
+
+       case -EROFS:
+       case -EIO:
+       case -EREMOTEIO:
+       case -EFBIG:
+       case -ENOENT:
+       case -ENOMEDIUM:
+       case -ENXIO:
+               afs_kill_pages(mapping, first, last);
+               mapping_set_error(mapping, ret);
+               break;
        }
 
        _leave(" = %d", ret);
@@ -496,16 +528,12 @@ static int afs_write_back_from_locked_page(struct afs_writeback *wb,
  */
 int afs_writepage(struct page *page, struct writeback_control *wbc)
 {
-       struct afs_writeback *wb;
        int ret;
 
        _enter("{%lx},", page->index);
 
-       wb = (struct afs_writeback *) page_private(page);
-       ASSERT(wb != NULL);
-
-       ret = afs_write_back_from_locked_page(wb, page);
-       unlock_page(page);
+       ret = afs_write_back_from_locked_page(page->mapping, wbc, page,
+                                             wbc->range_end >> PAGE_SHIFT);
        if (ret < 0) {
                _leave(" = %d", ret);
                return 0;
@@ -524,7 +552,6 @@ static int afs_writepages_region(struct address_space *mapping,
                                 struct writeback_control *wbc,
                                 pgoff_t index, pgoff_t end, pgoff_t *_next)
 {
-       struct afs_writeback *wb;
        struct page *page;
        int ret, n;
 
@@ -550,7 +577,12 @@ static int afs_writepages_region(struct address_space *mapping,
                 * (changing page->mapping to NULL), or even swizzled back from
                 * swapper_space to tmpfs file mapping
                 */
-               lock_page(page);
+               ret = lock_page_killable(page);
+               if (ret < 0) {
+                       put_page(page);
+                       _leave(" = %d", ret);
+                       return ret;
+               }
 
                if (page->mapping != mapping || !PageDirty(page)) {
                        unlock_page(page);
@@ -566,17 +598,9 @@ static int afs_writepages_region(struct address_space *mapping,
                        continue;
                }
 
-               wb = (struct afs_writeback *) page_private(page);
-               ASSERT(wb != NULL);
-
-               spin_lock(&wb->vnode->writeback_lock);
-               wb->state = AFS_WBACK_WRITING;
-               spin_unlock(&wb->vnode->writeback_lock);
-
                if (!clear_page_dirty_for_io(page))
                        BUG();
-               ret = afs_write_back_from_locked_page(wb, page);
-               unlock_page(page);
+               ret = afs_write_back_from_locked_page(mapping, wbc, page, end);
                put_page(page);
                if (ret < 0) {
                        _leave(" = %d", ret);
@@ -632,17 +656,13 @@ int afs_writepages(struct address_space *mapping,
  */
 void afs_pages_written_back(struct afs_vnode *vnode, struct afs_call *call)
 {
-       struct afs_writeback *wb = call->wb;
        struct pagevec pv;
        unsigned count, loop;
        pgoff_t first = call->first, last = call->last;
-       bool free_wb;
 
        _enter("{%x:%u},{%lx-%lx}",
               vnode->fid.vid, vnode->fid.vnode, first, last);
 
-       ASSERT(wb != NULL);
-
        pagevec_init(&pv, 0);
 
        do {
@@ -651,35 +671,19 @@ void afs_pages_written_back(struct afs_vnode *vnode, struct afs_call *call)
                count = last - first + 1;
                if (count > PAGEVEC_SIZE)
                        count = PAGEVEC_SIZE;
-               pv.nr = find_get_pages_contig(call->mapping, first, count,
-                                             pv.pages);
+               pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping,
+                                             first, count, pv.pages);
                ASSERTCMP(pv.nr, ==, count);
 
-               spin_lock(&vnode->writeback_lock);
                for (loop = 0; loop < count; loop++) {
-                       struct page *page = pv.pages[loop];
-                       end_page_writeback(page);
-                       if (page_private(page) == (unsigned long) wb) {
-                               set_page_private(page, 0);
-                               ClearPagePrivate(page);
-                               wb->usage--;
-                       }
+                       set_page_private(pv.pages[loop], 0);
+                       end_page_writeback(pv.pages[loop]);
                }
-               free_wb = false;
-               if (wb->usage == 0) {
-                       afs_unlink_writeback(wb);
-                       free_wb = true;
-               }
-               spin_unlock(&vnode->writeback_lock);
                first += count;
-               if (free_wb) {
-                       afs_free_writeback(wb);
-                       wb = NULL;
-               }
-
                __pagevec_release(&pv);
        } while (first <= last);
 
+       afs_prune_wb_keys(vnode);
        _leave("");
 }
 
@@ -710,28 +714,6 @@ ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from)
        return result;
 }
 
-/*
- * flush the vnode to the fileserver
- */
-int afs_writeback_all(struct afs_vnode *vnode)
-{
-       struct address_space *mapping = vnode->vfs_inode.i_mapping;
-       struct writeback_control wbc = {
-               .sync_mode      = WB_SYNC_ALL,
-               .nr_to_write    = LONG_MAX,
-               .range_cyclic   = 1,
-       };
-       int ret;
-
-       _enter("");
-
-       ret = mapping->a_ops->writepages(mapping, &wbc);
-       __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
-
-       _leave(" = %d", ret);
-       return ret;
-}
-
 /*
  * flush any dirty pages for this process, and check for write errors.
  * - the return status from this call provides a reliable indication of
@@ -740,61 +722,13 @@ int afs_writeback_all(struct afs_vnode *vnode)
 int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 {
        struct inode *inode = file_inode(file);
-       struct afs_writeback *wb, *xwb;
        struct afs_vnode *vnode = AFS_FS_I(inode);
-       int ret;
 
        _enter("{%x:%u},{n=%pD},%d",
               vnode->fid.vid, vnode->fid.vnode, file,
               datasync);
 
-       ret = file_write_and_wait_range(file, start, end);
-       if (ret)
-               return ret;
-       inode_lock(inode);
-
-       /* use a writeback record as a marker in the queue - when this reaches
-        * the front of the queue, all the outstanding writes are either
-        * completed or rejected */
-       wb = kzalloc(sizeof(*wb), GFP_KERNEL);
-       if (!wb) {
-               ret = -ENOMEM;
-               goto out;
-       }
-       wb->vnode = vnode;
-       wb->first = 0;
-       wb->last = -1;
-       wb->offset_first = 0;
-       wb->to_last = PAGE_SIZE;
-       wb->usage = 1;
-       wb->state = AFS_WBACK_SYNCING;
-       init_waitqueue_head(&wb->waitq);
-
-       spin_lock(&vnode->writeback_lock);
-       list_for_each_entry(xwb, &vnode->writebacks, link) {
-               if (xwb->state == AFS_WBACK_PENDING)
-                       xwb->state = AFS_WBACK_CONFLICTING;
-       }
-       list_add_tail(&wb->link, &vnode->writebacks);
-       spin_unlock(&vnode->writeback_lock);
-
-       /* push all the outstanding writebacks to the server */
-       ret = afs_writeback_all(vnode);
-       if (ret < 0) {
-               afs_put_writeback(wb);
-               _leave(" = %d [wb]", ret);
-               goto out;
-       }
-
-       /* wait for the preceding writes to actually complete */
-       ret = wait_event_interruptible(wb->waitq,
-                                      wb->state == AFS_WBACK_COMPLETE ||
-                                      vnode->writebacks.next == &wb->link);
-       afs_put_writeback(wb);
-       _leave(" = %d", ret);
-out:
-       inode_unlock(inode);
-       return ret;
+       return file_write_and_wait_range(file, start, end);
 }
 
 /*
@@ -831,3 +765,68 @@ int afs_page_mkwrite(struct vm_area_struct *vma, struct page *page)
        _leave(" = 0");
        return 0;
 }
+
+/*
+ * Prune the keys cached for writeback.  The caller must hold vnode->wb_lock.
+ */
+void afs_prune_wb_keys(struct afs_vnode *vnode)
+{
+       LIST_HEAD(graveyard);
+       struct afs_wb_key *wbk, *tmp;
+
+       /* Discard unused keys */
+       spin_lock(&vnode->wb_lock);
+
+       if (!mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_WRITEBACK) &&
+           !mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_DIRTY)) {
+               list_for_each_entry_safe(wbk, tmp, &vnode->wb_keys, vnode_link) {
+                       if (refcount_read(&wbk->usage) == 1)
+                               list_move(&wbk->vnode_link, &graveyard);
+               }
+       }
+
+       spin_unlock(&vnode->wb_lock);
+
+       while (!list_empty(&graveyard)) {
+               wbk = list_entry(graveyard.next, struct afs_wb_key, vnode_link);
+               list_del(&wbk->vnode_link);
+               afs_put_wb_key(wbk);
+       }
+}
+
+/*
+ * Clean up a page during invalidation.
+ */
+int afs_launder_page(struct page *page)
+{
+       struct address_space *mapping = page->mapping;
+       struct afs_vnode *vnode = AFS_FS_I(mapping->host);
+       unsigned long priv;
+       unsigned int f, t;
+       int ret = 0;
+
+       _enter("{%lx}", page->index);
+
+       priv = page_private(page);
+       if (clear_page_dirty_for_io(page)) {
+               f = 0;
+               t = PAGE_SIZE;
+               if (PagePrivate(page)) {
+                       f = priv & AFS_PRIV_MAX;
+                       t = priv >> AFS_PRIV_SHIFT;
+               }
+
+               ret = afs_store_data(mapping, page->index, page->index, t, f);
+       }
+
+       set_page_private(page, 0);
+       ClearPagePrivate(page);
+
+#ifdef CONFIG_AFS_FSCACHE
+       if (PageFsCache(page)) {
+               fscache_wait_on_page_write(vnode->cache, page);
+               fscache_uncache_page(vnode->cache, page);
+       }
+#endif
+       return ret;
+}
index 594d73fef8b43bae852f4f7ace1e8cfc46b23690..5bcc87adbeeb6020cbba0fc0b7f5dee03bce7224 100644 (file)
@@ -1041,6 +1041,7 @@ int wait_on_page_bit_killable(struct page *page, int bit_nr)
        wait_queue_head_t *q = page_waitqueue(page);
        return wait_on_page_bit_common(q, page, bit_nr, TASK_KILLABLE, false);
 }
+EXPORT_SYMBOL(wait_on_page_bit_killable);
 
 /**
  * add_page_wait_queue - Add an arbitrary waiter to a page's wait queue