X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=mm%2Fshmem.c;h=51b3d6ccddab75ba33b7fded5ffaf75700770ccd;hb=8f7b3d156d348b6766833cd4e272d0d19b501e64;hp=8a82342a8595019623c6ad2170cb9763de263b5e;hpb=92d15c2ccbb3e31a3fc71ad28fdb55e1319383c0;p=pandora-kernel.git

diff --git a/mm/shmem.c b/mm/shmem.c
index 8a82342a8595..51b3d6ccddab 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -915,6 +915,21 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
 	struct inode *inode;
 
 	BUG_ON(!PageLocked(page));
+	/*
+	 * shmem_backing_dev_info's capabilities prevent regular writeback or
+	 * sync from ever calling shmem_writepage; but a stacking filesystem
+	 * may use the ->writepage of its underlying filesystem, in which case
+	 * we want to do nothing when that underlying filesystem is tmpfs
+	 * (writing out to swap is useful as a response to memory pressure, but
+	 * of no use to stabilize the data) - just redirty the page, unlock it
+	 * and claim success in this case.  AOP_WRITEPAGE_ACTIVATE, and the
+	 * page_mapped check below, must be avoided unless we're in reclaim.
+	 */
+	if (!wbc->for_reclaim) {
+		set_page_dirty(page);
+		unlock_page(page);
+		return 0;
+	}
 	BUG_ON(page_mapped(page));
 
 	mapping = page->mapping;
@@ -1057,7 +1072,7 @@ shmem_alloc_page(gfp_t gfp, struct shmem_inode_info *info,
 	pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
 	pvma.vm_pgoff = idx;
 	pvma.vm_end = PAGE_SIZE;
-	page = alloc_page_vma(gfp | __GFP_ZERO, &pvma, 0);
+	page = alloc_page_vma(gfp, &pvma, 0);
 	mpol_free(pvma.vm_policy);
 	return page;
 }
@@ -1078,7 +1093,7 @@ shmem_swapin(struct shmem_inode_info *info,swp_entry_t entry,unsigned long idx)
 static inline struct page *
 shmem_alloc_page(gfp_t gfp,struct shmem_inode_info *info, unsigned long idx)
 {
-	return alloc_page(gfp | __GFP_ZERO);
+	return alloc_page(gfp);
 }
 #endif
 
@@ -1291,6 +1306,7 @@ repeat:
 
 		info->alloced++;
 		spin_unlock(&info->lock);
+		clear_highpage(filepage);
 		flush_dcache_page(filepage);
 		SetPageUptodate(filepage);
 	}
@@ -2020,33 +2036,25 @@ static int shmem_match(struct inode *ino, void *vfh)
 	return ino->i_ino == inum && fh[0] == ino->i_generation;
 }
 
-static struct dentry *shmem_get_dentry(struct super_block *sb, void *vfh)
+static struct dentry *shmem_fh_to_dentry(struct super_block *sb,
+		struct fid *fid, int fh_len, int fh_type)
 {
-	struct dentry *de = NULL;
 	struct inode *inode;
-	__u32 *fh = vfh;
-	__u64 inum = fh[2];
-	inum = (inum << 32) | fh[1];
+	struct dentry *dentry = NULL;
+	u64 inum = fid->raw[2];
+	inum = (inum << 32) | fid->raw[1];
 
-	inode = ilookup5(sb, (unsigned long)(inum+fh[0]), shmem_match, vfh);
+	if (fh_len < 3)
+		return NULL;
+
+	inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]),
+			shmem_match, fid->raw);
 	if (inode) {
-		de = d_find_alias(inode);
+		dentry = d_find_alias(inode);
 		iput(inode);
 	}
 
-	return de? de: ERR_PTR(-ESTALE);
-}
-
-static struct dentry *shmem_decode_fh(struct super_block *sb, __u32 *fh,
-		int len, int type,
-		int (*acceptable)(void *context, struct dentry *de),
-		void *context)
-{
-	if (len < 3)
-		return ERR_PTR(-ESTALE);
-
-	return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable,
-							context);
+	return dentry;
 }
 
 static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
@@ -2079,11 +2087,10 @@ static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
 	return 1;
 }
 
-static struct export_operations shmem_export_ops = {
+static const struct export_operations shmem_export_ops = {
 	.get_parent     = shmem_get_parent,
-	.get_dentry     = shmem_get_dentry,
 	.encode_fh      = shmem_encode_fh,
-	.decode_fh      = shmem_decode_fh,
+	.fh_to_dentry	= shmem_fh_to_dentry,
 };
 
 static int shmem_parse_options(char *options, int *mode, uid_t *uid,
@@ -2328,8 +2335,7 @@ static void shmem_destroy_inode(struct inode *inode)
 	kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
 }
 
-static void init_once(void *foo, struct kmem_cache *cachep,
-		      unsigned long flags)
+static void init_once(struct kmem_cache *cachep, void *foo)
 {
 	struct shmem_inode_info *p = (struct shmem_inode_info *) foo;
 
@@ -2344,9 +2350,7 @@ static int init_inodecache(void)
 {
 	shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
 				sizeof(struct shmem_inode_info),
-				0, 0, init_once);
-	if (shmem_inode_cachep == NULL)
-		return -ENOMEM;
+				0, SLAB_PANIC, init_once);
 	return 0;
 }
 
@@ -2464,6 +2468,10 @@ static int __init init_tmpfs(void)
 {
 	int error;
 
+	error = bdi_init(&shmem_backing_dev_info);
+	if (error)
+		goto out4;
+
 	error = init_inodecache();
 	if (error)
 		goto out3;
@@ -2488,6 +2496,8 @@ out1:
 out2:
 	destroy_inodecache();
 out3:
+	bdi_destroy(&shmem_backing_dev_info);
+out4:
 	shm_mnt = ERR_PTR(error);
 	return error;
 }
@@ -2540,11 +2550,8 @@ struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
 	d_instantiate(dentry, inode);
 	inode->i_size = size;
 	inode->i_nlink = 0;	/* It is unlinked */
-	file->f_path.mnt = mntget(shm_mnt);
-	file->f_path.dentry = dentry;
-	file->f_mapping = inode->i_mapping;
-	file->f_op = &shmem_file_operations;
-	file->f_mode = FMODE_WRITE | FMODE_READ;
+	init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
+			&shmem_file_operations);
 	return file;
 
 close_file: