1 files changed, 78 insertions, 55 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index f65f840..dfaa0f4 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -28,6 +28,7 @@
 #include <linux/file.h>
 #include <linux/mm.h>
 #include <linux/module.h>
+#include <linux/percpu_counter.h>
 #include <linux/swap.h>
 
 static struct vfsmount *shm_mnt;
@@ -233,10 +234,10 @@ static void shmem_free_blocks(struct inode *inode, long pages)
 {
 	struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
 	if (sbinfo->max_blocks) {
-		spin_lock(&sbinfo->stat_lock);
-		sbinfo->free_blocks += pages;
+		percpu_counter_add(&sbinfo->used_blocks, -pages);
+		spin_lock(&inode->i_lock);
 		inode->i_blocks -= pages*BLOCKS_PER_PAGE;
-		spin_unlock(&sbinfo->stat_lock);
+		spin_unlock(&inode->i_lock);
 	}
 }
 
@@ -416,19 +417,17 @@ static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long
 		if (sgp == SGP_READ)
 			return shmem_swp_map(ZERO_PAGE(0));
 		/*
-		 * Test free_blocks against 1 not 0, since we have 1 data
+		 * Test used_blocks against 1 less max_blocks, since we have 1 data
 		 * page (and perhaps indirect index pages) yet to allocate:
 		 * a waste to allocate index if we cannot allocate data.
 		 */
 		if (sbinfo->max_blocks) {
-			spin_lock(&sbinfo->stat_lock);
-			if (sbinfo->free_blocks <= 1) {
-				spin_unlock(&sbinfo->stat_lock);
+			if (percpu_counter_compare(&sbinfo->used_blocks, (sbinfo->max_blocks - 1)) > 0)
 				return ERR_PTR(-ENOSPC);
-			}
-			sbinfo->free_blocks--;
+			percpu_counter_inc(&sbinfo->used_blocks);
+			spin_lock(&inode->i_lock);
 			inode->i_blocks += BLOCKS_PER_PAGE;
-			spin_unlock(&sbinfo->stat_lock);
+			spin_unlock(&inode->i_lock);
 		}
 
 		spin_unlock(&info->lock);
@@ -767,6 +766,10 @@ static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
 	loff_t newsize = attr->ia_size;
 	int error;
 
+	error = inode_change_ok(inode, attr);
+	if (error)
+		return error;
+
 	if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)
 					&& newsize != inode->i_size) {
 		struct page *page = NULL;
@@ -801,25 +804,22 @@ static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
 			}
 		}
 
-		error = simple_setsize(inode, newsize);
+		/* XXX(truncate): truncate_setsize should be called last */
+		truncate_setsize(inode, newsize);
 		if (page)
 			page_cache_release(page);
-		if (error)
-			return error;
 		shmem_truncate_range(inode, newsize, (loff_t)-1);
 	}
 
-	error = inode_change_ok(inode, attr);
-	if (!error)
-		generic_setattr(inode, attr);
+	setattr_copy(inode, attr);
 #ifdef CONFIG_TMPFS_POSIX_ACL
-	if (!error && (attr->ia_valid & ATTR_MODE))
+	if (attr->ia_valid & ATTR_MODE)
 		error = generic_acl_chmod(inode);
 #endif
 	return error;
 }
 
-static void shmem_delete_inode(struct inode *inode)
+static void shmem_evict_inode(struct inode *inode)
 {
 	struct shmem_inode_info *info = SHMEM_I(inode);
 
@@ -836,7 +836,7 @@ static void shmem_delete_inode(struct inode *inode)
 	}
 	BUG_ON(inode->i_blocks);
 	shmem_free_inode(inode->i_sb);
-	clear_inode(inode);
+	end_writeback(inode);
 }
 
 static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir)
@@ -933,7 +933,7 @@ found:
 
 	/*
 	 * Move _head_ to start search for next from here.
-	 * But be careful: shmem_delete_inode checks list_empty without taking
+	 * But be careful: shmem_evict_inode checks list_empty without taking
 	 * mutex, and there's an instant in list_move_tail when info->swaplist
 	 * would appear empty, if it were the only one on shmem_swaplist.  We
 	 * could avoid doing it if inode NULL; or use this minor optimization.
@@ -1223,6 +1223,7 @@ static int shmem_getpage(struct inode *inode, unsigned long idx,
 	struct shmem_sb_info *sbinfo;
 	struct page *filepage = *pagep;
 	struct page *swappage;
+	struct page *prealloc_page = NULL;
 	swp_entry_t *entry;
 	swp_entry_t swap;
 	gfp_t gfp;
@@ -1247,7 +1248,6 @@ repeat:
 		filepage = find_lock_page(mapping, idx);
 	if (filepage && PageUptodate(filepage))
 		goto done;
-	error = 0;
 	gfp = mapping_gfp_mask(mapping);
 	if (!filepage) {
 		/*
@@ -1258,7 +1258,19 @@ repeat:
 		if (error)
 			goto failed;
 		radix_tree_preload_end();
+		if (sgp != SGP_READ && !prealloc_page) {
+			/* We don't care if this fails */
+			prealloc_page = shmem_alloc_page(gfp, info, idx);
+			if (prealloc_page) {
+				if (mem_cgroup_cache_charge(prealloc_page,
+						current->mm, GFP_KERNEL)) {
+					page_cache_release(prealloc_page);
+					prealloc_page = NULL;
+				}
+			}
+		}
 	}
+	error = 0;
 
 	spin_lock(&info->lock);
 	shmem_recalc_inode(inode);
@@ -1387,17 +1399,16 @@ repeat:
 		shmem_swp_unmap(entry);
 		sbinfo = SHMEM_SB(inode->i_sb);
 		if (sbinfo->max_blocks) {
-			spin_lock(&sbinfo->stat_lock);
-			if (sbinfo->free_blocks == 0 ||
+			if ((percpu_counter_compare(&sbinfo->used_blocks, sbinfo->max_blocks) > 0) ||
 			    shmem_acct_block(info->flags)) {
-				spin_unlock(&sbinfo->stat_lock);
 				spin_unlock(&info->lock);
 				error = -ENOSPC;
 				goto failed;
 			}
-			sbinfo->free_blocks--;
+			percpu_counter_inc(&sbinfo->used_blocks);
+			spin_lock(&inode->i_lock);
 			inode->i_blocks += BLOCKS_PER_PAGE;
-			spin_unlock(&sbinfo->stat_lock);
+			spin_unlock(&inode->i_lock);
 		} else if (shmem_acct_block(info->flags)) {
 			spin_unlock(&info->lock);
 			error = -ENOSPC;
@@ -1407,28 +1418,38 @@ repeat:
 		if (!filepage) {
 			int ret;
 
-			spin_unlock(&info->lock);
-			filepage = shmem_alloc_page(gfp, info, idx);
-			if (!filepage) {
-				shmem_unacct_blocks(info->flags, 1);
-				shmem_free_blocks(inode, 1);
-				error = -ENOMEM;
-				goto failed;
-			}
-			SetPageSwapBacked(filepage);
+			if (!prealloc_page) {
+				spin_unlock(&info->lock);
+				filepage = shmem_alloc_page(gfp, info, idx);
+				if (!filepage) {
+					shmem_unacct_blocks(info->flags, 1);
+					shmem_free_blocks(inode, 1);
+					error = -ENOMEM;
+					goto failed;
+				}
+				SetPageSwapBacked(filepage);
 
-			/* Precharge page while we can wait, compensate after */
-			error = mem_cgroup_cache_charge(filepage, current->mm,
-					GFP_KERNEL);
-			if (error) {
-				page_cache_release(filepage);
-				shmem_unacct_blocks(info->flags, 1);
-				shmem_free_blocks(inode, 1);
-				filepage = NULL;
-				goto failed;
+				/*
+				 * Precharge page while we can wait, compensate
+				 * after
+				 */
+				error = mem_cgroup_cache_charge(filepage,
+					current->mm, GFP_KERNEL);
+				if (error) {
+					page_cache_release(filepage);
+					shmem_unacct_blocks(info->flags, 1);
+					shmem_free_blocks(inode, 1);
+					filepage = NULL;
+					goto failed;
+				}
+
+				spin_lock(&info->lock);
+			} else {
+				filepage = prealloc_page;
+				prealloc_page = NULL;
+				SetPageSwapBacked(filepage);
 			}
 
-			spin_lock(&info->lock);
 			entry = shmem_swp_alloc(info, idx, sgp);
 			if (IS_ERR(entry))
 				error = PTR_ERR(entry);
@@ -1469,13 +1490,19 @@ repeat:
 	}
 done:
 	*pagep = filepage;
-	return 0;
+	error = 0;
+	goto out;
 
 failed:
 	if (*pagep != filepage) {
 		unlock_page(filepage);
 		page_cache_release(filepage);
 	}
+out:
+	if (prealloc_page) {
+		mem_cgroup_uncharge_cache_page(prealloc_page);
+		page_cache_release(prealloc_page);
+	}
 	return error;
 }
 
@@ -1791,17 +1818,16 @@ static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
 	buf->f_type = TMPFS_MAGIC;
 	buf->f_bsize = PAGE_CACHE_SIZE;
 	buf->f_namelen = NAME_MAX;
-	spin_lock(&sbinfo->stat_lock);
 	if (sbinfo->max_blocks) {
 		buf->f_blocks = sbinfo->max_blocks;
-		buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
+		buf->f_bavail = buf->f_bfree =
+				sbinfo->max_blocks - percpu_counter_sum(&sbinfo->used_blocks);
 	}
 	if (sbinfo->max_inodes) {
 		buf->f_files = sbinfo->max_inodes;
 		buf->f_ffree = sbinfo->free_inodes;
 	}
 	/* else leave those fields 0 like simple_statfs */
-	spin_unlock(&sbinfo->stat_lock);
 	return 0;
 }
 
@@ -2242,7 +2268,6 @@ static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
 {
 	struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
 	struct shmem_sb_info config = *sbinfo;
-	unsigned long blocks;
 	unsigned long inodes;
 	int error = -EINVAL;
 
@@ -2250,9 +2275,8 @@ static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
 		return error;
 
 	spin_lock(&sbinfo->stat_lock);
-	blocks = sbinfo->max_blocks - sbinfo->free_blocks;
 	inodes = sbinfo->max_inodes - sbinfo->free_inodes;
-	if (config.max_blocks < blocks)
+	if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0)
 		goto out;
 	if (config.max_inodes < inodes)
 		goto out;
@@ -2269,7 +2293,6 @@ static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
 
 	error = 0;
 	sbinfo->max_blocks  = config.max_blocks;
-	sbinfo->free_blocks = config.max_blocks - blocks;
 	sbinfo->max_inodes  = config.max_inodes;
 	sbinfo->free_inodes = config.max_inodes - inodes;
 
@@ -2344,7 +2367,7 @@ int shmem_fill_super(struct super_block *sb, void *data, int silent)
 #endif
 
 	spin_lock_init(&sbinfo->stat_lock);
-	sbinfo->free_blocks = sbinfo->max_blocks;
+	percpu_counter_init(&sbinfo->used_blocks, 0);
 	sbinfo->free_inodes = sbinfo->max_inodes;
 
 	sb->s_maxbytes = SHMEM_MAX_BYTES;
@@ -2496,7 +2519,7 @@ static const struct super_operations shmem_ops = {
 	.remount_fs	= shmem_remount_fs,
 	.show_options	= shmem_show_options,
 #endif
-	.delete_inode	= shmem_delete_inode,
+	.evict_inode	= shmem_evict_inode,
 	.drop_inode	= generic_delete_inode,
 	.put_super	= shmem_put_super,
 };