13 files changed, 357 insertions, 152 deletions

diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
index c573314806cf..21620054e1c4 100644
--- a/fs/fat/namei_vfat.c
+++ b/fs/fat/namei_vfat.c
@@ -889,22 +889,57 @@ out:
 	return err;
 }
 
-static int vfat_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
-		       struct dentry *old_dentry, struct inode *new_dir,
-		       struct dentry *new_dentry, unsigned int flags)
+static int vfat_get_dotdot_de(struct inode *inode, struct buffer_head **bh,
+			      struct msdos_dir_entry **de)
+{
+	if (S_ISDIR(inode->i_mode)) {
+		if (fat_get_dotdot_entry(inode, bh, de))
+			return -EIO;
+	}
+	return 0;
+}
+
+static int vfat_sync_ipos(struct inode *dir, struct inode *inode)
+{
+	if (IS_DIRSYNC(dir))
+		return fat_sync_inode(inode);
+	mark_inode_dirty(inode);
+	return 0;
+}
+
+static int vfat_update_dotdot_de(struct inode *dir, struct inode *inode,
+				 struct buffer_head *dotdot_bh,
+				 struct msdos_dir_entry *dotdot_de)
+{
+	fat_set_start(dotdot_de, MSDOS_I(dir)->i_logstart);
+	mark_buffer_dirty_inode(dotdot_bh, inode);
+	if (IS_DIRSYNC(dir))
+		return sync_dirty_buffer(dotdot_bh);
+	return 0;
+}
+
+static void vfat_update_dir_metadata(struct inode *dir, struct timespec64 *ts)
+{
+	inode_inc_iversion(dir);
+	fat_truncate_time(dir, ts, S_CTIME | S_MTIME);
+	if (IS_DIRSYNC(dir))
+		(void)fat_sync_inode(dir);
+	else
+		mark_inode_dirty(dir);
+}
+
+static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
+		       struct inode *new_dir, struct dentry *new_dentry)
 {
 	struct buffer_head *dotdot_bh;
-	struct msdos_dir_entry *dotdot_de;
+	struct msdos_dir_entry *dotdot_de = NULL;
 	struct inode *old_inode, *new_inode;
 	struct fat_slot_info old_sinfo, sinfo;
 	struct timespec64 ts;
 	loff_t new_i_pos;
-	int err, is_dir, update_dotdot, corrupt = 0;
+	int err, is_dir, corrupt = 0;
 	struct super_block *sb = old_dir->i_sb;
 
-	if (flags & ~RENAME_NOREPLACE)
-		return -EINVAL;
-
 	old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
 	old_inode = d_inode(old_dentry);
 	new_inode = d_inode(new_dentry);
@@ -913,15 +948,13 @@ static int vfat_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
 	if (err)
 		goto out;
 
-	is_dir = S_ISDIR(old_inode->i_mode);
-	update_dotdot = (is_dir && old_dir != new_dir);
-	if (update_dotdot) {
-		if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
-			err = -EIO;
+	if (old_dir != new_dir) {
+		err = vfat_get_dotdot_de(old_inode, &dotdot_bh, &dotdot_de);
+		if (err)
 			goto out;
-		}
 	}
 
+	is_dir = S_ISDIR(old_inode->i_mode);
 	ts = current_time(old_dir);
 	if (new_inode) {
 		if (is_dir) {
@@ -942,21 +975,15 @@ static int vfat_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
 
 	fat_detach(old_inode);
 	fat_attach(old_inode, new_i_pos);
-	if (IS_DIRSYNC(new_dir)) {
-		err = fat_sync_inode(old_inode);
-		if (err)
-			goto error_inode;
-	} else
-		mark_inode_dirty(old_inode);
+	err = vfat_sync_ipos(new_dir, old_inode);
+	if (err)
+		goto error_inode;
 
-	if (update_dotdot) {
-		fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
-		mark_buffer_dirty_inode(dotdot_bh, old_inode);
-		if (IS_DIRSYNC(new_dir)) {
-			err = sync_dirty_buffer(dotdot_bh);
-			if (err)
-				goto error_dotdot;
-		}
+	if (dotdot_de) {
+		err = vfat_update_dotdot_de(new_dir, old_inode, dotdot_bh,
+					    dotdot_de);
+		if (err)
+			goto error_dotdot;
 		drop_nlink(old_dir);
 		if (!new_inode)
  			inc_nlink(new_dir);
@@ -966,12 +993,7 @@ static int vfat_rename(struct user_namespace *mnt_userns, struct inode *old_dir,
 	old_sinfo.bh = NULL;
 	if (err)
 		goto error_dotdot;
-	inode_inc_iversion(old_dir);
-	fat_truncate_time(old_dir, &ts, S_CTIME|S_MTIME);
-	if (IS_DIRSYNC(old_dir))
-		(void)fat_sync_inode(old_dir);
-	else
-		mark_inode_dirty(old_dir);
+	vfat_update_dir_metadata(old_dir, &ts);
 
 	if (new_inode) {
 		drop_nlink(new_inode);
@@ -991,10 +1013,9 @@ error_dotdot:
 	/* data cluster is shared, serious corruption */
 	corrupt = 1;
 
-	if (update_dotdot) {
-		fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
-		mark_buffer_dirty_inode(dotdot_bh, old_inode);
-		corrupt |= sync_dirty_buffer(dotdot_bh);
+	if (dotdot_de) {
+		corrupt |= vfat_update_dotdot_de(old_dir, old_inode, dotdot_bh,
+						 dotdot_de);
 	}
 error_inode:
 	fat_detach(old_inode);
@@ -1021,13 +1042,145 @@ error_inode:
 	goto out;
 }
 
+static void vfat_exchange_ipos(struct inode *old_inode, struct inode *new_inode,
+			       loff_t old_i_pos, loff_t new_i_pos)
+{
+	fat_detach(old_inode);
+	fat_detach(new_inode);
+	fat_attach(old_inode, new_i_pos);
+	fat_attach(new_inode, old_i_pos);
+}
+
+static void vfat_move_nlink(struct inode *src, struct inode *dst)
+{
+	drop_nlink(src);
+	inc_nlink(dst);
+}
+
+static int vfat_rename_exchange(struct inode *old_dir, struct dentry *old_dentry,
+				struct inode *new_dir, struct dentry *new_dentry)
+{
+	struct buffer_head *old_dotdot_bh = NULL, *new_dotdot_bh = NULL;
+	struct msdos_dir_entry *old_dotdot_de = NULL, *new_dotdot_de = NULL;
+	struct inode *old_inode, *new_inode;
+	struct timespec64 ts = current_time(old_dir);
+	loff_t old_i_pos, new_i_pos;
+	int err, corrupt = 0;
+	struct super_block *sb = old_dir->i_sb;
+
+	old_inode = d_inode(old_dentry);
+	new_inode = d_inode(new_dentry);
+
+	/* Acquire super block lock for the operation to be atomic */
+	mutex_lock(&MSDOS_SB(sb)->s_lock);
+
+	/* if directories are not the same, get ".." info to update */
+	if (old_dir != new_dir) {
+		err = vfat_get_dotdot_de(old_inode, &old_dotdot_bh,
+					 &old_dotdot_de);
+		if (err)
+			goto out;
+
+		err = vfat_get_dotdot_de(new_inode, &new_dotdot_bh,
+					 &new_dotdot_de);
+		if (err)
+			goto out;
+	}
+
+	old_i_pos = MSDOS_I(old_inode)->i_pos;
+	new_i_pos = MSDOS_I(new_inode)->i_pos;
+
+	vfat_exchange_ipos(old_inode, new_inode, old_i_pos, new_i_pos);
+
+	err = vfat_sync_ipos(old_dir, new_inode);
+	if (err)
+		goto error_exchange;
+	err = vfat_sync_ipos(new_dir, old_inode);
+	if (err)
+		goto error_exchange;
+
+	/* update ".." directory entry info */
+	if (old_dotdot_de) {
+		err = vfat_update_dotdot_de(new_dir, old_inode, old_dotdot_bh,
+					    old_dotdot_de);
+		if (err)
+			goto error_old_dotdot;
+	}
+	if (new_dotdot_de) {
+		err = vfat_update_dotdot_de(old_dir, new_inode, new_dotdot_bh,
+					    new_dotdot_de);
+		if (err)
+			goto error_new_dotdot;
+	}
+
+	/* if cross directory and only one is a directory, adjust nlink */
+	if (!old_dotdot_de != !new_dotdot_de) {
+		if (old_dotdot_de)
+			vfat_move_nlink(old_dir, new_dir);
+		else
+			vfat_move_nlink(new_dir, old_dir);
+	}
+
+	vfat_update_dir_metadata(old_dir, &ts);
+	/* if directories are not the same, update new_dir as well */
+	if (old_dir != new_dir)
+		vfat_update_dir_metadata(new_dir, &ts);
+
+out:
+	brelse(old_dotdot_bh);
+	brelse(new_dotdot_bh);
+	mutex_unlock(&MSDOS_SB(sb)->s_lock);
+
+	return err;
+
+error_new_dotdot:
+	if (new_dotdot_de) {
+		corrupt |= vfat_update_dotdot_de(new_dir, new_inode,
+						 new_dotdot_bh, new_dotdot_de);
+	}
+
+error_old_dotdot:
+	if (old_dotdot_de) {
+		corrupt |= vfat_update_dotdot_de(old_dir, old_inode,
+						 old_dotdot_bh, old_dotdot_de);
+	}
+
+error_exchange:
+	vfat_exchange_ipos(old_inode, new_inode, new_i_pos, old_i_pos);
+	corrupt |= vfat_sync_ipos(new_dir, new_inode);
+	corrupt |= vfat_sync_ipos(old_dir, old_inode);
+
+	if (corrupt < 0) {
+		fat_fs_error(new_dir->i_sb,
+			     "%s: Filesystem corrupted (i_pos %lld, %lld)",
+			     __func__, old_i_pos, new_i_pos);
+	}
+	goto out;
+}
+
+static int vfat_rename2(struct user_namespace *mnt_userns, struct inode *old_dir,
+			struct dentry *old_dentry, struct inode *new_dir,
+			struct dentry *new_dentry, unsigned int flags)
+{
+	if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
+		return -EINVAL;
+
+	if (flags & RENAME_EXCHANGE) {
+		return vfat_rename_exchange(old_dir, old_dentry,
+					    new_dir, new_dentry);
+	}
+
+	/* VFS already handled RENAME_NOREPLACE, handle it as a normal rename */
+	return vfat_rename(old_dir, old_dentry, new_dir, new_dentry);
+}
+
 static const struct inode_operations vfat_dir_inode_operations = {
 	.create		= vfat_create,
 	.lookup		= vfat_lookup,
 	.unlink		= vfat_unlink,
 	.mkdir		= vfat_mkdir,
 	.rmdir		= vfat_rmdir,
-	.rename		= vfat_rename,
+	.rename		= vfat_rename2,
 	.setattr	= fat_setattr,
 	.getattr	= fat_getattr,
 	.update_time	= fat_update_time,
diff --git a/fs/kernel_read_file.c b/fs/kernel_read_file.c
index 1b07550485b9..5d826274570c 100644
--- a/fs/kernel_read_file.c
+++ b/fs/kernel_read_file.c
@@ -29,15 +29,15 @@
  * change between calls to kernel_read_file().
  *
  * Returns number of bytes read (no single read will be bigger
- * than INT_MAX), or negative on error.
+ * than SSIZE_MAX), or negative on error.
  *
  */
-int kernel_read_file(struct file *file, loff_t offset, void **buf,
-		     size_t buf_size, size_t *file_size,
-		     enum kernel_read_file_id id)
+ssize_t kernel_read_file(struct file *file, loff_t offset, void **buf,
+			 size_t buf_size, size_t *file_size,
+			 enum kernel_read_file_id id)
 {
 	loff_t i_size, pos;
-	size_t copied;
+	ssize_t copied;
 	void *allocated = NULL;
 	bool whole_file;
 	int ret;
@@ -58,7 +58,7 @@ int kernel_read_file(struct file *file, loff_t offset, void **buf,
 		goto out;
 	}
 	/* The file is too big for sane activities. */
-	if (i_size > INT_MAX) {
+	if (i_size > SSIZE_MAX) {
 		ret = -EFBIG;
 		goto out;
 	}
@@ -124,12 +124,12 @@ out:
 }
 EXPORT_SYMBOL_GPL(kernel_read_file);
 
-int kernel_read_file_from_path(const char *path, loff_t offset, void **buf,
-			       size_t buf_size, size_t *file_size,
-			       enum kernel_read_file_id id)
+ssize_t kernel_read_file_from_path(const char *path, loff_t offset, void **buf,
+				   size_t buf_size, size_t *file_size,
+				   enum kernel_read_file_id id)
 {
 	struct file *file;
-	int ret;
+	ssize_t ret;
 
 	if (!path || !*path)
 		return -EINVAL;
@@ -144,14 +144,14 @@ int kernel_read_file_from_path(const char *path, loff_t offset, void **buf,
 }
 EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
 
-int kernel_read_file_from_path_initns(const char *path, loff_t offset,
-				      void **buf, size_t buf_size,
-				      size_t *file_size,
-				      enum kernel_read_file_id id)
+ssize_t kernel_read_file_from_path_initns(const char *path, loff_t offset,
+					  void **buf, size_t buf_size,
+					  size_t *file_size,
+					  enum kernel_read_file_id id)
 {
 	struct file *file;
 	struct path root;
-	int ret;
+	ssize_t ret;
 
 	if (!path || !*path)
 		return -EINVAL;
@@ -171,12 +171,12 @@ int kernel_read_file_from_path_initns(const char *path, loff_t offset,
 }
 EXPORT_SYMBOL_GPL(kernel_read_file_from_path_initns);
 
-int kernel_read_file_from_fd(int fd, loff_t offset, void **buf,
-			     size_t buf_size, size_t *file_size,
-			     enum kernel_read_file_id id)
+ssize_t kernel_read_file_from_fd(int fd, loff_t offset, void **buf,
+				 size_t buf_size, size_t *file_size,
+				 enum kernel_read_file_id id)
 {
 	struct fd f = fdget(fd);
-	int ret = -EBADF;
+	ssize_t ret = -EBADF;
 
 	if (!f.file || !(f.file->f_mode & FMODE_READ))
 		goto out;
diff --git a/fs/ocfs2/dlmfs/dlmfs.c b/fs/ocfs2/dlmfs/dlmfs.c
index e360543ad7e7..8b2020f92b5f 100644
--- a/fs/ocfs2/dlmfs/dlmfs.c
+++ b/fs/ocfs2/dlmfs/dlmfs.c
@@ -296,17 +296,25 @@ static void dlmfs_evict_inode(struct inode *inode)
 {
 	int status;
 	struct dlmfs_inode_private *ip;
+	struct user_lock_res *lockres;
+	int teardown;
 
 	clear_inode(inode);
 
 	mlog(0, "inode %lu\n", inode->i_ino);
 
 	ip = DLMFS_I(inode);
+	lockres = &ip->ip_lockres;
 
 	if (S_ISREG(inode->i_mode)) {
-		status = user_dlm_destroy_lock(&ip->ip_lockres);
-		if (status < 0)
-			mlog_errno(status);
+		spin_lock(&lockres->l_lock);
+		teardown = !!(lockres->l_flags & USER_LOCK_IN_TEARDOWN);
+		spin_unlock(&lockres->l_lock);
+		if (!teardown) {
+			status = user_dlm_destroy_lock(lockres);
+			if (status < 0)
+				mlog_errno(status);
+		}
 		iput(ip->ip_parent);
 		goto clear_fields;
 	}
diff --git a/fs/squashfs/block.c b/fs/squashfs/block.c
index 8879d052f96c..833aca92301f 100644
--- a/fs/squashfs/block.c
+++ b/fs/squashfs/block.c
@@ -34,12 +34,15 @@ static int copy_bio_to_actor(struct bio *bio,
 			     struct squashfs_page_actor *actor,
 			     int offset, int req_length)
 {
-	void *actor_addr = squashfs_first_page(actor);
+	void *actor_addr;
 	struct bvec_iter_all iter_all = {};
 	struct bio_vec *bvec = bvec_init_iter_all(&iter_all);
 	int copied_bytes = 0;
 	int actor_offset = 0;
 
+	squashfs_actor_nobuff(actor);
+	actor_addr = squashfs_first_page(actor);
+
 	if (WARN_ON_ONCE(!bio_next_segment(bio, &iter_all)))
 		return 0;
 
@@ -49,8 +52,9 @@ static int copy_bio_to_actor(struct bio *bio,
 
 		bytes_to_copy = min_t(int, bytes_to_copy,
 				      req_length - copied_bytes);
-		memcpy(actor_addr + actor_offset, bvec_virt(bvec) + offset,
-		       bytes_to_copy);
+		if (!IS_ERR(actor_addr))
+			memcpy(actor_addr + actor_offset, bvec_virt(bvec) +
+					offset, bytes_to_copy);
 
 		actor_offset += bytes_to_copy;
 		copied_bytes += bytes_to_copy;
diff --git a/fs/squashfs/decompressor.h b/fs/squashfs/decompressor.h
index 1b9ccfd0aa51..19ab60834389 100644
--- a/fs/squashfs/decompressor.h
+++ b/fs/squashfs/decompressor.h
@@ -20,6 +20,7 @@ struct squashfs_decompressor {
 		struct bio *, int, int, struct squashfs_page_actor *);
 	int	id;
 	char	*name;
+	int	alloc_buffer;
 	int	supported;
 };
 
diff --git a/fs/squashfs/file_direct.c b/fs/squashfs/file_direct.c
index a4894cc59447..be4b12d31e0c 100644
--- a/fs/squashfs/file_direct.c
+++ b/fs/squashfs/file_direct.c
@@ -18,9 +18,6 @@
 #include "squashfs.h"
 #include "page_actor.h"
 
-static int squashfs_read_cache(struct page *target_page, u64 block, int bsize,
-	int pages, struct page **page, int bytes);
-
 /* Read separately compressed datablock directly into page cache */
 int squashfs_readpage_block(struct page *target_page, u64 block, int bsize,
 	int expected)
@@ -33,7 +30,7 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize,
 	int mask = (1 << (msblk->block_log - PAGE_SHIFT)) - 1;
 	int start_index = target_page->index & ~mask;
 	int end_index = start_index | mask;
-	int i, n, pages, missing_pages, bytes, res = -ENOMEM;
+	int i, n, pages, bytes, res = -ENOMEM;
 	struct page **page;
 	struct squashfs_page_actor *actor;
 	void *pageaddr;
@@ -47,50 +44,38 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize,
 	if (page == NULL)
 		return res;
 
-	/*
-	 * Create a "page actor" which will kmap and kunmap the
-	 * page cache pages appropriately within the decompressor
-	 */
-	actor = squashfs_page_actor_init_special(page, pages, 0);
-	if (actor == NULL)
-		goto out;
-
 	/* Try to grab all the pages covered by the Squashfs block */
-	for (missing_pages = 0, i = 0, n = start_index; i < pages; i++, n++) {
+	for (i = 0, n = start_index; n <= end_index; n++) {
 		page[i] = (n == target_page->index) ? target_page :
 			grab_cache_page_nowait(target_page->mapping, n);
 
-		if (page[i] == NULL) {
-			missing_pages++;
+		if (page[i] == NULL)
 			continue;
-		}
 
 		if (PageUptodate(page[i])) {
 			unlock_page(page[i]);
 			put_page(page[i]);
-			page[i] = NULL;
-			missing_pages++;
+			continue;
 		}
+
+		i++;
 	}
 
-	if (missing_pages) {
-		/*
-		 * Couldn't get one or more pages, this page has either
-		 * been VM reclaimed, but others are still in the page cache
-		 * and uptodate, or we're racing with another thread in
-		 * squashfs_readpage also trying to grab them.  Fall back to
-		 * using an intermediate buffer.
-		 */
-		res = squashfs_read_cache(target_page, block, bsize, pages,
-							page, expected);
-		if (res < 0)
-			goto mark_errored;
+	pages = i;
 
+	/*
+	 * Create a "page actor" which will kmap and kunmap the
+	 * page cache pages appropriately within the decompressor
+	 */
+	actor = squashfs_page_actor_init_special(msblk, page, pages, expected);
+	if (actor == NULL)
 		goto out;
-	}
 
 	/* Decompress directly into the page cache buffers */
 	res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor);
+
+	kfree(actor);
+
 	if (res < 0)
 		goto mark_errored;
 
@@ -99,12 +84,12 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize,
 		goto mark_errored;
 	}
 
-	/* Last page may have trailing bytes not filled */
+	/* Last page (if present) may have trailing bytes not filled */
 	bytes = res % PAGE_SIZE;
-	if (bytes) {
-		pageaddr = kmap_atomic(page[pages - 1]);
+	if (page[pages - 1]->index == end_index && bytes) {
+		pageaddr = kmap_local_page(page[pages - 1]);
 		memset(pageaddr + bytes, 0, PAGE_SIZE - bytes);
-		kunmap_atomic(pageaddr);
+		kunmap_local(pageaddr);
 	}
 
 	/* Mark pages as uptodate, unlock and release */
@@ -116,7 +101,6 @@ int squashfs_readpage_block(struct page *target_page, u64 block, int bsize,
 			put_page(page[i]);
 	}
 
-	kfree(actor);
 	kfree(page);
 
 	return 0;
@@ -135,40 +119,6 @@ mark_errored:
 	}
 
 out:
-	kfree(actor);
 	kfree(page);
 	return res;
 }
-
-
-static int squashfs_read_cache(struct page *target_page, u64 block, int bsize,
-	int pages, struct page **page, int bytes)
-{
-	struct inode *i = target_page->mapping->host;
-	struct squashfs_cache_entry *buffer = squashfs_get_datablock(i->i_sb,
-						 block, bsize);
-	int res = buffer->error, n, offset = 0;
-
-	if (res) {
-		ERROR("Unable to read page, block %llx, size %x\n", block,
-			bsize);
-		goto out;
-	}
-
-	for (n = 0; n < pages && bytes > 0; n++,
-			bytes -= PAGE_SIZE, offset += PAGE_SIZE) {
-		int avail = min_t(int, bytes, PAGE_SIZE);
-
-		if (page[n] == NULL)
-			continue;
-
-		squashfs_fill_page(page[n], buffer, offset, avail);
-		unlock_page(page[n]);
-		if (page[n] != target_page)
-			put_page(page[n]);
-	}
-
-out:
-	squashfs_cache_put(buffer);
-	return res;
-}
diff --git a/fs/squashfs/lz4_wrapper.c b/fs/squashfs/lz4_wrapper.c
index b685b6238316..49797729f143 100644
--- a/fs/squashfs/lz4_wrapper.c
+++ b/fs/squashfs/lz4_wrapper.c
@@ -119,10 +119,12 @@ static int lz4_uncompress(struct squashfs_sb_info *msblk, void *strm,
 	buff = stream->output;
 	while (data) {
 		if (bytes <= PAGE_SIZE) {
-			memcpy(data, buff, bytes);
+			if (!IS_ERR(data))
+				memcpy(data, buff, bytes);
 			break;
 		}
-		memcpy(data, buff, PAGE_SIZE);
+		if (!IS_ERR(data))
+			memcpy(data, buff, PAGE_SIZE);
 		buff += PAGE_SIZE;
 		bytes -= PAGE_SIZE;
 		data = squashfs_next_page(output);
@@ -139,5 +141,6 @@ const struct squashfs_decompressor squashfs_lz4_comp_ops = {
 	.decompress = lz4_uncompress,
 	.id = LZ4_COMPRESSION,
 	.name = "lz4",
+	.alloc_buffer = 0,
 	.supported = 1
 };
diff --git a/fs/squashfs/lzo_wrapper.c b/fs/squashfs/lzo_wrapper.c
index cb510a631968..d216aeefa865 100644
--- a/fs/squashfs/lzo_wrapper.c
+++ b/fs/squashfs/lzo_wrapper.c
@@ -93,10 +93,12 @@ static int lzo_uncompress(struct squashfs_sb_info *msblk, void *strm,
 	buff = stream->output;
 	while (data) {
 		if (bytes <= PAGE_SIZE) {
-			memcpy(data, buff, bytes);
+			if (!IS_ERR(data))
+				memcpy(data, buff, bytes);
 			break;
 		} else {
-			memcpy(data, buff, PAGE_SIZE);
+			if (!IS_ERR(data))
+				memcpy(data, buff, PAGE_SIZE);
 			buff += PAGE_SIZE;
 			bytes -= PAGE_SIZE;
 			data = squashfs_next_page(output);
@@ -116,5 +118,6 @@ const struct squashfs_decompressor squashfs_lzo_comp_ops = {
 	.decompress = lzo_uncompress,
 	.id = LZO_COMPRESSION,
 	.name = "lzo",
+	.alloc_buffer = 0,
 	.supported = 1
 };
diff --git a/fs/squashfs/page_actor.c b/fs/squashfs/page_actor.c
index 520d323a99ce..b23b780d8f42 100644
--- a/fs/squashfs/page_actor.c
+++ b/fs/squashfs/page_actor.c
@@ -7,6 +7,8 @@
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/pagemap.h>
+#include "squashfs_fs_sb.h"
+#include "decompressor.h"
 #include "page_actor.h"
 
 /*
@@ -57,29 +59,62 @@ struct squashfs_page_actor *squashfs_page_actor_init(void **buffer,
 }
 
 /* Implementation of page_actor for decompressing directly into page cache. */
+static void *handle_next_page(struct squashfs_page_actor *actor)
+{
+	int max_pages = (actor->length + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
+	if (actor->returned_pages == max_pages)
+		return NULL;
+
+	if ((actor->next_page == actor->pages) ||
+			(actor->next_index != actor->page[actor->next_page]->index)) {
+		if (actor->alloc_buffer) {
+			void *tmp_buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
+
+			if (tmp_buffer) {
+				actor->tmp_buffer = tmp_buffer;
+				actor->next_index++;
+				actor->returned_pages++;
+				return tmp_buffer;
+			}
+		}
+
+		actor->next_index++;
+		actor->returned_pages++;
+		return ERR_PTR(-ENOMEM);
+	}
+
+	actor->next_index++;
+	actor->returned_pages++;
+	return actor->pageaddr = kmap_local_page(actor->page[actor->next_page++]);
+}
+
 static void *direct_first_page(struct squashfs_page_actor *actor)
 {
-	actor->next_page = 1;
-	return actor->pageaddr = kmap_atomic(actor->page[0]);
+	return handle_next_page(actor);
 }
 
 static void *direct_next_page(struct squashfs_page_actor *actor)
 {
 	if (actor->pageaddr)
-		kunmap_atomic(actor->pageaddr);
+		kunmap_local(actor->pageaddr);
+
+	kfree(actor->tmp_buffer);
+	actor->pageaddr = actor->tmp_buffer = NULL;
 
-	return actor->pageaddr = actor->next_page == actor->pages ? NULL :
-		kmap_atomic(actor->page[actor->next_page++]);
+	return handle_next_page(actor);
 }
 
 static void direct_finish_page(struct squashfs_page_actor *actor)
 {
 	if (actor->pageaddr)
-		kunmap_atomic(actor->pageaddr);
+		kunmap_local(actor->pageaddr);
+
+	kfree(actor->tmp_buffer);
 }
 
-struct squashfs_page_actor *squashfs_page_actor_init_special(struct page **page,
-	int pages, int length)
+struct squashfs_page_actor *squashfs_page_actor_init_special(struct squashfs_sb_info *msblk,
+	struct page **page, int pages, int length)
 {
 	struct squashfs_page_actor *actor = kmalloc(sizeof(*actor), GFP_KERNEL);
 
@@ -90,7 +125,11 @@ struct squashfs_page_actor *squashfs_page_actor_init_special(struct page **page,
 	actor->page = page;
 	actor->pages = pages;
 	actor->next_page = 0;
+	actor->returned_pages = 0;
+	actor->next_index = page[0]->index & ~((1 << (msblk->block_log - PAGE_SHIFT)) - 1);
 	actor->pageaddr = NULL;
+	actor->tmp_buffer = NULL;
+	actor->alloc_buffer = msblk->decompressor->alloc_buffer;
 	actor->squashfs_first_page = direct_first_page;
 	actor->squashfs_next_page = direct_next_page;
 	actor->squashfs_finish_page = direct_finish_page;
diff --git a/fs/squashfs/page_actor.h b/fs/squashfs/page_actor.h
index 2e3073ace009..37523c54256f 100644
--- a/fs/squashfs/page_actor.h
+++ b/fs/squashfs/page_actor.h
@@ -45,6 +45,11 @@ static inline void squashfs_finish_page(struct squashfs_page_actor *actor)
 {
 	/* empty */
 }
+
+static inline void squashfs_actor_nobuff(struct squashfs_page_actor *actor)
+{
+	/* empty */
+}
 #else
 struct squashfs_page_actor {
 	union {
@@ -52,17 +57,23 @@ struct squashfs_page_actor {
 		struct page	**page;
 	};
 	void	*pageaddr;
+	void	*tmp_buffer;
 	void    *(*squashfs_first_page)(struct squashfs_page_actor *);
 	void    *(*squashfs_next_page)(struct squashfs_page_actor *);
 	void    (*squashfs_finish_page)(struct squashfs_page_actor *);
 	int	pages;
 	int	length;
 	int	next_page;
+	int	alloc_buffer;
+	int	returned_pages;
+	pgoff_t	next_index;
 };
 
-extern struct squashfs_page_actor *squashfs_page_actor_init(void **, int, int);
-extern struct squashfs_page_actor *squashfs_page_actor_init_special(struct page
-							 **, int, int);
+extern struct squashfs_page_actor *squashfs_page_actor_init(void **buffer,
+				int pages, int length);
+extern struct squashfs_page_actor *squashfs_page_actor_init_special(
+				struct squashfs_sb_info *msblk,
+				struct page **page, int pages, int length);
 static inline void *squashfs_first_page(struct squashfs_page_actor *actor)
 {
 	return actor->squashfs_first_page(actor);
@@ -75,5 +86,9 @@ static inline void squashfs_finish_page(struct squashfs_page_actor *actor)
 {
 	actor->squashfs_finish_page(actor);
 }
+static inline void squashfs_actor_nobuff(struct squashfs_page_actor *actor)
+{
+	actor->alloc_buffer = 0;
+}
 #endif
 #endif
diff --git a/fs/squashfs/xz_wrapper.c b/fs/squashfs/xz_wrapper.c
index 68f6d09bb3a2..6c49481a2f8c 100644
--- a/fs/squashfs/xz_wrapper.c
+++ b/fs/squashfs/xz_wrapper.c
@@ -131,6 +131,10 @@ static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm,
 	stream->buf.out_pos = 0;
 	stream->buf.out_size = PAGE_SIZE;
 	stream->buf.out = squashfs_first_page(output);
+	if (IS_ERR(stream->buf.out)) {
+		error = PTR_ERR(stream->buf.out);
+		goto finish;
+	}
 
 	for (;;) {
 		enum xz_ret xz_err;
@@ -156,7 +160,10 @@ static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm,
 
 		if (stream->buf.out_pos == stream->buf.out_size) {
 			stream->buf.out = squashfs_next_page(output);
-			if (stream->buf.out != NULL) {
+			if (IS_ERR(stream->buf.out)) {
+				error = PTR_ERR(stream->buf.out);
+				break;
+			} else if (stream->buf.out != NULL) {
 				stream->buf.out_pos = 0;
 				total += PAGE_SIZE;
 			}
@@ -171,6 +178,7 @@ static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm,
 		}
 	}
 
+finish:
 	squashfs_finish_page(output);
 
 	return error ? error : total + stream->buf.out_pos;
@@ -183,5 +191,6 @@ const struct squashfs_decompressor squashfs_xz_comp_ops = {
 	.decompress = squashfs_xz_uncompress,
 	.id = XZ_COMPRESSION,
 	.name = "xz",
+	.alloc_buffer = 1,
 	.supported = 1
 };
diff --git a/fs/squashfs/zlib_wrapper.c b/fs/squashfs/zlib_wrapper.c
index a20e9042146b..cbb7afe7bc46 100644
--- a/fs/squashfs/zlib_wrapper.c
+++ b/fs/squashfs/zlib_wrapper.c
@@ -62,6 +62,11 @@ static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,
 	stream->next_out = squashfs_first_page(output);
 	stream->avail_in = 0;
 
+	if (IS_ERR(stream->next_out)) {
+		error = PTR_ERR(stream->next_out);
+		goto finish;
+	}
+
 	for (;;) {
 		int zlib_err;
 
@@ -85,7 +90,10 @@ static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,
 
 		if (stream->avail_out == 0) {
 			stream->next_out = squashfs_next_page(output);
-			if (stream->next_out != NULL)
+			if (IS_ERR(stream->next_out)) {
+				error = PTR_ERR(stream->next_out);
+				break;
+			} else if (stream->next_out != NULL)
 				stream->avail_out = PAGE_SIZE;
 		}
 
@@ -107,6 +115,7 @@ static int zlib_uncompress(struct squashfs_sb_info *msblk, void *strm,
 		}
 	}
 
+finish:
 	squashfs_finish_page(output);
 
 	if (!error)
@@ -122,6 +131,7 @@ const struct squashfs_decompressor squashfs_zlib_comp_ops = {
 	.decompress = zlib_uncompress,
 	.id = ZLIB_COMPRESSION,
 	.name = "zlib",
+	.alloc_buffer = 1,
 	.supported = 1
 };
 
diff --git a/fs/squashfs/zstd_wrapper.c b/fs/squashfs/zstd_wrapper.c
index c40445dbf38c..0e407c4d8b3b 100644
--- a/fs/squashfs/zstd_wrapper.c
+++ b/fs/squashfs/zstd_wrapper.c
@@ -80,6 +80,10 @@ static int zstd_uncompress(struct squashfs_sb_info *msblk, void *strm,
 
 	out_buf.size = PAGE_SIZE;
 	out_buf.dst = squashfs_first_page(output);
+	if (IS_ERR(out_buf.dst)) {
+		error = PTR_ERR(out_buf.dst);
+		goto finish;
+	}
 
 	for (;;) {
 		size_t zstd_err;
@@ -104,7 +108,10 @@ static int zstd_uncompress(struct squashfs_sb_info *msblk, void *strm,
 
 		if (out_buf.pos == out_buf.size) {
 			out_buf.dst = squashfs_next_page(output);
-			if (out_buf.dst == NULL) {
+			if (IS_ERR(out_buf.dst)) {
+				error = PTR_ERR(out_buf.dst);
+				break;
+			} else if (out_buf.dst == NULL) {
 				/* Shouldn't run out of pages
 				 * before stream is done.
 				 */
@@ -129,6 +136,8 @@ static int zstd_uncompress(struct squashfs_sb_info *msblk, void *strm,
 		}
 	}
 
+finish:
+
 	squashfs_finish_page(output);
 
 	return error ? error : total_out;
@@ -140,5 +149,6 @@ const struct squashfs_decompressor squashfs_zstd_comp_ops = {
 	.decompress = zstd_uncompress,
 	.id = ZSTD_COMPRESSION,
 	.name = "zstd",
+	.alloc_buffer = 1,
 	.supported = 1
 };