fix truncate inode time modification breakage

mtime and ctime should be changed only if the file size has actually changed. Patches changing ext2 and tmpfs from vmtruncate to new truncate sequence has caused regressions where they always update timestamps. There is some strange cases in POSIX where truncate(2) must not update times unless the size has acutally changed, see 6e656be. This area is all still rather buggy in different ways in a lot of filesystems and needs a cleanup and audit (ideally the vfs will provide a simple attribute or call to direct all filesystems exactly which attributes to change). But coming up with the best solution will take a while and is not appropriate for rc anyway. So fix recent regression for now. Signed-off-by: Nick Piggin <[email protected]> Signed-off-by: Al Viro <[email protected]>
mna · Jun 4, 2010 · af5a30d · af5a30d
1 parent 8718d36
commit af5a30d
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diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
@@ -1552,7 +1552,7 @@ int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
 		if (error)
 			return error;
 	}
-	if (iattr->ia_valid & ATTR_SIZE) {
+	if (iattr->ia_valid & ATTR_SIZE && iattr->ia_size != inode->i_size) {
 		error = ext2_setsize(inode, iattr->ia_size);
 		if (error)
 			return error;

diff --git a/mm/shmem.c b/mm/shmem.c
@@ -764,10 +764,11 @@ static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end)
 static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
 {
 	struct inode *inode = dentry->d_inode;
+	loff_t newsize = attr->ia_size;
 	int error;
 
-	if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
-		loff_t newsize = attr->ia_size;
+	if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)
+					&& newsize != inode->i_size) {
 		struct page *page = NULL;
 
 		if (newsize < inode->i_size) {