From: Aneesh Kumar K.V Date: Tue, 29 Apr 2008 12:11:12 +0000 (-0400) Subject: ext4: make ext4_ext_get_blocks always return <= max_blocks X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e067ba0078cd6f00eb6c4052fec630b78ebe59de;p=linux-2.6 ext4: make ext4_ext_get_blocks always return <= max_blocks ext4_ext_get_blocks() returns number of blocks allocated with buffer heads unmapped for a read from prealloc space. This is needed so that delayed allocation doesn't do block reservation for prealloc space since the blocks are already resevred on disk. Fix ext4_ext_get_blocks to not return greater than max_blocks, since some of the code paths cannot handle such a return value. Signed-off-by: Aneesh Kumar K.V Signed-off-by: "Theodore Ts'o" --- diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index c2b004e29a..f4ef0b745a 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -2570,8 +2570,18 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode, } if (create == EXT4_CREATE_UNINITIALIZED_EXT) goto out; - if (!create) + if (!create) { + /* + * We have blocks reserved already. We + * return allocated blocks so that delalloc + * won't do block reservation for us. But + * the buffer head will be unmapped so that + * a read from the block returns 0s. + */ + if (allocated > max_blocks) + allocated = max_blocks; goto out2; + } ret = ext4_ext_convert_to_initialized(handle, inode, path, iblock,