From 749269facaf87f6e516c3af12763e03181b9c139 Mon Sep 17 00:00:00 2001 From: Amit Arora Date: Wed, 18 Jul 2007 09:02:56 -0400 Subject: Change on-disk format to support 2^15 uninitialized extents This change was suggested by Andreas Dilger. This patch changes the EXT_MAX_LEN value and extent code which marks/checks uninitialized extents. With this change it will be possible to have initialized extents with 2^15 blocks (earlier the max blocks we could have was 2^15 - 1). This way we can have better extent-to-block alignment. Now, maximum number of blocks we can have in an initialized extent is 2^15 and in an uninitialized extent is 2^15 - 1. Signed-off-by: Amit Arora --- fs/ext4/extents.c | 28 +++++++++++++++++++++++++--- 1 file changed, 25 insertions(+), 3 deletions(-) (limited to 'fs') diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index ded3d469f978..77146b826a13 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -1107,7 +1107,7 @@ static int ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, struct ext4_extent *ex2) { - unsigned short ext1_ee_len, ext2_ee_len; + unsigned short ext1_ee_len, ext2_ee_len, max_len; /* * Make sure that either both extents are uninitialized, or @@ -1116,6 +1116,11 @@ ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, if (ext4_ext_is_uninitialized(ex1) ^ ext4_ext_is_uninitialized(ex2)) return 0; + if (ext4_ext_is_uninitialized(ex1)) + max_len = EXT_UNINIT_MAX_LEN; + else + max_len = EXT_INIT_MAX_LEN; + ext1_ee_len = ext4_ext_get_actual_len(ex1); ext2_ee_len = ext4_ext_get_actual_len(ex2); @@ -1128,7 +1133,7 @@ ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1, * as an RO_COMPAT feature, refuse to merge to extents if * this can result in the top bit of ee_len being set. */ - if (ext1_ee_len + ext2_ee_len > EXT_MAX_LEN) + if (ext1_ee_len + ext2_ee_len > max_len) return 0; #ifdef AGGRESSIVE_TEST if (le16_to_cpu(ex1->ee_len) >= 4) @@ -1815,7 +1820,11 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode, ex->ee_block = cpu_to_le32(block); ex->ee_len = cpu_to_le16(num); - if (uninitialized) + /* + * Do not mark uninitialized if all the blocks in the + * extent have been removed. + */ + if (uninitialized && num) ext4_ext_mark_uninitialized(ex); err = ext4_ext_dirty(handle, inode, path + depth); @@ -2308,6 +2317,19 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode, /* allocate new block */ goal = ext4_ext_find_goal(inode, path, iblock); + /* + * See if request is beyond maximum number of blocks we can have in + * a single extent. For an initialized extent this limit is + * EXT_INIT_MAX_LEN and for an uninitialized extent this limit is + * EXT_UNINIT_MAX_LEN. + */ + if (max_blocks > EXT_INIT_MAX_LEN && + create != EXT4_CREATE_UNINITIALIZED_EXT) + max_blocks = EXT_INIT_MAX_LEN; + else if (max_blocks > EXT_UNINIT_MAX_LEN && + create == EXT4_CREATE_UNINITIALIZED_EXT) + max_blocks = EXT_UNINIT_MAX_LEN; + /* Check if we can really insert (iblock)::(iblock+max_blocks) extent */ newex.ee_block = cpu_to_le32(iblock); newex.ee_len = cpu_to_le16(max_blocks); -- cgit v1.2.3