[PATCH 6/7] ext4: support new modes in ext4

Amit K. Arora
2007-07-10T20:24:41Z

From: Amit Arora <aarora@in.ibm.com>
Support new values of mode in ext4.

This patch supports new mode values/flags in ext4. With this patch ext4
will be able to support FALLOC_ALLOCATE and FALLOC_RESV_SPACE modes. Supporting
FALLOC_DEALLOCATE and FALLOC_UNRESV_SPACE fallocate modes in ext4 is a work for
future.

Signed-off-by: Amit Arora <aarora@in.ibm.com>

Index: linux-2.6.22/fs/ext4/extents.c
===================================================================
--- linux-2.6.22.orig/fs/ext4/extents.c
+++ linux-2.6.22/fs/ext4/extents.c
@@ -2453,8 +2453,9 @@ int ext4_ext_writepage_trans_blocks(stru
/*
* preallocate space for a file. This implements ext4's fallocate inode
* operation, which gets called from sys_fallocate system call.
- * Currently only FA_ALLOCATE mode is supported on extent based files.
- * We may have more modes supported in future - like FA_DEALLOCATE, which
+ * Currently only FALLOC_ALLOCATE and FALLOC_RESV_SPACE modes are supported on
+ * extent based files.
+ * We may have more modes supported in future - like FALLOC_DEALLOCATE, which
* tells fallocate to unallocate previously (pre)allocated blocks.
* For block-mapped files, posix_fallocate should fall back to the method
* of writing zeroes to the required new blocks (the same behavior which is
@@ -2475,7 +2476,8 @@ long ext4_fallocate(struct inode *inode,
* currently supporting (pre)allocate mode for extent-based
* files _only_
*/
- if (mode != FA_ALLOCATE || !(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
+ if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) ||
+ !(mode == FALLOC_ALLOCATE || mode == FALLOC_RESV_SPACE))
return -EOPNOTSUPP;

/* preallocation to directories is currently not supported */
@@ -2548,9 +2550,11 @@ retry:

/*
* Time to update the file size.
- * Update only when preallocation was requested beyond the file size.
+ * Update only when preallocation was requested beyond the file size
+ * and when FALLOC_FL_KEEP_SIZE mode is not specified!
*/
- if ((offset + len) > i_size_read(inode)) {
+ if (!(mode & FALLOC_FL_KEEP_SIZE) &&
+ (offset + len) > i_size_read(inode)) {
if (ret > 0) {
/*
* if no error, we assume preallocation succeeded