There are a few redundant branches in this function and if there are
more than two blocks of holes after the last extent of file, it
would fail to add FIEMAP_EXTENT_LAST to the last extent.
Simplify the codes in this patch.
Signed-off-by: Fan Li <fanofcode.li@xxxxxxxxxxx>
---
fs/ioctl.c | 99 ++++++++++++++----------------------------------------------
1 file changed, 23 insertions(+), 76 deletions(-)
diff --git a/fs/ioctl.c b/fs/ioctl.c
index 5d54377..04e4120 100644
--- a/fs/ioctl.c
+++ b/fs/ioctl.c
@@ -256,7 +256,6 @@ int __generic_block_fiemap(struct inode *inode,
loff_t isize = i_size_read(inode);
u64 logical = 0, phys = 0, size = 0;
u32 flags = FIEMAP_EXTENT_MERGED;
- bool past_eof = false, whole_file = false;
int ret = 0;
ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);
@@ -271,10 +270,8 @@ int __generic_block_fiemap(struct inode *inode,
if (start >= isize)
return 0;
- if (start + len > isize) {
- whole_file = true;
+ if (start + len > isize)
len = isize - start;
- }
start_blk = logical_to_blk(inode, start);
last_blk = logical_to_blk(inode, start + len - 1);
@@ -300,91 +297,41 @@ int __generic_block_fiemap(struct inode *inode,
if (!buffer_mapped(&map_bh)) {
start_blk++;
- /*
- * We want to handle the case where there is an
- * allocated block at the front of the file, and then
- * nothing but holes up to the end of the file properly,
- * to make sure that extent at the front gets properly
- * marked with FIEMAP_EXTENT_LAST
- */
- if (!past_eof &&
- blk_to_logical(inode, start_blk) >= isize)
- past_eof = 1;
-
+ /* Skip holes unless it indicates the EOF */
+ if (blk_to_logical(inode, start_blk) < isize)
+ goto next;
/*
* First hole after going past the EOF, this is our
* last extent
*/
- if (past_eof && size) {
- flags = FIEMAP_EXTENT_MERGED|FIEMAP_EXTENT_LAST;
- ret = fiemap_fill_next_extent(fieinfo, logical,
- phys, size,
- flags);
- } else if (size) {
- ret = fiemap_fill_next_extent(fieinfo, logical,
- phys, size, flags);
- size = 0;
- }
-
- /* if we have holes up to/past EOF then we're done */
- if (start_blk > last_blk || past_eof || ret)
- break;
- } else {
- /*
- * We have gone over the length of what we wanted to
- * map, and it wasn't the entire file, so add the extent
- * we got last time and exit.
- *
- * This is for the case where say we want to map all the
- * way up to the second to the last block in a file, but
- * the last block is a hole, making the second to last
- * block FIEMAP_EXTENT_LAST. In this case we want to
- * see if there is a hole after the second to last block
- * so we can mark it properly. If we found data after
- * we exceeded the length we were requesting, then we
- * are good to go, just add the extent to the fieinfo
- * and break
- */
- if (start_blk > last_blk && !whole_file) {
- ret = fiemap_fill_next_extent(fieinfo, logical,
- phys, size,
- flags);
- break;
- }
+ flags |= FIEMAP_EXTENT_LAST;
+ }
- /*
- * if size != 0 then we know we already have an extent
- * to add, so add it.
- */
- if (size) {
- ret = fiemap_fill_next_extent(fieinfo, logical,
- phys, size,
- flags);
- if (ret)
- break;
- }
+ /*
+ * if size != 0 then we know we already have an extent
+ * to add, so add it.
+ */
+ if (size)
+ ret = fiemap_fill_next_extent(fieinfo, logical,
+ phys, size,
+ flags);
- logical = blk_to_logical(inode, start_blk);
- phys = blk_to_logical(inode, map_bh.b_blocknr);
- size = map_bh.b_size;
- flags = FIEMAP_EXTENT_MERGED;
+ if (start_blk > last_blk || ret)
+ break;
- start_blk += logical_to_blk(inode, size);
+ /* reset values for the next extent */
+ logical = blk_to_logical(inode, start_blk);
+ phys = blk_to_logical(inode, map_bh.b_blocknr);
+ size = map_bh.b_size;
+ flags = FIEMAP_EXTENT_MERGED;
- /*
- * If we are past the EOF, then we need to make sure as
- * soon as we find a hole that the last extent we found
- * is marked with FIEMAP_EXTENT_LAST
- */
- if (!past_eof && logical + size >= isize)
- past_eof = true;
- }
+ start_blk += logical_to_blk(inode, size);
+next:
cond_resched();
if (fatal_signal_pending(current)) {
ret = -EINTR;
break;
}
-
} while (1);
/* If ret is 1 then we just hit the end of the extent array */
--
1.7.9.5
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