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Message-id: <001601d13fc5$588bd000$09a37000$@samsung.com>
Date: Sat, 26 Dec 2015 18:07:41 +0800
From: Fan Li <fanofcode.li@...sung.com>
To: 'Jaegeuk Kim' <jaegeuk@...nel.org>
Cc: linux-f2fs-devel@...ts.sourceforge.net,
linux-kernel@...r.kernel.org
Subject: [f2fs-dev] [PATCH] f2fs: fix bugs and simplify codes of f2fs_fiemap
fix bugs:
1. len could be updated incorrectly when start+len is beyond isize.
2. If there is a hole consisting of more than two blocks, it could
fail to add FIEMAP_EXTENT_LAST flag for the last extent.
3. If there is an extent beyond isize, when we search extents in a range
that ends at isize, it will also return the extent beyond isize,
which is outside the range.
Signed-off-by: Fan li <fanofcode.li@...sung.com>
---
fs/f2fs/data.c | 80 +++++++++++++++++++-------------------------------------
1 file changed, 27 insertions(+), 53 deletions(-)
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 5c43b2d..d67c599 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -783,7 +783,6 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
loff_t isize = i_size_read(inode);
u64 logical = 0, phys = 0, size = 0;
u32 flags = 0;
- bool past_eof = false, whole_file = false;
int ret = 0;
ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);
@@ -797,17 +796,18 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
}
mutex_lock(&inode->i_mutex);
+ if (start >= isize)
+ goto out;
- if (len >= isize) {
- whole_file = true;
- len = isize;
- }
+ if (start + len > isize)
+ len = isize - start;
if (logical_to_blk(inode, len) == 0)
len = blk_to_logical(inode, 1);
start_blk = logical_to_blk(inode, start);
last_blk = logical_to_blk(inode, start + len - 1);
+
next:
memset(&map_bh, 0, sizeof(struct buffer_head));
map_bh.b_size = len;
@@ -819,59 +819,33 @@ next:
/* HOLE */
if (!buffer_mapped(&map_bh)) {
- start_blk++;
-
- if (!past_eof && blk_to_logical(inode, start_blk) >= isize)
- past_eof = 1;
-
- if (past_eof && size) {
- flags |= 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;
- }
+ /* Go through holes util pass the EOF */
+ if (blk_to_logical(inode, start_blk++) < isize)
+ goto prep_next;
+ /* Found a hole beyond isize means no more extents.
+ * Note that the premise is that filesystems don't
+ * punch holes beyond isize and keep size unchanged.
+ */
+ flags |= FIEMAP_EXTENT_LAST;
+ }
- /* if we have holes up to/past EOF then we're done */
- if (start_blk > last_blk || past_eof || ret)
- goto out;
- } else {
- if (start_blk > last_blk && !whole_file) {
- ret = fiemap_fill_next_extent(fieinfo, logical,
- phys, size, flags);
- goto out;
- }
+ if (size)
+ ret = fiemap_fill_next_extent(fieinfo, logical,
+ phys, size, flags);
- /*
- * 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)
- goto out;
- }
+ if (start_blk > last_blk || ret)
+ goto out;
- logical = blk_to_logical(inode, start_blk);
- phys = blk_to_logical(inode, map_bh.b_blocknr);
- size = map_bh.b_size;
- flags = 0;
- if (buffer_unwritten(&map_bh))
- flags = FIEMAP_EXTENT_UNWRITTEN;
+ logical = blk_to_logical(inode, start_blk);
+ phys = blk_to_logical(inode, map_bh.b_blocknr);
+ size = map_bh.b_size;
+ flags = 0;
+ if (buffer_unwritten(&map_bh))
+ flags = FIEMAP_EXTENT_UNWRITTEN;
- start_blk += logical_to_blk(inode, size);
+ start_blk += logical_to_blk(inode, size);
- /*
- * 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;
- }
+prep_next:
cond_resched();
if (fatal_signal_pending(current))
ret = -EINTR;
--
1.7.9.5
--
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