From 9a950d52b7f0e1c64c2cc70d350562fb18c8b451 Mon Sep 17 00:00:00 2001 From: Fan Li Date: Sat, 26 Dec 2015 18:07:41 +0800 Subject: [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 Signed-off-by: Jaegeuk Kim --- 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 5c43b2d606ec..d67c599510d9 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 @@ int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, /* 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; -- GitLab