From df3935ffd6166fdd00702cf548fb5bb55737758b Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Wed, 6 May 2009 16:02:53 -0700 Subject: fiemap: fix problem with setting FIEMAP_EXTENT_LAST Fix a problem where the generic block based fiemap stuff would not properly set FIEMAP_EXTENT_LAST on the last extent. I've reworked things to keep track if we go past the EOF, and mark the last extent properly. The problem was reported by and tested by Eric Sandeen. Tested-by: Eric Sandeen Signed-off-by: Josef Bacik Cc: Cc: Cc: Cc: Steven Whitehouse Cc: Mark Fasheh Cc: Joel Becker Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ioctl.c | 75 +++++++++++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 55 insertions(+), 20 deletions(-) diff --git a/fs/ioctl.c b/fs/ioctl.c index ac2d47e43926..82d9c42b8bac 100644 --- a/fs/ioctl.c +++ b/fs/ioctl.c @@ -258,7 +258,7 @@ int __generic_block_fiemap(struct inode *inode, long long length = 0, map_len = 0; u64 logical = 0, phys = 0, size = 0; u32 flags = FIEMAP_EXTENT_MERGED; - int ret = 0; + int ret = 0, past_eof = 0, whole_file = 0; if ((ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC))) return ret; @@ -266,6 +266,9 @@ int __generic_block_fiemap(struct inode *inode, start_blk = logical_to_blk(inode, start); length = (long long)min_t(u64, len, i_size_read(inode)); + if (length < len) + whole_file = 1; + map_len = length; do { @@ -282,11 +285,26 @@ int __generic_block_fiemap(struct inode *inode, /* HOLE */ if (!buffer_mapped(&tmp)) { + length -= blk_to_logical(inode, 1); + 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) >= + blk_to_logical(inode, 0)+i_size_read(inode)) + past_eof = 1; + /* * first hole after going past the EOF, this is our * last extent */ - if (length <= 0) { + if (past_eof && size) { flags = FIEMAP_EXTENT_MERGED|FIEMAP_EXTENT_LAST; ret = fiemap_fill_next_extent(fieinfo, logical, phys, size, @@ -294,15 +312,37 @@ int __generic_block_fiemap(struct inode *inode, break; } - length -= blk_to_logical(inode, 1); - /* if we have holes up to/past EOF then we're done */ - if (length <= 0) + if (length <= 0 || past_eof) break; - - start_blk++; } else { - if (length <= 0 && size) { + /* + * 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 (length <= 0 && !whole_file) { + ret = fiemap_fill_next_extent(fieinfo, logical, + phys, size, + flags); + 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); @@ -319,19 +359,14 @@ int __generic_block_fiemap(struct inode *inode, start_blk += logical_to_blk(inode, size); /* - * if we are past the EOF we need to loop again to see - * if there is a hole so we can mark this extent as the - * last one, and if not keep mapping things until we - * find a hole, or we run out of slots in the extent - * array + * 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 (length <= 0) - continue; - - ret = fiemap_fill_next_extent(fieinfo, logical, phys, - size, flags); - if (ret) - break; + if (!past_eof && + logical+size >= + blk_to_logical(inode, 0)+i_size_read(inode)) + past_eof = 1; } cond_resched(); } while (1); -- cgit v1.2.3