kernel/git/stable/linux.git/fs/gfs2/bmap.c, branch linux-4.16.y

gfs2: Check for the end of metadata in punch_hole

2018-05-30T06:17:30+00:00

[ Upstream commit bb491ce67aa7c1635e5ae4f2f304a7d13d3dbe71 ] When punching a hole or truncating an inode down to a given size, also check if the truncate point / start of the hole is within the range we have metadata for. Otherwise, we can end up freeing blocks that shouldn't be freed, corrupting the inode, or crashing the machine when trying to punch a hole into the void. When growing an inode via truncate, we set the new size but we don't allocate additional levels of indirect blocks and grow the inode height. When shrinking that inode again, the new size may still point beyond the end of the inode's metadata. Fixes xfstest generic/476. Debugged-by: Bob Peterson Signed-off-by: Andreas Gruenbacher Signed-off-by: Bob Peterson Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

gfs2: Fixes to "Implement iomap for block_map" (2)

2018-03-07T18:40:38+00:00

It turns out that commit 3229c18c0d6b2 'Fixes to "Implement iomap for block_map"' introduced another bug in gfs2_iomap_begin that can cause gfs2_block_map to set bh->b_size of an actual buffer to 0. This can lead to arbitrary incorrect behavior including crashes or disk corruption. Revert the incorrect part of that commit. Signed-off-by: Andreas Gruenbacher Signed-off-by: Bob Peterson

gfs2: Fixes to "Implement iomap for block_map"

2018-02-13T20:38:10+00:00

It turns out that commit 3974320ca6 "Implement iomap for block_map" introduced a few bugs that trigger occasional failures with xfstest generic/476: In gfs2_iomap_begin, we jump to do_alloc when we determine that we are beyond the end of the allocated metadata (height > ip->i_height). There, we can end up calling hole_size with a metapath that doesn't match the current metadata tree, which doesn't make sense. After untangling the code at do_alloc, fix this by checking if the block we are looking for is within the range of allocated metadata. In addition, add a BUG() in case gfs2_iomap_begin is accidentally called for reading stuffed files: this is handled separately. Make sure we don't truncate iomap->length for reads beyond the end of the file; in that case, the entire range counts as a hole. Finally, revert to taking a bitmap write lock when doing allocations. It's unclear why that change didn't lead to any failures during testing. Signed-off-by: Andreas Gruenbacher Signed-off-by: Bob Peterson

gfs2: Add gfs2_max_stuffed_size

2018-01-18T21:18:53+00:00

Add a small inline function for computing the maximum size of a stuffed inode instead of open coding that in several places throughout the code. Signed-off-by: Andreas Gruenbacher Signed-off-by: Bob Peterson

gfs2: Implement fallocate(FALLOC_FL_PUNCH_HOLE)

2018-01-18T20:15:58+00:00

Implement the top-level bits of punching a hole into a file. Signed-off-by: Andreas Gruenbacher Signed-off-by: Bob Peterson

gfs2: Turn trunc_dealloc into punch_hole

2018-01-18T20:15:57+00:00

Add an upper bound to the range of blocks to deallocate blocks to function trunc_dealloc so that this function can be used for truncating a file as well as for punching a hole into a file. Signed-off-by: Andreas Gruenbacher Signed-off-by: Bob Peterson

gfs2: Generalize truncate code

2018-01-18T20:15:37+00:00

Pull the code for computing the range of metapointers to iterate out of gfs2_metapath_ra (for readahead), sweep_bh_for_rgrps (for deallocating metapointers within a block), and trunc_dealloc (for walking the metadata tree). In sweep_bh_for_rgrps, move the code for looking up the resource group descriptor of the current resource group out of the inner loop. The metatype check moves to trunc_dealloc. Signed-off-by: Andreas Gruenbacher Signed-off-by: Bob Peterson

Turn gfs2_block_truncate_page into gfs2_block_zero_range

2018-01-17T13:35:53+00:00

Turn gfs2_block_truncate_page into a function that zeroes a range within a block rather than only the end of a block. This will be used for cleaning the end of the first partial block and the start of the last partial block when punching a hole in a file. Signed-off-by: Andreas Gruenbacher Signed-off-by: Bob Peterson

gfs2: Improve non-recursive delete algorithm

2018-01-17T13:35:52+00:00

In rare cases, the current non-recursive delete algorithm doesn't deallocate empty intermediary indirect blocks. This should have very little practical effect, but deallocating all blocks correctly should still be preferable as it is cleaner and easier to validate. The fix consists of using the first block to deallocate to compute the start marker of the truncate point instead of the last block that needs to be kept. With that change, computing which indirect blocks are still needed becomes relatively easy. Signed-off-by: Andreas Gruenbacher Signed-off-by: Bob Peterson

gfs2: Fix metadata read-ahead during truncate

2018-01-17T13:35:50+00:00

The metadata read-ahead algorithm broke when switching from recursive to non-recursive delete: the current algorithm reads ahead blocks at height N - 1 while deallocating the blocks at hight N. However, deallocating the blocks at height N requires a complete walk of the metadata tree, not only down to height N - 1. Consequently, all blocks below height N - 1 will be accessed without read-ahead. Fix this by issuing read-aheads as early as possible, after each metapath lookup. Signed-off-by: Andreas Gruenbacher Signed-off-by: Bob Peterson