kernel.git/fs/ext4/mballoc.c, branch linux-4.7.y

ext4: fix reference counting bug on block allocation error

2016-08-16T07:35:00Z

commit 554a5ccc4e4a20c5f3ec859de0842db4b4b9c77e upstream. If we hit this error when mounted with errors=continue or errors=remount-ro: EXT4-fs error (device loop0): ext4_mb_mark_diskspace_used:2940: comm ext4.exe: Allocating blocks 5090-6081 which overlap fs metadata then ext4_mb_new_blocks() will call ext4_mb_release_context() and try to continue. However, ext4_mb_release_context() is the wrong thing to call here since we are still actually using the allocation context. Instead, just error out. We could retry the allocation, but there is a possibility of getting stuck in an infinite loop instead, so this seems safer. [ Fixed up so we don't return EAGAIN to userspace. --tytso ] Fixes: 8556e8f3b6 ("ext4: Don't allow new groups to be added during block allocation") Signed-off-by: Vegard Nossum Signed-off-by: Theodore Ts'o Cc: Aneesh Kumar K.V Signed-off-by: Greg Kroah-Hartman

ext4: silence UBSAN in ext4_mb_init()

2016-05-05T23:46:19Z

Currently, in ext4_mb_init(), there's a loop like the following: do { ... offset += 1 << (sb->s_blocksize_bits - i); i++; } while (i <= sb->s_blocksize_bits + 1); Note that the updated offset is used in the loop's next iteration only. However, at the last iteration, that is at i == sb->s_blocksize_bits + 1, the shift count becomes equal to (unsigned)-1 > 31 (c.f. C99 6.5.7(3)) and UBSAN reports UBSAN: Undefined behaviour in fs/ext4/mballoc.c:2621:15 shift exponent 4294967295 is too large for 32-bit type 'int' [...] Call Trace: [] dump_stack+0xbc/0x117 [] ? _atomic_dec_and_lock+0x169/0x169 [] ubsan_epilogue+0xd/0x4e [] __ubsan_handle_shift_out_of_bounds+0x1fb/0x254 [] ? __ubsan_handle_load_invalid_value+0x158/0x158 [] ? kmem_cache_alloc+0x101/0x390 [] ? ext4_mb_init+0x13b/0xfd0 [] ? create_cache+0x57/0x1f0 [] ? create_cache+0x11a/0x1f0 [] ? mutex_lock+0x38/0x60 [] ? mutex_unlock+0x1b/0x50 [] ? put_online_mems+0x5b/0xc0 [] ? kmem_cache_create+0x117/0x2c0 [] ext4_mb_init+0xc49/0xfd0 [...] Observe that the mentioned shift exponent, 4294967295, equals (unsigned)-1. Unless compilers start to do some fancy transformations (which at least GCC 6.0.0 doesn't currently do), the issue is of cosmetic nature only: the such calculated value of offset is never used again. Silence UBSAN by introducing another variable, offset_incr, holding the next increment to apply to offset and adjust that one by right shifting it by one position per loop iteration. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=114701 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=112161 Cc: stable@vger.kernel.org Signed-off-by: Nicolai Stange Signed-off-by: Theodore Ts'o

ext4: address UBSAN warning in mb_find_order_for_block()

2016-05-05T21:38:03Z

Currently, in mb_find_order_for_block(), there's a loop like the following: while (order <= e4b->bd_blkbits + 1) { ... bb += 1 << (e4b->bd_blkbits - order); } Note that the updated bb is used in the loop's next iteration only. However, at the last iteration, that is at order == e4b->bd_blkbits + 1, the shift count becomes negative (c.f. C99 6.5.7(3)) and UBSAN reports UBSAN: Undefined behaviour in fs/ext4/mballoc.c:1281:11 shift exponent -1 is negative [...] Call Trace: [] dump_stack+0xbc/0x117 [] ? _atomic_dec_and_lock+0x169/0x169 [] ubsan_epilogue+0xd/0x4e [] __ubsan_handle_shift_out_of_bounds+0x1fb/0x254 [] ? __ubsan_handle_load_invalid_value+0x158/0x158 [] ? ext4_mb_generate_from_pa+0x590/0x590 [] ? ext4_read_block_bitmap_nowait+0x598/0xe80 [] mb_find_order_for_block+0x1ce/0x240 [...] Unless compilers start to do some fancy transformations (which at least GCC 6.0.0 doesn't currently do), the issue is of cosmetic nature only: the such calculated value of bb is never used again. Silence UBSAN by introducing another variable, bb_incr, holding the next increment to apply to bb and adjust that one by right shifting it by one position per loop iteration. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=114701 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=112161 Cc: stable@vger.kernel.org Signed-off-by: Nicolai Stange Signed-off-by: Theodore Ts'o

ext4: remove trailing \n from ext4_warning/ext4_error calls

2016-04-27T05:11:21Z

Messages passed to ext4_warning() or ext4_error() don't need trailing newlines, because these function add the newlines themselves. Signed-off-by: Jakub Wilk

mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage

2016-04-04T17:41:08Z

Mostly direct substitution with occasional adjustment or removing outdated comments. Signed-off-by: Kirill A. Shutemov Acked-by: Michal Hocko Signed-off-by: Linus Torvalds

mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros

2016-04-04T17:41:08Z

PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ; - >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> ; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov Acked-by: Michal Hocko Signed-off-by: Linus Torvalds

ext4: use __GFP_NOFAIL in ext4_free_blocks()

2016-03-13T21:29:06Z

This might be unexpected but pages allocated for sbi->s_buddy_cache are charged to current memory cgroup. So, GFP_NOFS allocation could fail if current task has been killed by OOM or if current memory cgroup has no free memory left. Block allocator cannot handle such failures here yet. Signed-off-by: Konstantin Khlebnikov Signed-off-by: Theodore Ts'o

ext4: fix misspellings in comments.

2016-03-10T04:49:05Z

Signed-off-by: Adam Buchbinder Signed-off-by: Theodore Ts'o

ext4: make sure to revoke all the freeable blocks in ext4_free_blocks

2016-02-21T23:31:41Z

Now, ext4_free_blocks() doesn't revoke data blocks of per-file data journalled inode and it can cause file data inconsistency problems. Even though data blocks of per-file data journalled inode are already forgotten by jbd2_journal_invalidatepage() in advance of invoking ext4_free_blocks(), we still need to revoke the data blocks here. Moreover some of the metadata blocks, which are not found by sb_find_get_block(), are still needed to be revoked, but this is also missing here. Signed-off-by: Daeho Jeong Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara

ext4: add a line break for proc mb_groups display

2016-02-12T05:17:16Z

This patch adds a line break for proc mb_groups display. Signed-off-by: Huaitong Han Signed-off-by: Theodore Ts'o Reviewed-by: Andreas Dilger