linux-stable.git/fs/ext4, branch v3.16.52

ext4: fix overflow caused by missing cast in ext4_resize_fs()

2017-11-11T13:33:16+00:00

commit aec51758ce10a9c847a62a48a168f8c804c6e053 upstream.

On a 32-bit platform, the value of n_blcoks_count may be wrong during
the file system is resized to size larger than 2^32 blocks.  This may
caused the superblock being corrupted with zero blocks count.

Fixes: 1c6bd7173d66
Signed-off-by: Jerry Lee 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Ben Hutchings

ext4: fix SEEK_HOLE/SEEK_DATA for blocksize < pagesize

2017-11-11T13:33:16+00:00

commit fcf5ea10992fbac3c7473a1db33d56a139333cd1 upstream.

ext4_find_unwritten_pgoff() does not properly handle a situation when
starting index is in the middle of a page and blocksize < pagesize. The
following command shows the bug on filesystem with 1k blocksize:

  xfs_io -f -c "falloc 0 4k" \
            -c "pwrite 1k 1k" \
            -c "pwrite 3k 1k" \
            -c "seek -a -r 0" foo

In this example, neither lseek(fd, 1024, SEEK_HOLE) nor lseek(fd, 2048,
SEEK_DATA) will return the correct result.

Fix the problem by neglecting buffers in a page before starting offset.

Reported-by: Andreas Gruenbacher 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Jan Kara 
Signed-off-by: Ben Hutchings

ext4: Don't clear SGID when inheriting ACLs

2017-10-12T14:28:09+00:00

commit a3bb2d5587521eea6dab2d05326abb0afb460abd upstream.

When new directory 'DIR1' is created in a directory 'DIR0' with SGID bit
set, DIR1 is expected to have SGID bit set (and owning group equal to
the owning group of 'DIR0'). However when 'DIR0' also has some default
ACLs that 'DIR1' inherits, setting these ACLs will result in SGID bit on
'DIR1' to get cleared if user is not member of the owning group.

Fix the problem by moving posix_acl_update_mode() out of
__ext4_set_acl() into ext4_set_acl(). That way the function will not be
called when inheriting ACLs which is what we want as it prevents SGID
bit clearing and the mode has been properly set by posix_acl_create()
anyway.

Fixes: 073931017b49d9458aa351605b43a7e34598caef
Signed-off-by: Theodore Ts'o 
Signed-off-by: Jan Kara 
Reviewed-by: Andreas Gruenbacher 
[bwh: Backported to 3.16:
 - Keep using ext4_current_time()
 - Adjust context]
Signed-off-by: Ben Hutchings

ext4: preserve i_mode if __ext4_set_acl() fails

2017-10-12T14:28:09+00:00

commit 397e434176bb62bc6068d2210af1d876c6212a7e upstream.

When changing a file's acl mask, __ext4_set_acl() will first set the group
bits of i_mode to the value of the mask, and only then set the actual
extended attribute representing the new acl.

If the second part fails (due to lack of space, for example) and the file
had no acl attribute to begin with, the system will from now on assume
that the mask permission bits are actual group permission bits, potentially
granting access to the wrong users.

Prevent this by only changing the inode mode after the acl has been set.

Signed-off-by: Ernesto A. Fernández 
Signed-off-by: Theodore Ts'o 
Reviewed-by: Jan Kara 
[bwh: Backported to 3.16: keep using ext4_current_time()]
Signed-off-by: Ben Hutchings

ext4: fix fdatasync(2) after extent manipulation operations

2017-09-15T17:29:52+00:00

commit 67a7d5f561f469ad2fa5154d2888258ab8e6df7c upstream.

Currently, extent manipulation operations such as hole punch, range
zeroing, or extent shifting do not record the fact that file data has
changed and thus fdatasync(2) has a work to do. As a result if we crash
e.g. after a punch hole and fdatasync, user can still possibly see the
punched out data after journal replay. Test generic/392 fails due to
these problems.

Fix the problem by properly marking that file data has changed in these
operations.

Fixes: a4bb6b64e39abc0e41ca077725f2a72c868e7622
Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o 
[bwh: Backported to 3.16: drop change in ext4_insert_range()]
Signed-off-by: Ben Hutchings

ext4: fix data corruption for mmap writes

2017-09-15T17:29:52+00:00

commit a056bdaae7a181f7dcc876cfab2f94538e508709 upstream.

mpage_submit_page() can race with another process growing i_size and
writing data via mmap to the written-back page. As mpage_submit_page()
samples i_size too early, it may happen that ext4_bio_write_page()
zeroes out too large tail of the page and thus corrupts user data.

Fix the problem by sampling i_size only after the page has been
write-protected in page tables by clear_page_dirty_for_io() call.

Reported-by: Michael Zimmer 
Fixes: cb20d5188366f04d96d2e07b1240cc92170ade40
Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

ext4: handle the rest of ext4_mb_load_buddy() ENOMEM errors

2017-09-15T17:29:48+00:00

commit 9651e6b2e20648d04d5e1fe6479a3056047e8781 upstream.

I've got another report about breaking ext4 by ENOMEM error returned from
ext4_mb_load_buddy() caused by memory shortage in memory cgroup.
This time inside ext4_discard_preallocations().

This patch replaces ext4_error() with ext4_warning() where errors returned
from ext4_mb_load_buddy() are not fatal and handled by caller:
* ext4_mb_discard_group_preallocations() - called before generating ENOSPC,
  we'll try to discard other group or return ENOSPC into user-space.
* ext4_trim_all_free() - just stop trimming and return ENOMEM from ioctl.

Some callers cannot handle errors, thus __GFP_NOFAIL is used for them:
* ext4_discard_preallocations()
* ext4_mb_discard_lg_preallocations()

Fixes: adb7ef600cc9 ("ext4: use __GFP_NOFAIL in ext4_free_blocks()")
Signed-off-by: Konstantin Khlebnikov 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Ben Hutchings

ext4: use __GFP_NOFAIL in ext4_free_blocks()

2017-09-15T17:29:48+00:00

commit adb7ef600cc9d9d15ecc934cc26af5c1379777df upstream.

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 
Signed-off-by: Ben Hutchings

ext4: keep existing extra fields when inode expands

2017-09-15T17:29:47+00:00

commit 887a9730614727c4fff7cb756711b190593fc1df upstream.

ext4_expand_extra_isize() should clear only space between old and new
size.

Fixes: 6dd4ee7cab7e # v2.6.23
Signed-off-by: Konstantin Khlebnikov 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Ben Hutchings

ext4: fix SEEK_HOLE

2017-09-15T17:29:47+00:00

commit 7d95eddf313c88b24f99d4ca9c2411a4b82fef33 upstream.

Currently, SEEK_HOLE implementation in ext4 may both return that there's
a hole at some offset although that offset already has data and skip
some holes during a search for the next hole. The first problem is
demostrated by:

xfs_io -c "falloc 0 256k" -c "pwrite 0 56k" -c "seek -h 0" file
wrote 57344/57344 bytes at offset 0
56 KiB, 14 ops; 0.0000 sec (2.054 GiB/sec and 538461.5385 ops/sec)
Whence	Result
HOLE	0

Where we can see that SEEK_HOLE wrongly returned offset 0 as containing
a hole although we have written data there. The second problem can be
demonstrated by:

xfs_io -c "falloc 0 256k" -c "pwrite 0 56k" -c "pwrite 128k 8k"
       -c "seek -h 0" file

wrote 57344/57344 bytes at offset 0
56 KiB, 14 ops; 0.0000 sec (1.978 GiB/sec and 518518.5185 ops/sec)
wrote 8192/8192 bytes at offset 131072
8 KiB, 2 ops; 0.0000 sec (2 GiB/sec and 500000.0000 ops/sec)
Whence	Result
HOLE	139264

Where we can see that hole at offsets 56k..128k has been ignored by the
SEEK_HOLE call.

The underlying problem is in the ext4_find_unwritten_pgoff() which is
just buggy. In some cases it fails to update returned offset when it
finds a hole (when no pages are found or when the first found page has
higher index than expected), in some cases conditions for detecting hole
are just missing (we fail to detect a situation where indices of
returned pages are not contiguous).

Fix ext4_find_unwritten_pgoff() to properly detect non-contiguous page
indices and also handle all cases where we got less pages then expected
in one place and handle it properly there.

Fixes: c8c0df241cc2719b1262e627f999638411934f60
CC: Zheng Liu 
Signed-off-by: Jan Kara 
Signed-off-by: Theodore Ts'o 
Signed-off-by: Ben Hutchings