All users of pagevec_lookup() and pagevec_lookup_range() now pass
PAGEVEC_SIZE as a desired number of pages.
Just drop the argument.
Link: http://lkml.kernel.org/r/20170726114704.7626-11-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Both occurences of pagevec_lookup() actually want only pages from a
given range. Use pagevec_lookup_range() for the lookup.
Link: http://lkml.kernel.org/r/20170726114704.7626-7-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Use pagevec_lookup_range() in ext4_find_unwritten_pgoff() since we are
interested only in pages in the given range. Simplify the logic as a
result of not getting pages out of range and index getting automatically
advanced.
Link: http://lkml.kernel.org/r/20170726114704.7626-6-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make pagevec_lookup() (and underlying find_get_pages()) update index to
the next page where iteration should continue. Most callers want this
and also pagevec_lookup_tag() already does this.
Link: http://lkml.kernel.org/r/20170726114704.7626-3-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When servicing mmap() reads from file holes the current DAX code
allocates a page cache page of all zeroes and places the struct page
pointer in the mapping->page_tree radix tree.
This has three major drawbacks:
1) It consumes memory unnecessarily. For every 4k page that is read via
a DAX mmap() over a hole, we allocate a new page cache page. This
means that if you read 1GiB worth of pages, you end up using 1GiB of
zeroed memory. This is easily visible by looking at the overall
memory consumption of the system or by looking at /proc/[pid]/smaps:
7f62e72b3000-7f63272b3000 rw-s 00000000 103:00 12 /root/dax/data
Size: 1048576 kB
Rss: 1048576 kB
Pss: 1048576 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 1048576 kB
Private_Dirty: 0 kB
Referenced: 1048576 kB
Anonymous: 0 kB
LazyFree: 0 kB
AnonHugePages: 0 kB
ShmemPmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
SwapPss: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
2) It is slower than using a common zero page because each page fault
has more work to do. Instead of just inserting a common zero page we
have to allocate a page cache page, zero it, and then insert it. Here
are the average latencies of dax_load_hole() as measured by ftrace on
a random test box:
Old method, using zeroed page cache pages: 3.4 us
New method, using the common 4k zero page: 0.8 us
This was the average latency over 1 GiB of sequential reads done by
this simple fio script:
[global]
size=1G
filename=/root/dax/data
fallocate=none
[io]
rw=read
ioengine=mmap
3) The fact that we had to check for both DAX exceptional entries and
for page cache pages in the radix tree made the DAX code more
complex.
Solve these issues by following the lead of the DAX PMD code and using a
common 4k zero page instead. As with the PMD code we will now insert a
DAX exceptional entry into the radix tree instead of a struct page
pointer which allows us to remove all the special casing in the DAX
code.
Note that we do still pretty aggressively check for regular pages in the
DAX radix tree, especially where we take action based on the bits set in
the page. If we ever find a regular page in our radix tree now that
most likely means that someone besides DAX is inserting pages (which has
happened lots of times in the past), and we want to find that out early
and fail loudly.
This solution also removes the extra memory consumption. Here is that
same /proc/[pid]/smaps after 1GiB of reading from a hole with the new
code:
7f2054a74000-7f2094a74000 rw-s 00000000 103:00 12 /root/dax/data
Size: 1048576 kB
Rss: 0 kB
Pss: 0 kB
Shared_Clean: 0 kB
Shared_Dirty: 0 kB
Private_Clean: 0 kB
Private_Dirty: 0 kB
Referenced: 0 kB
Anonymous: 0 kB
LazyFree: 0 kB
AnonHugePages: 0 kB
ShmemPmdMapped: 0 kB
Shared_Hugetlb: 0 kB
Private_Hugetlb: 0 kB
Swap: 0 kB
SwapPss: 0 kB
KernelPageSize: 4 kB
MMUPageSize: 4 kB
Locked: 0 kB
Overall system memory consumption is similarly improved.
Another major change is that we remove dax_pfn_mkwrite() from our fault
flow, and instead rely on the page fault itself to make the PTE dirty
and writeable. The following description from the patch adding the
vm_insert_mixed_mkwrite() call explains this a little more:
"To be able to use the common 4k zero page in DAX we need to have our
PTE fault path look more like our PMD fault path where a PTE entry
can be marked as dirty and writeable as it is first inserted rather
than waiting for a follow-up dax_pfn_mkwrite() =>
finish_mkwrite_fault() call.
Right now we can rely on having a dax_pfn_mkwrite() call because we
can distinguish between these two cases in do_wp_page():
case 1: 4k zero page => writable DAX storage
case 2: read-only DAX storage => writeable DAX storage
This distinction is made by via vm_normal_page(). vm_normal_page()
returns false for the common 4k zero page, though, just as it does
for DAX ptes. Instead of special casing the DAX + 4k zero page case
we will simplify our DAX PTE page fault sequence so that it matches
our DAX PMD sequence, and get rid of the dax_pfn_mkwrite() helper.
We will instead use dax_iomap_fault() to handle write-protection
faults.
This means that insert_pfn() needs to follow the lead of
insert_pfn_pmd() and allow us to pass in a 'mkwrite' flag. If
'mkwrite' is set insert_pfn() will do the work that was previously
done by wp_page_reuse() as part of the dax_pfn_mkwrite() call path"
Link: http://lkml.kernel.org/r/20170724170616.25810-4-ross.zwisler@linux.intel.com
Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When updating an extended attribute, if the padded value sizes are the
same, a shortcut is taken to avoid the bulk of the work. This was fine
until the xattr hash update was moved inside ext4_xattr_set_entry().
With that change, the hash update got missed in the shortcut case.
Thanks to ZhangYi (yizhang089@gmail.com) for root causing the problem.
Fixes: daf8328172 ("ext4: eliminate xattr entry e_hash recalculation for removes")
Reported-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Arnd Bergmann <arnd@arndb.de>
As Stefan pointed out, I misremembered what clang can do specifically,
and it turns out that the variable-length array at the end of the
structure did not work (a flexible array would have worked here
but not solved the problem):
fs/ext4/mballoc.c:2303:17: error: fields must have a constant size:
'variable length array in structure' extension will never be supported
ext4_grpblk_t counters[blocksize_bits + 2];
This reverts part of my previous patch, using a fixed-size array
again, but keeping the check for the array overflow.
Fixes: 2df2c3402f ("ext4: fix warning about stack corruption")
Reported-by: Stefan Agner <stefan@agner.ch>
Tested-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This bug was found by a static code checker tool for copy paste
problems.
Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
Signed-off-by: Vaneet Narang <v.narang@samsung.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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: 1c6bd7173d
Signed-off-by: Jerry Lee <jerrylee@qnap.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org # 3.7+
When upgrading from old format, try to set project id
to old file first time, it will return EOVERFLOW, but if
that file is dirtied(touch etc), changing project id will
be allowed, this might be confusing for users, we could
try to expand @i_extra_isize here too.
Reported-by: Zhang Yi <yi.zhang@huawei.com>
Signed-off-by: Miao Xie <miaoxie@huawei.com>
Signed-off-by: Wang Shilong <wshilong@ddn.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Clean up some goto statement, make ext4_expand_extra_isize_ea() clearer.
Signed-off-by: Miao Xie <miaoxie@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Wang Shilong <wshilong@ddn.com>
Current ext4_expand_extra_isize just tries to expand extra isize, if
someone is holding xattr lock or some check fails, it will give up.
So rename its name to ext4_try_to_expand_extra_isize.
Besides that, we clean up unnecessary check and move some relative checks
into it.
Signed-off-by: Miao Xie <miaoxie@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Wang Shilong <wshilong@ddn.com>
We should avoid the contention between the i_extra_isize update and
the inline data insertion, so move the xattr trylock in front of
i_extra_isize update.
Signed-off-by: Miao Xie <miaoxie@huawei.com>
Reviewed-by: Wang Shilong <wshilong@ddn.com>
ext4_xattr_inode_read() currently reads each block sequentially while
waiting for io operation to complete before moving on to the next
block. This prevents request merging in block layer.
Add a ext4_bread_batch() function that starts reads for all blocks
then optionally waits for them to complete. A similar logic is used
in ext4_find_entry(), so update that code to use the new function.
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When an xattr block has a single reference, block is updated inplace
and it is reinserted to the cache. Later, a cache lookup is performed
to see whether an existing block has the same contents. This cache
lookup will most of the time return the just inserted entry so
deduplication is not achieved.
Running the following test script will produce two xattr blocks which
can be observed in "File ACL: " line of debugfs output:
mke2fs -b 1024 -I 128 -F -O extent /dev/sdb 1G
mount /dev/sdb /mnt/sdb
touch /mnt/sdb/{x,y}
setfattr -n user.1 -v aaa /mnt/sdb/x
setfattr -n user.2 -v bbb /mnt/sdb/x
setfattr -n user.1 -v aaa /mnt/sdb/y
setfattr -n user.2 -v bbb /mnt/sdb/y
debugfs -R 'stat x' /dev/sdb | cat
debugfs -R 'stat y' /dev/sdb | cat
This patch defers the reinsertion to the cache so that we can locate
other blocks with the same contents.
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
ext4_alloc_file_blocks() does not use its mode parameter. Remove it.
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
After commit 62d1034f53e3 ("fortify: use WARN instead of BUG for now"),
we get a warning about possible stack overflow from a memcpy that
was not strictly bounded to the size of the local variable:
inlined from 'ext4_mb_seq_groups_show' at fs/ext4/mballoc.c:2322:2:
include/linux/string.h:309:9: error: '__builtin_memcpy': writing between 161 and 1116 bytes into a region of size 160 overflows the destination [-Werror=stringop-overflow=]
We actually had a bug here that would have been found by the warning,
but it was already fixed last year in commit 30a9d7afe7 ("ext4: fix
stack memory corruption with 64k block size").
This replaces the fixed-length structure on the stack with a variable-length
structure, using the correct upper bound that tells the compiler that
everything is really fine here. I also change the loop count to check
for the same upper bound for consistency, but the existing code is
already correct here.
Note that while clang won't allow certain kinds of variable-length arrays
in structures, this particular instance is fine, as the array is at the
end of the structure, and the size is strictly bounded.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The dir_nlink feature has been enabled by default for new ext4
filesystems since e2fsprogs-1.41 in 2008, and was automatically
enabled by the kernel for older ext4 filesystems since the
dir_nlink feature was added with ext4 in kernel 2.6.28+ when
the subdirectory count exceeded EXT4_LINK_MAX-1.
Automatically adding the file system features such as dir_nlink is
generally frowned upon, since it could cause the file system to not be
mountable on older kernel, thus preventing the administrator from
rolling back to an older kernel if necessary.
In this case, the administrator might also want to disable the feature
because glibc's fts_read() function does not correctly optimize
directory traversal for directories that use st_nlinks field of 1 to
indicate that the number of links in the directory are not tracked by
the file system, and could fail to traverse the full directory
hierarchy. Fortunately, in the past ten years very few users have
complained about incomplete file system traversal by glibc's
fts_read().
This commit also changes ext4_inc_count() to allow i_nlinks to reach
the full EXT4_LINK_MAX links on the parent directory (including "."
and "..") before changing i_links_count to be 1.
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=196405
Signed-off-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
I get a static checker warning:
fs/ext4/ext4.h:3091 ext4_set_de_type()
error: buffer overflow 'ext4_type_by_mode' 15 <= 15
It seems unlikely that we would hit this read overflow in real life, but
it's also simple enough to make the array 16 bytes instead of 15.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
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 <agruenba@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
CC: stable@vger.kernel.org # 3.8+
We've changed the discard command handling into parallel manner.
But, in this change, I forgot decreasing the usage count of the bio
which was used to send discard request. I'm sorry about that.
Fixes: a015434480 ("ext4: send parallel discards on commit completions")
Signed-off-by: Daeho Jeong <daeho.jeong@samsung.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
For some odd reason, it forces a byte-by-byte copy of each field. A
plain old swap() on most of these fields would be more efficient. We
do need to retain the memswap of i_data however as that field is an array.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
For Lustre, if ea_inode fails in hash validation but passes parent
inode and generation checks, it won't be added to the cache as well
as the error "-EFSCORRUPTED" should be cleared, otherwise it will
cause "Structure needs cleaning" when running getfattr command.
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-9723
Cc: stable@vger.kernel.org
Fixes: dec214d00e
Signed-off-by: Emoly Liu <emoly.liu@intel.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: tahsin@google.com
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: 073931017b
CC: stable@vger.kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Andreas Gruenbacher <agruenba@redhat.com>
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 <ernesto.mnd.fernandez@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Two variables in ext4_inode_info, i_reserved_meta_blocks and
i_allocated_meta_blocks, are unused. Removing them saves a little
memory per in-memory inode and cleans up clutter in several tracepoints.
Adjust tracepoint output from ext4_alloc_da_blocks() for consistency
and fix a typo and whitespace near these changes.
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Commit 914f82a32d "ext4: refactor direct IO code" deleted
ext4_ext_direct_IO(), but references to that function remain in
comments. Update them to refer to ext4_direct_IO_write().
Signed-off-by: Eric Whitney <enwlinux@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Jan Kara <jack@suse.cz>
feature, which allows ext4 directories to support over 2 billion
directory entries (assuming ~64 byte file names; in practice, users
will run into practical performance limits first.) This feature was
originally written by the Lustre team, and credit goes to Artem
Blagodarenko from Seagate for getting this feature upstream.
The second major major feature allows ext4 to support extended
attribute values up to 64k. This feature was also originally from
Lustre, and has been enhanced by Tahsin Erdogan from Google with a
deduplication feature so that if multiple files have the same xattr
value (for example, Windows ACL's stored by Samba), only one copy will
be stored on disk for encoding and caching efficiency.
We also have the usual set of bug fixes, cleanups, and optimizations.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"The first major feature for ext4 this merge window is the largedir
feature, which allows ext4 directories to support over 2 billion
directory entries (assuming ~64 byte file names; in practice, users
will run into practical performance limits first.) This feature was
originally written by the Lustre team, and credit goes to Artem
Blagodarenko from Seagate for getting this feature upstream.
The second major major feature allows ext4 to support extended
attribute values up to 64k. This feature was also originally from
Lustre, and has been enhanced by Tahsin Erdogan from Google with a
deduplication feature so that if multiple files have the same xattr
value (for example, Windows ACL's stored by Samba), only one copy will
be stored on disk for encoding and caching efficiency.
We also have the usual set of bug fixes, cleanups, and optimizations"
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (47 commits)
ext4: fix spelling mistake: "prellocated" -> "preallocated"
ext4: fix __ext4_new_inode() journal credits calculation
ext4: skip ext4_init_security() and encryption on ea_inodes
fs: generic_block_bmap(): initialize all of the fields in the temp bh
ext4: change fast symlink test to not rely on i_blocks
ext4: require key for truncate(2) of encrypted file
ext4: don't bother checking for encryption key in ->mmap()
ext4: check return value of kstrtoull correctly in reserved_clusters_store
ext4: fix off-by-one fsmap error on 1k block filesystems
ext4: return EFSBADCRC if a bad checksum error is found in ext4_find_entry()
ext4: return EIO on read error in ext4_find_entry
ext4: forbid encrypting root directory
ext4: send parallel discards on commit completions
ext4: avoid unnecessary stalls in ext4_evict_inode()
ext4: add nombcache mount option
ext4: strong binding of xattr inode references
ext4: eliminate xattr entry e_hash recalculation for removes
ext4: reserve space for xattr entries/names
quota: add get_inode_usage callback to transfer multi-inode charges
ext4: xattr inode deduplication
...
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Merge tag 'fscrypt_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/fscrypt
Pull fscrypt updates from Ted Ts'o:
"Add support for 128-bit AES and some cleanups to fscrypt"
* tag 'fscrypt_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/fscrypt:
fscrypt: make ->dummy_context() return bool
fscrypt: add support for AES-128-CBC
fscrypt: inline fscrypt_free_filename()
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Merge tag 'for-linus-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux
Pull Writeback error handling updates from Jeff Layton:
"This pile represents the bulk of the writeback error handling fixes
that I have for this cycle. Some of the earlier patches in this pile
may look trivial but they are prerequisites for later patches in the
series.
The aim of this set is to improve how we track and report writeback
errors to userland. Most applications that care about data integrity
will periodically call fsync/fdatasync/msync to ensure that their
writes have made it to the backing store.
For a very long time, we have tracked writeback errors using two flags
in the address_space: AS_EIO and AS_ENOSPC. Those flags are set when a
writeback error occurs (via mapping_set_error) and are cleared as a
side-effect of filemap_check_errors (as you noted yesterday). This
model really sucks for userland.
Only the first task to call fsync (or msync or fdatasync) will see the
error. Any subsequent task calling fsync on a file will get back 0
(unless another writeback error occurs in the interim). If I have
several tasks writing to a file and calling fsync to ensure that their
writes got stored, then I need to have them coordinate with one
another. That's difficult enough, but in a world of containerized
setups that coordination may even not be possible.
But wait...it gets worse!
The calls to filemap_check_errors can be buried pretty far down in the
call stack, and there are internal callers of filemap_write_and_wait
and the like that also end up clearing those errors. Many of those
callers ignore the error return from that function or return it to
userland at nonsensical times (e.g. truncate() or stat()). If I get
back -EIO on a truncate, there is no reason to think that it was
because some previous writeback failed, and a subsequent fsync() will
(incorrectly) return 0.
This pile aims to do three things:
1) ensure that when a writeback error occurs that that error will be
reported to userland on a subsequent fsync/fdatasync/msync call,
regardless of what internal callers are doing
2) report writeback errors on all file descriptions that were open at
the time that the error occurred. This is a user-visible change,
but I think most applications are written to assume this behavior
anyway. Those that aren't are unlikely to be hurt by it.
3) document what filesystems should do when there is a writeback
error. Today, there is very little consistency between them, and a
lot of cargo-cult copying. We need to make it very clear what
filesystems should do in this situation.
To achieve this, the set adds a new data type (errseq_t) and then
builds new writeback error tracking infrastructure around that. Once
all of that is in place, we change the filesystems to use the new
infrastructure for reporting wb errors to userland.
Note that this is just the initial foray into cleaning up this mess.
There is a lot of work remaining here:
1) convert the rest of the filesystems in a similar fashion. Once the
initial set is in, then I think most other fs' will be fairly
simple to convert. Hopefully most of those can in via individual
filesystem trees.
2) convert internal waiters on writeback to use errseq_t for
detecting errors instead of relying on the AS_* flags. I have some
draft patches for this for ext4, but they are not quite ready for
prime time yet.
This was a discussion topic this year at LSF/MM too. If you're
interested in the gory details, LWN has some good articles about this:
https://lwn.net/Articles/718734/https://lwn.net/Articles/724307/"
* tag 'for-linus-v4.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux:
btrfs: minimal conversion to errseq_t writeback error reporting on fsync
xfs: minimal conversion to errseq_t writeback error reporting
ext4: use errseq_t based error handling for reporting data writeback errors
fs: convert __generic_file_fsync to use errseq_t based reporting
block: convert to errseq_t based writeback error tracking
dax: set errors in mapping when writeback fails
Documentation: flesh out the section in vfs.txt on storing and reporting writeback errors
mm: set both AS_EIO/AS_ENOSPC and errseq_t in mapping_set_error
fs: new infrastructure for writeback error handling and reporting
lib: add errseq_t type and infrastructure for handling it
mm: don't TestClearPageError in __filemap_fdatawait_range
mm: clear AS_EIO/AS_ENOSPC when writeback initiation fails
jbd2: don't clear and reset errors after waiting on writeback
buffer: set errors in mapping at the time that the error occurs
fs: check for writeback errors after syncing out buffers in generic_file_fsync
buffer: use mapping_set_error instead of setting the flag
mm: fix mapping_set_error call in me_pagecache_dirty
Trivial fix to spelling mistake in mb_debug debug message
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Add a call to filemap_report_wb_err at the end of ext4_sync_file. This
will ensure that we check and advance the errseq_t in the file, which
allows us to track and report errors on all open fds when they occur.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
ea_inode feature allows creating extended attributes that are up to
64k in size. Update __ext4_new_inode() to pick increased credit limits.
To avoid overallocating too many journal credits, update
__ext4_xattr_set_credits() to make a distinction between xattr create
vs update. This helps __ext4_new_inode() because all attributes are
known to be new, so we can save credits that are normally needed to
delete old values.
Also, have fscrypt specify its maximum context size so that we don't
end up allocating credits for 64k size.
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Extended attribute inodes are internal to ext4. Adding encryption/security
related attributes on them would mean dealing with nested calls into ea code.
Since they have no direct exposure to user mode, just avoid creating ea
entries for them.
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
ext4_inode_info->i_data is the storage area for 4 types of data:
a) Extents data
b) Inline data
c) Block map
d) Fast symlink data (symlink length < 60)
Extents data case is positively identified by EXT4_INODE_EXTENTS flag.
Inline data case is also obvious because of EXT4_INODE_INLINE_DATA
flag.
Distinguishing c) and d) however requires additional logic. This
currently relies on i_blocks count. After subtracting external xattr
block from i_blocks, if it is greater than 0 then we know that some
data blocks exist, so there must be a block map.
This logic got broken after ea_inode feature was added. That feature
charges the data blocks of external xattr inodes to the referencing
inode and so adds them to the i_blocks. To fix this, we could subtract
ea_inode blocks by iterating through all xattr entries and then check
whether remaining i_blocks count is zero. Besides being complicated,
this won't change the fact that the current way of distinguishing
between c) and d) is fragile.
The alternative solution is to test whether i_size is less than 60 to
determine fast symlink case. ext4_symlink() uses the same test to decide
whether to store the symlink in i_data. There is one caveat to address
before this can work though.
If an inode's i_nlink is zero during eviction, its i_size is set to
zero and its data is truncated. If system crashes before inode is removed
from the orphan list, next boot orphan cleanup may find the inode with
zero i_size. So, a symlink that had its data stored in a block may now
appear to be a fast symlink. The solution used in this patch is to treat
i_size = 0 as a non-fast symlink case. A zero sized symlink is not legal
so the only time this can happen is the mentioned scenario. This is also
logically correct because a i_size = 0 symlink has no data stored in
i_data.
Suggested-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This makes it consistent with ->is_encrypted(), ->empty_dir(), and
fscrypt_dummy_context_enabled().
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Currently, filesystems allow truncate(2) on an encrypted file without
the encryption key. However, it's impossible to correctly handle the
case where the size being truncated to is not a multiple of the
filesystem block size, because that would require decrypting the final
block, zeroing the part beyond i_size, then encrypting the block.
As other modifications to encrypted file contents are prohibited without
the key, just prohibit truncate(2) as well, making it fail with ENOKEY.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Since only an open file can be mmap'ed, and we only allow open()ing an
encrypted file when its key is available, there is no need to check for
the key again before permitting each mmap().
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
kstrtoull returns 0 on success, however, in reserved_clusters_store we
will return -EINVAL if kstrtoull returns 0, it makes us fail to update
reserved_clusters value through sysfs.
Fixes: 76d33bca55
Cc: stable@vger.kernel.org # 4.4
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Miao Xie <miaoxie@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
For 1k-block filesystems, the filesystem starts at block 1, not block 0.
This fact is recorded in s_first_data_block, so use that to bump up the
start_fsb before we start querying the filesystem for its space map.
Without this, ext4/026 fails on 1k block ext4 because various functions
(notably ext4_get_group_no_and_offset) don't know what to do with an
fsblock that is "before" the start of the filesystem and return garbage
results (blockgroup 2^32-1, etc.) that confuse fsmap.
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Previously a bad directory block with a bad checksum is skipped; we
should be returning EFSBADCRC (aka EBADMSG).
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Previously, a read error would be ignored and we would eventually return
NULL from ext4_find_entry, which signals "no such file or directory". We
should be returning EIO.
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Currently it's possible to encrypt all files and directories on an ext4
filesystem by deleting everything, including lost+found, then setting an
encryption policy on the root directory. However, this is incompatible
with e2fsck because e2fsck expects to find, create, and/or write to
lost+found and does not have access to any encryption keys. Especially
problematic is that if e2fsck can't find lost+found, it will create it
without regard for whether the root directory is encrypted. This is
wrong for obvious reasons, and it causes a later run of e2fsck to
consider the lost+found directory entry to be corrupted.
Encrypting the root directory may also be of limited use because it is
the "all-or-nothing" use case, for which dm-crypt can be used instead.
(By design, encryption policies are inherited and cannot be overridden;
so the root directory having an encryption policy implies that all files
and directories on the filesystem have that same encryption policy.)
In any case, encrypting the root directory is broken currently and must
not be allowed; so start returning an error if userspace requests it.
For now only do this in ext4, because f2fs and ubifs do not appear to
have the lost+found requirement. We could move it into
fscrypt_ioctl_set_policy() later if desired, though.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Now, when we mount ext4 filesystem with '-o discard' option, we have to
issue all the discard commands for the blocks to be deallocated and
wait for the completion of the commands on the commit complete phase.
Because this procedure might involve a lot of sequential combinations of
issuing discard commands and waiting for that, the delay of this
procedure might be too much long, even to 17.0s in our test,
and it results in long commit delay and fsync() performance degradation.
To reduce this kind of delay, instead of adding callback for each
extent and handling all of them in a sequential manner on commit phase,
we instead add a separate list of extents to free to the superblock and
then process this list at once after transaction commits so that
we can issue all the discard commands in a parallel manner like XFS
filesystem.
Finally, we could enhance the discard command handling performance.
The result was such that 17.0s delay of a single commit in the worst
case has been enhanced to 4.8s.
Signed-off-by: Daeho Jeong <daeho.jeong@samsung.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Tested-by: Hobin Woo <hobin.woo@samsung.com>
Tested-by: Kitae Lee <kitae87.lee@samsung.com>
Reviewed-by: Jan Kara <jack@suse.cz>
These days inode reclaim calls evict_inode() only when it has no pages
in the mapping. In that case it is not necessary to wait for transaction
commit in ext4_evict_inode() as there can be no pages waiting to be
committed. So avoid unnecessary transaction waiting in that case.
We still have to keep the check for the case where ext4_evict_inode()
gets called from other paths (e.g. umount) where inode still can have
some page cache pages.
Reported-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
The main purpose of mb cache is to achieve deduplication in
extended attributes. In use cases where opportunity for deduplication
is unlikely, it only adds overhead.
Add a mount option to explicitly turn off mb cache.
Suggested-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
To verify that a xattr entry is not pointing to the wrong xattr inode,
we currently check that the target inode has EXT4_EA_INODE_FL flag set and
also the entry size matches the target inode size.
For stronger validation, also incorporate crc32c hash of the value into
the e_hash field. This is done regardless of whether the entry lives in
the inode body or external attribute block.
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When an extended attribute block is modified, ext4_xattr_hash_entry()
recalculates e_hash for the entry that is pointed by s->here. This is
unnecessary if the modification is to remove an entry.
Currently, if the removed entry is the last one and there are other
entries remaining, hash calculation targets the just erased entry which
has been filled with zeroes and effectively does nothing. If the removed
entry is not the last one and there are more entries, this time it will
recalculate hash on the next entry which is totally unnecessary.
Fix these by moving the decision on when to recalculate hash to
ext4_xattr_set_entry().
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
New ea_inode feature allows putting large xattr values into external
inodes. struct ext4_xattr_entry and the attribute name however have to
remain in the inode extra space or external attribute block. Once that
space is exhausted, no further entries can be added. Some of that space
could also be used by values that fit in there at the time of addition.
So, a single xattr entry whose value barely fits in the external block
could prevent further entries being added.
To mitigate the problem, this patch introduces a notion of reserved
space in the external attribute block that cannot be used by value data.
This reserve is enforced when ea_inode feature is enabled. The amount
of reserve is arbitrarily chosen to be min(block_size/8, 1024). The
table below shows how much space is reserved for each block size and the
guaranteed mininum number of entries that can be placed in the external
attribute block.
block size reserved bytes entries (name length = 16)
1k 128 3
2k 256 7
4k 512 15
8k 1024 31
16k 1024 31
32k 1024 31
64k 1024 31
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
