Removing sufficiently large files would create aliases for a large
number of segments. This in turn results in a large number of journal
entries and an overflow of s_je_array.
Cheap fix is to add a BUG_ON, turning memory corruption into something
annoying, but less dangerous. Real fix is to count the number of
affected segments and prevent the problem completely.
Signed-off-by: Joern Engel <joern@logfs.org>
If the device contains on old logfs image and the journal is moved to
segment that have never been used by the current logfs and not all
journal segments are erased before the next mount, the old content can
confuse mount code. To prevent this, always erase the new journal
segments.
Signed-off-by: Joern Engel <joern@logfs.org>
do_logfs_journal_wl_pass() must call freeseg(), thereby clear
PagePrivate on all pages of the current journal segment.
Signed-off-by: Joern Engel <joern@logfs.org>
A comment in the old code read:
/* The math in this function can surely use some love */
And indeed it did. In the case that area->a_used_bytes is exactly
4096 bytes below segment size it fell apart. pad_wbuf is now split
into two helpers that are significantly less complicated.
Signed-off-by: Joern Engel <joern@logfs.org>
The comment was correct, so make the code match the comment. As the
new comment indicates, we might be able to do a little less work. But
for the current -rc series let's keep it simple and just fix the bug.
Signed-off-by: Joern Engel <joern@logfs.org>
If the first superblock is wrong and the second gets written, there
will still be a mismatch on next mount. Write both to make sure they
match.
Signed-off-by: Joern Engel <joern@logfs.org>
Intel SSDs have a limit of 0xffff as queue_max_hw_sectors(q). Such a
limit may make sense from a hardware pov, but it causes bio_alloc() to
return NULL.
Signed-off-by: Joern Engel <joern@logfs.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/joern/logfs:
[LogFS] Change magic number
[LogFS] Remove h_version field
[LogFS] Check feature flags
[LogFS] Only write journal if dirty
[LogFS] Fix bdev erases
[LogFS] Silence gcc
[LogFS] Prevent 64bit divisions in hash_index
[LogFS] Plug memory leak on error paths
[LogFS] Add MAINTAINERS entry
[LogFS] add new flash file system
Fixed up trivial conflict in lib/Kconfig, and a semantic conflict in
fs/logfs/inode.c introduced by write_inode() being changed to use
writeback_control' by commit a9185b41a4
("pass writeback_control to ->write_inode")
Many changes were made during development that could result in old
versions of mklogfs and the kernel code being subtly incompatible.
Not being a friend of subtleties, I hereby change the magic number.
Any old version of mklogfs is now guaranteed to fail.
Erases for block devices were always just emulated by writing 0xff.
Some time back the write was removed and only the page cache was
changed to 0xff. Superficialy a good idea with two problems:
1. Touching the page cache isn't necessary either.
2. However, writing out 0xff _is_ necessary for the journal. As the
journal is scanned linearly, an old non-overwritten commit entry
can be used on next mount and cause havoc.
This should fix both aspects.
Andrew Morton sayeth:
fs/logfs/journal.c: In function 'logfs_init_journal':
fs/logfs/journal.c:266: warning: 'last_len' may be used uninitialized in this function
Can this be squished please?
