linux.git/fs/ramfs, branch v2.6.29

nommu: ramfs: don't leak pages when adding to page cache fails

2009-03-14T18:57:22+00:00

When a ramfs nommu mapping is expanded, contiguous pages are allocated
and added to the pagecache.  The caller's reference is then passed on
by moving whole pagevecs to the file lru list.

If the page cache adding fails, make sure that the error path also
moves the pagevec contents which might still contain up to PAGEVEC_SIZE
successfully added pages, of which we would leak references otherwise.

Signed-off-by: Johannes Weiner 
Cc: David Howells 
Cc: Enrik Berkhan 
Cc: Nick Piggin 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

nommu: ramfs: pages allocated to an inode's pagecache may get wrongly discarded

2009-03-14T18:57:22+00:00

The pages attached to a ramfs inode's pagecache by truncation from nothing
- as done by SYSV SHM for example - may get discarded under memory
pressure.

The problem is that the pages are not marked dirty.  Anything that creates
data in an MMU-based ramfs will cause the pages holding that data will
cause the set_page_dirty() aop to be called.

For the NOMMU-based mmap, set_page_dirty() may be called by write(), but
it won't be called by page-writing faults on writable mmaps, and it isn't
called by ramfs_nommu_expand_for_mapping() when a file is being truncated
from nothing to allocate a contiguous run.

The solution is to mark the pages dirty at the point of allocation by the
truncation code.

Signed-off-by: Enrik Berkhan 
Signed-off-by: David Howells 
Cc: Peter Zijlstra 
Cc: Nick Piggin 
Cc: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

NOMMU: Fix cleanup handling in ramfs_nommu_get_umapped_area()

2009-01-08T12:04:46+00:00

Fix cleanup handling in ramfs_nommu_get_umapped_area() by only freeing the
number of pages that find_get_pages() said it had returned (nr) rather than
attempting to free the number of pages we asked for (lpages) - thus avoiding
the situation whereby put_page() may be handed NULL pointers if
find_get_pages() returned fewer pages that were requested.

Also avoid a warning about nr being uninitialised and the need for an
if-statement in the cleanup path by using appropriate gotos.

Signed-off-by: David Howells

zero i_uid/i_gid on inode allocation

2009-01-05T16:54:28+00:00

... and don't bother in callers.  Don't bother with zeroing i_blocks,
while we are at it - it's already been zeroed.

i_mode is not worth the effort; it has no common default value.

Signed-off-by: Al Viro

CRED: Wrap task credential accesses in the RAMFS filesystem

2008-11-13T23:39:00+00:00

Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.

Signed-off-by: David Howells 
Reviewed-by: James Morris 
Acked-by: Serge Hallyn 
Signed-off-by: James Morris

Ramfs and Ram Disk pages are unevictable

2008-10-20T15:50:26+00:00

Christoph Lameter pointed out that ram disk pages also clutter the LRU
lists.  When vmscan finds them dirty and tries to clean them, the ram disk
writeback function just redirties the page so that it goes back onto the
active list.  Round and round she goes...

With the ram disk driver [rd.c] replaced by the newer 'brd.c', this is no
longer the case, as ram disk pages are no longer maintained on the lru.
[This makes them unmigratable for defrag or memory hot remove, but that
can be addressed by a separate patch series.] However, the ramfs pages
behave like ram disk pages used to, so:

Define new address_space flag [shares address_space flags member with
mapping's gfp mask] to indicate that the address space contains all
unevictable pages.  This will provide for efficient testing of ramfs pages
in page_evictable().

Also provide wrapper functions to set/test the unevictable state to
minimize #ifdefs in ramfs driver and any other users of this facility.

Set the unevictable state on address_space structures for new ramfs
inodes.  Test the unevictable state in page_evictable() to cull
unevictable pages.

These changes depend on [CONFIG_]UNEVICTABLE_LRU.

[riel@redhat.com: undo the brd.c part]
Signed-off-by: Lee Schermerhorn 
Signed-off-by: Rik van Riel 
Debugged-by: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

vmscan: split LRU lists into anon & file sets

2008-10-20T15:50:25+00:00

Split the LRU lists in two, one set for pages that are backed by real file
systems ("file") and one for pages that are backed by memory and swap
("anon").  The latter includes tmpfs.

The advantage of doing this is that the VM will not have to scan over lots
of anonymous pages (which we generally do not want to swap out), just to
find the page cache pages that it should evict.

This patch has the infrastructure and a basic policy to balance how much
we scan the anon lists and how much we scan the file lists.  The big
policy changes are in separate patches.

[lee.schermerhorn@hp.com: collect lru meminfo statistics from correct offset]
[kosaki.motohiro@jp.fujitsu.com: prevent incorrect oom under split_lru]
[kosaki.motohiro@jp.fujitsu.com: fix pagevec_move_tail() doesn't treat unevictable page]
[hugh@veritas.com: memcg swapbacked pages active]
[hugh@veritas.com: splitlru: BDI_CAP_SWAP_BACKED]
[akpm@linux-foundation.org: fix /proc/vmstat units]
[nishimura@mxp.nes.nec.co.jp: memcg: fix handling of shmem migration]
[kosaki.motohiro@jp.fujitsu.com: adjust Quicklists field of /proc/meminfo]
[kosaki.motohiro@jp.fujitsu.com: fix style issue of get_scan_ratio()]
Signed-off-by: Rik van Riel 
Signed-off-by: Lee Schermerhorn 
Signed-off-by: KOSAKI Motohiro 
Signed-off-by: Hugh Dickins 
Signed-off-by: Daisuke Nishimura 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: tiny-shmem nommu fix

2008-10-02T22:53:13+00:00

The previous patch db203d53d474aa068984e409d807628f5841da1b ("mm:
tiny-shmem fix lock ordering: mmap_sem vs i_mutex") to fix the lock
ordering in tiny-shmem breaks shared anonymous and IPC memory on NOMMU
architectures because it was using the expanding truncate to signal ramfs
to allocate a physically contiguous RAM backing the inode (otherwise it is
unusable for "memory mapping" it to userspace).

However do_truncate is what caused the lock ordering error, due to it
taking i_mutex.  In this case, we can actually just call ramfs directly to
allocate memory for the mapping, rather than go via truncate.

Acked-by: David Howells 
Acked-by: Hugh Dickins 
Signed-off-by: Nick Piggin 
Cc: Matt Mackall 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ramfs: enable splice write

2008-07-04T07:52:14+00:00

Signed-off-by: Octavian Purdila 
Signed-off-by: Andrew Morton 
Signed-off-by: Jens Axboe

mm: bdi: add separate writeback accounting capability

2008-04-30T15:29:50+00:00

Add a new BDI capability flag: BDI_CAP_NO_ACCT_WB.  If this flag is
set, then don't update the per-bdi writeback stats from
test_set_page_writeback() and test_clear_page_writeback().

Misc cleanups:

 - convert bdi_cap_writeback_dirty() and friends to static inline functions
 - create a flag that includes all three dirty/writeback related flags,
   since almst all users will want to have them toghether

Signed-off-by: Miklos Szeredi 
Cc: Peter Zijlstra 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds