diff options
| author | Jan Kara <jack@suse.cz> | 2017-02-08 14:30:53 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-12-09 22:01:54 +0100 |
| commit | c93c09a057b71fa152de9d56f971fd82248d6499 (patch) | |
| tree | a145f448175afea40290a42ec8c65b389a656b05 | |
| parent | 3e550debcf7557ca966388d5462519063aa75524 (diff) | |
mm: avoid returning VM_FAULT_RETRY from ->page_mkwrite handlers
[ Upstream commit 0911d0041c22922228ca52a977d7b0b0159fee4b ]
Some ->page_mkwrite handlers may return VM_FAULT_RETRY as its return
code (GFS2 or Lustre can definitely do this). However VM_FAULT_RETRY
from ->page_mkwrite is completely unhandled by the mm code and results
in locking and writeably mapping the page which definitely is not what
the caller wanted.
Fix Lustre and block_page_mkwrite_ret() used by other filesystems
(notably GFS2) to return VM_FAULT_NOPAGE instead which results in
bailing out from the fault code, the CPU then retries the access, and we
fault again effectively doing what the handler wanted.
Link: http://lkml.kernel.org/r/20170203150729.15863-1-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/staging/lustre/lustre/llite/llite_mmap.c | 4 | ||||
| -rw-r--r-- | include/linux/buffer_head.h | 4 |
2 files changed, 2 insertions, 6 deletions
diff --git a/drivers/staging/lustre/lustre/llite/llite_mmap.c b/drivers/staging/lustre/lustre/llite/llite_mmap.c index 436691814a5e..27333d973bcd 100644 --- a/drivers/staging/lustre/lustre/llite/llite_mmap.c +++ b/drivers/staging/lustre/lustre/llite/llite_mmap.c @@ -401,15 +401,13 @@ static int ll_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) result = VM_FAULT_LOCKED; break; case -ENODATA: + case -EAGAIN: case -EFAULT: result = VM_FAULT_NOPAGE; break; case -ENOMEM: result = VM_FAULT_OOM; break; - case -EAGAIN: - result = VM_FAULT_RETRY; - break; default: result = VM_FAULT_SIGBUS; break; diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 447a915db25d..4431ea2c8802 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -239,12 +239,10 @@ static inline int block_page_mkwrite_return(int err) { if (err == 0) return VM_FAULT_LOCKED; - if (err == -EFAULT) + if (err == -EFAULT || err == -EAGAIN) return VM_FAULT_NOPAGE; if (err == -ENOMEM) return VM_FAULT_OOM; - if (err == -EAGAIN) - return VM_FAULT_RETRY; /* -ENOSPC, -EDQUOT, -EIO ... */ return VM_FAULT_SIGBUS; } |