linux/mm/fadvise.c, branch v3.7-rc5

switch simple cases of fget_light to fdget

2012-09-27T02:20:08Z

Signed-off-by: Al Viro

switch fadvise(2) to fget_light()

2012-09-27T01:10:04Z

Signed-off-by: Al Viro

mm, fadvise: don't return -EINVAL when filesystem cannot implement fadvise()

2012-08-01T01:42:42Z

Eric Wong reported his test suite failex when /tmp is tmpfs. https://lkml.org/lkml/2012/2/24/479 Currentlt the input check of POSIX_FADV_WILLNEED has two problems. - requires a_ops->readpage. But in fact, force_page_cache_readahead() requires that the target filesystem has either ->readpage or ->readpages. - returns -EINVAL when the filesystem doesn't have ->readpage. But posix says that fadvise is merely a hint. Thus fadvise() should return 0 if filesystem has no means of implementing fadvise(). The userland application should not know nor care whcih type of filesystem backs the TMPDIR directory, as Eric pointed out. There is nothing which userspace can do to solve this error. So change the return value to 0 when filesytem doesn't support readahead. [akpm@linux-foundation.org: checkpatch fixes] Signed-off-by: KOSAKI Motohiro Cc: Hugh Dickins Cc: Hillf Danton Signed-off-by: Eric Wong Tested-by: Eric Wong Reviewed-by: Wanlong Gao Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

fadvise: only initiate writeback for specified range with FADV_DONTNEED

2012-01-11T00:30:43Z

Previously POSIX_FADV_DONTNEED would start writeback for the entire file when the bdi was not write congested. This negatively impacts performance if the file contains dirty pages outside of the requested range. This change uses __filemap_fdatawrite_range() to only initiate writeback for the requested range. Signed-off-by: Shawn Bohrer Acked-by: Johannes Weiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

readahead: introduce FMODE_RANDOM for POSIX_FADV_RANDOM

2010-03-06T19:26:25Z

This fixes inefficient page-by-page reads on POSIX_FADV_RANDOM. POSIX_FADV_RANDOM used to set ra_pages=0, which leads to poor performance: a 16K read will be carried out in 4 _sync_ 1-page reads. In other places, ra_pages==0 means - it's ramfs/tmpfs/hugetlbfs/sysfs/configfs - some IO error happened where multi-page read IO won't help or should be avoided. POSIX_FADV_RANDOM actually want a different semantics: to disable the *heuristic* readahead algorithm, and to use a dumb one which faithfully submit read IO for whatever application requests. So introduce a flag FMODE_RANDOM for POSIX_FADV_RANDOM. Note that the random hint is not likely to help random reads performance noticeably. And it may be too permissive on huge request size (its IO size is not limited by read_ahead_kb). In Quentin's report (http://lkml.org/lkml/2009/12/24/145), the overall (NFS read) performance of the application increased by 313%! Tested-by: Quentin Barnes Signed-off-by: Wu Fengguang Cc: Nick Piggin Cc: Andi Kleen Cc: Steven Whitehouse Cc: David Howells Cc: Jonathan Corbet Cc: Al Viro Cc: Christoph Hellwig Cc: Trond Myklebust Cc: Chuck Lever Cc: [2.6.33.x] Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

readahead: move max_sane_readahead() calls into force_page_cache_readahead()

2009-06-17T02:47:28Z

Impact: code simplification. Cc: Nick Piggin Signed-off-by: Wu Fengguang Cc: Ying Han Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[CVE-2009-0029] System call wrapper special cases

2009-01-14T13:15:18Z

System calls with an unsigned long long argument can't be converted with the standard wrappers since that would include a cast to long, which in turn means that we would lose the upper 32 bit on 32 bit architectures. Also semctl can't use the standard wrapper since it has a 'union' parameter. So we handle them as special case and add some extra wrappers instead. Signed-off-by: Heiko Carstens

Remove Andrew Morton's old email accounts

2008-10-16T18:21:32Z

People can use the real name an an index into MAINTAINERS to find the current email address. Signed-off-by: Francois Cami Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

xip: support non-struct page backed memory

2008-04-28T15:58:23Z

Convert XIP to support non-struct page backed memory, using VM_MIXEDMAP for the user mappings. This requires the get_xip_page API to be changed to an address based one. Improve the API layering a little bit too, while we're here. This is required in order to support XIP filesystems on memory that isn't backed with struct page (but memory with struct page is still supported too). Signed-off-by: Nick Piggin Acked-by: Carsten Otte Cc: Jared Hulbert Cc: Martin Schwidefsky Cc: Heiko Carstens Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

check ADVICE of fadvise64_64 even if get_xip_page is given

2008-02-05T17:44:19Z

I've written some test programs in ltp project. During writing I met an problem which I cannot solve in user land. So I wrote a patch for linux kernel. Please, include this patch if acceptable. The test program tests the 4th parameter of fadvise64_64: long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice); My test case calls fadvise64_64 with invalid advice value and checks errno is set to EINVAL. About the advice parameter man page says: ... Permissible values for advice include: POSIX_FADV_NORMAL ... POSIX_FADV_SEQUENTIAL ... POSIX_FADV_RANDOM ... POSIX_FADV_NOREUSE ... POSIX_FADV_WILLNEED ... POSIX_FADV_DONTNEED ... ERRORS ... EINVAL An invalid value was specified for advice. However, I got a bug report that the system call invocations in my test case returned 0 unexpectedly. I've inspected the kernel code: asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) { struct file *file = fget(fd); struct address_space *mapping; struct backing_dev_info *bdi; loff_t endbyte; /* inclusive */ pgoff_t start_index; pgoff_t end_index; unsigned long nrpages; int ret = 0; if (!file) return -EBADF; if (S_ISFIFO(file->f_path.dentry->d_inode->i_mode)) { ret = -ESPIPE; goto out; } mapping = file->f_mapping; if (!mapping || len < 0) { ret = -EINVAL; goto out; } if (mapping->a_ops->get_xip_page) /* no bad return value, but ignore advice */ goto out; ... out: fput(file); return ret; } I found the advice parameter is just ignored in the case mapping->a_ops->get_xip_page is given. This behavior is different from what is written on the man page. Is this o.k.? get_xip_page is given if CONFIG_EXT2_FS_XIP is true. Anyway I cannot find the easy way to detect get_xip_page field is given or CONFIG_EXT2_FS_XIP is true from the user space. I propose the following patch which checks the advice parameter even if get_xip_page is given. Signed-off-by: Masatake YAMATO Acked-by: Carsten Otte Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds