Message ID | 1535300717-26686-6-git-send-email-amir73il@gmail.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | Overlayfs stacked f_op fixes | expand |
On Sun, Aug 26, 2018 at 6:25 PM, Amir Goldstein <amir73il@gmail.com> wrote: > For an overlayfs file/inode, gage io is operating on the real underlying > file, so the readahead hints set by fadvise64() should also be set on the > real underlying file to take affect. Hmm, how about making this be an f_op? Would also fix readahead(2), which can be translated to fadvise(..., POSIX_FADV_WILLNEED). And possibly be useful for other filesystems, since there are cases when things are not done through a_ops, yet the filesystem would benefit from knowing the intentions of the user. Thanks, Miklos > > Fixes: d1d04ef8572b ("ovl: stack file ops") > Signed-off-by: Amir Goldstein <amir73il@gmail.com> > --- > mm/fadvise.c | 34 ++++++++++++++++++++-------------- > 1 file changed, 20 insertions(+), 14 deletions(-) > > diff --git a/mm/fadvise.c b/mm/fadvise.c > index 2d8376e3c640..d5528343ce77 100644 > --- a/mm/fadvise.c > +++ b/mm/fadvise.c > @@ -30,6 +30,7 @@ > int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) > { > struct fd f = fdget(fd); > + struct file *file; > struct inode *inode; > struct address_space *mapping; > struct backing_dev_info *bdi; > @@ -42,13 +43,18 @@ int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) > if (!f.file) > return -EBADF; > > - inode = file_inode(f.file); > + /* > + * XXX: We need to use file_real() for overlayfs stacked file because > + * readahead will be operating on the real underlying file/inode. > + */ > + file = file_real(f.file); > + inode = file_inode(file); > if (S_ISFIFO(inode->i_mode)) { > ret = -ESPIPE; > goto out; > } > > - mapping = f.file->f_mapping; > + mapping = file->f_mapping; > if (!mapping || len < 0) { > ret = -EINVAL; > goto out; > @@ -85,21 +91,21 @@ int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) > > switch (advice) { > case POSIX_FADV_NORMAL: > - f.file->f_ra.ra_pages = bdi->ra_pages; > - spin_lock(&f.file->f_lock); > - f.file->f_mode &= ~FMODE_RANDOM; > - spin_unlock(&f.file->f_lock); > + file->f_ra.ra_pages = bdi->ra_pages; > + spin_lock(&file->f_lock); > + file->f_mode &= ~FMODE_RANDOM; > + spin_unlock(&file->f_lock); > break; > case POSIX_FADV_RANDOM: > - spin_lock(&f.file->f_lock); > - f.file->f_mode |= FMODE_RANDOM; > - spin_unlock(&f.file->f_lock); > + spin_lock(&file->f_lock); > + file->f_mode |= FMODE_RANDOM; > + spin_unlock(&file->f_lock); > break; > case POSIX_FADV_SEQUENTIAL: > - f.file->f_ra.ra_pages = bdi->ra_pages * 2; > - spin_lock(&f.file->f_lock); > - f.file->f_mode &= ~FMODE_RANDOM; > - spin_unlock(&f.file->f_lock); > + file->f_ra.ra_pages = bdi->ra_pages * 2; > + spin_lock(&file->f_lock); > + file->f_mode &= ~FMODE_RANDOM; > + spin_unlock(&file->f_lock); > break; > case POSIX_FADV_WILLNEED: > /* First and last PARTIAL page! */ > @@ -115,7 +121,7 @@ int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) > * Ignore return value because fadvise() shall return > * success even if filesystem can't retrieve a hint, > */ > - force_page_cache_readahead(mapping, f.file, start_index, > + force_page_cache_readahead(mapping, file, start_index, > nrpages); > break; > case POSIX_FADV_NOREUSE: > -- > 2.7.4 >
On Sun, Aug 26, 2018 at 10:30 PM Miklos Szeredi <miklos@szeredi.hu> wrote: > > On Sun, Aug 26, 2018 at 6:25 PM, Amir Goldstein <amir73il@gmail.com> wrote: > > For an overlayfs file/inode, gage io is operating on the real underlying > > file, so the readahead hints set by fadvise64() should also be set on the > > real underlying file to take affect. > > Hmm, how about making this be an f_op? > > Would also fix readahead(2), which can be translated to fadvise(..., > POSIX_FADV_WILLNEED). > Ok. I guess we could match readahead(2) semantics to an advise for fs that implements f_op->advise(). Semantics are not currently the same for the case of !mapping->a_ops->readpages, but they are already the same (i.e. both return 0) for dax_mapping(mapping). Thanks, Amir.
diff --git a/mm/fadvise.c b/mm/fadvise.c index 2d8376e3c640..d5528343ce77 100644 --- a/mm/fadvise.c +++ b/mm/fadvise.c @@ -30,6 +30,7 @@ int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) { struct fd f = fdget(fd); + struct file *file; struct inode *inode; struct address_space *mapping; struct backing_dev_info *bdi; @@ -42,13 +43,18 @@ int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) if (!f.file) return -EBADF; - inode = file_inode(f.file); + /* + * XXX: We need to use file_real() for overlayfs stacked file because + * readahead will be operating on the real underlying file/inode. + */ + file = file_real(f.file); + inode = file_inode(file); if (S_ISFIFO(inode->i_mode)) { ret = -ESPIPE; goto out; } - mapping = f.file->f_mapping; + mapping = file->f_mapping; if (!mapping || len < 0) { ret = -EINVAL; goto out; @@ -85,21 +91,21 @@ int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) switch (advice) { case POSIX_FADV_NORMAL: - f.file->f_ra.ra_pages = bdi->ra_pages; - spin_lock(&f.file->f_lock); - f.file->f_mode &= ~FMODE_RANDOM; - spin_unlock(&f.file->f_lock); + file->f_ra.ra_pages = bdi->ra_pages; + spin_lock(&file->f_lock); + file->f_mode &= ~FMODE_RANDOM; + spin_unlock(&file->f_lock); break; case POSIX_FADV_RANDOM: - spin_lock(&f.file->f_lock); - f.file->f_mode |= FMODE_RANDOM; - spin_unlock(&f.file->f_lock); + spin_lock(&file->f_lock); + file->f_mode |= FMODE_RANDOM; + spin_unlock(&file->f_lock); break; case POSIX_FADV_SEQUENTIAL: - f.file->f_ra.ra_pages = bdi->ra_pages * 2; - spin_lock(&f.file->f_lock); - f.file->f_mode &= ~FMODE_RANDOM; - spin_unlock(&f.file->f_lock); + file->f_ra.ra_pages = bdi->ra_pages * 2; + spin_lock(&file->f_lock); + file->f_mode &= ~FMODE_RANDOM; + spin_unlock(&file->f_lock); break; case POSIX_FADV_WILLNEED: /* First and last PARTIAL page! */ @@ -115,7 +121,7 @@ int ksys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice) * Ignore return value because fadvise() shall return * success even if filesystem can't retrieve a hint, */ - force_page_cache_readahead(mapping, f.file, start_index, + force_page_cache_readahead(mapping, file, start_index, nrpages); break; case POSIX_FADV_NOREUSE:
For an overlayfs file/inode, gage io is operating on the real underlying file, so the readahead hints set by fadvise64() should also be set on the real underlying file to take affect. Fixes: d1d04ef8572b ("ovl: stack file ops") Signed-off-by: Amir Goldstein <amir73il@gmail.com> --- mm/fadvise.c | 34 ++++++++++++++++++++-------------- 1 file changed, 20 insertions(+), 14 deletions(-)