xfs
[Top] [All Lists]

Re: [RFC PATCH] xfs: enables file data inlining in inodes

To: xfs@xxxxxxxxxxx
Subject: Re: [RFC PATCH] xfs: enables file data inlining in inodes
From: Carlos Maiolino <cmaiolino@xxxxxxxxxx>
Date: Mon, 15 Oct 2012 14:19:05 -0300
In-reply-to: <507837E6.4040807@xxxxxxxxxx>
Mail-followup-to: xfs@xxxxxxxxxxx
References: <1349985158-9952-1-git-send-email-cmaiolino@xxxxxxxxxx> <507837E6.4040807@xxxxxxxxxx>
User-agent: Mutt/1.5.21 (2010-09-15)
On Fri, Oct 12, 2012 at 11:31:50AM -0400, Brian Foster wrote:
> On 10/11/2012 03:52 PM, Carlos Maiolino wrote:
> > Hi,
> > 
> > this is a first RFC patch of my work on data inlining, i.e. use the xfs 
> > inode's
> > literal area to store user's data.
> > 
> > This first patch just cares about write and read new files into inode's 
> > literal
> > area, it does not make any conversion from inline to extent or vice-versa.
> > 
> > The idea to send this patch to list is just to get comments about this first
> > work and see if anybody has some ideas/suggestions about it, mainly related
> > with page cache and journal handling, since it's the first time I deal with
> > journal and page cache handling, I'm not pretty sure if I did things right
> > or not.
> > 
> > Every comment is very appreciated.
> > 
> > Thanks
> > ---
> >  fs/xfs/xfs_aops.c  | 134 
> > ++++++++++++++++++++++++++++++++++++++++++++++++++---
> >  fs/xfs/xfs_inode.c |  15 +-----
> >  2 files changed, 130 insertions(+), 19 deletions(-)
> > 
> > diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
> > index e562dd4..3d30528 100644
> > --- a/fs/xfs/xfs_aops.c
> > +++ b/fs/xfs/xfs_aops.c
> > @@ -31,6 +31,7 @@
> >  #include "xfs_vnodeops.h"
> >  #include "xfs_trace.h"
> >  #include "xfs_bmap.h"
> > +#include "xfs_inode_item.h"
> >  #include <linux/gfp.h>
> >  #include <linux/mpage.h>
> >  #include <linux/pagevec.h>
> > @@ -460,6 +461,95 @@ xfs_start_page_writeback(
> >             end_page_writeback(page);
> >  }
> >  
> > +/* Write data inlined in inode */
> > +
> > +STATIC int
> > +xfs_inline_write(
> > +   struct xfs_inode        *ip,
> > +   struct page             *page,
> > +   struct buffer_head      *bh,
> > +   __uint64_t              end_offset)
> > +{
> > +   char            *data;
> > +   int             err = 0;
> > +   xfs_trans_t     *tp;
> > +   xfs_mount_t     *mp = ip->i_mount;
> > +
> > +   printk("%s: INLINING INODE %llu\n", __func__, ip->i_ino);
> > +   xfs_start_page_writeback(page, 1, 1);
> > +
> > +   tp = xfs_trans_alloc(mp, XFS_TRANS_CREATE);
> > +   err = xfs_trans_reserve(tp, 0, XFS_SWRITE_LOG_RES(mp), 0, 0, 0); /* Is 
> > this the right logspace? */
> > +
> > +   if (err) {
> > +           xfs_trans_cancel(tp, 0);
> 
> Do you need to undo xfs_start_page_writeback() here?
> 

Not sure if I got what you meant
> > +           return -1;
> > +   }
> > +
> > +   xfs_ilock(ip, XFS_ILOCK_EXCL);
> > +
> > +   xfs_trans_ijoin(tp, ip, XFS_ILOCK_EXCL);
> > +
> > +   if (!(ip->i_d.di_format & XFS_DINODE_FMT_LOCAL)) {
> > +           ip->i_df.if_flags &= ~XFS_IFEXTENTS;
> > +           ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
> > +           ip->i_df.if_flags |= XFS_IFINLINE;
> > +   }
> > +
> > +   ASSERT(ip->i_df.if_flags & XFS_IFINLINE);
> > +
> > +   if (end_offset > ip->i_df.if_bytes)
> > +           xfs_idata_realloc(ip, end_offset - ip->i_df.if_bytes,
> > +                             XFS_DATA_FORK);
> > +
> > +   xfs_trans_log_inode(tp, ip, XFS_ILOG_CORE | XFS_ILOG_DDATA);
> > +   data = kmap(page);
> > +   memcpy(ip->i_df.if_u1.if_data, data, end_offset);
> > +   kunmap(page);
> > +
> > +   ip->i_d.di_size = end_offset;
> > +
> > +   err = xfs_trans_commit(tp, 0);
> > +
> > +   set_buffer_uptodate(bh);
> > +   clear_buffer_dirty(bh);
> > +   clear_buffer_delay(bh);
> > +   SetPageUptodate(page);
> > +
> > +   end_page_writeback(page);
> > +   return err;
> > +}
> > +
> > +STATIC int
> > +xfs_inline_read(
> > +   struct xfs_inode        *ip,
> > +   struct page             *page,
> > +   struct address_space    *mapping)
> > +{
> > +   char *data;
> > +   unsigned long bsize = 1 << ip->i_vnode.i_blkbits;
> > +
> > +   ASSERT(ip->i_d.di_format == XFS_DINODE_FMT_LOCAL);
> > +   ASSERT(ip->i_df.if_flags & XFS_IFINLINE);
> > +
> > +   if (!page_has_buffers(page))
> > +           create_empty_buffers(page, bsize, 0);
> > +
> > +   xfs_ilock(ip, XFS_ILOCK_SHARED);
> > +
> > +   data = kmap(page);
> > +   memcpy(data, ip->i_df.if_u1.if_data, (int)ip->i_d.di_size);
> > +   kunmap(page);
> > +
> > +   /* We should not leave garbage after user data into the page */
> > +   memset(data + (int)ip->i_d.di_size, 0, PAGE_SIZE - ip->i_d.di_size);
> > +
> > +   SetPageUptodate(page);
> > +   xfs_iunlock(ip, XFS_ILOCK_SHARED);
> > +   unlock_page(page);
> > +   return 0;
> > +}
> > +
> >  static inline int bio_add_buffer(struct bio *bio, struct buffer_head *bh)
> >  {
> >     return bio_add_page(bio, bh->b_page, bh->b_size, bh_offset(bh));
> > @@ -900,6 +990,7 @@ xfs_vm_writepage(
> >     struct writeback_control *wbc)
> >  {
> >     struct inode            *inode = page->mapping->host;
> > +   xfs_inode_t             *ip = XFS_I(inode);
> >     struct buffer_head      *bh, *head;
> >     struct xfs_bmbt_irec    imap;
> >     xfs_ioend_t             *ioend = NULL, *iohead = NULL;
> > @@ -908,7 +999,7 @@ xfs_vm_writepage(
> >     __uint64_t              end_offset;
> >     pgoff_t                 end_index, last_index;
> >     ssize_t                 len;
> > -   int                     err, imap_valid = 0, uptodate = 1;
> > +   int                     err = 0, imap_valid = 0, uptodate = 1;
> >     int                     count = 0;
> >     int                     nonblocking = 0;
> >  
> > @@ -968,8 +1059,16 @@ xfs_vm_writepage(
> >                     (xfs_off_t)(page->index + 1) << PAGE_CACHE_SHIFT,
> >                     offset);
> >     len = 1 << inode->i_blkbits;
> > -
> >     bh = head = page_buffers(page);
> > +
> > +   if (end_offset + i_size_read(inode) <= XFS_IFORK_DSIZE(ip)) {
> 
> So end_offset looks like it is the size of the file if this page
> contains EOF, or the next page-aligned offset of the file otherwise. If
> I understand correctly, shouldn't we just check if end_offset falls
> within the data fork size here? IOW, I don't understand why you add
> end_offset and i_size_read(inode) here.
> 

Check by end_offset is not the right thing to do here, but it needs an inode
size check. What I tried to do was catch any file changes that occurs before the
asignment of end_offset and this check condition. Not sure if I'm right though
and should leave only:

if (i_size_read(inode) <= XFS_IFORK_DSIZE(ip)) {

> Brian
> 
> > +           err = xfs_inline_write(ip, page, bh, end_offset);
> > +
> > +           if (err)
> > +                   goto error;
> > +           return 0;
> > +   }
> > +
> >     offset = page_offset(page);
> >     type = XFS_IO_OVERWRITE;
> >  
> > @@ -1624,20 +1723,43 @@ xfs_vm_bmap(
> >  
> >  STATIC int
> >  xfs_vm_readpage(
> > -   struct file             *unused,
> > +   struct file             *filp,
> >     struct page             *page)
> >  {
> > -   return mpage_readpage(page, xfs_get_blocks);
> > +   struct inode            *inode = filp->f_mapping->host;
> > +   struct xfs_inode        *ip = XFS_I(inode);
> > +
> > +   if (ip->i_d.di_format == XFS_DINODE_FMT_LOCAL)
> > +           return xfs_inline_read(ip, page, page->mapping);
> > +   else
> > +           return mpage_readpage(page, xfs_get_blocks);
> >  }
> >  
> >  STATIC int
> >  xfs_vm_readpages(
> > -   struct file             *unused,
> > +   struct file             *filp,
> >     struct address_space    *mapping,
> >     struct list_head        *pages,
> >     unsigned                nr_pages)
> >  {
> > -   return mpage_readpages(mapping, pages, nr_pages, xfs_get_blocks);
> > +   struct inode            *inode = filp->f_mapping->host;
> > +   struct xfs_inode        *ip = XFS_I(inode);
> > +
> > +   if (ip->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
> > +           struct page     *page = list_first_entry(pages, struct page, 
> > lru);
> > +
> > +           ASSERT(i_size_read(VFS_I(ip) <= PAGE_CACHE_SIZE));
> > +
> > +           list_del(&page->lru);
> > +           if(!(add_to_page_cache_lru(page, mapping,
> > +                                       page->index, GFP_KERNEL)))
> > +                   return xfs_inline_read(ip, page, page->mapping);
> > +
> > +           page_cache_release(page);
> > +           return 0;
> > +   } else {
> > +           return mpage_readpages(mapping, pages, nr_pages, 
> > xfs_get_blocks);
> > +   }
> >  }
> >  
> >  const struct address_space_operations xfs_address_space_operations = {
> > diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
> > index 2778258..5e56e5c 100644
> > --- a/fs/xfs/xfs_inode.c
> > +++ b/fs/xfs/xfs_inode.c
> > @@ -287,18 +287,6 @@ xfs_iformat(
> >     case S_IFDIR:
> >             switch (dip->di_format) {
> >             case XFS_DINODE_FMT_LOCAL:
> > -                   /*
> > -                    * no local regular files yet
> > -                    */
> > -                   if (unlikely(S_ISREG(be16_to_cpu(dip->di_mode)))) {
> > -                           xfs_warn(ip->i_mount,
> > -                   "corrupt inode %Lu (local format for regular file).",
> > -                                   (unsigned long long) ip->i_ino);
> > -                           XFS_CORRUPTION_ERROR("xfs_iformat(4)",
> > -                                                XFS_ERRLEVEL_LOW,
> > -                                                ip->i_mount, dip);
> > -                           return XFS_ERROR(EFSCORRUPTED);
> > -                   }
> >  
> >                     di_size = be64_to_cpu(dip->di_size);
> >                     if (unlikely(di_size > XFS_DFORK_DSIZE(dip, 
> > ip->i_mount))) {
> > @@ -2471,7 +2459,8 @@ xfs_iflush_int(
> >     if (S_ISREG(ip->i_d.di_mode)) {
> >             if (XFS_TEST_ERROR(
> >                 (ip->i_d.di_format != XFS_DINODE_FMT_EXTENTS) &&
> > -               (ip->i_d.di_format != XFS_DINODE_FMT_BTREE),
> > +               (ip->i_d.di_format != XFS_DINODE_FMT_BTREE) &&
> > +               (ip->i_d.di_format != XFS_DINODE_FMT_LOCAL),
> >                 mp, XFS_ERRTAG_IFLUSH_3, XFS_RANDOM_IFLUSH_3)) {
> >                     xfs_alert_tag(mp, XFS_PTAG_IFLUSH,
> >                             "%s: Bad regular inode %Lu, ptr 0x%p",
> > 
> 
> _______________________________________________
> xfs mailing list
> xfs@xxxxxxxxxxx
> http://oss.sgi.com/mailman/listinfo/xfs

-- 
--Carlos

<Prev in Thread] Current Thread [Next in Thread>