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?
> + 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.
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",
>
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