XFS SEEK_DATA/SEEK_HOLE support V1
Jeff Liu
jeff.liu at oracle.com
Sat Nov 19 02:34:50 CST 2011
Sorry!! I forgot to write the subject beginning with "[PATCH]", will
re-sent it again.
Thanks,
-Jeff
On 11/19/2011 04:29 PM, Jeff Liu wrote:
> Hello,
>
> Sorry for the delay! I have worked on another high priority task these days.
>
> So the below patch is the first try to add SEEK_DATA/SEEK_HOLE to XFS, I have tested it through seek_test.c from Sunil, looks all works to me.
> http://oss.oracle.com/~smushran/seek_data/seek_test.c
>
> Any feedback are welcome, thank you!
>
> Signed-off-by: Jie Liu <jeff.liu at oracle.com>
>
> ---
> fs/xfs/xfs_bmap.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> fs/xfs/xfs_bmap.h | 1 +
> fs/xfs/xfs_file.c | 51 ++++++++++++++++++++++++++++++++-
> fs/xfs/xfs_iops.c | 64 +++++++++++++++++++++++++++++++++++++++++
> fs/xfs/xfs_iops.h | 3 ++
> 5 files changed, 199 insertions(+), 1 deletions(-)
>
> diff --git a/fs/xfs/xfs_bmap.c b/fs/xfs/xfs_bmap.c
> index c68baeb..04c3930 100644
> --- a/fs/xfs/xfs_bmap.c
> +++ b/fs/xfs/xfs_bmap.c
> @@ -6133,3 +6133,84 @@ next_block:
>
> return error;
> }
> +
> +
> +int
> +xfs_seek_data_hole(
> + struct xfs_inode *ip,
> + loff_t *start,
> + u32 type)
> +{
> + xfs_mount_t *mp = ip->i_mount;
> + xfs_fileoff_t seekoff = *start;
> + xfs_fileoff_t filelen;
> + xfs_extnum_t lastx;
> + xfs_ifork_t *ifp;
> + struct xfs_bmbt_irec got;
> + struct xfs_bmbt_irec prev;
> + u64 extoff;
> + u64 extlen;
> + int eof;
> +
> + if (xfs_get_extsz_hint(ip) ||
> + ip->i_d.di_flags & (XFS_DIFLAG_PREALLOC | XFS_DIFLAG_APPEND)) {
> + filelen = XFS_MAXIOFFSET(mp);
> + } else {
> + filelen = ip->i_size;
> + }
> +
> + ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
> + xfs_bmap_search_extents(ip, XFS_BB_TO_FSBT(mp, BTOBB(*start)),
> + XFS_DATA_FORK, &eof, &lastx, &got, &prev);
> +
> + if (type == SEEK_DATA) {
> + extoff = BBTOB(XFS_FSB_TO_BB(mp, got.br_startoff));
> + extlen = BBTOB(XFS_FSB_TO_BB(mp, got.br_blockcount));
> +
> + if (eof) {
> + if (seekoff < extoff + extlen)
> + *start = seekoff;
> + else {
> + /*
> + * There is no more data region past the
> + * supplied offset.
> + */
> + return XFS_ERROR(ENXIO);
> + }
> + }
> +
> + *start = seekoff < extoff ? extoff : seekoff;
> + } else {
> + for (;;) {
> + extoff = BBTOB(XFS_FSB_TO_BB(mp, got.br_startoff));
> + extlen = BBTOB(XFS_FSB_TO_BB(mp, got.br_blockcount));
> + if (eof) {
> + /*
> + * There might be a hole at the end of the
> + * file, adjust to the file size.
> + */
> + if (seekoff >= extoff) {
> + *start = min_t(xfs_fileoff_t, filelen,
> + (extoff + extlen));
> + }
> + break;
> + }
> +
> + /* A hole found */
> + if (seekoff < extoff) {
> + *start = seekoff;
> + break;
> + }
> +
> + /* Fetch the next extent */
> + seekoff = extoff + extlen;
> + if (++lastx < ifp->if_bytes / sizeof(xfs_bmbt_rec_t))
> + xfs_bmbt_get_all(xfs_iext_get_ext(ifp, lastx),
> + &got);
> + else
> + eof = 1;
> + }
> + }
> +
> + return 0;
> +}
> diff --git a/fs/xfs/xfs_bmap.h b/fs/xfs/xfs_bmap.h
> index 89ee672..964e29b 100644
> --- a/fs/xfs/xfs_bmap.h
> +++ b/fs/xfs/xfs_bmap.h
> @@ -196,6 +196,7 @@ int xfs_bunmapi(struct xfs_trans *tp, struct xfs_inode *ip,
> int xfs_check_nostate_extents(struct xfs_ifork *ifp, xfs_extnum_t idx,
> xfs_extnum_t num);
> uint xfs_default_attroffset(struct xfs_inode *ip);
> +int xfs_seek_data_hole(struct xfs_inode *ip, loff_t *start, u32 type);
>
> #ifdef __KERNEL__
> /* bmap to userspace formatter - copy to user & advance pointer */
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 753ed9b..bf5471b 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -1141,8 +1141,57 @@ xfs_vm_page_mkwrite(
> return block_page_mkwrite(vma, vmf, xfs_get_blocks);
> }
>
> +STATIC loff_t
> +xfs_file_llseek(
> + struct file *file,
> + loff_t offset,
> + int origin)
> +{
> + struct inode *inode = file->f_mapping->host;
> + int ret;
> +
> + if (origin != SEEK_DATA && origin != SEEK_HOLE)
> + return generic_file_llseek(file, offset, origin);
> +
> + mutex_lock(&inode->i_mutex);
> + switch (origin) {
> + case SEEK_DATA:
> + case SEEK_HOLE:
> + if (offset >= i_size_read(inode)) {
> + ret = -ENXIO;
> + goto error;
> + }
> +
> + ret = xfs_find_desired_extent(inode, &offset, origin);
> + if (ret)
> + goto error;
> + }
> +
> + if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET)) {
> + ret = -EINVAL;
> + goto error;
> + }
> +
> + if (offset > inode->i_sb->s_maxbytes) {
> + ret = -EINVAL;
> + goto error;
> + }
> +
> + if (offset != file->f_pos) {
> + file->f_pos = offset;
> + file->f_version = 0;
> + }
> +
> + mutex_unlock(&inode->i_mutex);
> + return offset;
> +
> +error:
> + mutex_unlock(&inode->i_mutex);
> + return ret;
> +}
> +
> const struct file_operations xfs_file_operations = {
> - .llseek = generic_file_llseek,
> + .llseek = xfs_file_llseek,
> .read = do_sync_read,
> .write = do_sync_write,
> .aio_read = xfs_file_aio_read,
> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
> index 23ce927..482c1ff 100644
> --- a/fs/xfs/xfs_iops.c
> +++ b/fs/xfs/xfs_iops.c
> @@ -1030,6 +1030,70 @@ xfs_vn_fiemap(
> return 0;
> }
>
> +int
> +xfs_find_desired_extent(
> + struct inode *inode,
> + loff_t *start,
> + u32 type)
> +{
> + xfs_inode_t *ip = XFS_I(inode);
> + xfs_mount_t *mp = ip->i_mount;
> + struct xfs_ifork *ifp;
> + int lock;
> + int error;
> +
> + if (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_LOCAL)
> + return XFS_ERROR(EINVAL);
> +
> + xfs_ilock(ip, XFS_IOLOCK_SHARED);
> +
> + /*
> + * Flush the delay alloc blocks. Even after flushing the inode,
> + * there can still be delalloc blocks on the inode beyond EOF
> + * due to speculative preallocation. These are not removed until
> + * the release function is called or the inode is inactivated.
> + * Hence we cannot assert here that ip->i_delayed_blks == 0.
> + */
> + if (ip->i_delayed_blks || ip->i_size > ip->i_d.di_size) {
> + error = xfs_flush_pages(ip, 0, -1, 0, FI_REMAPF);
> + if (error)
> + goto out_unlock_iolock;
> + }
> +
> + lock = xfs_ilock_map_shared(ip);
> +
> + if (XFS_FORCED_SHUTDOWN(mp)) {
> + error = EIO;
> + goto out_unlock_ilock;
> + }
> +
> + XFS_STATS_INC(xs_blk_mapr);
> + ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
> +
> + ASSERT(ifp->if_ext_max ==
> + XFS_IFORK_SIZE(ip, XFS_DATA_FORK) / (uint)sizeof(xfs_bmbt_rec_t));
> +
> + if (!(ifp->if_flags & XFS_IFEXTENTS)) {
> + error = xfs_iread_extents(NULL, ip, XFS_DATA_FORK);
> + if (error)
> + goto out_unlock_ilock;
> + }
> +
> + error = xfs_seek_data_hole(ip, start, type);
> +
> +out_unlock_ilock:
> + xfs_iunlock_map_shared(ip, lock);
> +out_unlock_iolock:
> + xfs_iunlock(ip, XFS_IOLOCK_SHARED);
> +
> + if (error)
> + return -error;
> +
> + return 0;
> +}
> +
> static const struct inode_operations xfs_inode_operations = {
> .get_acl = xfs_get_acl,
> .getattr = xfs_vn_getattr,
> diff --git a/fs/xfs/xfs_iops.h b/fs/xfs/xfs_iops.h
> index ef41c92..ea47abd 100644
> --- a/fs/xfs/xfs_iops.h
> +++ b/fs/xfs/xfs_iops.h
> @@ -27,4 +27,7 @@ extern ssize_t xfs_vn_listxattr(struct dentry *, char *data, size_t size);
>
> extern void xfs_setup_inode(struct xfs_inode *);
>
> +extern int xfs_find_desired_extent(struct inode *inode, loff_t *start,
> + u32 type);
> +
> #endif /* __XFS_IOPS_H__ */
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