From 30ee052e12b97c190b27fe6f20e3ac3047df7b5c Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 6 Apr 2016 07:53:29 +1000 Subject: xfs: optimize inline symlinks By overallocating the in-core inode fork data buffer and zero terminating the link target in xfs_init_local_fork we can avoid the memory allocation in ->follow_link. Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Signed-off-by: Dave Chinner --- fs/xfs/libxfs/xfs_inode_fork.c | 22 ++++++++++++++++++---- fs/xfs/xfs_inode_item.c | 4 ++-- fs/xfs/xfs_iops.c | 29 ++++++++++++++++++++++++++--- fs/xfs/xfs_symlink.c | 9 +++------ 4 files changed, 49 insertions(+), 15 deletions(-) diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c index 86a97f8a9de3..4fbe2263c1fc 100644 --- a/fs/xfs/libxfs/xfs_inode_fork.c +++ b/fs/xfs/libxfs/xfs_inode_fork.c @@ -239,19 +239,33 @@ xfs_init_local_fork( int size) { struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, whichfork); - int real_size = 0; + int mem_size = size, real_size = 0; + bool zero_terminate; + + /* + * If we are using the local fork to store a symlink body we need to + * zero-terminate it so that we can pass it back to the VFS directly. + * Overallocate the in-memory fork by one for that and add a zero + * to terminate it below. + */ + zero_terminate = S_ISLNK(VFS_I(ip)->i_mode); + if (zero_terminate) + mem_size++; if (size == 0) ifp->if_u1.if_data = NULL; - else if (size <= sizeof(ifp->if_u2.if_inline_data)) + else if (mem_size <= sizeof(ifp->if_u2.if_inline_data)) ifp->if_u1.if_data = ifp->if_u2.if_inline_data; else { - real_size = roundup(size, 4); + real_size = roundup(mem_size, 4); ifp->if_u1.if_data = kmem_alloc(real_size, KM_SLEEP | KM_NOFS); } - if (size) + if (size) { memcpy(ifp->if_u1.if_data, data, size); + if (zero_terminate) + ifp->if_u1.if_data[size] = '\0'; + } ifp->if_bytes = size; ifp->if_real_bytes = real_size; diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c index c48b5b18d771..37e23c7a5684 100644 --- a/fs/xfs/xfs_inode_item.c +++ b/fs/xfs/xfs_inode_item.c @@ -210,7 +210,7 @@ xfs_inode_item_format_data_fork( */ data_bytes = roundup(ip->i_df.if_bytes, 4); ASSERT(ip->i_df.if_real_bytes == 0 || - ip->i_df.if_real_bytes == data_bytes); + ip->i_df.if_real_bytes >= data_bytes); ASSERT(ip->i_df.if_u1.if_data != NULL); ASSERT(ip->i_d.di_size > 0); xlog_copy_iovec(lv, vecp, XLOG_REG_TYPE_ILOCAL, @@ -305,7 +305,7 @@ xfs_inode_item_format_attr_fork( */ data_bytes = roundup(ip->i_afp->if_bytes, 4); ASSERT(ip->i_afp->if_real_bytes == 0 || - ip->i_afp->if_real_bytes == data_bytes); + ip->i_afp->if_real_bytes >= data_bytes); ASSERT(ip->i_afp->if_u1.if_data != NULL); xlog_copy_iovec(lv, vecp, XLOG_REG_TYPE_IATTR_LOCAL, ip->i_afp->if_u1.if_data, diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c index f08d91c51b7f..aee06d9a7b6c 100644 --- a/fs/xfs/xfs_iops.c +++ b/fs/xfs/xfs_iops.c @@ -446,6 +446,16 @@ xfs_vn_get_link( return ERR_PTR(error); } +STATIC const char * +xfs_vn_get_link_inline( + struct dentry *dentry, + struct inode *inode, + struct delayed_call *done) +{ + ASSERT(XFS_I(inode)->i_df.if_flags & XFS_IFINLINE); + return XFS_I(inode)->i_df.if_u1.if_data; +} + STATIC int xfs_vn_getattr( struct vfsmount *mnt, @@ -1171,6 +1181,18 @@ static const struct inode_operations xfs_symlink_inode_operations = { .update_time = xfs_vn_update_time, }; +static const struct inode_operations xfs_inline_symlink_inode_operations = { + .readlink = generic_readlink, + .get_link = xfs_vn_get_link_inline, + .getattr = xfs_vn_getattr, + .setattr = xfs_vn_setattr, + .setxattr = generic_setxattr, + .getxattr = generic_getxattr, + .removexattr = generic_removexattr, + .listxattr = xfs_vn_listxattr, + .update_time = xfs_vn_update_time, +}; + STATIC void xfs_diflags_to_iflags( struct inode *inode, @@ -1282,9 +1304,10 @@ xfs_setup_iops( inode->i_fop = &xfs_dir_file_operations; break; case S_IFLNK: - inode->i_op = &xfs_symlink_inode_operations; - if (!(ip->i_df.if_flags & XFS_IFINLINE)) - inode->i_mapping->a_ops = &xfs_address_space_operations; + if (ip->i_df.if_flags & XFS_IFINLINE) + inode->i_op = &xfs_inline_symlink_inode_operations; + else + inode->i_op = &xfs_symlink_inode_operations; break; default: inode->i_op = &xfs_inode_operations; diff --git a/fs/xfs/xfs_symlink.c b/fs/xfs/xfs_symlink.c index b69f4a770fc9..5961c1e880c2 100644 --- a/fs/xfs/xfs_symlink.c +++ b/fs/xfs/xfs_symlink.c @@ -131,6 +131,8 @@ xfs_readlink( trace_xfs_readlink(ip); + ASSERT(!(ip->i_df.if_flags & XFS_IFINLINE)); + if (XFS_FORCED_SHUTDOWN(mp)) return -EIO; @@ -150,12 +152,7 @@ xfs_readlink( } - if (ip->i_df.if_flags & XFS_IFINLINE) { - memcpy(link, ip->i_df.if_u1.if_data, pathlen); - link[pathlen] = '\0'; - } else { - error = xfs_readlink_bmap(ip, link); - } + error = xfs_readlink_bmap(ip, link); out: xfs_iunlock(ip, XFS_ILOCK_SHARED); -- cgit v1.2.3