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 <hch@xxxxxx>
---
fs/xfs/libxfs/xfs_dir2_sf.c | 2 +-
fs/xfs/libxfs/xfs_inode_fork.c | 29 +++++++++++++++++++----------
fs/xfs/libxfs/xfs_inode_fork.h | 3 ++-
fs/xfs/xfs_inode_item.c | 4 ++--
fs/xfs/xfs_iops.c | 28 +++++++++++++++++++++++++---
fs/xfs/xfs_symlink.c | 14 ++++++--------
6 files changed, 55 insertions(+), 25 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_dir2_sf.c b/fs/xfs/libxfs/xfs_dir2_sf.c
index bf83116..a438058 100644
--- a/fs/xfs/libxfs/xfs_dir2_sf.c
+++ b/fs/xfs/libxfs/xfs_dir2_sf.c
@@ -258,7 +258,7 @@ xfs_dir2_block_to_sf(
* Convert the inode to local format and copy the data in.
*/
ASSERT(dp->i_df.if_bytes == 0);
- xfs_init_local_fork(dp, XFS_DATA_FORK, dst, size);
+ xfs_init_local_fork(dp, XFS_DATA_FORK, dst, size, false);
dp->i_d.di_format = XFS_DINODE_FMT_LOCAL;
dp->i_d.di_size = size;
diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c
index 86a3e11..dcadd07 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.c
+++ b/fs/xfs/libxfs/xfs_inode_fork.c
@@ -235,22 +235,29 @@ xfs_init_local_fork(
struct xfs_inode *ip,
int whichfork,
const void *data,
- int size)
+ int size,
+ bool zero_terminate)
{
struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, whichfork);
- int real_size = 0;
+ int mem_size = size, real_size = 0;
+
+ if (zero_terminate)
+ mem_size = size + 1;
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;
@@ -270,11 +277,12 @@ xfs_init_local_fork(
*/
STATIC int
xfs_iformat_local(
- xfs_inode_t *ip,
- xfs_dinode_t *dip,
- int whichfork,
- int size)
+ struct xfs_inode *ip,
+ struct xfs_dinode *dip,
+ int whichfork,
+ int size)
{
+ bool zero_terminate = S_ISDIR(dip->di_mode);
/*
* If the size is unreasonable, then something
@@ -291,7 +299,8 @@ xfs_iformat_local(
return -EFSCORRUPTED;
}
- xfs_init_local_fork(ip, whichfork, XFS_DFORK_PTR(dip, whichfork), size);
+ xfs_init_local_fork(ip, whichfork, XFS_DFORK_PTR(dip, whichfork), size,
+ zero_terminate);
return 0;
}
diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index dfb2966..f5f640f 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -135,7 +135,8 @@ void xfs_iroot_realloc(struct xfs_inode *, int, int);
int xfs_iread_extents(struct xfs_trans *, struct xfs_inode *, int);
int xfs_iextents_copy(struct xfs_inode *, struct xfs_bmbt_rec *,
int);
-void xfs_init_local_fork(struct xfs_inode *, int, const void *, int);
+void xfs_init_local_fork(struct xfs_inode *, int, const void *, int,
+ bool);
struct xfs_bmbt_rec_host *
xfs_iext_get_ext(struct xfs_ifork *, xfs_extnum_t);
diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
index bf13a5a..786d91a 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 d3505ff..439cf99 100644
--- a/fs/xfs/xfs_iops.c
+++ b/fs/xfs/xfs_iops.c
@@ -444,6 +444,15 @@ xfs_vn_follow_link(
return NULL;
}
+STATIC void *
+xfs_vn_follow_link_inline(
+ struct dentry *dentry,
+ struct nameidata *nd)
+{
+ nd_set_link(nd, XFS_I(dentry->d_inode)->i_df.if_u1.if_data);
+ return NULL;
+}
+
STATIC int
xfs_vn_getattr(
struct vfsmount *mnt,
@@ -1190,6 +1199,18 @@ 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,
+ .follow_link = xfs_vn_follow_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,
@@ -1308,9 +1329,10 @@ 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 7fa94dc..f474792 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);
@@ -302,12 +299,13 @@ xfs_symlink(
if (resblks)
resblks -= XFS_IALLOC_SPACE_RES(mp);
+
/*
* If the symlink will fit into the inode, write it inline.
*/
if (pathlen <= XFS_IFORK_DSIZE(ip)) {
- xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen);
-
+ xfs_init_local_fork(ip, XFS_DATA_FORK, target_path, pathlen,
+ true);
ip->i_d.di_size = pathlen;
ip->i_d.di_format = XFS_DINODE_FMT_LOCAL;
xfs_trans_log_inode(tp, ip, XFS_ILOG_DDATA | XFS_ILOG_CORE);
--
1.9.1
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