[PATCH V4 4/7] xfs: Introduce struct xfs_attr_set_resv

Chandan Rajendra
2020-02-23T07:28:51Z

The intermediate numbers calculated by xfs_attr_calc_size() will be needed by
a future commit to correctly calculate log reservation for xattr set
operation. Towards this goal, this commit introduces 'struct
xfs_attr_set_resv' to collect,
1. Number of dabtree blocks.
2. Number of remote blocks.
3. Number of Bmbt blocks.
4. Total number of blocks we need to reserve.

This will be returned as an out argument by xfs_attr_calc_size().

Signed-off-by: Chandan Rajendra <chandanrlinux@gmail.com>
---
libxfs/xfs_attr.c | 48 +++++++++++++++++++++++++----------------------
libxfs/xfs_attr.h | 13 +++++++++++++
2 files changed, 39 insertions(+), 22 deletions(-)

diff --git a/libxfs/xfs_attr.c b/libxfs/xfs_attr.c
index 967aac1d..23fcb110 100644
--- a/libxfs/xfs_attr.c
+++ b/libxfs/xfs_attr.c
@@ -136,16 +136,14 @@ xfs_attr_get(
/*
* Calculate how many blocks we need for the new attribute,
*/
-STATIC int
+STATIC void
xfs_attr_calc_size(
- struct xfs_da_args *args,
- int *local)
+ struct xfs_da_args *args,
+ struct xfs_attr_set_resv *resv,
+ int *local)
{
- struct xfs_mount *mp = args->dp->i_mount;
- unsigned int total_dablks;
- unsigned int bmbt_blks;
- unsigned int rmt_blks;
- int size;
+ struct xfs_mount *mp = args->dp->i_mount;
+ int size;

/*
* Determine space new attribute will use, and if it would be
@@ -153,25 +151,27 @@ xfs_attr_calc_size(
*/
size = xfs_attr_leaf_newentsize(args->geo, args->namelen,
args->valuelen, local);
- total_dablks = XFS_DAENTER_BLOCKS(mp, XFS_ATTR_FORK);
+ resv->total_dablks = XFS_DAENTER_BLOCKS(mp, XFS_ATTR_FORK);
if (*local) {
if (size > (args->geo->blksize / 2)) {
/* Double split possible */
- total_dablks *= 2;
+ resv->total_dablks *= 2;
}
- rmt_blks = 0;
+ resv->rmt_blks = 0;
} else {
/*
* Out of line attribute, cannot double split, but
* make room for the attribute value itself.
*/
- rmt_blks = xfs_attr3_rmt_blocks(mp, args->valuelen);
+ resv->rmt_blks = xfs_attr3_rmt_blocks(mp, args->valuelen);
}

- bmbt_blks = XFS_NEXTENTADD_SPACE_RES(mp, total_dablks + rmt_blks,
- XFS_ATTR_FORK);
+ resv->bmbt_blks = XFS_NEXTENTADD_SPACE_RES(mp,
+ resv->total_dablks + resv->rmt_blks,
+ XFS_ATTR_FORK);

- return total_dablks + rmt_blks + bmbt_blks;
+ resv->alloc_blks = resv->total_dablks + resv->rmt_blks +
+ resv->bmbt_blks;
}

STATIC int
@@ -297,12 +297,15 @@ int
xfs_attr_set(
struct xfs_da_args *args)
{
- struct xfs_inode *dp = args->dp;
- struct xfs_mount *mp = dp->i_mount;
- struct xfs_trans_res tres;
- bool rsvd = (args->attr_namespace & XFS_ATTR_ROOT);
- int error, local;
- unsigned int total;
+ struct xfs_inode *dp = args->dp;
+ struct xfs_mount *mp = dp->i_mount;
+ struct xfs_attr_set_resv resv;
+ struct xfs_trans_res tres;
+ bool rsvd;
+ int error, local;
+ unsigned int total;
+
+ rsvd = (args->attr_namespace & XFS_ATTR_ROOT);

if (XFS_FORCED_SHUTDOWN(dp->i_mount))
return -EIO;
@@ -326,7 +329,8 @@ xfs_attr_set(
XFS_STATS_INC(mp, xs_attr_set);

args->op_flags |= XFS_DA_OP_ADDNAME;
- args->total = xfs_attr_calc_size(args, &local);
+ xfs_attr_calc_size(args, &resv, &local);
+ args->total = resv.alloc_blks;

/*
* If the inode doesn't have an attribute fork, add one.
diff --git a/libxfs/xfs_attr.h b/libxfs/xfs_attr.h
index 861c81f9..dc08bdfb 100644
--- a/libxfs/xfs_attr.h
+++ b/libxfs/xfs_attr.h
@@ -73,6 +73,19 @@ struct xfs_attr_list_context {
int index; /* index into output buffer */
};

+struct xfs_attr_set_resv {
+ /* Number of unlogged blocks needed to store the remote attr value. */
+ unsigned int rmt_blks;
+
+ /* Number of filesystem blocks to allocate for the da btree. */
+ unsigned int total_dablks;
+
+ /* Blocks we might need to create all the new attr fork mappings. */
+ unsigned int bmbt_blks;
+
+ /* Total number of blocks we might have to allocate. */
+ unsigned int alloc_blks;
+};

/*========================================================================
* Function prototypes for the kernel.
--
2.19.1