On 9/19/19 10:47 AM, Brian Foster wrote:
On Thu, Sep 05, 2019 at 03:18:22PM -0700, Allison Collins wrote:
From: Allison Henderson <allison.henderson@xxxxxxxxxx>
This patch adds a new functions to check for the existence of
an attribute. Subroutines are also added to handle the cases
of leaf blocks, nodes or shortform. Common code that appears
in existing attr add and remove functions have been factored
out to help reduce the appearence of duplicated code. We will
need these routines later for delayed attributes since delayed
operations cannot return error codes.
Signed-off-by: Allison Henderson <allison.henderson@xxxxxxxxxx>
Signed-off-by: Allison Collins <allison.henderson@xxxxxxxxxx>
Extra s-o-b tag?
Oops, I thought I had caught all the old names. Will clean out :-)
---
fs/xfs/libxfs/xfs_attr.c | 150 +++++++++++++++++++++++++++---------------
fs/xfs/libxfs/xfs_attr.h | 1 +
fs/xfs/libxfs/xfs_attr_leaf.c | 92 +++++++++++++++++---------
fs/xfs/libxfs/xfs_attr_leaf.h | 2 +
4 files changed, 161 insertions(+), 84 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index 50e099f..a297857 100644
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -46,6 +46,7 @@ STATIC int xfs_attr_shortform_addname(xfs_da_args_t *args);
STATIC int xfs_attr_leaf_get(xfs_da_args_t *args);
STATIC int xfs_attr_leaf_addname(xfs_da_args_t *args);
STATIC int xfs_attr_leaf_removename(xfs_da_args_t *args);
+STATIC int xfs_leaf_has_attr(struct xfs_da_args *args, struct xfs_buf **bp);
The fact that this is not named xfs_attr_leaf_*() kind of stands out
here, particularly since the node variant uses the xfs_attr_* prefix.
Hm? (Same goes for xfs_shortform_has_attr() I suppose..).
Sure, I can flip the prefixes around to look a little more consistent
/*
* Internal routines when attribute list is more than one block.
@@ -53,6 +54,8 @@ STATIC int xfs_attr_leaf_removename(xfs_da_args_t *args);
STATIC int xfs_attr_node_get(xfs_da_args_t *args);
STATIC int xfs_attr_node_addname(xfs_da_args_t *args);
STATIC int xfs_attr_node_removename(xfs_da_args_t *args);
+STATIC int xfs_attr_node_hasname(xfs_da_args_t *args,
+ struct xfs_da_state **state);
STATIC int xfs_attr_fillstate(xfs_da_state_t *state);
STATIC int xfs_attr_refillstate(xfs_da_state_t *state);
@@ -309,6 +312,32 @@ xfs_attr_set_args(
}
/*
+ * Return EEXIST if attr is found, or ENOATTR if not
+ */
+int
+xfs_has_attr(
+ struct xfs_da_args *args)
+{
+ struct xfs_inode *dp = args->dp;
+ struct xfs_buf *bp;
+ int error;
+
+ if (!xfs_inode_hasattr(dp)) {
+ error = -ENOATTR;
+ } else if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
+ ASSERT(dp->i_afp->if_flags & XFS_IFINLINE);
+ error = xfs_shortform_has_attr(args, NULL, NULL);
+ } else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
+ error = xfs_leaf_has_attr(args, &bp);
+ xfs_trans_brelse(args->trans, bp);
+ } else {
+ error = xfs_attr_node_hasname(args, NULL);
+ }
+
+ return error;
+}
+
FWIW, I think it's preferable to include new functions like this with
the first user. I'm a bit curious about the use of error codes here as
opposed to returning a boolean. I could see being able to handle
unexpected errors as a good reason for doing that, but taking a quick
look ahead, it appears neither caller of xfs_has_attr() does so. ;)
(To be clear, I think keeping the function as is and fixing up the
eventual callers to handle unexpected errors is probably the right thing
to do.).
The new top level function actually doesnt get used until patch 18, but
I guess I try to keep the patch sizes small to make them easier for
people to review. Basically we use it to see if there is/isnt an
attribute present, and then return the appropriate error code right
away. IE, trying to remove an attribute that isnt there immediately
return EENOATTR rather than trying to start a delayed operation that
isnt going to be successful. The is because delayed operations are not
supposed to return error codes. If they do, they cause a shut down,
which is not correct here.
Initially I think I had it returning booleans, but it means the top
level function needs to do extra handling to translate the error codes,
and I thought it looked messy. So I decided to stick with the scheme
that the rest of the code was using.
I skipped ahead about unexpected error codes and see what you mean, so I
will add some extra handlers there.
+/*
* Remove the attribute specified in @args.
*/
int
@@ -574,26 +603,17 @@ STATIC int
xfs_attr_leaf_addname(
struct xfs_da_args *args)
{
- struct xfs_inode *dp;
struct xfs_buf *bp;
int retval, error, forkoff;
+ struct xfs_inode *dp = args->dp;
trace_xfs_attr_leaf_addname(args);
/*
- * Read the (only) block in the attribute list in.
- */
- dp = args->dp;
- args->blkno = 0;
- error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno, -1, &bp);
- if (error)
- return error;
-
It looks like we lose this unexpected error check here (i.e. suppose we
got -ENOMEM or -EFSCORRUPTED or something that indicates we shouldn't
continue). FWIW, this seems to repeat throughout this patch where we've
invoked the new helpers..
Ok, I'll add in an explicit check for (retval != -ENOATTR && retval !=
-EEXIST)
- /*
* Look up the given attribute in the leaf block. Figure out if
* the given flags produce an error or call for an atomic rename.
*/
- retval = xfs_attr3_leaf_lookup_int(bp, args);
+ retval = xfs_leaf_has_attr(args, &bp);
if ((args->name.type & ATTR_REPLACE) && (retval == -ENOATTR)) {
xfs_trans_brelse(args->trans, bp);
return retval;
@@ -745,6 +765,25 @@ xfs_attr_leaf_addname(
}
/*
+ * Return EEXIST if attr is found, or ENOATTR if not
+ */
+STATIC int
+xfs_leaf_has_attr(
+ struct xfs_da_args *args,
+ struct xfs_buf **bp)
+{
+ int error = 0;
+
+ args->blkno = 0;
This seems misplaced for a helper, but I could be missing context. Why
not just pass zero directly and leave the args->blkno assignment to the
caller?
I guess just I kept these two lines together since that's was how they
initially appeared before factoring them out, but it does look a bit
off. It should be ok leave the assignment to the caller. I can push it
back up.
+ error = xfs_attr3_leaf_read(args->trans, args->dp,
+ args->blkno, XFS_DABUF_MAP_NOMAPPING, bp);
+ if (error)
+ return error;
+
+ return xfs_attr3_leaf_lookup_int(*bp, args);
+}
+
+/*
* Remove a name from the leaf attribute list structure
*
* This leaf block cannot have a "remote" value, we only call this routine
@@ -764,12 +803,8 @@ xfs_attr_leaf_removename(
* Remove the attribute.
*/
dp = args->dp;
- args->blkno = 0;
- error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno, -1, &bp);
- if (error)
- return error;
Lost error check.
- error = xfs_attr3_leaf_lookup_int(bp, args);
+ error = xfs_leaf_has_attr(args, &bp);
if (error == -ENOATTR) {
xfs_trans_brelse(args->trans, bp);
return error;
@@ -808,12 +843,7 @@ xfs_attr_leaf_get(xfs_da_args_t *args)
trace_xfs_attr_leaf_get(args);
- args->blkno = 0;
- error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno, -1, &bp);
- if (error)
- return error;
-
^ here too. Not sure if I caught them all, but you get the idea. ;)
Ok,I'll sweep through and find them :-)
- error = xfs_attr3_leaf_lookup_int(bp, args);
+ error = xfs_leaf_has_attr(args, &bp);
if (error != -EEXIST) {
xfs_trans_brelse(args->trans, bp);
return error;
@@ -823,6 +853,43 @@ xfs_attr_leaf_get(xfs_da_args_t *args)
return error;
}
+/*
+ * Return EEXIST if attr is found, or ENOATTR if not
+ * statep: If not null is set to point at the found state. Caller will
+ * be responsible for freeing the state in this case.
+ */
+STATIC int
+xfs_attr_node_hasname(
+ struct xfs_da_args *args,
+ struct xfs_da_state **statep)
+{
+ struct xfs_da_state *state;
+ struct xfs_inode *dp;
+ int retval, error;
+
+ /*
+ * Tie a string around our finger to remind us where we are.
+ */
+ dp = args->dp;
+ state = xfs_da_state_alloc();
+ state->args = args;
+ state->mp = dp->i_mount;
+
No real need for the dp local variable here if it's just to reference
->i_mount. Also I know that comment isn't introduced by this patch, but
any idea what it actually means? It doesn't make much sense to me at a
glance. :P
Ok, will clean out assignment. I'm actually not sure as to the comments
origins either, I assumed it was in reference the the state? I suppose
state is used to keep track of a lot of things going on in the calling
function. But even in that context, I don't find the comment
particularly descriptive. Should I clean it out?
+ /*
+ * Search to see if name exists, and get back a pointer to it.
+ */
+ error = xfs_da3_node_lookup_int(state, &retval);
+ if (error == 0)
+ error = retval;
+
+ if (statep != NULL)
+ *statep = state;
+ else
+ xfs_da_state_free(state);
+
+ return error;
+}
+
/*========================================================================
* External routines when attribute list size > geo->blksize
*========================================================================*/
@@ -855,17 +922,14 @@ xfs_attr_node_addname(
dp = args->dp;
mp = dp->i_mount;
restart:
- state = xfs_da_state_alloc();
- state->args = args;
- state->mp = mp;
-
/*
* Search to see if name already exists, and get back a pointer
* to where it should go.
*/
- error = xfs_da3_node_lookup_int(state, &retval);
- if (error)
Error check again.
+ error = xfs_attr_node_hasname(args, &state);
+ if (error == -EEXIST)
goto out;
+
blk = &state->path.blk[ state->path.active-1 ];
ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
if ((args->name.type & ATTR_REPLACE) && (retval == -ENOATTR)) {
@@ -1070,29 +1134,15 @@ xfs_attr_node_removename(
{
struct xfs_da_state *state;
struct xfs_da_state_blk *blk;
- struct xfs_inode *dp;
struct xfs_buf *bp;
int retval, error, forkoff;
+ struct xfs_inode *dp = args->dp;
trace_xfs_attr_node_removename(args);
- /*
- * Tie a string around our finger to remind us where we are.
- */
- dp = args->dp;
- state = xfs_da_state_alloc();
- state->args = args;
- state->mp = dp->i_mount;
-
- /*
- * Search to see if name exists, and get back a pointer to it.
- */
- error = xfs_da3_node_lookup_int(state, &retval);
- if (error || (retval != -EEXIST)) {
- if (error == 0)
- error = retval;
+ error = xfs_attr_node_hasname(args, &state);
+ if (error != -EEXIST)
goto out;
- }
/*
* If there is an out-of-line value, de-allocate the blocks.
@@ -1314,20 +1364,14 @@ xfs_attr_node_get(xfs_da_args_t *args)
trace_xfs_attr_node_get(args);
- state = xfs_da_state_alloc();
- state->args = args;
- state->mp = args->dp->i_mount;
-
/*
* Search to see if name exists, and get back a pointer to it.
*/
- error = xfs_da3_node_lookup_int(state, &retval);
- if (error) {
+ error = xfs_attr_node_hasname(args, &state);
+ if (error != -EEXIST) {
retval = error;
goto out_release;
}
- if (retval != -EEXIST)
- goto out_release;
/*
* Get the value, local or "remote"
diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
index cedb4e2..fb56d81 100644
--- a/fs/xfs/libxfs/xfs_attr.h
+++ b/fs/xfs/libxfs/xfs_attr.h
@@ -150,6 +150,7 @@ int xfs_attr_set(struct xfs_inode *dp, struct xfs_name *name,
unsigned char *value, int valuelen);
int xfs_attr_set_args(struct xfs_da_args *args);
int xfs_attr_remove(struct xfs_inode *dp, struct xfs_name *name);
+int xfs_has_attr(struct xfs_da_args *args);
int xfs_attr_remove_args(struct xfs_da_args *args);
int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
int flags, struct attrlist_cursor_kern *cursor);
diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
index 07ce320..a501538 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.c
+++ b/fs/xfs/libxfs/xfs_attr_leaf.c
@@ -590,6 +590,53 @@ xfs_attr_shortform_create(xfs_da_args_t *args)
}
/*
+ * Return EEXIST if attr is found, or ENOATTR if not
+ * args: args containing attribute name and namelen
+ * sfep: If not null, pointer will be set to the last attr entry found
+ * basep: If not null, pointer is set to the byte offset of the entry in the
+ * list
+ */
+int
+xfs_shortform_has_attr(
+ struct xfs_da_args *args,
+ struct xfs_attr_sf_entry **sfep,
+ int *basep)
+{
+ struct xfs_attr_shortform *sf;
+ struct xfs_attr_sf_entry *sfe;
+ int base = sizeof(struct xfs_attr_sf_hdr);
+ int size = 0;
+ int end;
+ int i;
+
+ base = sizeof(struct xfs_attr_sf_hdr);
+ sf = (struct xfs_attr_shortform *)args->dp->i_afp->if_u1.if_data;
+ sfe = &sf->list[0];
+ end = sf->hdr.count;
+ for (i = 0; i < end; sfe = XFS_ATTR_SF_NEXTENTRY(sfe),
+ base += size, i++) {
+ size = XFS_ATTR_SF_ENTSIZE(sfe);
+ if (sfe->namelen != args->name.len)
+ continue;
+ if (memcmp(sfe->nameval, args->name.name, args->name.len) != 0)
+ continue;
+ if (!xfs_attr_namesp_match(args->name.type, sfe->flags))
+ continue;
+ break;
+ }
+
+ if (sfep != NULL)
+ *sfep = sfe;
+
+ if (basep != NULL)
+ *basep = base;
+
+ if (i == end)
+ return -ENOATTR;
+ return -EEXIST;
This function seems like it could just return a bool. Eh, I suppose it's
better to be consistent with the other variants if those ones can return
unrelated errors.
Ok, I prefer the consistency as well.
+}
+
+/*
* Add a name/value pair to the shortform attribute list.
* Overflow from the inode has already been checked for.
*/
@@ -598,7 +645,7 @@ xfs_attr_shortform_add(xfs_da_args_t *args, int forkoff)
{
xfs_attr_shortform_t *sf;
xfs_attr_sf_entry_t *sfe;
- int i, offset, size;
+ int offset, size, error;
xfs_mount_t *mp;
xfs_inode_t *dp;
Nit: might be good to clean up the typedefs here since you do it in the
remove function as well.
Sure, will do.
struct xfs_ifork *ifp;
@@ -612,18 +659,10 @@ xfs_attr_shortform_add(xfs_da_args_t *args, int forkoff)
ifp = dp->i_afp;
ASSERT(ifp->if_flags & XFS_IFINLINE);
sf = (xfs_attr_shortform_t *)ifp->if_u1.if_data;
- sfe = &sf->list[0];
- for (i = 0; i < sf->hdr.count; sfe = XFS_ATTR_SF_NEXTENTRY(sfe), i++) {
+ error = xfs_shortform_has_attr(args, &sfe, NULL);
#ifdef DEBUG
- if (sfe->namelen != args->name.len)
- continue;
- if (memcmp(args->name.name, sfe->nameval, args->name.len) != 0)
- continue;
- if (!xfs_attr_namesp_match(args->name.type, sfe->flags))
- continue;
- ASSERT(0);
+ ASSERT(error != -EEXIST);
#endif
Hmm, interesting. So basically this code walks to the end of the list
for the purpose of placement of the new attr and the debug code simply
asserts that we don't find an existing attr. The only thing that
concerns me is that nothing about xfs_shortform_has_attr() indicates
that the output values are important when the lookup fails. The comment
only explains what the values are when a lookup succeeds. Could we
update the comment to elaborate on this use case to prevent somebody
from unknowingly breaking it down the road?
Also, there's no need for the #ifdef DEBUG any more with just the assert
check in that block.
Sure, I will clearify the comments and pull out the DEBUG
- }
offset = (char *)sfe - (char *)sf;
size = XFS_ATTR_SF_ENTSIZE_BYNAME(args->name.len, args->valuelen);
@@ -668,33 +707,24 @@ xfs_attr_fork_remove(
int
xfs_attr_shortform_remove(xfs_da_args_t *args)
{
- xfs_attr_shortform_t *sf;
- xfs_attr_sf_entry_t *sfe;
- int base, size=0, end, totsize, i;
- xfs_mount_t *mp;
- xfs_inode_t *dp;
+ struct xfs_attr_shortform *sf;
+ struct xfs_attr_sf_entry *sfe;
+ int base, size = 0, end, totsize;
+ struct xfs_mount *mp;
+ struct xfs_inode *dp;
+ int error;
trace_xfs_attr_sf_remove(args);
dp = args->dp;
mp = dp->i_mount;
- base = sizeof(xfs_attr_sf_hdr_t);
sf = (xfs_attr_shortform_t *)dp->i_afp->if_u1.if_data;
- sfe = &sf->list[0];
end = sf->hdr.count;
This value of end is unused (end is immediately reassigned further down
in the function).
Brian
Ok, I will pick that out. Thank you for the thorough reviews!
Allison
- for (i = 0; i < end; sfe = XFS_ATTR_SF_NEXTENTRY(sfe),
- base += size, i++) {
- size = XFS_ATTR_SF_ENTSIZE(sfe);
- if (sfe->namelen != args->name.len)
- continue;
- if (memcmp(sfe->nameval, args->name.name, args->name.len) != 0)
- continue;
- if (!xfs_attr_namesp_match(args->name.type, sfe->flags))
- continue;
- break;
- }
- if (i == end)
- return -ENOATTR;
+
+ error = xfs_shortform_has_attr(args, &sfe, &base);
+ if (error == -ENOATTR)
+ return error;
+ size = XFS_ATTR_SF_ENTSIZE(sfe);
/*
* Fix up the attribute fork data, covering the hole
diff --git a/fs/xfs/libxfs/xfs_attr_leaf.h b/fs/xfs/libxfs/xfs_attr_leaf.h
index 536a290..58e9327 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.h
+++ b/fs/xfs/libxfs/xfs_attr_leaf.h
@@ -42,6 +42,8 @@ int xfs_attr_shortform_getvalue(struct xfs_da_args *args);
int xfs_attr_shortform_to_leaf(struct xfs_da_args *args,
struct xfs_buf **leaf_bp);
int xfs_attr_shortform_remove(struct xfs_da_args *args);
+int xfs_shortform_has_attr(struct xfs_da_args *args,
+ struct xfs_attr_sf_entry **sfep, int *basep);
int xfs_attr_shortform_allfit(struct xfs_buf *bp, struct xfs_inode *dp);
int xfs_attr_shortform_bytesfit(struct xfs_inode *dp, int bytes);
xfs_failaddr_t xfs_attr_shortform_verify(struct xfs_inode *ip);
--
2.7.4
