* [PATCH 2/2] remove manual lookup from xfs_rename and simplify locking
2008-04-10 18:44 [PATCH 2/2] simplify xfs_lock_for_rename Christoph Hellwig
2008-04-11 0:24 ` Barry Naujok
2008-04-11 4:40 ` Barry Naujok
@ 2008-04-11 9:11 ` Christoph Hellwig
2 siblings, 0 replies; 7+ messages in thread
From: Christoph Hellwig @ 2008-04-11 9:11 UTC (permalink / raw)
To: xfs
->rename already gets the target inode passed if it exits. Pass it down
to xfs_rename so that we can avoid looking it up again. Also simplify
locking as the first lock section in xfs_rename can go away now: the
isdir is an invariant over the lifetime of the inode, and new_parent and
the nlink check are namespace topology protected by i_mutex in the VFS.
The projid check needs to move into the second lock section anyway to
not be racy.
Also kill the now unused xfs_dir_lookup_int and remove the now-unused
first_locked argumet to xfs_lock_inodes.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Index: linux-2.6-xfs/fs/xfs/xfs_rename.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_rename.c 2008-04-09 18:35:28.000000000 +0200
+++ linux-2.6-xfs/fs/xfs/xfs_rename.c 2008-04-11 09:06:51.000000000 +0200
@@ -55,85 +55,32 @@ xfs_rename_unlock4(
xfs_iunlock(i_tab[0], lock_mode);
for (i = 1; i < 4; i++) {
- if (i_tab[i] == NULL) {
+ if (i_tab[i] == NULL)
break;
- }
+
/*
* Watch out for duplicate entries in the table.
*/
- if (i_tab[i] != i_tab[i-1]) {
+ if (i_tab[i] != i_tab[i-1])
xfs_iunlock(i_tab[i], lock_mode);
- }
}
}
-#ifdef DEBUG
-int xfs_rename_skip, xfs_rename_nskip;
-#endif
-
/*
- * The following routine will acquire the locks required for a rename
- * operation. The code understands the semantics of renames and will
- * validate that name1 exists under dp1 & that name2 may or may not
- * exist under dp2.
- *
- * We are renaming dp1/name1 to dp2/name2.
- *
- * Return ENOENT if dp1 does not exist, other lookup errors, or 0 for success.
+ * Enter all inodes for a rename transaction into a sorted array.
*/
-STATIC int
-xfs_lock_for_rename(
+STATIC void
+xfs_sort_for_rename(
xfs_inode_t *dp1, /* in: old (source) directory inode */
xfs_inode_t *dp2, /* in: new (target) directory inode */
xfs_inode_t *ip1, /* in: inode of old entry */
- struct xfs_name *name2, /* in: new entry name */
- xfs_inode_t **ipp2, /* out: inode of new entry, if it
+ xfs_inode_t *ip2, /* in: inode of new entry, if it
already exists, NULL otherwise. */
xfs_inode_t **i_tab,/* out: array of inode returned, sorted */
int *num_inodes) /* out: number of inodes in array */
{
- xfs_inode_t *ip2 = NULL;
xfs_inode_t *temp;
- xfs_ino_t inum1, inum2;
- int error;
int i, j;
- uint lock_mode;
- int diff_dirs = (dp1 != dp2);
-
- /*
- * First, find out the current inums of the entries so that we
- * can determine the initial locking order. We'll have to
- * sanity check stuff after all the locks have been acquired
- * to see if we still have the right inodes, directories, etc.
- */
- lock_mode = xfs_ilock_map_shared(dp1);
- IHOLD(ip1);
- xfs_itrace_ref(ip1);
-
- inum1 = ip1->i_ino;
-
- /*
- * Unlock dp1 and lock dp2 if they are different.
- */
- if (diff_dirs) {
- xfs_iunlock_map_shared(dp1, lock_mode);
- lock_mode = xfs_ilock_map_shared(dp2);
- }
-
- error = xfs_dir_lookup_int(dp2, lock_mode, name2, &inum2, &ip2);
- if (error == ENOENT) { /* target does not need to exist. */
- inum2 = 0;
- } else if (error) {
- /*
- * If dp2 and dp1 are the same, the next line unlocks dp1.
- * Got it?
- */
- xfs_iunlock_map_shared(dp2, lock_mode);
- IRELE (ip1);
- return error;
- } else {
- xfs_itrace_ref(ip2);
- }
/*
* i_tab contains a list of pointers to inodes. We initialize
@@ -145,21 +92,20 @@ xfs_lock_for_rename(
i_tab[0] = dp1;
i_tab[1] = dp2;
i_tab[2] = ip1;
- if (inum2 == 0) {
- *num_inodes = 3;
- i_tab[3] = NULL;
- } else {
+ if (ip2) {
*num_inodes = 4;
i_tab[3] = ip2;
+ } else {
+ *num_inodes = 3;
+ i_tab[3] = NULL;
}
- *ipp2 = i_tab[3];
/*
* Sort the elements via bubble sort. (Remember, there are at
* most 4 elements to sort, so this is adequate.)
*/
- for (i=0; i < *num_inodes; i++) {
- for (j=1; j < *num_inodes; j++) {
+ for (i = 0; i < *num_inodes; i++) {
+ for (j = 1; j < *num_inodes; j++) {
if (i_tab[j]->i_ino < i_tab[j-1]->i_ino) {
temp = i_tab[j];
i_tab[j] = i_tab[j-1];
@@ -167,30 +113,6 @@ xfs_lock_for_rename(
}
}
}
-
- /*
- * We have dp2 locked. If it isn't first, unlock it.
- * If it is first, tell xfs_lock_inodes so it can skip it
- * when locking. if dp1 == dp2, xfs_lock_inodes will skip both
- * since they are equal. xfs_lock_inodes needs all these inodes
- * so that it can unlock and retry if there might be a dead-lock
- * potential with the log.
- */
-
- if (i_tab[0] == dp2 && lock_mode == XFS_ILOCK_SHARED) {
-#ifdef DEBUG
- xfs_rename_skip++;
-#endif
- xfs_lock_inodes(i_tab, *num_inodes, 1, XFS_ILOCK_SHARED);
- } else {
-#ifdef DEBUG
- xfs_rename_nskip++;
-#endif
- xfs_iunlock_map_shared(dp2, lock_mode);
- xfs_lock_inodes(i_tab, *num_inodes, 0, XFS_ILOCK_SHARED);
- }
-
- return 0;
}
/*
@@ -202,10 +124,10 @@ xfs_rename(
struct xfs_name *src_name,
xfs_inode_t *src_ip,
xfs_inode_t *target_dp,
- struct xfs_name *target_name)
+ struct xfs_name *target_name,
+ xfs_inode_t *target_ip)
{
- xfs_trans_t *tp;
- xfs_inode_t *target_ip;
+ xfs_trans_t *tp = NULL;
xfs_mount_t *mp = src_dp->i_mount;
int new_parent; /* moving to a new dir */
int src_is_directory; /* src_name is a directory */
@@ -230,64 +152,31 @@ xfs_rename(
target_dp, DM_RIGHT_NULL,
src_name->name, target_name->name,
0, 0, 0);
- if (error) {
+ if (error)
return error;
- }
}
/* Return through std_return after this point. */
- /*
- * Lock all the participating inodes. Depending upon whether
- * the target_name exists in the target directory, and
- * whether the target directory is the same as the source
- * directory, we can lock from 2 to 4 inodes.
- * xfs_lock_for_rename() will return ENOENT if src_name
- * does not exist in the source directory.
- */
- tp = NULL;
- error = xfs_lock_for_rename(src_dp, target_dp, src_ip, target_name,
- &target_ip, inodes, &num_inodes);
- if (error) {
- /*
- * We have nothing locked, no inode references, and
- * no transaction, so just get out.
- */
- goto std_return;
- }
-
- ASSERT(src_ip != NULL);
+ new_parent = (src_dp != target_dp);
+ src_is_directory = ((src_ip->i_d.di_mode & S_IFMT) == S_IFDIR);
- if ((src_ip->i_d.di_mode & S_IFMT) == S_IFDIR) {
+ if (src_is_directory) {
/*
* Check for link count overflow on target_dp
*/
- if (target_ip == NULL && (src_dp != target_dp) &&
+ if (target_ip == NULL && new_parent &&
target_dp->i_d.di_nlink >= XFS_MAXLINK) {
error = XFS_ERROR(EMLINK);
- xfs_rename_unlock4(inodes, XFS_ILOCK_SHARED);
- goto rele_return;
+ goto std_return;
}
}
- /*
- * If we are using project inheritance, we only allow renames
- * into our tree when the project IDs are the same; else the
- * tree quota mechanism would be circumvented.
- */
- if (unlikely((target_dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) &&
- (target_dp->i_d.di_projid != src_ip->i_d.di_projid))) {
- error = XFS_ERROR(EXDEV);
- xfs_rename_unlock4(inodes, XFS_ILOCK_SHARED);
- goto rele_return;
- }
-
- new_parent = (src_dp != target_dp);
- src_is_directory = ((src_ip->i_d.di_mode & S_IFMT) == S_IFDIR);
+ xfs_sort_for_rename(src_dp, target_dp, src_ip, target_ip,
+ inodes, &num_inodes);
- /*
- * Drop the locks on our inodes so that we can start the transaction.
- */
- xfs_rename_unlock4(inodes, XFS_ILOCK_SHARED);
+ IHOLD(src_ip);
+ if (target_ip)
+ IHOLD(target_ip);
XFS_BMAP_INIT(&free_list, &first_block);
tp = xfs_trans_alloc(mp, XFS_TRANS_RENAME);
@@ -314,9 +203,25 @@ xfs_rename(
}
/*
- * Reacquire the inode locks we dropped above.
+ * Lock all the participating inodes. Depending upon whether
+ * the target_name exists in the target directory, and
+ * whether the target directory is the same as the source
+ * directory, we can lock from 2 to 4 inodes.
+ */
+ xfs_lock_inodes(inodes, num_inodes, XFS_ILOCK_EXCL);
+
+ /*
+ * If we are using project inheritance, we only allow renames
+ * into our tree when the project IDs are the same; else the
+ * tree quota mechanism would be circumvented.
*/
- xfs_lock_inodes(inodes, num_inodes, 0, XFS_ILOCK_EXCL);
+ if (unlikely((target_dp->i_d.di_flags & XFS_DIFLAG_PROJINHERIT) &&
+ (target_dp->i_d.di_projid != src_ip->i_d.di_projid))) {
+ error = XFS_ERROR(EXDEV);
+ xfs_rename_unlock4(inodes, XFS_ILOCK_SHARED);
+ xfs_trans_cancel(tp, cancel_flags);
+ goto rele_return;
+ }
/*
* Join all the inodes to the transaction. From this point on,
Index: linux-2.6-xfs/fs/xfs/xfs_utils.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_utils.c 2008-04-09 18:35:28.000000000 +0200
+++ linux-2.6-xfs/fs/xfs/xfs_utils.c 2008-04-11 08:41:32.000000000 +0200
@@ -41,49 +41,6 @@
#include "xfs_utils.h"
-int
-xfs_dir_lookup_int(
- xfs_inode_t *dp,
- uint lock_mode,
- struct xfs_name *name,
- xfs_ino_t *inum,
- xfs_inode_t **ipp)
-{
- int error;
-
- xfs_itrace_entry(dp);
-
- error = xfs_dir_lookup(NULL, dp, name, inum);
- if (!error) {
- /*
- * Unlock the directory. We do this because we can't
- * hold the directory lock while doing the vn_get()
- * in xfs_iget(). Doing so could cause us to hold
- * a lock while waiting for the inode to finish
- * being inactive while it's waiting for a log
- * reservation in the inactive routine.
- */
- xfs_iunlock(dp, lock_mode);
- error = xfs_iget(dp->i_mount, NULL, *inum, 0, 0, ipp, 0);
- xfs_ilock(dp, lock_mode);
-
- if (error) {
- *ipp = NULL;
- } else if ((*ipp)->i_d.di_mode == 0) {
- /*
- * The inode has been freed. Something is
- * wrong so just get out of here.
- */
- xfs_iunlock(dp, lock_mode);
- xfs_iput_new(*ipp, 0);
- *ipp = NULL;
- xfs_ilock(dp, lock_mode);
- error = XFS_ERROR(ENOENT);
- }
- }
- return error;
-}
-
/*
* Allocates a new inode from disk and return a pointer to the
* incore copy. This routine will internally commit the current
Index: linux-2.6-xfs/fs/xfs/xfs_utils.h
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_utils.h 2008-04-09 18:35:28.000000000 +0200
+++ linux-2.6-xfs/fs/xfs/xfs_utils.h 2008-04-10 20:40:36.000000000 +0200
@@ -21,8 +21,6 @@
#define IRELE(ip) VN_RELE(XFS_ITOV(ip))
#define IHOLD(ip) VN_HOLD(XFS_ITOV(ip))
-extern int xfs_dir_lookup_int(xfs_inode_t *, uint, struct xfs_name *,
- xfs_ino_t *, xfs_inode_t **);
extern int xfs_truncate_file(xfs_mount_t *, xfs_inode_t *);
extern int xfs_dir_ialloc(xfs_trans_t **, xfs_inode_t *, mode_t, xfs_nlink_t,
xfs_dev_t, cred_t *, prid_t, int,
Index: linux-2.6-xfs/fs/xfs/linux-2.6/xfs_iops.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/linux-2.6/xfs_iops.c 2008-04-11 08:42:18.000000000 +0200
+++ linux-2.6-xfs/fs/xfs/linux-2.6/xfs_iops.c 2008-04-11 08:43:47.000000000 +0200
@@ -518,7 +518,8 @@ xfs_vn_rename(
xfs_dentry_to_name(&nname, ndentry);
error = xfs_rename(XFS_I(odir), &oname, XFS_I(odentry->d_inode),
- XFS_I(ndir), &nname);
+ XFS_I(ndir), &nname, new_inode ?
+ XFS_I(new_inode) : NULL);
if (likely(!error)) {
if (new_inode)
xfs_validate_fields(new_inode);
Index: linux-2.6-xfs/fs/xfs/xfs_vnodeops.h
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_vnodeops.h 2008-04-11 08:43:54.000000000 +0200
+++ linux-2.6-xfs/fs/xfs/xfs_vnodeops.h 2008-04-11 08:44:19.000000000 +0200
@@ -48,7 +48,7 @@ int xfs_change_file_space(struct xfs_ino
struct cred *credp, int attr_flags);
int xfs_rename(struct xfs_inode *src_dp, struct xfs_name *src_name,
struct xfs_inode *src_ip, struct xfs_inode *target_dp,
- struct xfs_name *target_name);
+ struct xfs_name *target_name, struct xfs_inode *target_ip);
int xfs_attr_get(struct xfs_inode *ip, const char *name, char *value,
int *valuelenp, int flags, cred_t *cred);
int xfs_attr_set(struct xfs_inode *dp, const char *name, char *value,
Index: linux-2.6-xfs/fs/xfs/xfs_dfrag.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_dfrag.c 2008-04-11 09:06:56.000000000 +0200
+++ linux-2.6-xfs/fs/xfs/xfs_dfrag.c 2008-04-11 09:07:06.000000000 +0200
@@ -162,7 +162,7 @@ xfs_swap_extents(
ips[1] = ip;
}
- xfs_lock_inodes(ips, 2, 0, lock_flags);
+ xfs_lock_inodes(ips, 2, lock_flags);
locked = 1;
/* Verify that both files have the same format */
@@ -265,7 +265,7 @@ xfs_swap_extents(
locked = 0;
goto error0;
}
- xfs_lock_inodes(ips, 2, 0, XFS_ILOCK_EXCL);
+ xfs_lock_inodes(ips, 2, XFS_ILOCK_EXCL);
/*
* Count the number of extended attribute blocks
Index: linux-2.6-xfs/fs/xfs/xfs_inode.h
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_inode.h 2008-04-11 09:07:13.000000000 +0200
+++ linux-2.6-xfs/fs/xfs/xfs_inode.h 2008-04-11 09:07:22.000000000 +0200
@@ -534,7 +534,7 @@ int xfs_iflush(xfs_inode_t *, uint);
void xfs_iflush_all(struct xfs_mount *);
void xfs_ichgtime(xfs_inode_t *, int);
xfs_fsize_t xfs_file_last_byte(xfs_inode_t *);
-void xfs_lock_inodes(xfs_inode_t **, int, int, uint);
+void xfs_lock_inodes(xfs_inode_t **, int, uint);
void xfs_synchronize_atime(xfs_inode_t *);
void xfs_mark_inode_dirty_sync(xfs_inode_t *);
Index: linux-2.6-xfs/fs/xfs/xfs_vnodeops.c
===================================================================
--- linux-2.6-xfs.orig/fs/xfs/xfs_vnodeops.c 2008-04-11 09:07:28.000000000 +0200
+++ linux-2.6-xfs/fs/xfs/xfs_vnodeops.c 2008-04-11 09:08:56.000000000 +0200
@@ -2120,7 +2120,7 @@ again:
ips[0] = ip;
ips[1] = dp;
- xfs_lock_inodes(ips, 2, 0, XFS_ILOCK_EXCL);
+ xfs_lock_inodes(ips, 2, XFS_ILOCK_EXCL);
}
/* else e_inum == dp->i_ino */
/* This can happen if we're asked to lock /x/..
@@ -2168,7 +2168,6 @@ void
xfs_lock_inodes(
xfs_inode_t **ips,
int inodes,
- int first_locked,
uint lock_mode)
{
int attempts = 0, i, j, try_lock;
@@ -2176,13 +2175,8 @@ xfs_lock_inodes(
ASSERT(ips && (inodes >= 2)); /* we need at least two */
- if (first_locked) {
- try_lock = 1;
- i = 1;
- } else {
- try_lock = 0;
- i = 0;
- }
+ try_lock = 0;
+ i = 0;
again:
for (; i < inodes; i++) {
@@ -2544,7 +2538,7 @@ xfs_link(
ips[1] = sip;
}
- xfs_lock_inodes(ips, 2, 0, XFS_ILOCK_EXCL);
+ xfs_lock_inodes(ips, 2, XFS_ILOCK_EXCL);
/*
* Increment vnode ref counts since xfs_trans_commit &
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