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Add range locking to xattr ops

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We can use easy xattrs to test range locking and item consistency
between mounts.

Signed-off-by: Zach Brown <zab@versity.com>
This commit is contained in:
Zach Brown
2017-02-15 08:49:47 -08:00
parent b3b2693939
commit 607eff9b7c
1 changed files with 40 additions and 5 deletions
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45
kmod/src/xattr.c
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@@ -23,6 +23,7 @@
#include "item.h"
#include "trans.h"
#include "xattr.h"
#include "lock.h"
/*
* In the simple case an xattr is stored in a single item whose key and
@@ -149,7 +150,9 @@ ssize_t scoutfs_getxattr(struct dentry *dentry, const char *name, void *buffer,
struct scoutfs_inode_info *si = SCOUTFS_I(inode);
struct scoutfs_xattr_val_header vh;
struct scoutfs_key_buf *key = NULL;
struct scoutfs_key_buf *last = NULL;
SCOUTFS_DECLARE_KVEC(val);
struct scoutfs_lock lck;
unsigned int total;
unsigned int bytes;
unsigned int off;
@@ -169,8 +172,15 @@ ssize_t scoutfs_getxattr(struct dentry *dentry, const char *name, void *buffer,
return SCOUTFS_XATTR_MAX_SIZE;
key = alloc_xattr_key(sb, scoutfs_ino(inode), name, name_len, 0);
if (!key)
return -ENOMEM;
last = alloc_xattr_key(sb, scoutfs_ino(inode), name, name_len, 0xff);
if (!key || !last) {
ret = -ENOMEM;
goto out;
}
ret = scoutfs_lock_range(sb, SCOUTFS_LOCK_MODE_READ, key, last, &lck);
if (ret)
goto out;
down_read(&si->xattr_rwsem);
@@ -219,8 +229,11 @@ ssize_t scoutfs_getxattr(struct dentry *dentry, const char *name, void *buffer,
ret = -ERANGE;
up_read(&si->xattr_rwsem);
scoutfs_key_free(sb, key);
scoutfs_unlock_range(sb, &lck);
out:
scoutfs_key_free(sb, key);
scoutfs_key_free(sb, last);
return ret;
}
@@ -250,6 +263,7 @@ static int scoutfs_xattr_set(struct dentry *dentry, const char *name,
struct scoutfs_xattr_val_header vh;
size_t name_len = strlen(name);
SCOUTFS_DECLARE_KVEC(val);
struct scoutfs_lock lck;
unsigned int bytes;
unsigned int off;
LIST_HEAD(list);
@@ -274,6 +288,10 @@ static int scoutfs_xattr_set(struct dentry *dentry, const char *name,
goto out;
}
ret = scoutfs_lock_range(sb, SCOUTFS_LOCK_MODE_WRITE, key, last, &lck);
if (ret)
goto out;
/* build up batch of new items for the new xattr */
if (value) {
for_each_xattr_item(key, val, &vh, (void *)value, size,
@@ -281,7 +299,7 @@ static int scoutfs_xattr_set(struct dentry *dentry, const char *name,
ret = scoutfs_item_add_batch(sb, &list, key, val);
if (ret)
goto out;
goto unlock;
}
}
@@ -299,7 +317,7 @@ static int scoutfs_xattr_set(struct dentry *dentry, const char *name,
ret = scoutfs_hold_trans(sb);
if (ret)
goto out;
goto unlock;
down_write(&si->xattr_rwsem);
@@ -315,6 +333,9 @@ static int scoutfs_xattr_set(struct dentry *dentry, const char *name,
up_write(&si->xattr_rwsem);
scoutfs_release_trans(sb);
unlock:
scoutfs_unlock_range(sb, &lck);
out:
scoutfs_item_free_batch(sb, &list);
scoutfs_key_free(sb, key);
@@ -346,6 +367,7 @@ ssize_t scoutfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
struct scoutfs_xattr_key *xkey;
struct scoutfs_key_buf *key;
struct scoutfs_key_buf *last;
struct scoutfs_lock lck;
ssize_t total;
int name_len;
int ret;
@@ -362,6 +384,10 @@ ssize_t scoutfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
xkey = key->data;
xkey->name[0] = '\0';
ret = scoutfs_lock_range(sb, SCOUTFS_LOCK_MODE_READ, key, last, &lck);
if (ret)
goto out;
down_read(&si->xattr_rwsem);
total = 0;
@@ -408,6 +434,7 @@ ssize_t scoutfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
}
up_read(&si->xattr_rwsem);
scoutfs_unlock_range(sb, &lck);
out:
scoutfs_key_free(sb, key);
scoutfs_key_free(sb, last);
@@ -428,6 +455,7 @@ int scoutfs_xattr_drop(struct super_block *sb, u64 ino)
{
struct scoutfs_key_buf *key;
struct scoutfs_key_buf *last;
struct scoutfs_lock lck;
int ret;
key = alloc_xattr_key(sb, ino, NULL, SCOUTFS_XATTR_MAX_NAME_LEN, 0);
@@ -438,6 +466,11 @@ int scoutfs_xattr_drop(struct super_block *sb, u64 ino)
goto out;
}
/* while we read to delete we need to writeback others */
ret = scoutfs_lock_range(sb, SCOUTFS_LOCK_MODE_WRITE, key, last, &lck);
if (ret)
goto out;
/* the inode is dead so we don't need the xattr sem */
for (;;) {
@@ -455,6 +488,8 @@ int scoutfs_xattr_drop(struct super_block *sb, u64 ino)
/* don't need to increment past deleted key */
}
scoutfs_unlock_range(sb, &lck);
out:
scoutfs_key_free(sb, key);
scoutfs_key_free(sb, last);