ext4: xattr-in-inode support

Large xattr support is implemented for EXT4_FEATURE_INCOMPAT_EA_INODE.

If the size of an xattr value is larger than will fit in a single
external block, then the xattr value will be saved into the body
of an external xattr inode.

The also helps support a larger number of xattr, since only the headers
will be stored in the in-inode space or the single external block.

The inode is referenced from the xattr header via "e_value_inum",
which was formerly "e_value_block", but that field was never used.
The e_value_size still contains the xattr size so that listing
xattrs does not need to look up the inode if the data is not accessed.

struct ext4_xattr_entry {
        __u8    e_name_len;     /* length of name */
        __u8    e_name_index;   /* attribute name index */
        __le16  e_value_offs;   /* offset in disk block of value */
        __le32  e_value_inum;   /* inode in which value is stored */
        __le32  e_value_size;   /* size of attribute value */
        __le32  e_hash;         /* hash value of name and value */
        char    e_name[0];      /* attribute name */
};

The xattr inode is marked with the EXT4_EA_INODE_FL flag and also
holds a back-reference to the owning inode in its i_mtime field,
allowing the ext4/e2fsck to verify the correct inode is accessed.

[ Applied fix by Dan Carpenter to avoid freeing an ERR_PTR. ]

Lustre-Jira: https://jira.hpdd.intel.com/browse/LU-80
Lustre-bugzilla: https://bugzilla.lustre.org/show_bug.cgi?id=4424
Signed-off-by: Kalpak Shah <kalpak.shah@sun.com>
Signed-off-by: James Simmons <uja.ornl@gmail.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Tahsin Erdogan <tahsin@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

1 files changed, 40 insertions, 9 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 47604d1352fc..986efd9511ac 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -139,8 +139,6 @@ static void ext4_invalidatepage(struct page *page, unsigned int offset,
 				unsigned int length);
 static int __ext4_journalled_writepage(struct page *page, unsigned int len);
 static int ext4_bh_delay_or_unwritten(handle_t *handle, struct buffer_head *bh);
-static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
-				  int pextents);
 
 /*
  * Test whether an inode is a fast symlink.
@@ -189,6 +187,8 @@ void ext4_evict_inode(struct inode *inode)
 {
 	handle_t *handle;
 	int err;
+	int extra_credits = 3;
+	struct ext4_xattr_ino_array *lea_ino_array = NULL;
 
 	trace_ext4_evict_inode(inode);
 
@@ -238,8 +238,8 @@ void ext4_evict_inode(struct inode *inode)
 	 * protection against it
 	 */
 	sb_start_intwrite(inode->i_sb);
-	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE,
-				    ext4_blocks_for_truncate(inode)+3);
+
+	handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, extra_credits);
 	if (IS_ERR(handle)) {
 		ext4_std_error(inode->i_sb, PTR_ERR(handle));
 		/*
@@ -251,9 +251,36 @@ void ext4_evict_inode(struct inode *inode)
 		sb_end_intwrite(inode->i_sb);
 		goto no_delete;
 	}
-
 	if (IS_SYNC(inode))
 		ext4_handle_sync(handle);
+
+	/*
+	 * Delete xattr inode before deleting the main inode.
+	 */
+	err = ext4_xattr_delete_inode(handle, inode, &lea_ino_array);
+	if (err) {
+		ext4_warning(inode->i_sb,
+			     "couldn't delete inode's xattr (err %d)", err);
+		goto stop_handle;
+	}
+
+	if (!IS_NOQUOTA(inode))
+		extra_credits += 2 * EXT4_QUOTA_DEL_BLOCKS(inode->i_sb);
+
+	if (!ext4_handle_has_enough_credits(handle,
+			ext4_blocks_for_truncate(inode) + extra_credits)) {
+		err = ext4_journal_extend(handle,
+			ext4_blocks_for_truncate(inode) + extra_credits);
+		if (err > 0)
+			err = ext4_journal_restart(handle,
+			ext4_blocks_for_truncate(inode) + extra_credits);
+		if (err != 0) {
+			ext4_warning(inode->i_sb,
+				     "couldn't extend journal (err %d)", err);
+			goto stop_handle;
+		}
+	}
+
 	inode->i_size = 0;
 	err = ext4_mark_inode_dirty(handle, inode);
 	if (err) {
@@ -277,10 +304,10 @@ void ext4_evict_inode(struct inode *inode)
 	 * enough credits left in the handle to remove the inode from
 	 * the orphan list and set the dtime field.
 	 */
-	if (!ext4_handle_has_enough_credits(handle, 3)) {
-		err = ext4_journal_extend(handle, 3);
+	if (!ext4_handle_has_enough_credits(handle, extra_credits)) {
+		err = ext4_journal_extend(handle, extra_credits);
 		if (err > 0)
-			err = ext4_journal_restart(handle, 3);
+			err = ext4_journal_restart(handle, extra_credits);
 		if (err != 0) {
 			ext4_warning(inode->i_sb,
 				     "couldn't extend journal (err %d)", err);
@@ -315,8 +342,12 @@ void ext4_evict_inode(struct inode *inode)
 		ext4_clear_inode(inode);
 	else
 		ext4_free_inode(handle, inode);
+
 	ext4_journal_stop(handle);
 	sb_end_intwrite(inode->i_sb);
+
+	if (lea_ino_array != NULL)
+		ext4_xattr_inode_array_free(inode, lea_ino_array);
 	return;
 no_delete:
 	ext4_clear_inode(inode);	/* We must guarantee clearing of inode... */
@@ -5504,7 +5535,7 @@ static int ext4_index_trans_blocks(struct inode *inode, int lblocks,
  *
  * Also account for superblock, inode, quota and xattr blocks
  */
-static int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
+int ext4_meta_trans_blocks(struct inode *inode, int lblocks,
 				  int pextents)
 {
 	ext4_group_t groups, ngroups = ext4_get_groups_count(inode->i_sb);