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Message-Id: <1360466977-8843-1-git-send-email-tytso@mit.edu>
Date: Sat, 9 Feb 2013 22:29:37 -0500
From: Theodore Ts'o <tytso@....edu>
To: Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc: Theodore Ts'o <tytso@....edu>
Subject: [PATCH] ext4: support simple conversion of extent-mapped inodes to use i_blocks
In order to make it simpler to test the code which support
i_blocks/indirect-mapped inodes, support the conversion of inodes
which are less than 12 blocks and which are contained in no more than
a single extent.
The primary intended use of this code is to converting freshly created
zero-length files and empty directories.
Note that the version of chattr in e2fsprogs 1.42.7 and earlier has a
check that prevents the clearing of the extent flag. A simple patch
which allows "chattr -e <file>" to work will be checked into the
e2fsprogs git repository.
Signed-off-by: "Theodore Ts'o" <tytso@....edu>
---
fs/ext4/ext4.h | 3 ++-
fs/ext4/extents.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
fs/ext4/ioctl.c | 20 ++++++++------------
3 files changed, 60 insertions(+), 13 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 1876b95..95d01ec 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -403,7 +403,7 @@ struct flex_groups {
#define EXT4_RESERVED_FL 0x80000000 /* reserved for ext4 lib */
#define EXT4_FL_USER_VISIBLE 0x004BDFFF /* User visible flags */
-#define EXT4_FL_USER_MODIFIABLE 0x004B80FF /* User modifiable flags */
+#define EXT4_FL_USER_MODIFIABLE 0x004380FF /* User modifiable flags */
/* Flags that should be inherited by new inodes from their parent. */
#define EXT4_FL_INHERITED (EXT4_SECRM_FL | EXT4_UNRM_FL | EXT4_COMPR_FL |\
@@ -2602,6 +2602,7 @@ extern int ext4_ext_check_inode(struct inode *inode);
extern int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk);
extern int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
__u64 start, __u64 len);
+extern int ext4_ind_migrate(struct inode *inode);
/* move_extent.c */
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 143cb77..2034146 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4766,3 +4766,53 @@ int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
return error;
}
+
+/*
+ * Migrate a simple extent-based inode to use the i_blocks[] array
+ */
+int ext4_ind_migrate(struct inode *inode)
+{
+ struct ext4_extent_header *eh;
+ struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
+ struct ext4_inode_info *ei = EXT4_I(inode);
+ struct ext4_extent *ex;
+ unsigned int i, len;
+ ext4_fsblk_t blk;
+ handle_t *handle;
+ int ret;
+
+ if (!EXT4_HAS_INCOMPAT_FEATURE(inode->i_sb,
+ EXT4_FEATURE_INCOMPAT_EXTENTS) ||
+ (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
+ return -EINVAL;
+
+ ret = ext4_ext_check_inode(inode);
+ if (ret)
+ return ret;
+
+ eh = ext_inode_hdr(inode);
+ ex = EXT_FIRST_EXTENT(eh);
+ if (ext4_blocks_count(es) > EXT4_MAX_BLOCK_FILE_PHYS ||
+ eh->eh_depth != 0 || eh->eh_entries > 1)
+ return -EOPNOTSUPP;
+ if (eh->eh_entries == 0)
+ blk = len = 0;
+ else {
+ len = ex->ee_len;
+ blk = ext4_ext_pblock(ex);
+ if (len > EXT4_NDIR_BLOCKS)
+ return -EOPNOTSUPP;
+ }
+
+ handle = ext4_journal_start(inode, EXT4_HT_MIGRATE, 1);
+ if (IS_ERR(handle))
+ return PTR_ERR(handle);
+
+ ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);
+ memset(ei->i_data, 0, sizeof(ei->i_data));
+ for (i=0; i < len; i++)
+ ei->i_data[i] = cpu_to_le32(blk++);
+ ext4_mark_inode_dirty(handle, inode);
+ ext4_journal_stop(handle);
+ return 0;
+}
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 31f4f56..a9aab2e 100644
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -83,17 +83,8 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
if (!capable(CAP_SYS_RESOURCE))
goto flags_out;
}
- if (oldflags & EXT4_EXTENTS_FL) {
- /* We don't support clearning extent flags */
- if (!(flags & EXT4_EXTENTS_FL)) {
- err = -EOPNOTSUPP;
- goto flags_out;
- }
- } else if (flags & EXT4_EXTENTS_FL) {
- /* migrate the file */
+ if ((flags ^ oldflags) & EXT4_EXTENTS_FL)
migrate = 1;
- flags &= ~EXT4_EXTENTS_FL;
- }
if (flags & EXT4_EOFBLOCKS_FL) {
/* we don't support adding EOFBLOCKS flag */
@@ -137,8 +128,13 @@ flags_err:
err = ext4_change_inode_journal_flag(inode, jflag);
if (err)
goto flags_out;
- if (migrate)
- err = ext4_ext_migrate(inode);
+ if (migrate) {
+ if (flags & EXT4_EXTENTS_FL)
+ err = ext4_ext_migrate(inode);
+ else
+ err = ext4_ind_migrate(inode);
+ }
+
flags_out:
mutex_unlock(&inode->i_mutex);
mnt_drop_write_file(filp);
--
1.7.12.rc0.22.gcdd159b
--
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