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Message-ID: <1395155384.15587.10.camel@zerobox.home>
Date: Tue, 18 Mar 2014 16:09:44 +0100
From: Lubos Uhliarik <uhliarik@...nam.cz>
To: linux-ext4@...r.kernel.org
Cc: vojnar@....vutbr.cz, lczerner@...hat.com
Subject: [RFC][PATCH 1/1] ext4: Undelete Feature for Ext4
This patch should make undelete process for deleted files under ext4 fs easier.
Signed-off-by: Lubos Uhliarik <uhliarik@...nam.cz>
---
fs/ext4/ext4_extents.h | 14 +++++++++++
fs/ext4/extents.c | 67 +++++++++++++++++++++++++++++++++++++++++++++-----
2 files changed, 75 insertions(+), 6 deletions(-)
diff --git a/fs/ext4/ext4_extents.h b/fs/ext4/ext4_extents.h
index 5074fe2..22cf2cd 100644
--- a/fs/ext4/ext4_extents.h
+++ b/fs/ext4/ext4_extents.h
@@ -251,6 +251,20 @@ static inline void ext4_ext_store_pblock(struct ext4_extent *ex,
0xffff);
}
+static inline void ext4_ext_store_entries(struct ext4_extent_header *eh,
+ __u16 eh_entries){
+ eh->eh_generation &= cpu_to_le32((unsigned long) 0x0000ffff);
+ eh->eh_generation |= cpu_to_le32(((unsigned long) (eh_entries) << 16)
+ & 0xffff0000);
+}
+
+static inline void ext4_ext_store_depth(struct ext4_extent_header *eh,
+ __u16 eh_depth){
+ eh->eh_generation &= cpu_to_le32((unsigned long) 0xffff0000);
+ eh->eh_generation |= cpu_to_le32(((unsigned long) (eh_depth))
+ & 0x0000ffff);
+}
+
/*
* ext4_idx_store_pblock:
* stores a large physical block number into an index struct,
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 74bc2d5..f0f3615 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -2565,6 +2565,7 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
ext4_lblk_t ex_ee_block;
unsigned short ex_ee_len;
unsigned uninitialized = 0;
+ unsigned short ex_ee_entries;
struct ext4_extent *ex;
ext4_fsblk_t pblk;
@@ -2584,6 +2585,7 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
ex_ee_block = le32_to_cpu(ex->ee_block);
ex_ee_len = ext4_ext_get_actual_len(ex);
+ ex_ee_entries = le16_to_cpu(eh->eh_entries);
trace_ext4_ext_rm_leaf(inode, start, ex, *partial_cluster);
@@ -2662,11 +2664,9 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
if (err)
goto out;
- if (num == 0)
- /* this extent is removed; mark slot entirely unused */
- ext4_ext_store_pblock(ex, 0);
+ if (num != 0)
+ ex->ee_len = cpu_to_le16(num);
- ex->ee_len = cpu_to_le16(num);
/*
* Do not mark uninitialized if all the blocks in the
* extent have been removed.
@@ -2726,8 +2726,19 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
/* if this leaf is free, then we should
* remove it from index block above */
- if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
+ if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL) {
+ err = ext4_ext_get_access(handle, inode, path + depth);
+ if (err)
+ goto out;
+
+ ext4_ext_store_entries(path[depth].p_hdr, ex_ee_entries);
+
+ err = ext4_ext_dirty(handle, inode, path + depth);
+ if (err)
+ goto out;
+
err = ext4_ext_rm_idx(handle, inode, path, depth);
+ }
out:
return err;
@@ -2760,6 +2771,7 @@ int ext4_ext_remove_space(struct inode *inode, ext4_lblk_t start,
struct super_block *sb = inode->i_sb;
int depth = ext_depth(inode);
struct ext4_ext_path *path = NULL;
+ unsigned short *entries_path = NULL;
long long partial_cluster = 0;
handle_t *handle;
int i = 0, err = 0;
@@ -2864,6 +2876,18 @@ again:
}
err = 0;
+ if (!inode->i_nlink) {
+ entries_path = kzalloc(sizeof(short) * (depth + 1),
+ GFP_NOFS);
+ if (entries_path == NULL) {
+ kfree(path);
+ ext4_journal_stop(handle);
+ return -ENOMEM;
+ }
+
+ entries_path[0] = le16_to_cpu(ext_inode_hdr(inode)->eh_entries);
+ }
+
while (i >= 0 && err == 0) {
if (i == depth) {
/* this is leaf block */
@@ -2890,6 +2914,10 @@ again:
ext_debug("init index ptr: hdr 0x%p, num %d\n",
path[i].p_hdr,
le16_to_cpu(path[i].p_hdr->eh_entries));
+ if (entries_path != NULL) {
+ entries_path[i] = le16_to_cpu(
+ path[i].p_hdr->eh_entries);
+ }
} else {
/* we were already here, see at next index */
path[i].p_idx--;
@@ -2928,10 +2956,24 @@ again:
} else {
/* we finished processing this index, go up */
if (path[i].p_hdr->eh_entries == 0 && i > 0) {
+ if (entries_path != NULL) {
+ err = ext4_ext_get_access(handle,
+ inode, path);
+ if (err == 0) {
+ ext4_ext_store_entries(
+ path[i].p_hdr,
+ (entries_path[i]));
+ err = ext4_ext_dirty(handle,
+ inode, path);
+ }
+ }
+
/* index is empty, remove it;
* handle must be already prepared by the
* truncatei_leaf() */
- err = ext4_ext_rm_idx(handle, inode, path, i);
+ if (err == 0)
+ err = ext4_ext_rm_idx(handle, inode,
+ path, i);
}
/* root level has p_bh == NULL, brelse() eats this */
brelse(path[i].p_bh);
@@ -2964,6 +3006,17 @@ again:
*/
err = ext4_ext_get_access(handle, inode, path);
if (err == 0) {
+ /* Store depth and entries to eh_generation to make
+ * recovering deleted files easier. */
+ if (entries_path != NULL) {
+ ext4_ext_store_entries(ext_inode_hdr(inode),
+ (entries_path[0]));
+
+ ext4_ext_store_depth(ext_inode_hdr(inode),
+ le16_to_cpu(
+ ext_inode_hdr(inode)->eh_depth));
+ }
+
ext_inode_hdr(inode)->eh_depth = 0;
ext_inode_hdr(inode)->eh_max =
cpu_to_le16(ext4_ext_space_root(inode, 0));
@@ -2973,6 +3026,8 @@ again:
out:
ext4_ext_drop_refs(path);
kfree(path);
+ kfree(entries_path);
+
if (err == -EAGAIN) {
path = NULL;
goto again;
--
1.8.3.2
--
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