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Date: Tue, 20 Jul 2010 18:16:11 +0300
From: Amir Goldstein <amir73il@...il.com>
To: tytso@....edu, andreas.dilger@...cle.com, jack@...e.cz
Cc: linux-ext4@...r.kernel.org, Amir Goldstein <amir73il@...rs.sf.net>
Subject: [PATCH 10/12] e2fsprogs: Map maximum filesystem size with a single snapshot file
To map 2^32 logical blocks, 4 triple indirect blocks are used instead
of just one. The extra 3 triple indirect blocks are stored in-place
of direct blocks, which are not in use by snapshot files.
Snapshots cannot be enabled on filesytem with block size < 4K.
Signed-off-by: Amir Goldstein <amir73il@...rs.sf.net>
---
e2fsck/pass1.c | 14 ++++++++++----
lib/ext2fs/block.c | 15 +++++++++++++++
lib/ext2fs/bmap.c | 19 +++++++++++++++++--
lib/ext2fs/ext2_fs.h | 11 +++++++++++
lib/ext2fs/i_block.c | 12 +++++++++---
misc/e2image.c | 1 +
6 files changed, 63 insertions(+), 9 deletions(-)
diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index daecce6..cd4432b 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -1081,6 +1081,7 @@ void e2fsck_pass1(e2fsck_t ctx)
(inode->i_block[EXT2_IND_BLOCK] ||
inode->i_block[EXT2_DIND_BLOCK] ||
inode->i_block[EXT2_TIND_BLOCK] ||
+ (inode->i_flags & EXT4_SNAPFILE_FL) ||
ext2fs_file_acl_block(inode))) {
inodes_to_process[process_inode_count].ino = ino;
inodes_to_process[process_inode_count].inode = *inode;
@@ -2007,8 +2008,10 @@ static void check_blocks(e2fsck_t ctx, struct problem_context *pctx,
}
}
- if (!(fs->super->s_feature_ro_compat &
- EXT4_FEATURE_RO_COMPAT_HUGE_FILE) ||
+ if ((!(fs->super->s_feature_ro_compat &
+ EXT4_FEATURE_RO_COMPAT_HUGE_FILE) &&
+ /* snapshot file always supports the 'huge_file' flag */
+ !(inode->i_flags & EXT4_SNAPFILE_FL)) ||
!(inode->i_flags & EXT4_HUGE_FILE_FL))
pb.num_blocks *= (fs->blocksize / 512);
#if 0
@@ -2039,6 +2042,7 @@ static void check_blocks(e2fsck_t ctx, struct problem_context *pctx,
!(inode->i_flags & EXT4_EOFBLOCKS_FL))
bad_size = 3;
else if (!(extent_fs && (inode->i_flags & EXT4_EXTENTS_FL)) &&
+ !(pb.is_reg && (inode->i_flags & EXT4_SNAPFILE_FL)) &&
size > ext2_max_sizes[fs->super->s_log_block_size])
/* too big for a direct/indirect-mapped file */
bad_size = 4;
@@ -2077,8 +2081,10 @@ static void check_blocks(e2fsck_t ctx, struct problem_context *pctx,
(inode->i_size_high || inode->i_size & 0x80000000UL))
ctx->large_files++;
if ((pb.num_blocks != ext2fs_inode_i_blocks(fs, inode)) ||
- ((fs->super->s_feature_ro_compat &
- EXT4_FEATURE_RO_COMPAT_HUGE_FILE) &&
+ (((fs->super->s_feature_ro_compat &
+ EXT4_FEATURE_RO_COMPAT_HUGE_FILE) ||
+ /* snapshot file always supports the 'huge_file' flag */
+ (inode->i_flags & EXT4_SNAPFILE_FL)) &&
(inode->i_flags & EXT4_HUGE_FILE_FL) &&
(inode->osd2.linux2.l_i_blocks_hi != 0))) {
pctx->num = pb.num_blocks;
diff --git a/lib/ext2fs/block.c b/lib/ext2fs/block.c
index ff0d8bd..dfc0791 100644
--- a/lib/ext2fs/block.c
+++ b/lib/ext2fs/block.c
@@ -484,6 +484,12 @@ errcode_t ext2fs_block_iterate3(ext2_filsys fs,
* Iterate over normal data blocks
*/
for (i = 0; i < EXT2_NDIR_BLOCKS ; i++, ctx.bcount++) {
+ if ((inode.i_flags & EXT4_SNAPFILE_FL) &&
+ LINUX_S_ISREG(inode.i_mode) &&
+ i < NEXT3_EXTRA_TIND_BLOCKS)
+ /* snapshot file extra triple indirect blocks */
+ continue;
+
if (inode.i_block[i] || (flags & BLOCK_FLAG_APPEND)) {
blk64 = inode.i_block[i];
ret |= (*ctx.func)(fs, &blk64, ctx.bcount, 0, i,
@@ -514,6 +520,15 @@ errcode_t ext2fs_block_iterate3(ext2_filsys fs,
if (ret & BLOCK_ABORT)
goto abort_exit;
}
+ if ((inode.i_flags & EXT4_SNAPFILE_FL) && LINUX_S_ISREG(inode.i_mode)) {
+ /* iterate snapshot file extra triple indirect blocks */
+ for (i = 0; i < NEXT3_EXTRA_TIND_BLOCKS; i++) {
+ ret |= block_iterate_tind(&inode.i_block[i],
+ 0, EXT2_N_BLOCKS+i, &ctx);
+ if (ret & BLOCK_ABORT)
+ goto abort_exit;
+ }
+ }
abort_exit:
if (ret & BLOCK_CHANGED) {
diff --git a/lib/ext2fs/bmap.c b/lib/ext2fs/bmap.c
index fbcb375..d92e981 100644
--- a/lib/ext2fs/bmap.c
+++ b/lib/ext2fs/bmap.c
@@ -136,6 +136,8 @@ errcode_t ext2fs_bmap2(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
struct ext2_inode inode_buf;
ext2_extent_handle_t handle = 0;
blk_t addr_per_block;
+ blk64_t addr_per_tind_block;
+ int tind;
blk_t b, blk32;
char *buf = 0;
errcode_t retval = 0;
@@ -286,7 +288,20 @@ errcode_t ext2fs_bmap2(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
/* Triply indirect block */
block -= addr_per_block * addr_per_block;
- b = inode_bmap(inode, EXT2_TIND_BLOCK);
+ tind = EXT2_TIND_BLOCK;
+ addr_per_tind_block = addr_per_block * addr_per_block * addr_per_block;
+ if (block > addr_per_tind_block) {
+ /* use direct blocks as extra triple indirect blocks? */
+ tind = block / addr_per_tind_block;
+ block -= tind * addr_per_tind_block;
+ if (!(inode->i_flags & EXT4_SNAPFILE_FL) ||
+ !LINUX_S_ISREG(inode->i_mode) ||
+ tind >= NEXT3_EXTRA_TIND_BLOCKS) {
+ retval = EXT2_ET_BAD_BLOCK_NUM;
+ goto done;
+ }
+ }
+ b = inode_bmap(inode, tind);
if (!b) {
if (!(bmap_flags & BMAP_ALLOC)) {
if (bmap_flags & BMAP_SET)
@@ -298,7 +313,7 @@ errcode_t ext2fs_bmap2(ext2_filsys fs, ext2_ino_t ino, struct ext2_inode *inode,
retval = ext2fs_alloc_block(fs, b, block_buf, &b);
if (retval)
goto done;
- inode_bmap(inode, EXT2_TIND_BLOCK) = b;
+ inode_bmap(inode, tind) = b;
blocks_alloc++;
}
retval = block_tind_bmap(fs, bmap_flags, b, block_buf,
diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
index 8e850eb..3a48486 100644
--- a/lib/ext2fs/ext2_fs.h
+++ b/lib/ext2fs/ext2_fs.h
@@ -250,6 +250,17 @@ struct ext2_dx_countlimit {
#define EXT2_DIND_BLOCK (EXT2_IND_BLOCK + 1)
#define EXT2_TIND_BLOCK (EXT2_DIND_BLOCK + 1)
#define EXT2_N_BLOCKS (EXT2_TIND_BLOCK + 1)
+/*
+ * Snapshot files have different indirection mapping that can map up to 2^32
+ * logical blocks, so they can cover the mapped filesystem block address space.
+ * Next3 must use either 4K or 8K blocks (depending on PAGE_SIZE).
+ * With 8K blocks, 1 triple indirect block maps 2^33 logical blocks.
+ * With 4K blocks (the system default), each triple indirect block maps 2^30
+ * logical blocks, so 4 triple indirect blocks map 2^32 logical blocks.
+ * Snapshot files in small filesystems (<= 4G), use only 1 double indirect
+ * block to map the entire filesystem.
+ */
+#define NEXT3_EXTRA_TIND_BLOCKS 3
/*
* Inode flags
diff --git a/lib/ext2fs/i_block.c b/lib/ext2fs/i_block.c
index 822776d..8079d8e 100644
--- a/lib/ext2fs/i_block.c
+++ b/lib/ext2fs/i_block.c
@@ -31,8 +31,10 @@ errcode_t ext2fs_iblk_add_blocks(ext2_filsys fs, struct ext2_inode *inode,
{
unsigned long long b = inode->i_blocks;
- if (!(fs->super->s_feature_ro_compat &
+ if (!((fs->super->s_feature_ro_compat &
EXT4_FEATURE_RO_COMPAT_HUGE_FILE) ||
+ /* snapshot file always supports the 'huge_file' flag */
+ (inode->i_flags & EXT4_SNAPFILE_FL)) ||
!(inode->i_flags & EXT4_HUGE_FILE_FL))
num_blocks *= fs->blocksize / 512;
@@ -53,8 +55,10 @@ errcode_t ext2fs_iblk_sub_blocks(ext2_filsys fs, struct ext2_inode *inode,
{
unsigned long long b = inode->i_blocks;
- if (!(fs->super->s_feature_ro_compat &
+ if (!((fs->super->s_feature_ro_compat &
EXT4_FEATURE_RO_COMPAT_HUGE_FILE) ||
+ /* snapshot file always supports the 'huge_file' flag */
+ (inode->i_flags & EXT4_SNAPFILE_FL)) ||
!(inode->i_flags & EXT4_HUGE_FILE_FL))
num_blocks *= fs->blocksize / 512;
@@ -74,8 +78,10 @@ errcode_t ext2fs_iblk_sub_blocks(ext2_filsys fs, struct ext2_inode *inode,
errcode_t ext2fs_iblk_set(ext2_filsys fs, struct ext2_inode *inode, blk64_t b)
{
- if (!(fs->super->s_feature_ro_compat &
+ if (!((fs->super->s_feature_ro_compat &
EXT4_FEATURE_RO_COMPAT_HUGE_FILE) ||
+ /* snapshot file always supports the 'huge_file' flag */
+ (inode->i_flags & EXT4_SNAPFILE_FL)) ||
!(inode->i_flags & EXT4_HUGE_FILE_FL))
b *= fs->blocksize / 512;
diff --git a/misc/e2image.c b/misc/e2image.c
index 003ac5a..d9e0681 100644
--- a/misc/e2image.c
+++ b/misc/e2image.c
@@ -536,6 +536,7 @@ static void write_raw_image_file(ext2_filsys fs, int fd, int scramble_flag)
}
} else {
if ((inode.i_flags & EXT4_EXTENTS_FL) ||
+ (inode.i_flags & EXT4_SNAPFILE_FL) ||
inode.i_block[EXT2_IND_BLOCK] ||
inode.i_block[EXT2_DIND_BLOCK] ||
inode.i_block[EXT2_TIND_BLOCK]) {
--
1.6.6
--
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