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Date: Fri, 19 Nov 2010 15:48:17 -0500
From: Valerie Aurora <vaurora@...hat.com>
To: linux-ext4@...r.kernel.org
Cc: Theodore Tso <tytso@....edu>, Eric Sandeen <sandeen@...hat.com>
Subject: [RFC PATCH 1/2] union-mount: Add support for whiteouts
This is a request for review, not a pull. Does this file type-based
approach to supporting whiteouts and fallthrus in ext* make sense?
(Fallthru support in next patch.)
-VAL
From: Valerie Aurora <vaurora@...hat.com>
union-mount: Add support for whiteouts
Whiteouts are used to record deleted directory entries in a union
mounted file system. Whiteouts are enabled with the incompat feature
"whiteout". e2fsck on a file system with the whiteout feature
disabled removes all whiteouts and opaque flags.
Signed-off-by: Valerie Aurora <vaurora@...hat.com>
---
e2fsck/e2fsck.c | 2 ++
e2fsck/e2fsck.h | 2 ++
e2fsck/pass1.c | 19 +++++++++++++++++++
e2fsck/pass2.c | 40 +++++++++++++++++++++++++++++++++++++---
e2fsck/problem.c | 10 ++++++++++
e2fsck/problem.h | 6 ++++++
e2fsck/unix.c | 4 ++++
e2fsck/util.c | 5 +++++
lib/blkid/probe.h | 3 +++
lib/e2p/feature.c | 2 ++
lib/ext2fs/ext2_fs.h | 10 +++++++---
lib/ext2fs/ext2fs.h | 2 ++
misc/mke2fs.c | 10 ++++++++++
misc/tune2fs.8.in | 18 +++++++++++++++++-
misc/tune2fs.c | 22 ++++++++++++++++++++++
15 files changed, 148 insertions(+), 7 deletions(-)
diff --git a/e2fsck/e2fsck.c b/e2fsck/e2fsck.c
index f1da97a..7a2f2a5 100644
--- a/e2fsck/e2fsck.c
+++ b/e2fsck/e2fsck.c
@@ -152,6 +152,8 @@ errcode_t e2fsck_reset_context(e2fsck_t ctx)
ctx->fs_total_count = 0;
ctx->fs_badblocks_count = 0;
ctx->fs_sockets_count = 0;
+ ctx->fs_whiteouts_count = 0;
+ ctx->fs_opaque_dirs_count = 0;
ctx->fs_ind_count = 0;
ctx->fs_dind_count = 0;
ctx->fs_tind_count = 0;
diff --git a/e2fsck/e2fsck.h b/e2fsck/e2fsck.h
index d4df5f3..e768997 100644
--- a/e2fsck/e2fsck.h
+++ b/e2fsck/e2fsck.h
@@ -330,6 +330,8 @@ struct e2fsck_struct {
__u32 fs_total_count;
__u32 fs_badblocks_count;
__u32 fs_sockets_count;
+ __u32 fs_whiteouts_count;
+ __u32 fs_opaque_dirs_count;
__u32 fs_ind_count;
__u32 fs_dind_count;
__u32 fs_tind_count;
diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index 93763cd..c1572a6 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -508,6 +508,24 @@ static void check_is_really_dir(e2fsck_t ctx, struct problem_context *pctx,
}
}
+static void check_opaque_flag(e2fsck_t ctx, struct problem_context *pctx)
+{
+ struct ext2_inode *inode = pctx->inode;
+ if (inode->i_flags & EXT2_OPAQUE_FL) {
+ if (!(ctx->fs->super->s_feature_incompat &
+ EXT2_FEATURE_INCOMPAT_WHITEOUT)) {
+ if (!fix_problem(ctx, PR_1_CLEAR_OPAQUE, pctx))
+ return;
+ inode->i_flags &= ~EXT2_OPAQUE_FL;
+ e2fsck_write_inode_full(ctx, pctx->ino, inode,
+ EXT2_INODE_SIZE(ctx->fs->super),
+ "check_opaque_flag");
+ } else {
+ ctx->fs_opaque_dirs_count++;
+ }
+ }
+}
+
extern void e2fsck_setup_tdb_icount(e2fsck_t ctx, int flags,
ext2_icount_t *ret)
{
@@ -1006,6 +1024,7 @@ void e2fsck_pass1(e2fsck_t ctx)
check_inode_extra_space(ctx, &pctx);
check_is_really_dir(ctx, &pctx, block_buf);
+ check_opaque_flag(ctx, &pctx);
/*
* ext2fs_inode_has_valid_blocks does not actually look
diff --git a/e2fsck/pass2.c b/e2fsck/pass2.c
index 8d1cbc6..bff5d9a 100644
--- a/e2fsck/pass2.c
+++ b/e2fsck/pass2.c
@@ -489,6 +489,35 @@ static _INLINE_ int check_filetype(e2fsck_t ctx,
return 1;
}
+ /*
+ * Whiteouts have no inodes and therefore no way to disagree
+ * with the dentry's idea of the file type. However, we need
+ * to check them against the feature flags in the superblock
+ * and clear the dentry if the feature isn't enabled. Thus,
+ * tunefs -O ^whiteout followed by e2fsck -f is a poor man's
+ * method of removing all whiteouts in a file system.
+ */
+ if (filetype == EXT2_FT_WHT) {
+ if (!(ctx->fs->super->s_feature_incompat &
+ EXT2_FEATURE_INCOMPAT_WHITEOUT)) {
+ if (!fix_problem(ctx, PR_2_CLEAR_WHITEOUT, pctx))
+ return 0;
+ /*
+ * A directory entry with an inode number of 0 and no
+ * filetype is free. The inode is already zero, so
+ * clear the filetype and this dentry is free.
+ */
+ dirent->name_len = dirent->name_len & 0xFF;
+ return 1;
+ } else {
+ ctx->fs_whiteouts_count++;
+ }
+ }
+
+ /* Otherwise, if there's no inode, there's nothing to check. */
+ if (!dirent->inode)
+ return 0;
+
if (ext2fs_test_inode_bitmap2(ctx->inode_dir_map, dirent->inode)) {
should_be = EXT2_FT_DIR;
} else if (ext2fs_test_inode_bitmap2(ctx->inode_reg_map,
@@ -881,6 +910,14 @@ out_htree:
goto next;
}
}
+
+ /*
+ * File type check moved here, since whiteouts and
+ * fallthrus don't necessarily have inodes.
+ */
+ if (check_filetype(ctx, dirent, ino, &cd->pctx))
+ dir_modified++;
+
if (!dirent->inode)
goto next;
@@ -1035,9 +1072,6 @@ out_htree:
if (check_name(ctx, dirent, ino, &cd->pctx))
dir_modified++;
- if (check_filetype(ctx, dirent, ino, &cd->pctx))
- dir_modified++;
-
#ifdef ENABLE_HTREE
if (dx_db) {
ext2fs_dirhash(dx_dir->hashversion, dirent->name,
diff --git a/e2fsck/problem.c b/e2fsck/problem.c
index 8032fda..25b0295 100644
--- a/e2fsck/problem.c
+++ b/e2fsck/problem.c
@@ -890,6 +890,11 @@ static struct e2fsck_problem problem_table[] = {
"(size %Is, lblk %r)\n"),
PROMPT_CLEAR, PR_PREEN_OK },
+ /* Opaque flag set in a non-whiteout enabled fs */
+ { PR_1_CLEAR_OPAQUE,
+ N_("@i %i has opaque flag set but file system whiteout feature is disabled.\n"),
+ PROMPT_CLEAR, 0 },
+
/* Pass 1b errors */
/* Pass 1B: Rescan for duplicate/bad blocks */
@@ -1313,6 +1318,11 @@ static struct e2fsck_problem problem_table[] = {
N_("i_file_acl_hi @F %N, @s zero.\n"),
PROMPT_CLEAR, PR_PREEN_OK },
+ /* Whiteout in a non-whiteout enabled fs */
+ { PR_2_CLEAR_WHITEOUT,
+ N_("@E is a whiteout but file system whiteout feature is disabled.\n"),
+ PROMPT_CLEAR, 0 },
+
/* Pass 3 errors */
/* Pass 3: Checking directory connectivity */
diff --git a/e2fsck/problem.h b/e2fsck/problem.h
index 7c4c156..9850274 100644
--- a/e2fsck/problem.h
+++ b/e2fsck/problem.h
@@ -520,6 +520,9 @@ struct problem_context {
/* EOFBLOCKS flag set when not necessary */
#define PR_1_EOFBLOCKS_FL_SET 0x010060
+/* Opaque flag set in a non-whiteout enabled fs */
+#define PR_1_CLEAR_OPAQUE 0x010061
+
/*
* Pass 1b errors
*/
@@ -785,6 +788,9 @@ struct problem_context {
/* i_file_acl_hi should be zero */
#define PR_2_I_FILE_ACL_HI_ZERO 0x020048
+/* Whiteout in a non-whiteout enabled fs */
+#define PR_2_CLEAR_WHITEOUT 0x020049
+
/*
* Pass 3 errors
*/
diff --git a/e2fsck/unix.c b/e2fsck/unix.c
index 6cb2214..b9dd26f 100644
--- a/e2fsck/unix.c
+++ b/e2fsck/unix.c
@@ -190,6 +190,10 @@ static void show_stats(e2fsck_t ctx)
ctx->fs_fast_symlinks_count), ctx->fs_fast_symlinks_count);
printf (P_("%8u socket\n", "%8u sockets\n", ctx->fs_sockets_count),
ctx->fs_sockets_count);
+ printf (P_("%8u whiteout\n", "%8u whiteouts\n", ctx->fs_whiteouts_count),
+ ctx->fs_whiteouts_count);
+ printf (P_("%8u opaque dir\n", "%8u opaque dirs\n", ctx->fs_opaque_dirs_count),
+ ctx->fs_opaque_dirs_count);
printf ("--------\n");
printf (P_("%8u file\n", "%8u files\n",
ctx->fs_total_count - dir_links),
diff --git a/e2fsck/util.c b/e2fsck/util.c
index fa156a1..1fef6d5 100644
--- a/e2fsck/util.c
+++ b/e2fsck/util.c
@@ -544,6 +544,11 @@ int ext2_file_type(unsigned int mode)
if (LINUX_S_ISSOCK(mode))
return EXT2_FT_SOCK;
+ /*
+ * This function is called on the mode of an inode. Whiteouts
+ * don't have inodes, therefore we will never see EXT2_FT_WHT.
+ */
+
return 0;
}
diff --git a/lib/blkid/probe.h b/lib/blkid/probe.h
index 37fc9c0..374d8ae 100644
--- a/lib/blkid/probe.h
+++ b/lib/blkid/probe.h
@@ -115,6 +115,7 @@ struct ext2_super_block {
#define EXT3_FEATURE_INCOMPAT_RECOVER 0x0004
#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008
#define EXT2_FEATURE_INCOMPAT_META_BG 0x0010
+#define EXT2_FEATURE_INCOMPAT_WHITEOUT 0x0020
#define EXT4_FEATURE_INCOMPAT_EXTENTS 0x0040 /* extents support */
#define EXT4_FEATURE_INCOMPAT_64BIT 0x0080
#define EXT4_FEATURE_INCOMPAT_MMP 0x0100
@@ -124,6 +125,7 @@ struct ext2_super_block {
EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
#define EXT2_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE| \
+ EXT2_FEATURE_INCOMPAT_WHITEOUT| \
EXT2_FEATURE_INCOMPAT_META_BG)
#define EXT2_FEATURE_INCOMPAT_UNSUPPORTED ~EXT2_FEATURE_INCOMPAT_SUPP
#define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED ~EXT2_FEATURE_RO_COMPAT_SUPP
@@ -132,6 +134,7 @@ struct ext2_super_block {
EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
#define EXT3_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE| \
+ EXT2_FEATURE_INCOMPAT_WHITEOUT| \
EXT3_FEATURE_INCOMPAT_RECOVER| \
EXT2_FEATURE_INCOMPAT_META_BG)
#define EXT3_FEATURE_INCOMPAT_UNSUPPORTED ~EXT3_FEATURE_INCOMPAT_SUPP
diff --git a/lib/e2p/feature.c b/lib/e2p/feature.c
index c7f8a35..245e6ae 100644
--- a/lib/e2p/feature.c
+++ b/lib/e2p/feature.c
@@ -74,6 +74,8 @@ static struct feature feature_list[] = {
"64bit" },
{ E2P_FEATURE_INCOMPAT, EXT4_FEATURE_INCOMPAT_FLEX_BG,
"flex_bg"},
+ { E2P_FEATURE_INCOMPAT, EXT2_FEATURE_INCOMPAT_WHITEOUT,
+ "whiteout" },
{ 0, 0, 0 },
};
diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
index fa256e5..a945434 100644
--- a/lib/ext2fs/ext2_fs.h
+++ b/lib/ext2fs/ext2_fs.h
@@ -279,6 +279,7 @@ struct ext2_dx_countlimit {
#define EXT4_EXTENTS_FL 0x00080000 /* Inode uses extents */
#define EXT4_EA_INODE_FL 0x00200000 /* Inode used for large EA */
#define EXT4_EOFBLOCKS_FL 0x00400000 /* Blocks allocated beyond EOF */
+#define EXT2_OPAQUE_FL 0x00800000 /* Dir is opaque */
#define EXT4_SNAPFILE_FL 0x01000000 /* Inode is a snapshot */
#define EXT4_SNAPFILE_DELETED_FL 0x04000000 /* Snapshot is being deleted */
#define EXT4_SNAPFILE_SHRUNK_FL 0x08000000 /* Snapshot shrink has completed */
@@ -680,6 +681,7 @@ struct ext2_super_block {
#define EXT3_FEATURE_INCOMPAT_RECOVER 0x0004 /* Needs recovery */
#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008 /* Journal device */
#define EXT2_FEATURE_INCOMPAT_META_BG 0x0010
+#define EXT2_FEATURE_INCOMPAT_WHITEOUT 0x0020
#define EXT3_FEATURE_INCOMPAT_EXTENTS 0x0040
#define EXT4_FEATURE_INCOMPAT_64BIT 0x0080
#define EXT4_FEATURE_INCOMPAT_MMP 0x0100
@@ -689,7 +691,8 @@ struct ext2_super_block {
#define EXT2_FEATURE_COMPAT_SUPP 0
-#define EXT2_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE)
+#define EXT2_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE| \
+ EXT2_FEATURE_INCOMPAT_WHITEOUT)
#define EXT2_FEATURE_RO_COMPAT_SUPP (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
EXT4_FEATURE_RO_COMPAT_DIR_NLINK| \
@@ -741,7 +744,7 @@ struct ext2_dir_entry_2 {
};
/*
- * Ext2 directory file types. Only the low 3 bits are used. The
+ * Ext2 directory file types. Only the low 4 bits are used. The
* other bits are reserved for now.
*/
#define EXT2_FT_UNKNOWN 0
@@ -752,8 +755,9 @@ struct ext2_dir_entry_2 {
#define EXT2_FT_FIFO 5
#define EXT2_FT_SOCK 6
#define EXT2_FT_SYMLINK 7
+#define EXT2_FT_WHT 8
-#define EXT2_FT_MAX 8
+#define EXT2_FT_MAX 9
/*
* EXT2_DIR_PAD defines the directory entries boundaries
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index e2c3b09..45001b7 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -530,6 +530,7 @@ typedef struct ext2_icount *ext2_icount_t;
#warning "Compression support is experimental"
#endif
#define EXT2_LIB_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE|\
+ EXT2_FEATURE_INCOMPAT_WHITEOUT|\
EXT2_FEATURE_INCOMPAT_COMPRESSION|\
EXT3_FEATURE_INCOMPAT_JOURNAL_DEV|\
EXT2_FEATURE_INCOMPAT_META_BG|\
@@ -539,6 +540,7 @@ typedef struct ext2_icount *ext2_icount_t;
EXT4_FEATURE_INCOMPAT_64BIT)
#else
#define EXT2_LIB_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE|\
+ EXT2_FEATURE_INCOMPAT_WHITEOUT|\
EXT3_FEATURE_INCOMPAT_JOURNAL_DEV|\
EXT2_FEATURE_INCOMPAT_META_BG|\
EXT3_FEATURE_INCOMPAT_RECOVER|\
diff --git a/misc/mke2fs.c b/misc/mke2fs.c
index add7c0c..033d261 100644
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -789,6 +789,7 @@ static __u32 ok_features[3] = {
EXT2_FEATURE_COMPAT_EXT_ATTR,
/* Incompat */
EXT2_FEATURE_INCOMPAT_FILETYPE|
+ EXT2_FEATURE_INCOMPAT_WHITEOUT|
EXT3_FEATURE_INCOMPAT_EXTENTS|
EXT3_FEATURE_INCOMPAT_JOURNAL_DEV|
EXT2_FEATURE_INCOMPAT_META_BG|
@@ -1590,6 +1591,15 @@ static void PRS(int argc, char *argv[])
exit(1);
}
+ /* Whiteout feature requires filetype feature */
+ if ((fs_param.s_feature_incompat &
+ EXT2_FEATURE_INCOMPAT_WHITEOUT) &&
+ !(fs_param.s_feature_incompat &
+ EXT2_FEATURE_INCOMPAT_FILETYPE)) {
+ fprintf(stderr, _("Whiteout support requires filetype support\n"));
+ exit(1);
+ }
+
/* Set first meta blockgroup via an environment variable */
/* (this is mostly for debugging purposes) */
if ((fs_param.s_feature_incompat & EXT2_FEATURE_INCOMPAT_META_BG) &&
diff --git a/misc/tune2fs.8.in b/misc/tune2fs.8.in
index 62934f7..0457759 100644
--- a/misc/tune2fs.8.in
+++ b/misc/tune2fs.8.in
@@ -474,14 +474,19 @@ watermark for the unused inodes in a filesystem, to reduce
time. This first e2fsck run after enabling this feature will take the
full time, but subsequent e2fsck runs will take only a fraction of the
original time, depending on how full the file system is.
+.TP
+.B whiteout
+Support whiteouts, which record directory entries that have been
+deleted on a union mounted file system.
.RE
.IP
After setting or clearing
.BR sparse_super ,
.BR uninit_bg ,
.BR filetype ,
+.B resize_inode ,
or
-.B resize_inode
+.B whiteout
filesystem features,
.BR e2fsck (8)
must be run on the filesystem to return the filesystem to a consistent state.
@@ -499,6 +504,17 @@ mounted by kernels which do not support those features. In particular, the
and
.BR flex_bg
features are only supported by the ext4 filesystem.
+.IP
+.B Warning:
+Linux kernels without union mounts enabled do not support file systems
+with whiteouts. Enabling the whiteout feature on a filesystem will
+prevent it from being mounted by kernels without union mount support.
+Disabling the whiteout feature with
+.B tune2fs
+followed by running
+.B e2fsck
+on the file system will delete all the whiteouts and allow the
+filesystem to be mounted again.
.TP
.BI \-r " reserved-blocks-count"
Set the number of reserved filesystem blocks.
diff --git a/misc/tune2fs.c b/misc/tune2fs.c
index 4734331..a7624b2 100644
--- a/misc/tune2fs.c
+++ b/misc/tune2fs.c
@@ -122,6 +122,7 @@ static __u32 ok_features[3] = {
EXT2_FEATURE_COMPAT_DIR_INDEX,
/* Incompat */
EXT2_FEATURE_INCOMPAT_FILETYPE |
+ EXT2_FEATURE_INCOMPAT_WHITEOUT |
EXT3_FEATURE_INCOMPAT_EXTENTS |
EXT4_FEATURE_INCOMPAT_FLEX_BG,
/* R/O compat */
@@ -140,6 +141,7 @@ static __u32 clear_ok_features[3] = {
EXT2_FEATURE_COMPAT_DIR_INDEX,
/* Incompat */
EXT2_FEATURE_INCOMPAT_FILETYPE |
+ EXT2_FEATURE_INCOMPAT_WHITEOUT |
EXT4_FEATURE_INCOMPAT_FLEX_BG,
/* R/O compat */
EXT2_FEATURE_RO_COMPAT_LARGE_FILE |
@@ -435,6 +437,24 @@ static void update_feature_set(ext2_filsys fs, char *features)
}
}
+ if (FEATURE_OFF(E2P_FEATURE_INCOMPAT, EXT2_FEATURE_INCOMPAT_WHITEOUT)) {
+ if (mount_flags & EXT2_MF_MOUNTED) {
+ fputs(_("The whiteout flag may only be "
+ "cleared when the filesystem is\n"
+ "unmounted.\n"), stderr);
+ exit(1);
+ }
+ sb->s_state &= ~EXT2_VALID_FS;
+ printf(_("\nWhiteout superblock flag cleared. %s"),
+ _(please_fsck));
+ }
+
+ if (FEATURE_ON(E2P_FEATURE_INCOMPAT, EXT2_FEATURE_INCOMPAT_WHITEOUT)) {
+ sb->s_state &= ~EXT2_VALID_FS;
+ printf(_("\nWhiteout superblock flag set. %s"),
+ _(please_fsck));
+ }
+
if (FEATURE_OFF(E2P_FEATURE_RO_INCOMPAT,
EXT4_FEATURE_RO_COMPAT_HUGE_FILE)) {
if ((mount_flags & EXT2_MF_MOUNTED) &&
@@ -488,6 +508,8 @@ static void update_feature_set(ext2_filsys fs, char *features)
EXT4_FEATURE_RO_COMPAT_HUGE_FILE) ||
FEATURE_CHANGED(E2P_FEATURE_INCOMPAT,
EXT2_FEATURE_INCOMPAT_FILETYPE) ||
+ FEATURE_CHANGED(E2P_FEATURE_INCOMPAT,
+ EXT2_FEATURE_INCOMPAT_WHITEOUT) ||
FEATURE_CHANGED(E2P_FEATURE_COMPAT,
EXT2_FEATURE_COMPAT_RESIZE_INODE) ||
FEATURE_OFF(E2P_FEATURE_RO_INCOMPAT,
--
1.6.3.3
--
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