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Message-ID: <20101119204900.GB26824@shell>
Date: Fri, 19 Nov 2010 15:49:00 -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 2/2] union-mount: Add support for fallthrus
Support fallthrus, which allow lookup to fall through to the lower
layer filesystems in a union mounted filesystem. Fallthrus are
enabled with the incompat feature "fallthru". e2fsck on a file system
with the fallthru feature disabled removes all fallthrus.
Signed-off-by: Valerie Aurora <vaurora@...hat.com>
---
e2fsck/e2fsck.c | 1 +
e2fsck/e2fsck.h | 1 +
e2fsck/pass2.c | 13 +++++++++++++
e2fsck/problem.c | 5 +++++
e2fsck/problem.h | 3 +++
e2fsck/util.c | 3 ++-
lib/e2p/feature.c | 2 ++
lib/ext2fs/ext2_fs.h | 7 +++++--
lib/ext2fs/ext2fs.h | 2 ++
misc/mke2fs.c | 10 ++++++++++
misc/tune2fs.8.in | 18 ++++++++++++------
misc/tune2fs.c | 22 ++++++++++++++++++++++
12 files changed, 78 insertions(+), 9 deletions(-)
diff --git a/e2fsck/e2fsck.c b/e2fsck/e2fsck.c
index 7a2f2a5..48f0f61 100644
--- a/e2fsck/e2fsck.c
+++ b/e2fsck/e2fsck.c
@@ -154,6 +154,7 @@ errcode_t e2fsck_reset_context(e2fsck_t ctx)
ctx->fs_sockets_count = 0;
ctx->fs_whiteouts_count = 0;
ctx->fs_opaque_dirs_count = 0;
+ ctx->fs_fallthrus_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 e768997..97cd115 100644
--- a/e2fsck/e2fsck.h
+++ b/e2fsck/e2fsck.h
@@ -332,6 +332,7 @@ struct e2fsck_struct {
__u32 fs_sockets_count;
__u32 fs_whiteouts_count;
__u32 fs_opaque_dirs_count;
+ __u32 fs_fallthrus_count;
__u32 fs_ind_count;
__u32 fs_dind_count;
__u32 fs_tind_count;
diff --git a/e2fsck/pass2.c b/e2fsck/pass2.c
index bff5d9a..b25da6b 100644
--- a/e2fsck/pass2.c
+++ b/e2fsck/pass2.c
@@ -514,6 +514,19 @@ static _INLINE_ int check_filetype(e2fsck_t ctx,
}
}
+ /* Same goes for fallthrus */
+ if (filetype == EXT2_FT_FALLTHRU) {
+ if (!(ctx->fs->super->s_feature_incompat &
+ EXT2_FEATURE_INCOMPAT_FALLTHRU)) {
+ if (!fix_problem(ctx, PR_2_CLEAR_FALLTHRU, pctx))
+ return 0;
+ dirent->name_len = dirent->name_len & 0xFF;
+ return 1;
+ } else {
+ ctx->fs_fallthrus_count++;
+ }
+ }
+
/* Otherwise, if there's no inode, there's nothing to check. */
if (!dirent->inode)
return 0;
diff --git a/e2fsck/problem.c b/e2fsck/problem.c
index 25b0295..59659d0 100644
--- a/e2fsck/problem.c
+++ b/e2fsck/problem.c
@@ -1323,6 +1323,11 @@ static struct e2fsck_problem problem_table[] = {
N_("@E is a whiteout but file system whiteout feature is disabled.\n"),
PROMPT_CLEAR, 0 },
+ /* Fallthru in a non-fallthru enabled fs */
+ { PR_2_CLEAR_FALLTHRU,
+ N_("@E is a fallthru but file system fallthru 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 9850274..a91b1a0 100644
--- a/e2fsck/problem.h
+++ b/e2fsck/problem.h
@@ -791,6 +791,9 @@ struct problem_context {
/* Whiteout in a non-whiteout enabled fs */
#define PR_2_CLEAR_WHITEOUT 0x020049
+/* Fallthru in a non-fallthru enabled fs */
+#define PR_2_CLEAR_FALLTHRU 0x020049
+
/*
* Pass 3 errors
*/
diff --git a/e2fsck/util.c b/e2fsck/util.c
index 1fef6d5..32cccb0 100644
--- a/e2fsck/util.c
+++ b/e2fsck/util.c
@@ -546,7 +546,8 @@ int ext2_file_type(unsigned int mode)
/*
* This function is called on the mode of an inode. Whiteouts
- * don't have inodes, therefore we will never see EXT2_FT_WHT.
+ * and fallthrus don't have inodes, therefore we will never
+ * see EXT2_FT_WHT or EXT2_FT_FALLTHRU.
*/
return 0;
diff --git a/lib/e2p/feature.c b/lib/e2p/feature.c
index 245e6ae..0c06c94 100644
--- a/lib/e2p/feature.c
+++ b/lib/e2p/feature.c
@@ -76,6 +76,8 @@ static struct feature feature_list[] = {
"flex_bg"},
{ E2P_FEATURE_INCOMPAT, EXT2_FEATURE_INCOMPAT_WHITEOUT,
"whiteout" },
+ { E2P_FEATURE_INCOMPAT, EXT2_FEATURE_INCOMPAT_FALLTHRU,
+ "fallthru" },
{ 0, 0, 0 },
};
diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
index a945434..9f4584f 100644
--- a/lib/ext2fs/ext2_fs.h
+++ b/lib/ext2fs/ext2_fs.h
@@ -688,11 +688,13 @@ struct ext2_super_block {
#define EXT4_FEATURE_INCOMPAT_FLEX_BG 0x0200
#define EXT4_FEATURE_INCOMPAT_EA_INODE 0x0400
#define EXT4_FEATURE_INCOMPAT_DIRDATA 0x1000
+#define EXT2_FEATURE_INCOMPAT_FALLTHRU 0x2000
#define EXT2_FEATURE_COMPAT_SUPP 0
#define EXT2_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE| \
- EXT2_FEATURE_INCOMPAT_WHITEOUT)
+ EXT2_FEATURE_INCOMPAT_WHITEOUT| \
+ EXT2_FEATURE_INCOMPAT_FALLTHRU)
#define EXT2_FEATURE_RO_COMPAT_SUPP (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \
EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \
EXT4_FEATURE_RO_COMPAT_DIR_NLINK| \
@@ -756,8 +758,9 @@ struct ext2_dir_entry_2 {
#define EXT2_FT_SOCK 6
#define EXT2_FT_SYMLINK 7
#define EXT2_FT_WHT 8
+#define EXT2_FT_FALLTHRU 9
-#define EXT2_FT_MAX 9
+#define EXT2_FT_MAX 10
/*
* EXT2_DIR_PAD defines the directory entries boundaries
diff --git a/lib/ext2fs/ext2fs.h b/lib/ext2fs/ext2fs.h
index 45001b7..c313578 100644
--- a/lib/ext2fs/ext2fs.h
+++ b/lib/ext2fs/ext2fs.h
@@ -531,6 +531,7 @@ typedef struct ext2_icount *ext2_icount_t;
#endif
#define EXT2_LIB_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE|\
EXT2_FEATURE_INCOMPAT_WHITEOUT|\
+ EXT2_FEATURE_INCOMPAT_FALLTHRU|\
EXT2_FEATURE_INCOMPAT_COMPRESSION|\
EXT3_FEATURE_INCOMPAT_JOURNAL_DEV|\
EXT2_FEATURE_INCOMPAT_META_BG|\
@@ -541,6 +542,7 @@ typedef struct ext2_icount *ext2_icount_t;
#else
#define EXT2_LIB_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE|\
EXT2_FEATURE_INCOMPAT_WHITEOUT|\
+ EXT2_FEATURE_INCOMPAT_FALLTHRU|\
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 033d261..a180cd9 100644
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -790,6 +790,7 @@ static __u32 ok_features[3] = {
/* Incompat */
EXT2_FEATURE_INCOMPAT_FILETYPE|
EXT2_FEATURE_INCOMPAT_WHITEOUT|
+ EXT2_FEATURE_INCOMPAT_FALLTHRU|
EXT3_FEATURE_INCOMPAT_EXTENTS|
EXT3_FEATURE_INCOMPAT_JOURNAL_DEV|
EXT2_FEATURE_INCOMPAT_META_BG|
@@ -1600,6 +1601,15 @@ static void PRS(int argc, char *argv[])
exit(1);
}
+ /* Fallthru feature requires filetype feature */
+ if ((fs_param.s_feature_incompat &
+ EXT2_FEATURE_INCOMPAT_FALLTHRU) &&
+ !(fs_param.s_feature_incompat &
+ EXT2_FEATURE_INCOMPAT_FILETYPE)) {
+ fprintf(stderr, _("Fallthru 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 0457759..74db33d 100644
--- a/misc/tune2fs.8.in
+++ b/misc/tune2fs.8.in
@@ -478,6 +478,10 @@ original time, depending on how full the file system is.
.B whiteout
Support whiteouts, which record directory entries that have been
deleted on a union mounted file system.
+.TP
+.B fallthru
+Support fallthrus, which allow lookup to fall through to the lower
+layer filesystems in a union mounted filesystem.
.RE
.IP
After setting or clearing
@@ -485,8 +489,9 @@ After setting or clearing
.BR uninit_bg ,
.BR filetype ,
.B resize_inode ,
+.B whiteout ,
or
-.B whiteout
+.B fallthru
filesystem features,
.BR e2fsck (8)
must be run on the filesystem to return the filesystem to a consistent state.
@@ -507,14 +512,15 @@ 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
+with whiteouts or fallthrus. Enabling the whiteout or fallthru
+features on a filesystem will prevent it from being mounted by kernels
+without union mount support. Disabling the whiteout and fallthru
+features 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.
+on the file system will delete all the whiteouts and fallthrus 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 a7624b2..badb44e 100644
--- a/misc/tune2fs.c
+++ b/misc/tune2fs.c
@@ -123,6 +123,7 @@ static __u32 ok_features[3] = {
/* Incompat */
EXT2_FEATURE_INCOMPAT_FILETYPE |
EXT2_FEATURE_INCOMPAT_WHITEOUT |
+ EXT2_FEATURE_INCOMPAT_FALLTHRU |
EXT3_FEATURE_INCOMPAT_EXTENTS |
EXT4_FEATURE_INCOMPAT_FLEX_BG,
/* R/O compat */
@@ -142,6 +143,7 @@ static __u32 clear_ok_features[3] = {
/* Incompat */
EXT2_FEATURE_INCOMPAT_FILETYPE |
EXT2_FEATURE_INCOMPAT_WHITEOUT |
+ EXT2_FEATURE_INCOMPAT_FALLTHRU |
EXT4_FEATURE_INCOMPAT_FLEX_BG,
/* R/O compat */
EXT2_FEATURE_RO_COMPAT_LARGE_FILE |
@@ -455,6 +457,24 @@ static void update_feature_set(ext2_filsys fs, char *features)
_(please_fsck));
}
+ if (FEATURE_OFF(E2P_FEATURE_INCOMPAT, EXT2_FEATURE_INCOMPAT_FALLTHRU)) {
+ if (mount_flags & EXT2_MF_MOUNTED) {
+ fputs(_("The fallthru flag may only be "
+ "cleared when the filesystem is\n"
+ "unmounted.\n"), stderr);
+ exit(1);
+ }
+ sb->s_state &= ~EXT2_VALID_FS;
+ printf(_("\nFallthru superblock flag cleared. %s"),
+ _(please_fsck));
+ }
+
+ if (FEATURE_ON(E2P_FEATURE_INCOMPAT, EXT2_FEATURE_INCOMPAT_FALLTHRU)) {
+ sb->s_state &= ~EXT2_VALID_FS;
+ printf(_("\nFallthru 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) &&
@@ -510,6 +530,8 @@ static void update_feature_set(ext2_filsys fs, char *features)
EXT2_FEATURE_INCOMPAT_FILETYPE) ||
FEATURE_CHANGED(E2P_FEATURE_INCOMPAT,
EXT2_FEATURE_INCOMPAT_WHITEOUT) ||
+ FEATURE_CHANGED(E2P_FEATURE_INCOMPAT,
+ EXT2_FEATURE_INCOMPAT_FALLTHRU) ||
FEATURE_CHANGED(E2P_FEATURE_COMPAT,
EXT2_FEATURE_COMPAT_RESIZE_INODE) ||
FEATURE_OFF(E2P_FEATURE_RO_INCOMPAT,
--
1.6.3.3
--
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