From: "Darrick J. Wong" Subject: [PATCH 01/23] ext4: Create a new BH_Verified flag to avoid unnecessary metadata validation Date: Tue, 13 Dec 2011 16:46:20 -0800 Message-ID: <20111214004620.28243.38094.stgit@elm3c44.beaverton.ibm.com> References: <20111214004613.28243.54122.stgit@elm3c44.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: Sunil Mushran , Martin K Petersen , Greg Freemyer , Amir Goldstein , linux-kernel , Andi Kleen , Mingming Cao , Joel Becker , linux-fsdevel , linux-ext4@vger.kernel.org, Coly Li To: Andreas Dilger , Theodore Tso , "Darrick J. Wong" Return-path: In-Reply-To: <20111214004613.28243.54122.stgit@elm3c44.beaverton.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org Create a new BH_Verified flag to indicate that we've verified all the data in a buffer_head for correctness. This allows us to bypass expensive verification steps when they are not necessary without missing them when they are. v2: The later jbd2 metadata checksumming patches need a BH_Verified flag for journal metadata, so put the flag in jbd2.h so that both drivers can share the same bit. Signed-off-by: Darrick J. Wong --- fs/ext4/extents.c | 35 ++++++++++++++++++++++++++--------- include/linux/jbd_common.h | 2 ++ 2 files changed, 28 insertions(+), 9 deletions(-) diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index 61fa9e1..00f97f4 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -396,6 +396,26 @@ int ext4_ext_check_inode(struct inode *inode) return ext4_ext_check(inode, ext_inode_hdr(inode), ext_depth(inode)); } +static int __ext4_ext_check_block(const char *function, unsigned int line, + struct inode *inode, + struct ext4_extent_header *eh, + int depth, + struct buffer_head *bh) +{ + int ret; + + if (buffer_verified(bh)) + return 0; + ret = ext4_ext_check(inode, eh, depth); + if (ret) + return ret; + set_buffer_verified(bh); + return ret; +} + +#define ext4_ext_check_block(inode, eh, depth, bh) \ + __ext4_ext_check_block(__func__, __LINE__, inode, eh, depth, bh) + #ifdef EXT_DEBUG static void ext4_ext_show_path(struct inode *inode, struct ext4_ext_path *path) { @@ -652,8 +672,6 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, i = depth; /* walk through the tree */ while (i) { - int need_to_validate = 0; - ext_debug("depth %d: num %d, max %d\n", ppos, le16_to_cpu(eh->eh_entries), le16_to_cpu(eh->eh_max)); @@ -672,8 +690,6 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, put_bh(bh); goto err; } - /* validate the extent entries */ - need_to_validate = 1; } eh = ext_block_hdr(bh); ppos++; @@ -687,7 +703,7 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block, path[ppos].p_hdr = eh; i--; - if (need_to_validate && ext4_ext_check(inode, eh, i)) + if (ext4_ext_check_block(inode, eh, i, bh)) goto err; } @@ -1328,7 +1344,8 @@ got_index: return -EIO; eh = ext_block_hdr(bh); /* subtract from p_depth to get proper eh_depth */ - if (ext4_ext_check(inode, eh, path->p_depth - depth)) { + if (ext4_ext_check_block(inode, eh, + path->p_depth - depth, bh)) { put_bh(bh); return -EIO; } @@ -1341,7 +1358,7 @@ got_index: if (bh == NULL) return -EIO; eh = ext_block_hdr(bh); - if (ext4_ext_check(inode, eh, path->p_depth - depth)) { + if (ext4_ext_check_block(inode, eh, path->p_depth - depth, bh)) { put_bh(bh); return -EIO; } @@ -2572,8 +2589,8 @@ again: err = -EIO; break; } - if (ext4_ext_check(inode, ext_block_hdr(bh), - depth - i - 1)) { + if (ext4_ext_check_block(inode, ext_block_hdr(bh), + depth - i - 1, bh)) { err = -EIO; break; } diff --git a/include/linux/jbd_common.h b/include/linux/jbd_common.h index 6230f85..6133679 100644 --- a/include/linux/jbd_common.h +++ b/include/linux/jbd_common.h @@ -12,6 +12,7 @@ enum jbd_state_bits { BH_State, /* Pins most journal_head state */ BH_JournalHead, /* Pins bh->b_private and jh->b_bh */ BH_Unshadow, /* Dummy bit, for BJ_Shadow wakeup filtering */ + BH_Verified, /* Metadata block has been verified ok */ BH_JBDPrivateStart, /* First bit available for private use by FS */ }; @@ -24,6 +25,7 @@ TAS_BUFFER_FNS(Revoked, revoked) BUFFER_FNS(RevokeValid, revokevalid) TAS_BUFFER_FNS(RevokeValid, revokevalid) BUFFER_FNS(Freed, freed) +BUFFER_FNS(Verified, verified) static inline struct buffer_head *jh2bh(struct journal_head *jh) {