From: Artem Bityutskiy Date: Wed, 20 Aug 2008 14:16:34 +0000 (+0300) Subject: UBIFS: fix zero-length truncations X-Git-Tag: v2.6.27-rc6~7^2~14 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=04da11bfcf511544ae19e0a7e5f994b3237752ac;p=linux-2.6 UBIFS: fix zero-length truncations Always allow truncations to zero, even if budgeting thinks there is no space. UBIFS reserves some space for deletions anyway. Otherwise, the following happans: 1. create a file, and write as much as possible there, until ENOSPC 2. truncate the file, which fails with ENOSPC, which is not good. Signed-off-by: Artem Bityutskiy --- diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index 5c96f1fb70..2b267c9a18 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -587,7 +587,6 @@ static int ubifs_unlink(struct inode *dir, struct dentry *dentry) if (err) { if (err != -ENOSPC) return err; - err = 0; budgeted = 0; } diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c index 4071d1cae2..3d698e2022 100644 --- a/fs/ubifs/file.c +++ b/fs/ubifs/file.c @@ -793,7 +793,7 @@ static int do_truncation(struct ubifs_info *c, struct inode *inode, int err; struct ubifs_budget_req req; loff_t old_size = inode->i_size, new_size = attr->ia_size; - int offset = new_size & (UBIFS_BLOCK_SIZE - 1); + int offset = new_size & (UBIFS_BLOCK_SIZE - 1), budgeted = 1; struct ubifs_inode *ui = ubifs_inode(inode); dbg_gen("ino %lu, size %lld -> %lld", inode->i_ino, old_size, new_size); @@ -811,8 +811,15 @@ static int do_truncation(struct ubifs_info *c, struct inode *inode, /* A funny way to budget for truncation node */ req.dirtied_ino_d = UBIFS_TRUN_NODE_SZ; err = ubifs_budget_space(c, &req); - if (err) - return err; + if (err) { + /* + * Treat truncations to zero as deletion and always allow them, + * just like we do for '->unlink()'. + */ + if (new_size || err != -ENOSPC) + return err; + budgeted = 0; + } err = vmtruncate(inode, new_size); if (err) @@ -869,7 +876,12 @@ static int do_truncation(struct ubifs_info *c, struct inode *inode, err = ubifs_jnl_truncate(c, inode, old_size, new_size); mutex_unlock(&ui->ui_mutex); out_budg: - ubifs_release_budget(c, &req); + if (budgeted) + ubifs_release_budget(c, &req); + else { + c->nospace = c->nospace_rp = 0; + smp_wmb(); + } return err; }